Creep Properties Assessment by Shear Punch Creep Test and IMC Morphology of Aged Pb-Free Solder Joint/UBM

Round 1

Reviewer 1 Report

The article has a high scientific interest. The study is well planned, and the results are very interesting. The graphics are clear and well explained. The conclusions, are a little poor, should be reviewed and completed. In general, it seems an interesting article. It has enough quality to be published.

Author Response

First, we would like to thank the editors and reviewers for careful reading of my submitted manuscript and give the comments and suggestions, which help to enhance the quality of my manuscript for the publication in the Metals journal. According to your comments, the yellow highlights were appeared on the modified or added statements in manuscript. 

Author Response File: Author Response.pdf

Reviewer 2 Report

The scientific interest to readers of this specific topic, materials and temperatures should be justified. Does it become from a collaboration with a private company?

Why the SPT specimen selected has a 3.5mm of diameter hole? Did you considered other geometries?

Does it exist any mechanical parameter of this type of solder joint in bibliography? If so, state it and compare it to your results.

Figure 2 should be completted including a real photo of one test while taking place in the equipament described.

In section 2.2 it is explained how the solder joints are etched, but then in the results there is not any photo shwing it. It Will be interesting to include images of the etching in the results.

It Will be advisable to include macro-images of the specimes after the test in section 3.1, showing the tipe of faylure and, maybe any detail if interesting.

Images in Figures 8 and 9 should be enlarged and clarified.

It can be stated in the conclusions what consequences may have the behaviour observed for industrial applications (if it Will have any).

Author Response

First, we would like to thank the editors and reviewers for careful reading of my submitted manuscript and give the comments and suggestions, which help to enhance the quality of my manuscript for the publication in the Metals journal. According to your comments, the yellow highlights were appeared on the modified or added statements in manuscript. 

Author Response File: Author Response.pdf

Reviewer 3 Report

The paper presents interesting research using miniature specimen technology. The preparation of the specimen and testing the joint interface is quite original. The results are presented and discussed in readable way. No principal comments to the methodology, I have just several comments to formal issues. The authors claim that they use small punch test (ball or hemispherical punch), but they use shear punch test technique (flat punch). The name of the paper and name of the technique must be corrected according to this fact.

see e.g. Guduru et al., Materials Science and Engineering A 395 (2005) 307–314

Formal issues:

- size of the graphs can be increased for better readability

- some references do not match (e.g. line 34 Naveena [7] is Sun et al.) please duble check carefully!

- journal abbreviations and doi are missing in many of the refs. -please format properly

- improve the grammar - proof check by native speaker would be beneficial e.g. line 35 and 36 have to be replaced by an eutectic..., have to replace an eutectic..., line 77 , which were generated... line 125 which is widely used...

- use punch not puncher in the text, in Figs. it is correct.

- add value of  the punch diameter to section 2.2.

- not clear to me what is the difference between region A (in Fig. 2b and B in Fig. 3.

- I cannot find Eq. 2 in the paper [12] which is about small punch test, not shear punch test, so membrane stretching theory is used in [12].

- Eq. 4 is same for both alloys, right column must change according to Fig. 6.

In Fig. 4a the initial displacement is much larger for 49N then 53.9N, which seems not logical. For other creep curves (solders, aging) it is not occurring. The authors should try to explain this phenomenon in the discussion.

If these formalities are corrected the paper is eligible for publication.

Author Response

First, we would like to thank the editors and reviewers for careful reading of my submitted manuscript and give the comments and suggestions, which help to enhance the quality of my manuscript for the publication in the Metals journal. According to your comments, the yellow highlights were appeared on the modified or added statements in manuscript. 

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

The revisions introduced are the ones requested.