Next Article in Journal
Research on Optimizing Forming Accuracy in Food 3D Printing Based on Temperature–Pressure Dual Closed-Loop Control
Previous Article in Journal
Analysis of Key Factors Affecting the Sensitivity of Dual-Backplate Capacitive MEMS Microphones
Previous Article in Special Issue
Thermal Side-Channel Threats in Densely Integrated Microarchitectures: A Comprehensive Review for Cyber–Physical System Security
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Micromachines
Volume 16
Issue 10
10.3390/mi16101155
micromachines-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Post Wire-Bonding Corrosion Prevention Strategies to Mitigate Chloride- and Bromide-Induced Corrosion Failures in Cu- and PCC-Based Wire-Bonded Packages

by
Dinesh Kumar Kumaravel
1,
Shinoj Sridharan Nair
1,
Khanh Tuyet Anh Tran
1,
Pavan Ahluwalia
2,
Kevin Antony Jesu Durai
1 and
Oliver Chyan
1,*
1
Department of Chemistry, University of North Texas, Denton, TX 76201, USA
2
Texas Academy of Mathematics and Science, University of North Texas, Denton, TX 76201, USA
*
Author to whom correspondence should be addressed.
Micromachines 2025, 16(10), 1155; https://doi.org/10.3390/mi16101155 (registering DOI)
Submission received: 7 March 2025 / Revised: 7 October 2025 / Accepted: 9 October 2025 / Published: 12 October 2025
(This article belongs to the Special Issue Microelectronics Assembly and Packaging: Materials and Technologies, 2nd Edition)
Browse Figures
Versions Notes

Abstract

To ensure the highest safety standards in modern automobiles, the industry is constantly adopting zero-defect frameworks, such as AEC-Q100, which aims for defective-parts-per-billion (DPPB) or grade-0 level reliability standards in automotive integrated-circuit (IC) packages. Most contemporary wire-bonded packages use either pure copper (Cu) or palladium (Pd)-coated copper (PCC) wires bonded to aluminum (Al) bond pads as interconnections. This choice is made due to their lower cost and superior electrical and mechanical performance, compared to traditional gold wire-based devices. However, these Cu–Al wire-bonded interconnections are prone to ion-induced lift-off/open-circuit corrosion failures when exposed to even trace amounts (<20 ppm) of extrinsic and/or intrinsic halide (Cl− and Br−) contaminants, decreasing device longevity. This study investigates corrosion failure mechanisms in Cu and PCC wire-based devices by subjecting non-encapsulated devices to a highly accelerated aqueous-immersion screening test containing 100 ppm chloride (Cl−), 100 ppm bromide (Br−), and a mixed-ion solution (MX: Cl− + Br−). The screening results indicate that even control PCC-Al devices with a Pd overlayer can be susceptible to Cl− and Br− induced corrosion, with 21 ± 1.6% lift-off failures in MX-solution. In contrast, applying a novel Cu-selective passivation reduced lift-off to 3.3 ± 0.6% and introducing phosphonic-acid-based inhibitor into the MX solution eliminated lift-off failures, demonstrating markedly improved reliability.

