Failure Analysis of Printed Circuit Board Solder Joint under Thermal Shock
Round 1
Reviewer 1 Report
Off course, it is crucial to look at the solder joint failure mechanisms under various temperature settings to maintain the longevity of printed circuit boards (PCB). Taking into account this idea, in this study, high and low-temperature thermal shock tests were used to examine the stress and strain distribution of PCB solder joints. After thermal shock testing, the cross-section of the solder junction was measured with a 3D stereoscopic microscope and an SEM with EDS. By using XRD, the phase of the IMC layer and the microstructure of the lead-free solder joint were investigated. By using the finite element method, the working state of a PCB solder joint under thermal stress was simulated and examined. The authors of the paper summarized the findings and demonstrated that thermal shock has a significant impact on solder joint dependability. They also concluded that the greatest stress-strain concentration area of the simulated solder junction and the position of the actual crack are both consistent. The interface's brittle Cu6Sn5 and Cu3Sn phases hasten the failure of solder connections. As a suggestion, the authors said that the dependability of solder junctions can be increased by limiting the expansion of the Cu6Sn5 and Cu3Sn phases. As a result, the work is worthy of publication if the remarks listed are taken into account:
1- First of all, the paper's similarity ratio was 22% when the similarity check was finished, which is not ideal because it is improper to use ideas from sources without making any changes, even though references are included for the aforementioned lines. It is therefore expected that the writers will have read the article again and revised any similar portions into their own words.
2- On page 1, lines 34 and 35, it is stated that "According to existing research, solder joint failure is responsible for nearly 60% of electronic product failures." I believe that this material needs to be discussed in detail or used as a reference/references.
3- It is said on page 1 in lines 35 to 38 that "The solder joint of PCB is a weak part of the whole electronic product. It is prone to produce crack initiation, propagation and even fracture in harsh environments such as high temperature, low temperature and violent vibration environment." Once more, I believe that this information either needs to be supported by reference(s) or, if the authors have any personal experiences to draw from, explanations and illustrations might be provided.
4- Convergence analysis must be performed in FE Analysis prior to the final analysis. As a result, it is necessary to incorporate convergence analysis results to the article, like a picture. In addition, the element type utilized must be mentioned, and the justification for the usage of the ostensible element must be stated.
5- Stress distributions in Figure 4 are not clear. I believe the issue can be resolved by expanding the figure.
6- The conclusion should be written in bullet points with only the most important findings.
7- Some minor typos should be corrected.
For instance:
- Page 1, line 12, add “a” before “Printed”
- Page 1, line 13, replace "low temperature" with "low-temperature" by inserting a dash (-) between "low" and "temperature"
- Page 1, line 13, add “the” before “PCB”
- Page 1, line 14, replace "cross section" with "cross-section" by inserting a dash (-) between "cross" and "section"
- Page 1, line 14, replace “test” with “tests”
- Page 1, line 15, add “the” before “lead-free”
- Page 1, line 16, add “the” before “IMC”
- Page 1, line 16, add “the” before “PCB”
- Page 1, line 17, add “the” before “finite element”
- Page 1, line 28, use a comma (,) before “and”
- Page 1, line 30, add “the” before “above”
- Page 1, line 30, replace “automotives” with “automotive”
- Page 1, line 34, use a comma (,) before “and”
- Page 1, line 35, add “the” before “PCB”
- Page 1, line 37, use a comma (,) before “and even fracture”
- Page 1, lines 37-38, use a comma (,) before “and violent vibration”
- Page 1, line 38, replace “environment” with “environments”
- Page 1, line 42, replace "low temperature" with "low-temperature" by inserting a dash (-) between "low" and "temperature"
- Page 2, line 49, use a comma (,) before “and”
- Page 2, line 50, add “the” before “square”
- Page 2, line 53, delete the word “which”
- Page 2, line 67, replace "single component" with "single-component" by inserting a dash (-) between "single" and "component"
- Page 3, line 71, “nephogram”????
