Development of a Reliable High-Performance WLP for a SAW Device
Abstract
:1. Introduction
1.1. Historical View of SAW Device Package
1.2. SAW Device Package Design
2. Process Flow of the SAW Device’s WLP and the Typical Failure Mode
2.1. Process Flow of SAW Device WLP
2.2. The Experimental Results of Typical Failure Mode
3. FE Model of a SAW Filter’s WLP
3.1. Single-Die FE Model to Solve the RDL Crack Failure Mode
3.2. Effect of Geometric Parameters on Stress Distribution
3.3. Deflection Prediction of Different Cavity Sizes
4. Reliability Evaluation
5. Conclusions
- (1)
- A wafer-level lamination process was conducted on the SAW filter substrate with the CW dam layer together before the electrical interconnection process. Laser drilling was used to form the connection vias, which was characterized by a gradual increase in diameter from the bottom to the top of the TFVs, and the side walls were smooth without steps.
- (2)
- Parameters, such as material properties and geometry, affect the maximum stress of the package significantly. Following practical verification, the cavity collapse amount was projected to be about 6.6 μm at a larger size of 980 μm × 320 μm, resolving the collapse problem caused by the encapsulating pressure of the SAW filter WLP. In terms of the effect of the geometric parameters on stress distribution, by comparing the top-side molded with the conventional SAW filter WLP, the maximum von Mises values were 74.487 MPa and 154.06 MPa, respectively, with a 51.65% reduction.
- (3)
- After Pre Con L3 and uHAST 96-h, no electrical breakdown was seen during the reliability tests. The results show that the proposed SAW filter package based on 3D WLP technology is reliable for large-scale industrial manufacture. We infer from this that our technique can significantly enhance the development and use of consumer market band applications.
6. Patents
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Items | Young Modulus | Poisson Ratio | CTE |
---|---|---|---|
SAW device substrate | 230 Gpa | 0.22 | 16.1 ppm/°C 4.1 ppm/°C |
Cavity wall layer | 4.4 Gpa | 0.34 | 65 ppm/°C |
Roof layer | 9 Gpa | 0.34 | CTE1: 18 ppm/°C (25–150 °C) CTE2: 45 ppm/°C (150–240 °C) |
Cu | 119 Gpa | 0.326 | 17.5 ppm/°C |
Cu Thickness | Stress Point (MPa) | Ratio |
---|---|---|
2 µm | 416.07 | 1.00 |
8 µm | 363.84 | 1.14 |
filled via | 350.45 | 1.19 |
Items | Conditions | Failure Rate (%) | Result | |
---|---|---|---|---|
Pre-Con L3 | Bake | 125 °C/24 H | 0.00 | Pass |
Soak | 30 °C/60%/192 H | 0.00 | Pass | |
Reflow | 260 °C (+5/−0) 3× | 0.00 | Pass | |
uHAST | 130 °C/85% RH, 96 H | 0.00 | Pass |
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Chen, Z.; Yu, D. Development of a Reliable High-Performance WLP for a SAW Device. Sensors 2022, 22, 5760. https://doi.org/10.3390/s22155760
Chen Z, Yu D. Development of a Reliable High-Performance WLP for a SAW Device. Sensors. 2022; 22(15):5760. https://doi.org/10.3390/s22155760
Chicago/Turabian StyleChen, Zuohuan, and Daquan Yu. 2022. "Development of a Reliable High-Performance WLP for a SAW Device" Sensors 22, no. 15: 5760. https://doi.org/10.3390/s22155760
APA StyleChen, Z., & Yu, D. (2022). Development of a Reliable High-Performance WLP for a SAW Device. Sensors, 22(15), 5760. https://doi.org/10.3390/s22155760