1. Introduction

Wire bonding remains one of the most mature and widely deployed interconnect technologies in current IC packages. Its continued prevalence is mainly due to its cost effectiveness and compatibility with high-volume manufacturing. Recent heterogeneous integration schemes even combine wire bonding with 3D die stacking in the same devices to reduce costs and enhance scalability [1].
Over the past decade, the industry has shifted from gold (Au) and silver (Ag) wires to copper (Cu) wires bonded to aluminum (Al) pads, and it is widely adopted across most applications. Aside from the cost, previous studies indicated that Au–Al has poor reliability at high temperatures, and Ag–Al is susceptible to corrosion and electromigration, making copper a much-preferred choice [2,3,4]. Additionally, Zhong et al. and Zhou et al. have provided in-depth analyses of the advantages and current challenges associated with the use of Cu wires, emphasizing their superior electrical and thermal conductivity, high mechanical strength, slower intermetallic compound (IMC) growth, propensity for corrosion, and increased susceptibility to oxidation [2,5]. Notably, high-temperature annealing studies of Cu–Al wire-bonded devices conducted by C.-P. Liu et al. simulated real-world operating environments and demonstrated the sequential formation of three intermetallic compounds: CuAl2, CuAl, and Cu9Al4 at the Cu/Al interfaces [6]. These phases, along with the parent Cu and Al at the bimetallic interface, exhibit sizable galvanic potential differences. When coupled with the hydrophilic epoxy molding compound (EMC), which shows accelerated water uptake and ionic migration, such galvanic interactions create an environment that is highly conducive to corrosion [7,8,9,10]. This has been one of the significant challenges for automotive wire bond packages, which are exposed to high-humidity and high-temperature operating conditions. Most reliability studies indicate that Cu9Al4 and CuAl phases are major corrosion sites, and the concentration of Cl− ions and pH values directly affect the corrosion rate [9,10,11,12,13,14]. V. Mathew et al. employed extraction–immersion testing (EIT) as guideline metrology, alongside biased highly accelerated temperature-and-humidity stress (HAST), to assess the effect of halide concentration, solution pH, and applied bias on lift-off or open-circuit failures. Their results correlate with previous findings, indicating that, at pH lower than or equal to 6, halide levels as low as 20 ppm of Br− and/or Cl− are sufficient to trigger lift-off failures. Moreover, the failure rate increases as the device bias is raised, and results from immersion screening are directly correlated with HAST results [15,16]. N. Ross et al. further investigated the corrosion mechanism of (20 ppm) Cl− ion-induced wire bond failures using aqueous immersion screening metrology. Their study highlighted the Cu–Al bimetallic contact between the Cu wire and Al splash, illustrated in Figure 1, as a significant initiating factor for corrosion. Furthermore, the study identified hydrogen evolution as the major cathodic reaction associated with this corrosion [17].
One obvious way to eliminate these corrosion failures is to eliminate halide ions from the wire-bonding vicinity inside the EMCs [16,17,18]. However, these halide contaminants are difficult to control as they can originate from intrinsic sources (such as EMC, adhesion promoters) and extrinsic sources (such as the fabrication environment and other bill of materials), highlighting the need for alternative strategies [18]. Various researchers have explored metal passivation methods for wires and bond pads, and only the inclusion of Pd in Cu wire has effectively minimized the formation of pure Cu–Al IMCs at the same time without deforming the free air ball (FAB) during wire bonding; this technique has therefore been widely adopted for various applications [2,19]. Lim et al. and Qin et al. report on Pd inclusion in copper wires, detailing the electrochemical and metallurgical aspects of reliability improvement in ionic environments [20,21]. Their results highlight that the Pd inclusion mainly forms Pd-mixed Cu–Al IMCs and reduces the formation of Cu-rich IMC, thereby reducing the corrosion sites. However, during manufacturing, Pd coverage can be difficult to control due to differing Cu and Pd solidification temperatures, potentially exposing some copper areas (as shown in Figure 2b) and reducing reliability [22]. As an alternative approach, C.-P. Liu et al. tested the effect of incorporating corrosion inhibitors (CI) and flame retardants (FR) within EMCs to evaluate their effectiveness in mitigating Cu–Al device failures under HAST conditions [9]. Their results showed that including CI and FR significantly increases the mean time to failure (MTTF) compared to unmodified control EMCs. However, even in the presence of CIs and FRs, an increase in chloride ion (Cl−) concentration still led to higher failure rates. A recent study evaluated epoxy resins, bismaleimides (BMI), and Parylene-based polymers as coatings applied after wire bonding for PCC–Al devices. They aimed to eliminate halide ions from the immediate vicinity (<100 µm) and assessed their effectiveness in reducing Cl−-induced corrosion failures as well as their compatibility with manufacturing [18]. The results showed that only epoxy resins are suitable for manufacturing processes, while the other two materials failed thermal reliability tests. Further research is needed to identify and study new materials that could serve as post-wire-bonding coatings to eliminate halide-induced corrosion failures in Cu–Al wire-bonded devices.
This study utilizes accelerated aqueous immersion stress tests to systematically compare the corrosion trends of Cu- and PCC-based wire-bonded devices, investigating their lift-off failure mechanisms in 100 ppm Cl−, Br−, and mixed-ionic (100 ppm Cl− + 100 ppm Br−) environments. This method allows for rapid and highly aggressive corrosion quantification since ionic diffusivity is higher in aqueous solutions (on the order of 104 cm2/s greater) than typical EMCs, and higher ionic concentrations were utilized, compared to the levels of less than 20 ppm typically present in EMCs [23,24,25]. Furthermore, two complementary novel passivation approaches are introduced: (i) a copper-selective overcoat applied after wire bonding, and (ii) an organic phosphonic-acid-based inhibitor in screening solutions. The copper-selective passivation with precise thickness control can conformally coat only the copper-exposed ball area. This may eliminate the cathodic reactions on Cu without affecting other materials in an IC package, making it compatible with manufacturing processes and suitable for integration into real-world microelectronic devices. Phosphonic-acid-based organic molecules are known to form complexes with metal oxides, offering high tunability and surface modification capabilities [26]. Some recent reports have explored the utilization of phosphonate or phosphonic-acid-based complexes for preventing corrosion on Al and its alloys [27,28,29]. Nevertheless, the effectiveness of organic phosphonic acid complexes in suppressing corrosion induced by Cl− and Br− on aluminum bond pads remains unexplored in wire-bonded IC packages. This study presents a novel phosphonic-acid-based passivation treatment for Al bond pads in both Cu–Al and PCC-Al wire-bond assemblies, delivering robust inhibition of bimetallic corrosion at exposed Cu–Al interfaces and markedly enhancing package reliability by preventing lift-off failures and ensuring functional safety in automotive ICs.

2. Materials and Methods

2.1. Wirebond Devices

This study utilizes two types of wire-bonded devices, as shown in Figure 2. The first type consists of 5 mm × 4.6 mm functional dies, which are surface-mounted on Cu-based lead frames from low-profile quad flat packages (LQFP). These devices featured Cu wires (approximately 25 µm in diameter) that were thermosonically wire-bonded to Al pads measuring 70 µm × 78 µm on the dies. Throughout this article, these devices will be referred to as “Cu-Al Devices.” Similarly, the second type of device consists of dies measuring approximately 5.5 mm × 5.5 mm, and they were surface mounted onto the lead frames from a mold array process ball grid array (MAPBGA) packages. These devices used PCC wires of approximately 20 µm diameter for ball bonding and will be referred to as “PCC-Al devices”. All the devices were plasma cleaned to remove any particle contamination with a Harrick Plasma etcher using 30 W power and 5 SCCM of 95% Ar-H2 gas mixture for 5 min before being subjected to any treatment.

2.2. Accelerated Immersion Screening Metrology

The corrosion screening solutions containing 100 ppm chloride (Cl−), 100 ppm bromide (Br−), and mixed ions (MX: 100 ppm Cl− and 100 ppm Br− ions) were prepared by dissolving ACS-grade sodium chloride (EMDMillipore Corporation, Billerica, MA, USA) and potassium bromide (Fisher Scientific, Fair Lawn, NJ, USA) in ultrapure water (UPW) obtained from a EQ-7008 (Millipore Sigma, Burlington, MA, USA) water system with a resistivity of 18.2 MΩ·cm. The screening solutions were adjusted to pH 6 using ACS-grade ammonium hydroxide (Fisher Chemical, Fair Lawn, NJ, USA) and sulfuric acid (Fisher Scientific, Fair Lawn, NJ, USA) solutions to emulate the typical pH reported in the EMCs [16]. The corrosion process was monitored in real-time using a Nikon Eclipse LV 150N microscope (New York, NY, USA), and the time-dependent images were captured using a DS-Ri2 camera (New York, NY, USA). For further corrosion quantification and comparison, the number of lifted wire bonds, similar to those in Figure 3b, was counted and used to calculate the wire bond lift-off percentage and then plotted in Origin software (Version 2025b).

