Self-Assembled Monolayers on Highly Porous Low-k Dielectrics by 3-Aminopropyltrimethoxysilane Treatment
Round 1
Reviewer 1 Report
In the manuscript entitled “Self-Assembled Monolayers on Highly Porous Low-k Dielectrics by 3-Aminopropyltrimethoxysilane Treatment” by Yi-Lung Cheng et al. the authors report properties of the highly porous low-k dielectric film with self-assembled monolayers. Certainly, the paper is worth to publish in Coatings after some corrections in the text. Generally, the results are well described and self-consistent. A large amount of experimental data is presented, however, some of them need to be a comment.
My specific comments are listed below:
1. Please explain in details Figure 9. Figure 9 concludes the whole manuscript, therefore the formation mechanism of SAMs should be provided based on the experimental data.
2. Line 266: should be “ … as shown in Figure 9.”
3. Please provide an explanation of STD in the text.
4. Please provide an explanation of the following abbreviations in figure captions: AMPTMS_1H, AMPTMS_3H. This will help readers to follow the text.
5. How the authors calculate/estimate errors? I think this is crucial to analyze data by readers, especially in Figure 3.
6. The authors should show data/figures/microscope pictures regarding lines 236-247? Why authors do not demonstrate surface morphology from AFM analysis?
Author Response
In the manuscript entitled “Self-Assembled Monolayers on Highly Porous Low-k Dielectrics by 3-Aminopropyltrimethoxysilane Treatment” by Yi-Lung Cheng et al. the authors report properties of the highly porous low-k dielectric film with self-assembled monolayers. Certainly, the paper is worth to publish in Coatings after some corrections in the text. Generally, the results are well described and self-consistent. A large amount of experimental data is presented, however, some of them need to be a comment.
My specific comments are listed below:
1. Please explain in details Figure 9. Figure 9 concludes the whole manuscript, therefore the formation mechanism of SAMs should be provided based on the experimental data.
[Reply] The explanation about the formation mechanism of SAMs had been added in the revised manuscript.
2. Line 266: should be “ … as shown in Fig. 9.”
[Reply] It is typo. The error had been corrected.
3. Please provide an explanation of STD in the text.
[Reply] We had added the explanation for STD in the text.
4. Please provide an explanation of the following abbreviations in figure captions: AMPTMS_1H, AMPTMS_3H. This will help readers to follow the text.
[Reply] We had added the explanation for AMPTMS_1H, AMPTMS_3H in the text.
5. How the authors calculate/estimate errors? I think this is crucial to analyze data by readers, especially in Figure 3.
[Reply] We had added “ The average value and 3 d variation (error bar) were shown”. in the revised text.
6. The authors should show data/figures/microscope pictures regarding lines 236-247? Why authors do not demonstrate surface morphology from AFM analysis?
[Reply] We only showed RMS values determined from AFM analysis in the text, and did not show AFM images because of no significant difference.
Reviewer 2 Report
Manuscript ID: Coatings 465541
Self-Assembled Monolayers on Highly 1 Porous Low-k Dielectrics by 3-Aminopropyltrimethoxysilane Treatment
In this manuscript the authors describe the procedure used to form self-assembled monolayers (SAMs) from treatment with 3-Aminopropyltrimethoxysilane of a highly porous low-k dielectric film. The analysis of the materials were carried out by means of the capacitance-voltage, current-voltage and time-independent-dielectric-breakdown parameters
The materials prepared and analyzed in this paper can be interesting to readers of Coatings, however, several changes should be made before their publication.
Experimental section:
· Page 2, line 79-85: The authors indicate that the samples were heated to 200 ° C to remove the moisture absorbed from the sample. Why 200ºC?, and how long were they subjected to this temperature? But afterwards, the samples are treated for subsequent changes in aqueous solutions of different reagents, to finally be dried again at 200 ° C. Please, detail in the text the objective and the need for each of the steps to which the sample is submitted.
In general, the experimental section should be rewritten and all the experimental methods with their conditions used in the characterization of the samples should be collected in this section (....., AFM, XPS do not appear).