- Page 3, line 84, replace "well formed" with "well-formed" by inserting a dash (-) between "well" and "formed"
- Page 3, line 85, replace "streamline" with "streamlined"
- Page 3, line 90, use a comma (,) before “and solder”
- Page 3, line 104, add “the” before “solder”
- Page 5, line 113, use a comma (,) before “and”
- Page 5, line 116, replace "high stress" with "high-stress" by inserting a dash (-) between "high” and "stress"
- Page 5, line 124, replace "of" with "in"
- Page 6, line 136, add “an” before “elastic”
- Page 6, line 136, add “the” before “solder joint”
- Page 6, line 139, “nephogram”????
- Page 6, line 142, add “the” before “thermal”
- Page 6, line 142, replace "cross section" with "cross-section" by inserting a dash (-) between "cross" and "section"
- Page 6, line 145, use a comma (,) before “and compressive”
- Page 6, line 149, replace "of" with "in"
- Page 8, line 164, replace "cross section" with "cross-section" by inserting a dash (-) between "cross" and "section"
- Page 8, line 173, add “the” before “PCB”
- Page 8, line 175, use a comma (,) before “and”
8- The following studies must be evaluated and cited because the authors have used some information from them directly or indirectly, or because there are relevant researches that the authors have not discussed or cited or can be used some data to compare their results:
- " Analysis of enhancement in available power transfer capacity by STATCOM integrated SMES by numerical simulation studies”, Engineering Science and Technology, an International Journal, 2016.
- “Dual MPPT algorithm for dual PV source fed open-end winding induction motor drive for pumping application”, Engineering Science and Technology, an International Journal, 2016.
- “Genetic algorithm based reference current control extraction based shunt active power filter” International Transactions on Electrical Energy Systems, 2021
- " High-voltage dc-dc converter topology for pv energy utilization—Investigation and implementation ", Electric Power Components and Systems, 2017.
- “Wavelet-fuzzy speed indirect field oriented controller for three-phase AC motor drive–Investigation and implementation”, Engineering Science and Technology, an International Journal, 2016.
- “Recent Progress in lead-free solder technology”, Book, 2022.
- “Thermal Stress Analysis of BGA Solder Joint Power Load Based on COMSOL”, 19th International Conference on Electronic Packaging Technology, 2018.
- “Fracture Life Evaluation of Cu-Cored Solder Joint in BGA Package”, ASME 2009 InterPACK Conference, 2009.
9- Finally, while the work is well-written in general, it, unfortunately, contains some grammatical and typographical problems. Before resubmitting the manuscript, it is suggested that the authors reread it again.
Author Response
Response to Reviewer 1 Comments
Point 1: First of all, the paper's similarity ratio was 22% when the similarity check was finished, which is not ideal because it is improper to use ideas from sources without making any changes, even though references are included for the aforementioned lines. It is therefore expected that the writers will have read the article again and revised any similar portions into their own words.
Response 1: Thanks for your careful check. I have modified the content of the article.
Point 2: On page 1, lines 34 and 35, it is stated that "According to existing research, solder joint failure is responsible for nearly 60% of electronic product failures." I believe that this material needs to be discussed in detail or used as a reference/references.
Response 2: Thank you for your suggestion. Relevant references have been added, please check the Ref [31] for details.
Point 3: It is said on page 1 in lines 35 to 38 that "The solder joint of PCB is a weak part of the whole electronic product. It is prone to produce crack initiation, propagation and even fracture in harsh environments such as high temperature, low temperature and violent vibration environment." Once more, I believe that this information either needs to be supported by reference(s) or, if the authors have any personal experiences to draw from, explanations and illustrations might be provided.
Response 3: Thank you for your suggestion. Relevant references have been added. Please check the Ref [27] for details.
Point 4: Convergence analysis must be performed in FE Analysis prior to the final analysis. As a result, it is necessary to incorporate convergence analysis results to the article, like a picture. In addition, the element type utilized must be mentioned, and the justification for the usage of the ostensible element must be stated.
Response 4: Thank you for your suggestion. We fully agree with your proposal. Convergence analysis is also part of our future experimental plan. We have supplemented the missing information according to your suggestion. Please find them in the line 59.
Point 5: Stress distributions in Figure 4 are not clear. I believe the issue can be resolved by expanding the figure.
Response 5: Thank you for your suggestion. We accordingly revised Figure 4 based on your suggestion.
