Method of Processing a Silicon Carbide Containing Crystalline Substrate, Silicon Carbide Chip, and Processing Chamber

• US 20190308274A1
• Filed: 04/03/2019
• Published: 10/10/2019
• Est. Priority Date: 04/04/2018
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Roesner, Michael, Menath, Markus, Stranzl, Gudrun
• Granted Patent: US 11,077,525 B2
• Time in Patent Office: Days
• CPC Class Codes: B23K 2101/34 Coated articles , e.g. plated or painted; Surface treated articles
• CPC Class Codes: B23K 2101/40 Semiconductor devices
• CPC Class Codes: B23K 2103/56 semiconducting
• CPC Class Codes: B23K 26/0006 taking account of the properties of the material involved B23K26/32, B23K26/40 take precedence
• CPC Class Codes: B23K 26/0624 using ultrashort pulses, i.e. pulses of 1ns or less
• CPC Class Codes: B23K 26/0661 disposed on the workpiece
• CPC Class Codes: B23K 26/082 Scanning systems, i.e. devices involving movement of the laser beam relative to the laser head
• CPC Class Codes: B23K 26/127 in an enclosure
• CPC Class Codes: B23K 26/359 by providing a line or line pattern, e.g. a dotted break initiation line
• CPC Class Codes: B23K 26/362 Laser etching
• CPC Class Codes: B23K 26/364 for making a groove or trench, e.g. for scribing a break initiation groove
• CPC Class Codes: B23K 26/40 taking account of the properties of the material involved
• CPC Class Codes: B23K 26/402 involving non-metallic material, e.g. isolators
• CPC Class Codes: C30B 29/36 Carbides
• CPC Class Codes: C30B 33/00 After-treatment of single crystals or homogeneous polycrystalline material with defined structure C30B31/00 takes precedence
• CPC Class Codes: C30B 33/08 Etching
• CPC Class Codes: H01L 21/02019 Chemical etching
• CPC Class Codes: H01L 21/30604 Chemical etching
• CPC Class Codes: H01L 21/3065 Plasma etching; Reactive-ion etching
• CPC Class Codes: H01L 21/67069 for drying etching
• CPC Class Codes: H01L 21/6708 : using mainly spraying means, e.g. nozzles
• CPC Class Codes: H01L 21/6719 : characterized by the construction of the processing chambers, e.g. modular processing chambers
• CPC Class Codes: H01L 21/68764 : characterised by a movable susceptor, stage or support, others than those only rotating on their own vertical axis, e.g. susceptors on a rotating caroussel
• CPC Class Codes: H01L 21/78 : with subsequent division of the substrate into plural individual devices cutting to change the surface-physical characteristics or shape of semiconductor bodies H01L21/304
• CPC Class Codes: H01L 29/1608 : Silicon carbide

Abstract

A method of processing silicon carbide containing crystalline substrate is provided. The method includes pyrolyzing a surface of the silicon carbide containing crystalline substrate to produce a silicon and carbon containing debris layer over the silicon carbide containing crystalline substrate, and removing the silicon and carbon containing debris layer, wherein the pyrolyzing and the removing is repeated at least once.

Claims

1. A method of processing silicon carbide containing crystalline substrate, the method comprising:

pyrolyzing a surface of the silicon carbide containing crystalline substrate to produce a silicon and carbon containing debris layer over the silicon carbide containing crystalline substrate; and

removing the silicon and carbon containing debris layer,

wherein the pyrolyzing and the removing is repeated at least once.

2. The method of claim 1, wherein the pyrolyzing comprises supplying energy to the surface.

3. The method of claim 2, wherein the energy is supplied to the surface with an intensity in a range from about 1 J/cm² to less than 10 J/cm².

4. The method of claim 2, wherein the energy is supplied to the surface using at least one energy supply device.

5. The method of claim 4, wherein supplying energy to the surface comprises moving the at least one energy supply device relative to the silicon carbide containing crystalline substrate or vice-versa.

6. The method of claim 5, wherein moving the at least one energy supply device comprises a combination of scanning and stepping the at least one energy supply device across the silicon carbide containing crystalline substrate, such that the pyrolyzed surface comprises one or more areas of pyrolyzed silicon carbide adjacent to unpyrolyzed areas of silicon carbide.