Results and Discussion section:
· Page 3, line 106: Please give more detail of the number of samples were tested in each one of the analysis carried out. This information is necessary in order to verify the veracity of the results. It could be interesting that the authors present statistical analysis of their results.
How many monolayers were deposited in 3h? Were trials conducted with longer times?
Why the selected temperature for the cooling zone was 20 ° C less than the temperature of the heating zone?
· Page 3, caption Figure 1: Please, indicate the meaning of STD
· Page 4, line 130: Where is the 2.74MV/cm value plotted in figure 3?
· Page 5, line 145: Add “Time-Dependent Dielectric Breakdown” before TDDB test.
· Page 5, line 158: As the highly porous low-k dielectric was treated by APTMS in wet solution, positive charges in the form of NH3+ bonds were generated at the film’s surface during the formation of SAMs. Please, I indicated as follows what is indicated. If you take this deduction from other work previously done, please add the reference.
· You are talking about the existence of pores and the effect of them. How has this parameter been evaluated? Please, provide pore size of analyzed samples.
· Page 7, Caption Figure 5: indicate the meaning of the symbols depicted in the foot of figure: “Figure 5. TTFs as a function of the electric-field of highly porous low-k dielectrics without (full symbols) and with (open symbols) AMTMS treatment”
· Page 7, line 190-193: Please, in order to clarify, reformulate the sentence: “Under an electric-field, Cu atoms diffuse into the dielectric film [24]. As Cu atoms exist in the dielectric film, the large size Cu ions catalyzed the bond breakage reaction by inducing permanent bond displacement in the dielectric film, resulting in degraded electrical characteristics and reliability.”
· Page 8, line 223-226: Please, in order to clarify, reformulate the sentence: “The degradation in the dielectric breakdown field caused by annealing maybe resulted from the diffusion of Cu ions into the dielectric. This result demonstrated again that the formation SAMs derived from APTMS treatment slowed down the thermal diffusion of Cu atoms.”
· Conclusion section: The conclusions should be reformulated after the proposed questions have been clarified.
Minor questions:
· Page 2, Line 47: To reemplace “…internally, This provides…” by …internally. This provides”
· Page 6 line 186: Finish with “.” the end of the sentence
· Unify nomenclature for flat-band voltage: page 7, line 196 appears as VFB and in Figure 6 as Vfb.
Comments for author File: 
Comments.pdf
Author Response
Self-Assembled Monolayers on Highly 1 Porous Low-k Dielectrics by 3-Aminopropyltrimethoxysilane Treatment
In this manuscript the authors describe the procedure used to form self-assembled monolayers (SAMs) from treatment with 3-Aminopropyltrimethoxysilane of a highly porous low-k dielectric film. The analysis of the materials were carried out by means of the capacitance-voltage, current-voltage and time-independent-dielectric-breakdown parameters
The materials prepared and analyzed in this paper can be interesting to readers of Coatings, however, several changes should be made before their publication.
Experimental section:
· Page 2, line 79-85: The authors indicate that the samples were heated to 200 ° C to remove the moisture absorbed from the sample. Why 200ºC?, and how long were they subjected to this temperature? But afterwards, the samples are treated for subsequent changes in aqueous solutions of different reagents, to finally be dried again at 200 ° C. Please, detail in the text the objective and the need for each of the steps to which the sample is submitted.
[Reply] In the revised manuscript, we had added the purpose of each step during the sample preparation. Also, we had added the heating time for the heating process.
In general, the experimental section should be rewritten and all the experimental methods with their conditions used in the characterization of the samples should be collected in this section (....., AFM, XPS do not appear).
[Reply] We had added the purpose of each step during the sample preparation. Also, we had added the heating time for the heating process.
Results and Discussion section:
· Page 3, line 106: Please give more detail of the number of samples were tested in each one of the analysis carried out. This information is necessary in order to verify the veracity of the results. It could be interesting that the authors present statistical analysis of their results.
[Reply] All experimental results had been added the number of testing samples.