2.3. Passivation Approach and Quantification Metrologies

As described earlier, two distinct targeted passivation approaches were explored in this study. First, a copper selective passivation film was applied to Cu–Al and PCC–Al wire-bonded devices. Reflection–absorption infrared spectroscopy (RAIRS) was conducted using a Thermo-Nicolet iS50 (Dallas, TX, USA) spectrometer for chemical quantification and tuning passivation thickness. The exact method of calibration for this metrology is discussed in our previous report [30]. Based on the calibration, the passivation thickness of 2–3 microns was coated on Cu-Al and PCC-Al devices. The passivation chemistry and the processing steps are detailed in our previous work and patent application [31]. Typically, the passivation process may include a plasma cleaning, a liquid or gas phase coating process, and post-coating rinsing with UPW to remove any physisorption. After the passivation process, contact angle measurements on passivated Cu lead frames (no. of devices = 3) were performed using a YSC M400 power scope (Fremount, CA, USA) by making 10 µL UPW droplets, and the images were analyzed using ImageJ software (version 1.54g).
The second approach introduced Nitrilotris (methylene) phosphonic acid (NTMP) to the corrosion screening solutions. A 50% NTMP (Sigma-Aldrich, St. Louis, MO, USA) solution from Sigma-Aldrich was used to make 0.5% NTMP-contaminated ionic (100 ppm Cl−, 100 ppm Br−, 100 ppm Cl− + 100 ppm Br−) screening solutions and adjusted to pH 6. The Cu–Al and PCC–Al devices were directly immersed in these screening solutions and observed under the microscope to study the corrosion inhibition effectiveness.

2.4. SEM, GI-XRD, and XPS Analysis

The JEOL IT 200-Scanning Electron Microscope (SEM) was utilized to image wire bond devices at various stages of our coating and testing processes. The SEM was operated at 5 kV with the standard current value of 50 mA, and both the secondary electron detector (SED) and the backscattered electron detector in composition mode (BED-C) were utilized for imaging purposes. Energy Dispersive X-ray spectroscopy (EDX) analysis was conducted using the same microscope, utilizing T4 resolution and a live scan of 120 s in circular and polygon modes. The EDX-map analysis was performed on non-wire-bonded Al bond pads at 5 kV with a resolution of 512 × 384 pixels and a dwell time of 0.2 ms for 30 min. The grazing incidence X-ray diffraction patterns (GI-XRD) were obtained using a Rigaku Smart lab diffractometer (Woodlands, TX, USA) with the incidence parallel beam angle of 0.5°, and the data were plotted using Origin software (Version 2025b). X-ray Photoemission Spectroscopy (XPS) was performed with a PHI 5000 Versaprobe Scanning XPS microprobe, utilizing an Al-Kα source with an anode voltage of 11 kV and pass energy of 29.35 eV, to analyze the chemical–mechanical planarized (CMP) Al-wafer (0.5% Cu) and Cu-wafer samples. For effective charge calibration, the Al-2p metallic peak was calibrated to 72.9 eV for Al wafers, and the Cu-2p3/2 metallic peak was calibrated to 932.7 eV for Cu wafers. The post-processing of XP spectra was performed manually using CasaXPS (Version 2.3.26PR1.0), and the curve fitting was performed using mixed Gaussian–Laurensian [GL(30)] peak profiles, and the full width half-maximum (FWHM) was constrained to be less than 3 eV [32].

2.5. Electrochemical Analysis

Potentiodynamic polarization measurements were performed on the CMP polished Al wafers (0.5% Cu) using a CHI-760D potentiostat (Austin, TX, USA). These experiments used ionic screening solutions as electrolytes, platinum (Pt) foil as a counter electrode, and silver/silver chloride (Ag/AgCl) as a reference electrode. The working electrode was prepared by masking the Al-wafer samples using a polyimide tape, exposing only a 1 cm2 active area. Each sample was immersed in the solution for at least 15 min before conducting open-circuit potential (OCP) measurements. Polarization curves were obtained within a range of ±100 mV at a scan rate of 1 mV/s relative to the OCP measurements. The corrosion potential, Ecorr, was determined based on the intersection of the anodic and cathodic polarization curves. As shown in Figure S5, the intersection point of slopes drawn from the cathodic and anodic branches to the Ecorr line was taken for corrosion current, Icorr.

3. Results and Discussion

3.1. Accelerated Corrosion Screening Analysis

We first tested the corrosion performance of control Cu and PCC wires by subjecting Cu–Al and PCC–Al devices to highly accelerated immersion testing in 100 ppm ionic solutions (Cl−, Br−, Cl− + Br−) for 2 h. The Cu–Al devices with pure Cu wire underwent severe corrosion, with 99 ± 0.2% wire-bond lift-off in Cl- media and 70 ± 18% wire-bond lift-off in Br− based ionic screening. Although the industrial-standard PCC-Al devices performed better in the Br− solution (1.8 ± 0.9%), they still showed 23 ± 8.2% wire-bond lift-off in the Cl− solution, indicating severe corrosion vulnerability. Notably, chloride ions predominantly influenced the corrosion behavior in the MX solution, yielding results identical to those observed in the pure Cl− solution (Figure 4).
Figure 5 demonstrates the time-dependent corrosion progression in wire bond devices observed under mixed ionic screening conditions. The corrosion mechanism for both Cu–Al and PCC–Al followed a three-stage process:
  • Corrosion initiation is characterized by bubble formation at the Cu–Al interface.
  • Propagation of Al pad corrosion, leading to dendrite and mud crack formation in the aluminum pads.
  • Corrosion of the underlying IMCs ultimately results in the ball lift-off.
This corrosion progression aligns with previously reported Cl−-based mechanistic studies by N. Ross et al., in which they demonstrated that, in addition to the IMCs, the Cu–Al (Cu to Al splash) bimetallic contact is another critical factor for corrosion failures, and the bubbles observed were the result of cathodic hydrogen evolution [17]. In our case, the corrosion rate is faster as we tested under 100 ppm Cl− and Br− instead of 20 ppm as mentioned elsewhere [17]. In PCC–Al devices, the time taken for the final IMC corrosion leading to lift-off varied from a few minutes to more than 30 min. This slower corrosion rate and the high variation in the lift-off percentage can be attributed to the difference in the distribution of Pd in the Cu–Al IMCs. The corrosion mechanism for the Br− solution also followed a similar trend for both Cu–Al and PCC–Al devices, with a reduced lift-off percentage (Figure 4) being the only difference.

3.2. Optical and SEM Comparison on Passivated Wirebond Devices

The optical and SEM-EDX analysis of control PCC–Al devices revealed the presence of copper-rich and palladium-rich regions, as shown in Figure 6b and Figure S1. We hypothesize that the Cu-rich regions in PCC-Al devices, which retain the Cu–Al bimetallic contact (Figure 1), are responsible for similar corrosion behavior. Following SEM-EDX analysis, the wire-bonded devices were subjected to the Cu-selective passivation process. After the coating process, SEM-backscattered images (Figure 6) of the Cu–Al and PCC–Al devices displayed a passivation layer formation that was conformal only to the copper exposed area across all wire bonds. The subsequent contact angle measurements from the lead frames of Cu-Al devices consistently indicated increased hydrophobicity, indicating the presence of uniform passivation across the entire Cu lead frames (Figure 6a). These devices will be referred to as “passivated Cu-Al devices” and “passivated PCC-Al devices.” In our previous work, passivated PCC–Al devices were subjected to film stability and thermal reliability tests including temperature cycling (TC: −55 °C to 150 °C), temperature humidity bias (THB: 85 °C/85% RH), and High-Temperature Storage Life (HTSL: 175 °C) and passed electrical and delamination failure analyses [22].