Point 6: The conclusion should be written in bullet points with only the most important findings.
Response 6: Thank you for your suggestion.The conclusion format has been revised.The revised sentences have been highlighted in blue.
Point 7: Some minor typos should be corrected.
Response 7: Thanks for your careful check. All minor typos have been corrected. The revised sentences have been highlighted in blue.
Point 8: The following studies must be evaluated and cited because the authors have used some information from them directly or indirectly, or because there are relevant researches that the authors have not discussed or cited or can be used some data to compare their results.
Response 8: Thank you for your suggestion.Relevant references have been added. Please check the Ref [34-38] for details.
Point 9: Finally, while the work is well-written in general, it, unfortunately, contains some grammatical and typographical problems. Before resubmitting the manuscript, it is suggested that the authors reread it again.
Response 9: Thank you for your suggestion. I've fixed grammar and typography issues.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Please see the enclosed comment file.
Comments for author File: Comments.pdf
Author Response
Response to Reviewer 2 Comments
Point 1: Define the abbreviation IMC in the abstract.
Response 1: Thanks for your careful check. I have defined the abbreviation IMC in the abstract.
Point 2: Lines 56-57.
Authors wrote “The time of temperature change was controlled within 2min, and the temperature
was kept at -18 ℃ and -155 ℃ for 2 hours respectively (10 cycles).”
The dash sign in front of -18 ℃ and -155 ℃ are misleading. They can be confused for a -ve
temperature. Please remove them.
Response 2: Thanks for your careful check. The “-” has been removed.
Point 3: In equations (1) and (2) there are several variables. Please mention them in the discussion
part.
Response 3:Thank you for your suggestion. All variables in equations (1) and (2) have been accounted for in the text. Please refer to lines 89-92 and lines 96-99 in blue for details.
Point 4: Provide references for equations (1) and (2).
Response 4: Thank you for your suggestion.Reference [39] has been cited. Please check in the line 83 for details.
Point 5: Insets in Figure 4 (a-d) have poor resolution.
Response 5: Thank you for your suggestion. We accordingly revised Figure 4 based on your suggestion.
Point 6: Fix punctuation and space related errors such as (c)10 ℃, (d)40 ℃, (e)80 ℃ and (f)155
℃ etc.
Response 6: Thanks for your careful check. All minor typos have been corrected.
Point 7: Fig 3 shows the circuit board with a processor. Depending on the speed of a processor,
the amount of heat generated heat is enormous. However, I did not see any discussion on
the failure of solder due to generated heat.
Response 7: Thank you for your suggestion. We have supplemented the related discussion in the revised manuscript.
Point 8: The effect of thermal shock on the reliability of solder joints is well known. In what
aspects, the current research is new. Please explain.
Response 8: In this study, ANSYS simulation and specific experiments were combined to analyze PCB boards failure. Micromorphology observation and phase analysis of PCB solder failure parts were performed. The failure mechanisms of SAC305, a commonly used joint solder in the industry, under thermal shock are summarized. This study can provide a basis for the analysis of possible failures in PCB board manufacturing and use.
Author Response File: Author Response.pdf
Reviewer 3 Report
In Fig. 6b, a crack cannot be confirmed. Rather, it looks like a lack of wettability of the filler material on the substrate. Only Fig. 7b clarifies the issue. I propose to combine Fig. 6a with Fig. 7a and Fig. 6b with Fig. 7b. This will avoid unnecessary discussion.
On line 48 the authors state: "SAC305 solder [26]". I do not know what the recall [26] with the SAC305 binder gives. It would be reasonable to provide the binder standard instead of [26].
Author Response
Response to Reviewer 3 Comments
Point 1: In Fig. 6b, a crack cannot be confirmed. Rather, it looks like a lack of wettability of the filler material on the substrate. Only Fig. 7b clarifies the issue. I propose to combine Fig. 6a with Fig. 7a and Fig. 6b with Fig. 7b. This will avoid unnecessary discussion.
Response 1: Thank you for your suggestion. We accordingly revised these pictures based on your suggestion.
Point 2:On line 48 the authors state: "SAC305 solder [26]". I do not know what the recall [26] with the SAC305 binder gives. It would be reasonable to provide the binder standard instead of [26].