How many monolayers were deposited in 3h? Were trials conducted with longer times?
Why the selected temperature for the cooling zone was 20 ° C less than the temperature of the heating zone?
[Reply] We had tried deposition times of 1 h and 3 h in AMTMS aqueous solution. The experimental result indicated that 1 hr AMTMS treatment is not enough to provide a better efficiency. A longer time to form SAMs for this proposed method is the main drawback. In the future work, we will find solutions to solve this issue.
· Page 3, caption Figure 1: Please, indicate the meaning of STD
[Reply] We had added the explanation for STD in the text.
· Page 4, line 130: Where is the 2.74MV/cm value plotted in figure 3?
[Reply] It is typo. We had corrected in the revised manuscript.
· Page 5, line 145: Add “Time-Dependent Dielectric Breakdown” before TDDB test.
[Reply] We had added “Time-Dependent Dielectric Breakdown” in the revised manuscript.
· Page 5, line 158: As the highly porous low-k dielectric was treated by APTMS in wet solution, positive charges in the form of NH3+ bonds were generated at the film’s surface during the formation of SAMs. Please, I indicated as follows what is indicated. If you take this deduction from other work previously done, please add the reference.
[Reply] This explanation is confirmed from the result of Fig.8. So, we added (Evidenced as shown in Figure 8) in the text.
· You are talking about the existence of pores and the effect of them. How has this parameter been evaluated? Please, provide pore size of analyzed samples.
[Reply] In the part of experimental, these information had been provided.
” The average pore size and porosity of the resulting highly porous low-k films are around 1.15 nm and 32.0%, respectively, which were determined from the isotherm of ethanol adsorption and desorption using ellipsometric porosimetry.”
· Page 7, Caption Figure 5: indicate the meaning of the symbols depicted in the foot of figure: “Figure 5. TTFs as a function of the electric-field of highly porous low-k dielectrics without (full symbols) and with (open symbols) AMTMS treatment”
[Reply] According to review’s suggestion, We had added these words in the text.
· Page 7, line 190-193: Please, in order to clarify, reformulate the sentence: “Under an electric-field, Cu atoms diffuse into the dielectric film [24]. As Cu atoms exist in the dielectric film, the large size Cu ions catalyzed the bond breakage reaction by inducing permanent bond displacement in the dielectric film, resulting in degraded electrical characteristics and reliability.”
[Reply] The sentences in line 190-193 had been revised.
“Cu easily penetrates into porous low-k dielectrics under thermal or electrical stress. The drifted Cu ion can induce permanent bond displacement and catalyze the bond breakage reaction in the dielectric film, resulting in degraded electrical characteristics and reliability [24, 25].”
· Page 8, line 223-226: Please, in order to clarify, reformulate the sentence: “The degradation in the dielectric breakdown field caused by annealing maybe resulted from the diffusion of Cu ions into the dielectric. This result demonstrated again that the formation SAMs derived from APTMS treatment slowed down the thermal diffusion of Cu atoms.”
[Reply] The sentences in line 223-226 had been revised.
“Thermal annealing easily drives Cu atoms to diffuse into the porous dielectric, thus degrading the dielectric breakdown field. A lower degradation in the highly porous low-k dielectrics with APTMS treatment indicates again that the formation SAMs derived from APTMS treatment slowed down the thermal diffusion of Cu atoms.”
· Conclusion section: The conclusions should be reformulated after the proposed questions have been clarified.
[Reply] The conclusion had been re-written according to the experimental results.
Minor questions:
· Page 2, Line 47: To reemplace “…internally, This provides…” by …internally. This provides”
[Reply] It is typo!! We had corrected it!
· Page 6 line 186: Finish with “.” the end of the sentence
[Reply] We had added it!
· Unify nomenclature for flat-band voltage: page 7, line 196 appears as VFB and in Figure 6 as Vfb.
[Reply] We had corrected it!
Round 2
Reviewer 2 Report
The authors have answered all my comments. For this reason I propose to accept the publication of your revised manuscript