3.3. Accelerated Corrosion Screening Results on Passivated Devices

As shown in Figure 7, the passivated Cu–Al and PCC–Al devices showed significant improvements with at least ~45× and ~7× reductions in ball lift-off percentage across all the ionic solutions compared to the control Cu–Al and PCC–Al devices (Figure 4). These results highlight that reducing cathodic half-cell reactivity by passivating the exposed Cu area (Figure 6) decreases the lift-off failures in the wire-bonded devices. Furthermore, Figure 7 demonstrates the effect of 0.5% NTMP inclusion in ionic solutions, which exhibited excellent corrosion inhibition, achieving less than 1.5% lift-off in most ionic screening conditions. Even after 24 h of immersion in a 0.5% NTMP-added 100 ppm Cl− solution (Figure 8), the Cu–Al devices showed superior corrosion performance, with less than 3% ball lift-off. Furthermore, applying the combined approach, Cu-selective passivation, along with 0.5% NTMP inclusion in the screening solution, achieved 0% ball lift-off consistently across both types of devices, indicating excellent reliability.

3.4. Post-Screening SEM Analysis

After two hours of immersion screening, the Cu–Al and PCC–Al devices were further examined for microscopic IMC degradation by etching away the copper wires [33]. This method is widely used to determine cracks and corrosion degradation in the IMC region and can be used to measure the contact resistance variation and the bond strength in the wire-bonded interconnects [34]. As illustrated in the SEM backscattered images (Figure 9), the bright center region corresponds to the IMC present between the Cu wire and the Al Pad. The results reveal that the IMCs in the non-corroded Al pads, following corrosion screening, were similar to those in the control Al pads, showing no visible signs of IMC degradation. This suggests that preventing corrosion initiation at the Cu–Al bimetallic interface can effectively reduce halide-ion-induced IMC degradation, with no impact on contact resistance. Additionally, SEM images of Cu–Al devices (Figure S2) after 24 h screening did not show any Al pad structure modification. However, the EDX area analysis on non-wire-bonded Al pads detected a minor presence of phosphorus in Al pad surfaces (Figure S2). At the same time, EDX-mapping did not show a significant difference between control and NTMP-treated samples (Figures S3 and S4). This may be due to the higher penetration depth of the EDX, and the surface modification on Al might be relatively thin.

3.5. NTMP Interactions with Al and Cu Surface

To investigate NTMP-based surface modification on Al pads, Al (0.5% Cu) wafers, which have a similar chemical composition to the Al bond pads, were immersed in NTMP-contaminated 100 ppm Cl− solutions for 24 h. The treated Al wafers were then rinsed with UPW, and XPS analyses were performed (Figure 10). The aluminum 2p XP spectrum, in Figure 10a, can be resolved into three peaks at 72.9 eV, 73.8 eV, and 75.6 eV. The lower-energy peak is associated with metallic aluminum, which has unresolved 2p3/2 and 2p1/2 orbital coupling. The peak at 73.8 eV can correspond to AlOx in the Al2O3 network [35]. The higher-energy component is likely due to overlapping contributions from aluminum oxide, aluminum hydroxide, and aluminum phosphonates [29,35,36,37,38,39,40]. Previous XPS studies examining the Al valence band region after phosphonic acid treatment also indicated challenges in distinguishing contributions due to the dominance of amorphous Al2O3 at the surface [28]. Additionally, the peak separation between Al (0) and Al2O3 is slightly different (2.7 eV) from the value of 2.9 eV reported in the literature, which may be due to the contributions from hydroxides and phosphates [39]. Xia et al. demonstrated through experimental and computational studies that aluminum substrates with Lewis acidic oxides and/or hydroxides can interact with the P-O group from phosphonic acids. This interaction renders the phosphorus (P) more electrophilic and promotes heterocondensation, ultimately forming stable P-O-Al groups on the aluminum surface [29].
The broad oxygen 1s X-ray Photoelectron Spectroscopy (XPS) spectrum, summarized in Table 1, shows contributions from several groups, including Al2O3/Al (OH)3, P = O/P-O-H, P-O-R, P-O-Al coordination groups [36]. The phosphorus 2p XPS peak can be deconvoluted into two distinct components. The higher-energy component at 134.4 eV is associated with a free, non-bonded phosphonic acid group, while the lower energy component at 133 eV aligns well with reported values for phosphorus anchoring groups found in typical metal oxide–phosphonate coordination [36,41,42]. Additionally, the peak area ratio between free phosphonic acid and metal phosphonates is 1.88:1, indicating that NTMP forms a mixture of monodentate and bidentate coordination modes with the aluminum surface, with monodentate binding being the more prevalent. These findings confirm the stable formation of chemical bonds between NTMP and the aluminum oxide on the Al wafers and bond pads. Furthermore, these chemically bonded complexes can serve as a barrier on the aluminum oxide surface, protecting it from Cl− and/or Br− attack. Additionally, Tafel analysis (Figure S5) indicates a notable increase in corrosion potential and a decrease in corrosion current density for the Al wafers immersed in NTMP-contaminated solution compared to those in a control solution containing 100 ppm Cl−. This behavior is attributed to the passivation effect.
In contrast to the Al wafers, the metal phosphonate peak was not observed in the P-2p spectra of NTMP-treated Cu-wafers (Figure S6). To further investigate the interaction between copper oxide and the NTMP screening solutions, we utilized grazing incidence X-ray diffraction (GI-XRD) and reflection–absorption infrared spectroscopy (RAIRS). As illustrated in Figure 11, the GI-XRD results confirm the presence of Cu2O on the surface of as-received copper wafers. Upon immersing the wafers in NTMP screening solutions for 2 h, the GI-XRD indicated the dissolution of the copper oxide layer from the Cu wafer. Moreover, the RAIRS (Figure 11b) comparison between control 100 ppm Cl- and NTMP contaminated solutions showed that the copper oxide stretching peak decreases only when NTMP was present in the solution [30]. These findings show that copper oxides form easily dissolvable complexes with NTMP in aqueous solutions, while the Al-oxides form a stable complex. Similarly, Kozlica et al. reported comparable behavior in their corrosion studies, where octyl phosphonic acid served as an inhibitor for aluminum but not for copper [36].

