Functionalized Three-Dimensional Multilayer Ceramic Modules

Round 1

Reviewer 1 Report

The presented technology enables  complex sensor integration in confined
spaces under rough operation conditions. This functional expansion will open new markets for LTCC multilayer circuits in the future. 

I would say this paper is interesting with nice modeling and fabrication data. I suggeste accept with minor revisions, which the author can add more refrences and illustrated more on its potential applications.

Author Response

Dear Mr. or Mrs. Reviewer,

first of all, I would like to thank you for your time and critical comments. You helped me a lot to improve my manuscript. Many Thanks.

I have completely revised the manuscript due to the many points of criticism.Some areas have been crossed out and a reorganization was necessary.I have therefore not marked the corrected passages.That would have been too confusing.I have completely rebuilt the document.

Please see the corrected version of the paper in the attachment.

Manja Kloska

Author Response File: Author Response.pdf

Reviewer 2 Report

Report on paper "Functionalized 3-Dimensional Multilayer Ceramic Modules" submitted by Kloska et al., for publication in Electronics (electronics-1003721).

The authors reported the possibility of producing and assembling a three dimensional fully functional LTCC substrate. The paper is interesting, globally well written and the presented technology may have a significant impact in the field of LTCC multilayer circuits. The paper can be improved by addressing the following comments:

1. In the introduction, the literature survey lacks of references in the field of 3D LTCC structures and circuits, a topic that has been investigated in the recent past
2. The originality of the presented work should be highlighted with respect to the literature at the end of the introduction.
3. In subsection 3.3, the impact of manual assembly of the device reliability should be discussed.
4. A comparison of the obtained results with respect to the state of the art in terms of technology advantages and limitations could strengthen the highlight of this work.
5. The references to the figures in the text should be fixed.
6. The quality of several figures should be enhanced.

Author Response

Dear Mr. or Mrs. Reviewer,

first of all, I would like to thank you for your time and critical comments. You helped me a lot to improve my manuscript. Many Thanks.

I have completely revised the manuscript due to the many points of criticism.Some areas have been crossed out and a reorganization was necessary.I have therefore not marked the corrected passages.That would have been too confusing.I have completely rebuilt the document.

Please see the corrected version of the paper in the attachment.

Manja Kloska

Author Response File: Author Response.pdf

Reviewer 3 Report

The idea of electronic devices on bended LTCC substrates is know and can be found on the research literature. Nevertheless, the manufacturing process involves a lot of troubles that have to be solved, thus the manuscript submitted for review is important. I am especially impressed with the final result presented in the Figure 11. Although research in this area is welcome, the paper is written on a very low level, full of understatements and general expressions.

The description of the experiment assumptions and investigation set-up is very limited. For example, in lines 90-97 we read that the Authors performed a lot of research and developed test samples of the level 2 but they did not revealed any details. The reader can only find general conclusions (both in Section 2.1 as well as in Section 3.2) without confirmation by any results. The Authors should clarify the following issues:

--- they have used “variant metals” for metallization – what kind of metals (what kind of pastes)?;

--- “different geometric dimension” – the patterns should be presented in a figure, I think that it is perhaps describe in the line 96 and 97 (and also something in line 102) but it is still not enough;

--- “different bending radii” were taken into consideration – according to Section 2.2 only samples with radius of 22.5 mm were tested, thus what about the other results?; what were kind of substrates taken into considerations?;

--- “the behaviour of the metallization is examined” – there are not any results of these examinations;

--- what is “the optimal conductor track”? – please describe it by details, not by general statements;

--- “gold metallization was examined for the possibility of using bond connections” – what kind of examinations were performed, what are the results?;

--- “it has an influence on the mechanical stability” – how was it examined; what are the results?

--- the Authors sate that trace with at least 200 microns is required – what is its thickness?; how does the thickness influences results of bending experiments?; why was the trace 200 microns choosen - maybe the trace of 220 microns would was better?;

--- the Authors say that they examined test samples of level two after sintering by X-ray imaging - they should attach the results (images) of the examinations that confirm the written conclusions.

As it can be seen, the Authors claim to have performed multitude of very interesting investigations that could be enough for just one paper, but apart from general conclusions I could not find any confirmatory results in the manuscript. The same remarks I have also according to tests on the sample groups of level 3, 4, 5. Also involved experiments and conclusions are described very inaccurately.

Example of the inaccuracies:

--- The Authors write: “the connection of the inner vias to the conductor tracks is also considered” - in what a way, where are the results and conclusions of the examinations?

--- The Authors write: “the metalized samples were measured electrically with a multimeter” - where are the results and what are conclusions?

The English style is very poor. There is a lot of repeated information in the paper (e.g. please compare the two sentences in the line 60 – 64 or 241-249 with 250/259). There are a lot of grammar mistakes in the text. “The substrates is processed in 4 stages.”; “Table 1. overview”, etc.

There are also some inconsistencies, e.g.
- the Authors should distinguished the name of laminating step and the name of the next step involved with shaping the curvature of the substrate;

- what is the difference between the second upper mold (line 66) and matching quart-glass inlay (81);

- what do the Authors mean by “theoretical design” (line 135).

Additional remarks:

 --- there is no reference to Table 1 in the text – the Authors should introduce an ordering description of Table 1 contents;

--- instead of the references, I see only "Error! Reference source not found";

--- Figure 9 and 10 are illegible, the descriptions in Figure 9 do not correspond to the description in the text.