7. The method of claim 6, wherein the silicon carbide containing crystalline substrate is a silicon carbide wafer comprising a plurality of chips, and wherein the one or more areas of pyrolyzed silicon carbide are located in predefined separation regions between the plurality of chips.

8. The method of claim 1, wherein the repeating at least once comprises repeating the pyrolyzing and the removing until an opening formed in the silicon carbide containing crystalline substrate by the pyrolyzing and the removing extends completely through the silicon carbide containing crystalline substrate.

9. The method of claim 1, wherein the pyrolyzing comprises irradiating the surface with laser light.

10. The method of claim 1, wherein the pyrolyzing comprises micro-spark eroding the surface.

11. The method of claim 10, wherein micro-spark eroding the surface comprises arranging at least one wire above the surface.

12. The method of claim 10, wherein micro-spark eroding the surface comprises arranging a plurality of wires above the surface.

13. The method of claim 12, wherein the plurality of wires are arranged as a grid.

14. The method of claim 12, wherein the silicon carbide containing crystalline substrate is a silicon carbide wafer comprising a plurality of chips, and wherein the plurality of wires is arranged above predefined separation regions between the plurality of chips.

15. The method of claim 1, wherein removing the silicon and carbon containing debris layer comprises etching with an etchant suitable for removing the silicon and carbon containing debris layer.

16. The method of claim 15, wherein the etching comprises plasma etching or wet etching.

17. The method of claim 16, wherein the etchant comprises Ar, O₂, and SF₆.

18. The method of claim 1, wherein the silicon carbide containing crystalline substrate is a silicon carbide wafer comprising a plurality of chips, the wafer having a front side comprising active areas of the plurality of chips, and a back side opposite the front side.

19. The method of claim 18, further comprising:

mounting the silicon carbide wafer on a carrier with the front side facing the carrier,

wherein pyrolyzing the surface and the removing the silicon and carbon containing debris layer are performed on the back side of the wafer.

20. The method of claim 18, further comprising:

mounting the silicon carbide wafer on a carrier with the back side facing the carrier,

wherein pyrolyzing the surface and the removing the silicon and carbon containing debris layer are performed on the front side of the wafer.

21. The method of claim 1, further comprising:

arranging a structured mask layer over the silicon carbide containing crystalline substrate, the structured mask layer being configured to mask at least one region of the silicon carbide containing crystalline substrate from an etchant used to remove the silicon and carbon containing debris layer.

22. The method of claim 21, wherein arranging the structured mask layer comprises arranging an unstructured mask layer over the silicon carbide containing crystalline substrate and structuring the unstructured mask layer using a laser, wherein the laser is further used for the pyrolyzing of the surface.

23. The method of claim 1, wherein pyrolyzing the surface and the removing the silicon and carbon containing debris layer are performed in a common process chamber.

24. The method of claim 1, wherein the pyrolyzing is configured to produce the silicon and carbon containing debris layer with a thickness of between 1 μ

m and 10 μ

m.

25. A processing chamber, comprising:

an energy supply device configured to pyrolyze a surface of a silicon carbide containing crystalline substrate to produce a silicon and carbon containing debris layer over the silicon carbide containing crystalline substrate; and

a removing device configured to remove the silicon and carbon containing debris layer,

wherein the processing chamber is further configured to repeat the pyrolyzing and the removing at least once.

26. The processing chamber of claim 25, wherein the processing chamber is further configured to have the silicon carbide containing crystalline substrate remain in the processing chamber between the pyrolyzing and the removing.

27. The processing chamber of claim 25, wherein the removing device is an etching device.

28. The processing chamber of claim 25, wherein the energy supply device comprises at least one laser or a micro-spark erosion device.

29. The processing chamber of claim 25, further comprising a moveable substrate support structure configured to move the silicon carbide containing crystalline substrate from a position for the pyrolyzing to a position for the etching and vice-versa.

30. The processing chamber of claim 29, wherein the moveable substrate support structure is further configured to move the silicon carbide containing crystalline substrate during the pyrolyzing in order to scan the energy supply device across the silicon carbide containing crystalline substrate.

31. A silicon carbide chip, comprising:

a first main surface;

a second main surface opposite the first main surface; and

a side surface connecting the first main surface and the second main surface,

wherein the side surface is essentially orthogonal to the first main surface and/or to the second main surface,

wherein at least a portion of the side surface has an undulating shape in a direction from the first main surface to the second main surface.