4. Conclusions

This study systematically compared the corrosion tendency, failure rate, and underlying corrosion mechanisms of Cu and PCC wire-bond devices in the presence of two ubiquitous ionic contaminants (Cl− and Br−) in an IC manufacturing process. Both ions showed similar three-stage corrosion progression under aqueous immersion screening conditions; however, the Br− ions exhibited a slower failure rate. Under highly accelerated immersion screening tests, the PCC–Al devices performed better than Cu–Al devices but still suffered severe corrosion in the presence of Cl− ions, with 23 ± 8.2% lift-off failures within 2 h of immersion. This behavior was attributed to the presence of exposed copper areas in the thermosonic ball region.
In the second part of this study, we explored copper-selective passivation and NTMP-based aluminum passivation strategies to prevent wire bond failures induced by Cl− and Br−. The backscattered SEM and contact angle analysis confirmed the conformal Cu-selective film formation on Cu exposed areas in Cu-Al and PCC-Al devices. Even in extreme MX screening conditions, copper selective passivation demonstrated 97 ± 0.2% and 96 ± 0.6% corrosion protection for Cu–Al and PCC–Al devices, respectively. Similarly, including 0.5% NTMP in the screening solutions also improved corrosion protection, with only 0–1% lift-off across all the solutions. XPS and potentiodynamic polarization confirm that NTMP forms a stable phosphonate–aluminum-oxide coordination layer on the Al bond pads, while GI-XRD and IRRAS reveal that Cu-oxide–phosphonate complexes remain unstable in aqueous media. These results collectively show that NTMP eliminates corrosion by suppressing Cl− and Br− attack towards the Al pad, thereby improving the reliability of wire-bonded devices.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/mi16101155/s1, Figure S1. SEM-EDX Analysis of the Control non-passivated PCC–Al devices; Figure S2. SEM-EDX Analysis of Cu–Al devices after 24 h of immersion in 0.5% NTMP contaminated 100 ppm Cl− solution indicated no structural change to the Al bond pad, and EDX-analysis detected a minor presence of a phosphorus signal; Figure S3. SEM-EDX Map Analysis of Cu–Al devices after 24 h of immersion in 0.5% NTMP contaminated 100 ppm Cl− solution indicated a non-quantifiable presence of a phosphorus signal; Figure S4. SEM-EDX Map Analysis on PCC–Al devices after 24 h of immersion in 0.5% NTMP contaminated 100 ppm Cl− solution indicated a non-quantifiable presence of a phosphorus signal; Figure S5. Potentiodynamic polarization plots confirming the reduction in Al wafer reactivity in the presence of NTMP; Figure S6. XP spectra of P-2p on Cu wafers in NTMP solutions indicate an absence of P-O-Cu peak at 133 eV after water rinsing.

Author Contributions

O.C.: conceptualization, funding acquisition, and writing—review and editing; D.K.K. and S.S.N.: methodology, writing—original draft preparation, and data analysis; K.T.A.T. and P.A.: data curation and analysis (optical and SEM), K.A.J.D.: data curation and analysis (cross-sectional polishing and XPS analysis). All authors have read and agreed to the published version of the manuscript.

Funding

This research was supported by the University of North Texas.

Data Availability Statement

Email the corresponding author for any data availability.

Acknowledgments

The authors acknowledge NXP Semiconductors for providing wire-bonded devices and Al wafer samples for testing. We also extend our gratitude to Shyam. M. Nair, D. Anushka. S. Perera, Nandini Voruganti, and Shree Mishra for their assistance in setting up the experiments. XPS was collected in part at the University of North Texas’s Materials Research Facility, a shared research facility for multi-dimensional fabrication and characterization. SEM imaging was conducted using the shared instrumentation of the University of North Texas Department of Chemistry.

Conflicts of Interest

The authors declare no conflicts of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.

Abbreviations

The following abbreviations are used in this manuscript:
PCCPalladium-coated copper
ICIntegrated circuit
LQFPLow-profile quad flat packages
MAPBGAMold array process ball grid array
EMCEpoxy molding compounds
NTMPNitrilotris (methylene)phosphonic acid
IMCInter-metallic compounds
MXMixed-ion screening solution