Symbols are wrong format. It is important to use appropriate typefaces according to the sense of symbols: variables in italics, vectors and matrices in bold letters, functions and abbreviations in upright letters, etc. The Authors should consequently insert space between the value and its unit. The rules should be applied to the text, tables as well as to figures.

Author Response

Dear Mr. or Mrs. Reviewer,

first of all, I would like to thank you for your time and critical comments. You helped me a lot to improve my manuscript. Many Thanks.

I have completely revised the manuscript due to the many points of criticism.Some areas have been crossed out and a reorganization was necessary.I have therefore not marked the corrected passages.That would have been too confusing.I have completely rebuilt the document.

Replying to your comments:

The description of the experiment assumptions and investigation set-up is very limited. For example, in lines 90-97 we read that the Authors performed a lot of research and developed test samples of the level 2 but they did not revealed any details. The reader can only find general conclusions (both in Section 2.1 as well as in Section 3.2) without confirmation by any results. The Authors should clarify the following issues:

--- they have used “variant metals” for metallization – what kind of metals (what kind of pastes)?;

I improved this point and you can find a table in the document showing all used materials.

--- “different geometric dimension” – the patterns should be presented in a figure, I think that it is perhaps describe in the line 96 and 97 (and also something in line 102) but it is still not enough;

I cut it out. This was really too much.

--- “different bending radii” were taken into consideration – according to Section 2.2 only samples with radius of 22.5 mm were tested, thus what about the other results?; what were kind of substrates taken into considerations?;

In this paper the results of the substrates with a radius r = 22,5 mm shown. I took measurements in the way that I measured the surface of the LTCC substrate with the faro arm. The result from the faro arm was a dxf-file that contains millions of points matched to a geometric shape. This shape is the compared virtually compared with the theoretically designed shape and the deviations are highlighted in color. 

--- “the behaviour of the metallization is examined” – there are not any results of these examinations;

In this point I mean I tried to get reliable conductor tracks with enough paste material for bending. In the beginning the conductor tracks cracked during bending into concave shape and they formed wave-like faults during bending into convex shape.

--- “gold metallization was examined for the possibility of using bond connections” – what kind of examinations were performed, what are the results?;

I added more information in the paper.

--- the Authors sate that trace with at least 200 microns is required – what is its thickness?; how does the thickness influences results of bending experiments?; why was the trace 200 microns choosen - maybe the trace of 220 microns would was better?

Please see the corrected version of the paper in the attachment.

Manja Kloska

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Although the authors have addressed most of my comments, they could extend and improve the quality of the introduction.

Author Response

Dear Reviewer, Thank you very much for your time and criticism of my manuscript. I have accepted the comments and I revised the manuscript and marked my corrections as follows:

Deletions are still included as strikethrough text e.g. delete something.

Insertions are marked in green.

The introduction has been completely revised.

Sincerely yours Manja Kloska

Author Response File: Author Response.pdf

Reviewer 3 Report

At the second round of the reviewing process I have obtained totally different manuscript, especially in the text content. I like this much more than the previous version, although the Authors did not address most of my doubts included in the first review. Nevertheless, I have still some remarks. The manuscript is still too general and in my opinion some details and results of conducted experiments (that I mentioned in the first review) should be included in it. But even in the present form it is worth to publish it.

My additional remarks

-- The Authors should reveal the thickness of the conductive layer (paths/tracks have: thickness, width and length). In the paper the word thickness is used improperly – the technical paper must be very precise.

-- On what number of test samples the failure rate was determined (lines from 177 – 198) - the more detailed description of the experiment and its results is welcome. Let the reader to assess the validity of the conclusions for himself.

-- The Introduction should be improved significantly.

-- Some grammar and punctuation mistakes are still in the text.

-- Instead of the references to Table 1, I see only "Error! Reference source not found".

-- Symbols are wrong format. It is important to use appropriate typefaces according to the sense of symbols: variables in italics, vectors and matrices in bold letters, functions and abbreviations in upright letters, etc. The Authors should consequently insert space between the value and its unit. The rules should be applied to the text, tables as well as to figures.

-- Please check in "For Authors/MDPI Style Guide - section 6.5" how to write equations.

-- Please check in "For Aauthors/MDPI Style Guide - section 7" how to refer to figures and tables.

-- The citation should be in order of their appearances.

-- The Authors use three forms of spelling the phrase: freefrorm (in keywords) sintering, free-form sintering (in text), free-form-sintering (in figure capture).

-- Letters (a), (b), (c) should be used instead of "left, middle, right" in Figure 7.

-- I think that in the line 168 the level 3 of the experiment is discussed instead level 1.

-- I think that in the line 186 the level 3 of the experiment is discussed instead level 2.

-- There is no (C) point in the caption of Figure 1.

-- I cannot see the unit of resistances in Table 3.

Please do not change the entire text again, just make some improvements, in my opinion that should be enough. 

Author Response

Dear Reviewer, Thank you very much for your time and criticism of my manuscript.

I revised the manuscript and marked my corrections as follows:

Deletions are still included as strikethrough text e.g. delete something.

Insertions are marked in green.

The introduction has been completely revised.

To your remark: "the manuscript is still too general" I would like to tell you: you are right, this paper is very general. This research field is not just vias in bended substrates, it is very complex and this complexity should be represented. Further publications will follow in future wherein the individual aspects will be examined more precisely. But it is important to us to show the complexity of the investigation.

I corrected all the other remarks and hope to answer your expectations.

Sincerely yours 

Manja Kloska