Response 2: Thanks for your careful check. This reference has been superseded. Please check the Ref [26] for details.
Author Response File: Author Response.pdf
Reviewer 4 Report
The article submitted for review touches on an important area of research - the performance of materials under conditions of cyclic thermal stress. This is especially important for modern microprocessor technology, which, due to its great mobility, is often subjected to both high heating and rapid cooling. In this regard, the topic chosen by the authors of the work is relevant.
1. The literature review is based on fairly modern sources, but is written too briefly and does not sufficiently reveal either the problem or possible solutions to it.
2. Materials and methods of research. The description of the methods is not complete.
3. The results are generally well presented, but there are shortcomings in the illustrations.
4. Conclusions should be reworked.
Remarks
1. The literary review is written in general terms. It is not clear from it what the current state of research in this area is. Mostly, the solders used are simply listed. There is no description of the problem and no similar studies in this area are given.
2. Materials and methods are not written for the entire list of work performed. There is no description of methods for studying the structure and phase composition. There is no description of equipment for computed x-ray microtomography.
Line 57 shows a temperature of -155°C. Need to correct for a hyphen. After all, the tests were not carried out in the field of cryogenic temperatures?!
3. Not all abbreviations in the text are given transcripts.
4. Images.
Figures 6 and 7 does not give a normal idea of the location of the crack formation. You should add a diagram explaining the area shown in the photo.
Figure 9 has small captions. you can enlarge the picture itself and everything will become better.
5. In the first section, the specific purpose of the work performed is not given. The choice of solder material is not quite obvious. Because of this, there are also problems with conclusions.
6. The final part of the conclusions about increasing the reliability of solder joints is not substantiated and not proven in any way. Why even use a solder that tends to form brittle phases that will induce cracking?
In addition, the conclusions should reflect the achievement of the goal set in the work. But for this, it must first be formulated in the introduction.
Author Response
Response to Reviewer 4 Comments
Point 1: The literary review is written in general terms. It is not clear from it what the current state of research in this area is. Mostly, the solders used are simply listed. There is no description of the problem and no similar studies in this area are given.
Response 1: Thank you for your suggestion. We have accordingly supplemented the related information in the revised manuscript.
Point 2: Materials and methods are not written for the entire list of work performed. There is no description of methods for studying the structure and phase composition. There is no description of equipment for computed x-ray microtomography.
Line 57 shows a temperature of -155°C. Need to correct for a hyphen. After all, the tests were not carried out in the field of cryogenic temperatures?!
Response 2: Thanks for your careful check. Methods for studying structure and phase composition and descriptions of computed X-ray microtomography equipment have been added .Please find it in 2.4. Characterization.
The “-” has been removed.The revised sentences have been highlighted in blue.Please find it in paragraph 5.
Point 3: Not all abbreviations in the text are given transcripts.
Response 3: Thanks for your careful check. All abbreviations in the text are given transcripts.
Point 4: Images.
Figures 6 and 7 does not give a normal idea of the location of the crack formation. You should add a diagram explaining the area shown in the photo.
Figure 9 has small captions. you can enlarge the picture itself and everything will become better.
Response 4: Thank you for your suggestion. We have accordingly revised the corresponding part based on your suggestion.
Point 5: In the first section, the specific purpose of the work performed is not given. The choice of solder material is not quite obvious. Because of this, there are also problems with conclusions.
Response 5: Thank you for your suggestion.The specific purpose of the study and the selection of welding materials have been added.The revised sentences have been highlighted in blue.Please find it in paragraph 2&3.
Point 6: The final part of the conclusions about increasing the reliability of solder joints is not substantiated and not proven in any way. Why even use a solder that tends to form brittle phases that will induce cracking?
In addition, the conclusions should reflect the achievement of the goal set in the work. But for this, it must first be formulated in the introduction.
Response 6: Thank you for your suggestion. We have accordingly revised the corresponding part based on your suggestion. The revised sentences have been highlighted in blue. Please find it in the line 52-56 and 210-223.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The paper seems okay now and can be published.
Reviewer 4 Report
The authors made the necessary corrections to the text of the article and corrected the graphic material.
In its current form, the article can be accepted for publication.