References

  1. Qin, I.; Yauw, O.; Schulze, G.; Shah, A.; Chylak, B.; Wong, N. Advances in Wire Bonding Technology for 3D Die Stacking and Fan Out Wafer Level Package. In Proceedings of the 2017 IEEE 67th Electronic Components and Technology Conference (ECTC), Orlando, FL, USA, 30 May–2 June 2017. [Google Scholar] [CrossRef]
  2. Zhou, H.; Chang, A.; Fan, J.; Cao, J.; An, B.; Xia, J.; Yao, J.; Cui, X.; Zhang, Y. Copper Wire Bonding: A Review. Micromachines 2023, 14, 1612. [Google Scholar] [CrossRef]
  3. Gan, C.L.; Hashim, U. Reliability Assessment and Activation Energy Study of Au and Pd-Coated Cu Wires Post High Temperature Aging in Nanoscale Semiconductor Packaging. ASME. J. Electron. Packag. 2013, 135, 021010. [Google Scholar] [CrossRef]
  4. An, B.; Zhou, H.; Cao, J.; Ming, P.; Persic, J.; Yao, J.; Chang, A. A Review of Silver Wire Bonding Techniques. Micromachines 2023, 14, 2129. [Google Scholar] [CrossRef] [PubMed]
  5. Zhong, Z.W. Overview of wire bonding using copper wire or insulated wire. Microelectron. Reliab. 2011, 51, 4–12. [Google Scholar] [CrossRef]
  6. Liu, C.P.; Chang, S.J.; Liu, Y.F.; Chen, W.S. Cu-Al interfacial formation and kinetic growth behavior during HTS reliability test. J. Mater. Process. Technol. 2019, 267, 90–102. [Google Scholar] [CrossRef]
  7. Yoo, Y.-R.; Kim, G.; Jeon, S.-M.; Park, H.-J.; Seo, W.-W.; Moon, J.-T.; Kim, Y.-S. Influence of HCl Concentration on Corrosion Behavior between Au or Cu Bonding Wires and the Bond Pad for Semiconductor Packaging. Materials 2023, 16, 7275. [Google Scholar] [CrossRef]
  8. Uno, T. Bond reliability under humid environment for coated copper wire and bare copper wire. Microelectron. Reliab. 2011, 51, 148–156. [Google Scholar] [CrossRef]
  9. Liu, C.; Chang, S.; Liu, Y.; Su, J. Corrosion-induced degradation and its mechanism study of Cu–Al interface for Cu-wire bonding under HAST conditions. J. Alloys Compd. 2020, 825, 154046. [Google Scholar] [CrossRef]
  10. Van Soestbergen, M.; Mavinkurve, A.; Zaal, J.J.M.; O’Halloran, G.M.; Rongen, R.T.H.; Farrugia, M.L. Crevice Corrosion of Ball Bond Intermetallics of Cu and Ag Wire. In Proceedings of the 2016 IEEE 66th Electronic Components and Technology Conference (ECTC), Las Vegas, NV, USA, 31 May–3 June 2016; pp. 774–781. [Google Scholar] [CrossRef]
  11. Qin, W.; Anderson, H.; Anderson, T.; Chang, G.; Barrientos, D. Corrosion Mechanisms of Cu Wire Bonding on Al Pads. In Proceedings of the 2018 IEEE 68th Electronic Components and Technology Conference (ECTC), San Diego, CA, USA, 29 May–1 June 2018. [Google Scholar] [CrossRef]
  12. Belfort, Y.; Caignard, J.M.; Keller, S.; Guerveno, J.-P. Failures on DC–DC Modules Following a Change of Wire Bonding Material from Gold to Copper. Microelectron. Reliab. 2015, 55, 2003–2006. [Google Scholar] [CrossRef]
  13. Gan, C.L.; Ng, E.K.; Chan, B.L.; Hashim, U.; Classe, F.C. Technical Barriers and Development of Cu Wirebonding in Nanoelectronics Device Packaging. J. Nanomater. 2012, 173025. [Google Scholar] [CrossRef]
  14. Osenbach, J.; Wang, B.Q.; Emerich, S.; DeLucca, J.; Meng, D. Corrosion of the Cu/Al Interface in Cu-Wire-Bonded Integrated Circuits. In Proceedings of the 2013 IEEE 63rd Electronic Components and Technology Conference (ECTC), Las Vegas, NV, USA, 28–31 May 2013; IEEE: New York, NY, USA, 2013. [Google Scholar] [CrossRef]
  15. Mathew, V.; Chopin, S. Corrosion Reliability of Copper Wirebond (CuWB) Packages-Impact of Voltage and Corrosive Ions from Packaging Materials. IMAPSource Proc. 2015, 2015, 286–291. [Google Scholar] [CrossRef]
  16. Mathew, V.; Chopin, S.; Higgins, L.; Zhang, Y. Copper Wirebond Compatibility with Organic and Inorganic Ions Present in Mold Compounds. J. Microelectron. Electron. Packag. 2014, 11, 70–74. [Google Scholar] [CrossRef]
  17. Ross, N.; Asokan, M.; Ashok Kumar, G.I.; Caperton, J.; Alptekin, J.; Salunke, A.S.; Chyan, O.M. Mechanistic Study of Copper Wire-Bonding Failures on Packaging Devices in Acidic Chloride Environments. Microelectron. Reliab. 2020, 113, 113917. [Google Scholar] [CrossRef]
  18. Mathew, V.; Chopin, S.; Li, G.; Xu, S. Post wirebonding coating for prevention of corrosion of wire bonded packages by chlorine containing foreign particles. In Proceedings of the 2022 IEEE 72nd Electronic Components and Technology Conference (ECTC), San Diego, CA, USA, 31 May–3 June 2022; pp. 495–501. [Google Scholar] [CrossRef]
  19. Qin, I.; Xu, H.; Clauberg, H.; Cathcart, R.; Acoff, V.L.; Chylak, B.; Huynh, C. Wire Bonding of Cu and Pd Coated Cu Wire: Bondability, Reliability, and IMC Formation. In Proceedings of the 2011 IEEE 61st Electronic Components and Technology Conference (ECTC), Lake Buena Vista, FL, USA, 31 May–3 June 2011. [Google Scholar] [CrossRef]
  20. Lim, A.B.Y.; Neo, W.J.; Yauw, O.; Chylak, B.; Gan, C.L.; Chen, Z. Evaluation of the Corrosion Performance of Cu–Al Intermetallic Compounds and the Effect of Pd Addition. Microelectron. Reliab. 2016, 56, 155–161. [Google Scholar] [CrossRef]
  21. Qin, W.; Anderson, T.; Chang, G. Mechanism to Improve the Reliability of Copper Wire Bonding with Palladium-Coating of the Wire. Microelectron. Reliab. 2019, 99, 239–244. [Google Scholar] [CrossRef]
  22. Kumaravel, D.K.; Jesu Durai, K.A.; Nair, S.M.; Tran, K.T.A.; Chyan, O.; Poliah, R.; Chan, M.Z.; Mathew, V. Innovative Cu-Selective Passivation Coatings for Enhanced Reliability in Cu Interconnects for IC Packaging. In Proceedings of the 2024 IEEE 26th Electronics Packaging Technology Conference (EPTC), Singapore, 3–6 December 2024; pp. 534–540. [Google Scholar] [CrossRef]
  23. Li, Z.; Merz, K.M. Systematic Evaluation of Ion Diffusion and Water Exchange. J. Chem. Theory Comput. 2022, 18, 3017–3026. [Google Scholar] [CrossRef]
  24. Lantz, L.; Pecht, M.G. Pecht Ion transport in encapsulants used in microcircuit packaging. IEEE Trans. Compon. Packag. Technol. 2003, 26, 199–205. [Google Scholar] [CrossRef]
  25. Van Soestbergen, M.; Ernst, L.J.; Zhang, G.Q.; Rongen, R.T.H. Transport of Corrosive Constituents in Epoxy Moulding Compounds. In Proceedings of the 2007 International Conference on Thermal, Mechanical and Multi-Physics Simulation Experiments in Microelectronics and Micro-Systems EuroSime 2007, London, UK, 16–18 April 2007; pp. 1–5. [Google Scholar] [CrossRef]
  26. Paniagua, S.A.; Giordano, A.J.; Smith, O.L.; Barlow, S.; Li, H.; Armstrong, N.R.; Pemberton, J.E.; Brédas, J.; Ginger, D.; Marder, S.R. Phosphonic Acids for Interfacial Engineering of Transparent Conductive Oxides. Chem. Rev. 2016, 116, 7117. [Google Scholar] [CrossRef]
  27. Karlsson, P.M.; Anderson, M.W.; Palmqvist, A.E.C. Adsorption of sodium dodecyl sulfate and sodium dodecyl phosphate at the surface of aluminium oxide studied with AFM. Corros. Sci. 2009, 52, 1103. [Google Scholar] [CrossRef]
  28. Zhao, R.; Hauert, R.; Crockett, R.; Cancellieri, C.; Gaan, S.; Schmutz, P.; Heuberger, M.; Jeurgens, L.P.H. Aqueous phosphonic acid treatments of aluminium: Effect of oxide dissolution and re-oxidation on adsorbate formation. Appl. Surf. Sci. 2024, 667, 160363. [Google Scholar] [CrossRef]
  29. Xia, D.; Pan, C.; Qin, Z.; Fan, B.; Song, S.; Jin, W.; Hu, W. Covalent surface modification of LY12 aluminum alloy surface by self-assembly dodecyl phosphate film towards corrosion protection. Prog. Org. Coat. 2020, 143, 105638. [Google Scholar] [CrossRef]
  30. Alptekin, J.; Antony Jesu Durai, K.; Kumaravel, D.K.; Estridge, L.; Chyan, O.; Ibrahim, R.; Li, G.; Mathew, V. A Cu–Cu Wire-Bonding Enabled by a Cu-Selective Passivation Coating to Enhance Packaging Reliability. IEEE Trans. Compon. Packag. Manufact. Technol. 2023, 13, 1923. [Google Scholar] [CrossRef]
  31. Chyan, O.; Ashokan, M. Selective Surface Finishing for Corrosion Inhibition via Chemical Vapor Deposition. Google Patents US20210071308A1, 11 March 2021. Available online: https://patents.google.com/patent/US20210071308A1/en (accessed on 4 March 2025).
