Method for producing patterns in a substrate

Patent metadata

Field	Value
Publication number	US-11049724-B2
Application number	US-201816616275-A
Country	US
Kind code	B2
Filing date	May 24, 2018
Priority date	May 24, 2017
Publication date	Jun 29, 2021
Grant date	Jun 29, 2021

Abstract

A method for producing at least one pattern in a substrate is provided, including providing a substrate having a front face surmounted by at least one masking layer carrying at least one mask pattern, carrying out an ion implantation of the substrate so as to form at least one first zone having a resistivity ρ1 less than a resistivity ρ2 of at least one second non-modified zone, after the ion implantation step, immersing the substrate in an electrolyte, and removing the at least one first zone selectively at the at least one second zone, the removing including at least an application of an electrochemistry step to the substrate to cause a porosification of the at least one first zone selectively at the at least one second zone.

First claim

The invention claimed is:

1. A method for structuring a front face of a substrate by producing at least one pattern on the front face of the substrate, the method comprising:
providing a substrate having a front face surmounted by at least one masking layer;
defining at least one mask pattern in the masking layer such that the masking layer comprises adjacent regions having different height levels;
producing an ion implantation of the substrate by the front face and at least to the right of the mask pattern, so as to form at least one first zone modified by implantation and at least one second zone not modified by implantation or less modified than the at least one first zone, the implantation conditions being selected such that after implantation, the at least one first zone has a resistivity ρ1 less than a resistivity ρ2 of the at least one second zone;
removing the masking layer such that the front face of the substrate is stripped; and
at least the following successive steps:
after the ion implantation, immersing the substrate in an electrolyte such that the stripped front face of the substrate is fully in contact with the electrolyte, and
removing the at least one first zone selectively at the at least one second zone so as to form on the front face of the substrate, the at least one pattern of which a geometry is according to the mask pattern, said removing comprising at least an application of an electrochemistry step on the substrate to cause a porosification of the at least one first zone selectively at the at least one second zone, said removing being carried out such that at least during the electrochemistry step, at least one rear face of the substrate opposite the front face has charge carriers.

2. The method according to claim 1 , wherein the ion implantation is carried out such that ρ2≥1.1*ρ1.

3. The method according to claim 1 , wherein the electrochemistry step is carried out such that the porosification leads to a complete detachment of the at least one first zone with respect to the at least one second zone.

4. The method according to claim 1 , wherein the electrochemistry step is carried out such that the porosification does not lead to a complete detachment of the at least one first zone with respect to the at least one second zone, and the removing of the at least one first zone selectively further comprises, after the electrochemistry step, a step of etching the at least one first zone made porous selectively at the at least one second zone.

5. The method according to claim 1 ,
wherein the ion implantation of the substrate is carried out so as to form several zones modified by implantation, and
wherein the electrochemistry step is carried out such that the porosification:
leads to a complete detachment of only some of said formed several zones with respect to the at least one second zone, and
does not lead to a complete detachment of other first zones with respect to the at least one second zone, and the removing of the at least one first zone selectively further comprises, after the electrochemistry step, a step of etching said other first zones.

6. The method according to claim 1 , wherein ions implanted during the ion implantation have an atomic mass greater than an atomic mass of boron.

7. The method according to claim 1 , wherein ions implanted during the ion implantation are chosen from among hydrogen (H)-based ions and helium (He)-based ions.

8. The method according to claim 1 , wherein the ion implantation of the substrate is carried out such that ions are implanted with an energy less than or equal to 150 keV.

9. The method according to claim 1 , wherein the removing the at least one first zone selectively further comprises a selective wet etching of the at least one first zone made porous selectively at the at least one second zone.

10. The method according to claim 9 , wherein the wet etching is carried out in an alkaline environment.

11. The method according to claim 10 , wherein the wet etching is based on one of the following solutions: potassium hydroxide (KOH) or tetramethylammonium hydroxide (TMAH).

12. The method according to claim 1 , wherein the removing the at least one first zone selectively further comprises an illumination of the at least one rear face of the substrate such that the at least one rear face has charge carriers during the electrochemistry step.

13. The method according to claim 12 , wherein the illumination is carried out during the electrochemistry step.

14. The method according to claim 1 , further comprising, before the immersing the substrate in the electrolyte, a step of doping the at least one rear face such that the at least one rear face has charge carriers during the electrochemistry step.

15. The method according to claim 1 , wherein the masking layer is a resin layer, and the step of defining the at least one mask pattern in the masking layer comprises at least one from among: an optical lithography, an electronic lithography, a nano-printing lithography, and a direct self-assembled (DSA) method.

16. The method according to claim 1 , wherein during the ion implantation, the substrate is surmounted on a buffer layer situated between the front face of the substrate and the masking layer.

17. The method according to claim 16 ,
wherein the masking layer comprises carbon atoms, and
wherein the buffer layer is shaped so as to trap the carbon atoms, which would be obtained from the masking layer during the ion implantation.

18. The method according to claim 1 , wherein the defining the at least one mask pattern in the masking layer is carried out such that the masking layer comprises at least one first region having a non-zero height level and at least one second region, adjacent to the first region and having a zero height level, said first and second regions defining, in the masking layer, at least one two-dimensional mask pattern.

19. The method according to claim 1 , wherein the defining the at least one mask pattern in the masking layer is carried out such that the masking layer comprises at least one first region having a first non-zero height level and at least one second region, adjacent to the first region and having a second non-zero height level and different from the non-zero first height level, said first and second regions defining, in the masking layer, at least one three-dimensional mask pattern.

20. The method according to claim 1 , wherein the masking layer is shaped and the ion implantation is carried out so as to form, in the substrate, at least two first adjacent zones and having different and non-zero implantation depths.

21. The method according to claim 1 , wherein during the electrochemistry step, a constant intensity of current passing between an anode formed partially at least by the substrate and a cathode immersed in electrolyte is maintained, an evolution of voltage between the anode and the cathode is monitored, and when a stabilization is detected, deducing that all of the at least one first zone has been made porous.

22. The method according to claim 1 , wherein said pattern formed on the front face of the substrate from the removal step, has dimensions proportional to those of the mask pattern.

23. The method according to claim 1 , configured such that the at least one pattern formed on the front face of the substrate from the removing the at least one first zone selectively is identical to the mask pattern.

24. The method according t

Assignees

• Commissariat Energie Atomique

Inventors

• Nouri Lamia
• Gaillard Frederic-Xavier
• Landis Stefan
• Posseme Nicolas

Classifications

• H10P50/642

  Chemical etching · CPC title

• H10P30/208

  of electrically inactive species · CPC title

• H10P30/204

  into Group IV semiconductors · CPC title

• H10P30/22

  using masks · CPC title

• H10P50/613 Primary

  of Group IV materials · CPC title