  32. Fairley, N.; Fernandez, V.; Richard-Plouet, M.; Guillot-Deudon, C.; Walton, J.; Smith, E.; Flahaut, D.; Greiner, M.; Biesinger, M.; Tougaard, S.; et al. Systematic and collaborative approach to problem solving using X-ray photoelectron spectroscopy. Appl. Surf. Sci. Adv. 2021, 5, 100112. [Google Scholar] [CrossRef]
  33. O’Halloran, G.M.; Van Ijzerloo, A.; Rongen, R.; Zachariasse, F. Planar Analysis of Copper-Aluminium Intermetallics. In Proceedings of the 39th International Symposium for Testing and Failure Analysis, San Jose, CA, USA, 3–7 November 2013. [Google Scholar] [CrossRef]
  34. Mavinkurve, A.; Goumans, L.; O’Halloran, G.M.; Rongen, R.T.H.; Farrugia, M.-L. Copper wire interconnect reliability evaluation using in-situ High Temperature Storage Life (HTSL) tests. Microelectron. Reliab. 2014, 54, 1661–1665. [Google Scholar] [CrossRef]
  35. Hoque, E.; DeRose, J.A.; Hoffmann, P.; Mathieu, H.J.; Bhushan, B.; Cichomski, M. Phosphonate self-assembled monolayers on aluminum surfaces. J. Chem. Phys. 2006, 124, 174710. [Google Scholar] [CrossRef] [PubMed]
  36. Kozlica, D.K.; Milošev, I. Corrosion inhibition of copper and aluminium by 2-mercaptobenzimidazole and octylphosphonic acid—Surface pre-treatment and method of film preparation. Electrochim. Acta 2022, 431, 141154. [Google Scholar] [CrossRef]
  37. Pan, C.; Wang, X.; Behnamian, Y.; Wu, Z.; Qin, Z.; Xia, D.-H.; Hu, W. Monododecyl Phosphate Film on LY12 Aluminum Alloy: PH-Controlled Self-Assembly and Corrosion Resistance. J. Electrochem. Soc. 2020, 167, 161510. [Google Scholar] [CrossRef]
  38. Attavar, S.; Diwekar, M.; Linford, M.R.; Davis, M.A.; Blair, S. Passivation of aluminum with alkyl phosphonic acids for biochip applications. Appl. Surf. Sci. 2010, 256, 7146–7150. [Google Scholar] [CrossRef]
  39. Hoque, E.; DeRose, J.A.; Kulik, G.; Hoffmann, P.; Mathieu, H.J.; Bhushan, B. Alkylphosphonate Modified Aluminum Oxide Surfaces. J. Phys. Chem. B 2006, 110, 10855–10861. [Google Scholar] [CrossRef]
  40. Scandurra, A.; Currò, G.; Frisina, F.; Pignataro, S. Corrosion Inhibition of Al Metal in Microelectronic Devices Assembled in Plastic Packages. J. Electrochem. Soc. 2001, 148, B289. [Google Scholar] [CrossRef]
  41. Wan, X.; Lieberman, I.; Asyuda, A.; Resch, S.; Seim, H.; Kirsch, P.; Zharnikov, M. Thermal Stability of Phosphonic Acid Self-Assembled Monolayers on Alumina Substrates. J. Phys. Chem. C 2020, 124, 2531. [Google Scholar] [CrossRef]
  42. Smecca, E.; Motta, A.; Fragalà, M.E.; Aleeva, Y.; Condorelli, G.G. Spectroscopic and Theoretical Study of the Grafting Modes of Phosphonic Acids on ZnO Nanorods. J. Phys. Chem. C 2013, 117, 5364–5372. [Google Scholar] [CrossRef]
Micromachines 16 01155 g001
Figure 1. SEM cross-sectional image of a Cu-wire-bonded device, highlighting the Cu–Al bimetallic contact.
Figure 1. SEM cross-sectional image of a Cu-wire-bonded device, highlighting the Cu–Al bimetallic contact.
Micromachines 16 01155 g001
Micromachines 16 01155 g002
Figure 2. Optical image comparison of (a) Cu-Al (134 wire-bonds) and (b) PCC-Al (409 wire bonds) wire-bonded devices. Center inset: zoomed-in top-down view of a single ball bond to the bond pad surface.
Figure 2. Optical image comparison of (a) Cu-Al (134 wire-bonds) and (b) PCC-Al (409 wire bonds) wire-bonded devices. Center inset: zoomed-in top-down view of a single ball bond to the bond pad surface.
Micromachines 16 01155 g002
Micromachines 16 01155 g003
Figure 3. (a) Schematics of the corrosion screening metrology and (b) microscopic images of wire bond lift-off considered as failure defects for assessing corrosion and statistical analysis.
Figure 3. (a) Schematics of the corrosion screening metrology and (b) microscopic images of wire bond lift-off considered as failure defects for assessing corrosion and statistical analysis.
Micromachines 16 01155 g003
Micromachines 16 01155 g004
Figure 4. Accelerated screening results on Cu–Al and PCC–Al devices showing extensive corrosion in ionic screening solutions after 2 h, based on wire-bond lift-off counts (no. of devices tested per condition = 3).
Figure 4. Accelerated screening results on Cu–Al and PCC–Al devices showing extensive corrosion in ionic screening solutions after 2 h, based on wire-bond lift-off counts (no. of devices tested per condition = 3).
Micromachines 16 01155 g004
Micromachines 16 01155 g005
Figure 5. Real-time corrosion mechanism of Cu–Al device in mixed ion screening solution (100 ppm Cl− and 100 ppm Br−).
Figure 5. Real-time corrosion mechanism of Cu–Al device in mixed ion screening solution (100 ppm Cl− and 100 ppm Br−).
Micromachines 16 01155 g005
Micromachines 16 01155 g006
Figure 6. Optical and back-scattered SEM comparison of control and passivated (a) Cu–Al and (b) PCC–Al wire-bonded devices, demonstrating a conformal passivation. (No: of leadframes tested for contact angle: 3).
Figure 6. Optical and back-scattered SEM comparison of control and passivated (a) Cu–Al and (b) PCC–Al wire-bonded devices, demonstrating a conformal passivation. (No: of leadframes tested for contact angle: 3).
Micromachines 16 01155 g006
Micromachines 16 01155 g007
Figure 7. Accelerated screening results on Cu–Al and PCC–Al devices with copper selective passivation, 0.5% NTMP in ionic screening solutions, and the combined approach after 2 h. (No. of devices tested per condition = 3).
Figure 7. Accelerated screening results on Cu–Al and PCC–Al devices with copper selective passivation, 0.5% NTMP in ionic screening solutions, and the combined approach after 2 h. (No. of devices tested per condition = 3).
Micromachines 16 01155 g007
Micromachines 16 01155 g008
Figure 8. Optical image of Cu–Al device before and after 24-h immersion in 0.5% NTMP contaminated Cl- screening with annotated (red box) ball lift-off areas.
Figure 8. Optical image of Cu–Al device before and after 24-h immersion in 0.5% NTMP contaminated Cl- screening with annotated (red box) ball lift-off areas.
Micromachines 16 01155 g008
Micromachines 16 01155 g009
Figure 9. Back-scattered SEM images of control and corrosion-screened Cu–Al (a,c) and PCC–Al (b,d) devices, indicating similar IMC presence.
Figure 9. Back-scattered SEM images of control and corrosion-screened Cu–Al (a,c) and PCC–Al (b,d) devices, indicating similar IMC presence.
Micromachines 16 01155 g009
Micromachines 16 01155 g010
Figure 10. (a–c) XP spectra of Al wafers immersed in NTMP-contaminated Cl− solution show passivation formation on the Al surface. (Colored regions represent the deconvoluted components as shown in the Table 1).
Figure 10. (a–c) XP spectra of Al wafers immersed in NTMP-contaminated Cl− solution show passivation formation on the Al surface. (Colored regions represent the deconvoluted components as shown in the Table 1).
Micromachines 16 01155 g010
Micromachines 16 01155 g011
Figure 11. (a) Grazing incident X-ray diffraction and (b) RAIRS analysis of Cu wafers in various solutions.
Figure 11. (a) Grazing incident X-ray diffraction and (b) RAIRS analysis of Cu wafers in various solutions.
Micromachines 16 01155 g011
Table 1. XPS curve fitting results of Al-2p, O-1s and P-2p after NTMP immersion.
Table 1. XPS curve fitting results of Al-2p, O-1s and P-2p after NTMP immersion.
ElementComponentsBinding EnergyAtom%References
Al-2pAl (0) metal72.919.6[35,36,37,38,39]
AlOx73.82.9
Al3+ species75.677.5
O-1sAl2O3/Al (OH)3531.436.6[36]
P = O/P-OH531.954.61
P-O-R532.57.61
P-O-Al533.51.23
P-2pR-P(O)(OH)2134.465.3[36,41,42]
R-P-O-Al133.034.7
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Kumaravel, D.K.; Sridharan Nair, S.; Tran, K.T.A.; Ahluwalia, P.; Antony Jesu Durai, K.; Chyan, O. Post Wire-Bonding Corrosion Prevention Strategies to Mitigate Chloride- and Bromide-Induced Corrosion Failures in Cu- and PCC-Based Wire-Bonded Packages. Micromachines 2025, 16, 1155. https://doi.org/10.3390/mi16101155

AMA Style

Kumaravel DK, Sridharan Nair S, Tran KTA, Ahluwalia P, Antony Jesu Durai K, Chyan O. Post Wire-Bonding Corrosion Prevention Strategies to Mitigate Chloride- and Bromide-Induced Corrosion Failures in Cu- and PCC-Based Wire-Bonded Packages. Micromachines. 2025; 16(10):1155. https://doi.org/10.3390/mi16101155

Chicago/Turabian Style

Kumaravel, Dinesh Kumar, Shinoj Sridharan Nair, Khanh Tuyet Anh Tran, Pavan Ahluwalia, Kevin Antony Jesu Durai, and Oliver Chyan. 2025. "Post Wire-Bonding Corrosion Prevention Strategies to Mitigate Chloride- and Bromide-Induced Corrosion Failures in Cu- and PCC-Based Wire-Bonded Packages" Micromachines 16, no. 10: 1155. https://doi.org/10.3390/mi16101155

APA Style

Kumaravel, D. K., Sridharan Nair, S., Tran, K. T. A., Ahluwalia, P., Antony Jesu Durai, K., & Chyan, O. (2025). Post Wire-Bonding Corrosion Prevention Strategies to Mitigate Chloride- and Bromide-Induced Corrosion Failures in Cu- and PCC-Based Wire-Bonded Packages. Micromachines, 16(10), 1155. https://doi.org/10.3390/mi16101155

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop