Hybrid substrate processing

Patent metadata

Field	Value
Publication number	US-10300557-B2
Application number	US-201715712646-A
Country	US
Kind code	B2
Filing date	Sep 22, 2017
Priority date	Sep 23, 2016
Publication date	May 28, 2019
Grant date	May 28, 2019

Abstract

A hybrid laser modulation and acid etch process for the creation of a patterned substrate. According to some embodiments, a hole is formed in a glass substrate by first modulating a portion of the substrate in the desired shape. A mask is coated on the glass substrate and is patterned to expose the modulated portion. The glass substrate is then acid etched to remove the modulated portion. Once the modulated portion has been etched, the desired shape may be removed from the glass substrate and the mask may be stripped.

First claim

What is claimed is:

1. A method of forming a hole in a substrate comprising material transparent to a laser, the method comprising:
forming a modulated area according to a first predetermined pattern in the substrate by exposing the substrate to a pulsed laser beam according to the first predetermined pattern, wherein the first predetermined pattern defines a perimeter of the hole and surrounds a first portion of the substrate, and wherein a wavelength, power and pulse duration of the laser beam are selected to modify properties of the substrate in the modulated area without ablating the substrate;
depositing a mask over the substrate including the modulated area, the first portion of the substrate and a second portion of the substrate that surrounds the modulated area;
patterning the mask according to a second predetermined pattern that corresponds with the first predetermined pattern to form a patterned mask area;
etching through the mask and the substrate in the patterned mask area;
stripping the mask from the substrate; and
separating the first portion of the substrate from the second portion of the substrate.

2. The method of claim 1 wherein the first portion of the substrate is exposed to pulses from a picosecond laser during the modulating.

3. The method of claim 2 wherein the laser creates a Bessel beam.

4. The method of claim 2 wherein the laser modulates the first portion of the substrate at a power level below an ablation threshold of the substrate.

5. The method of claim 1 wherein modulating the first portion of the substrate changes a refractive index of the first portion of the substrate.

6. The method of claim 1 wherein modulating the first portion of the substrate changes a microstructure of the first portion of the substrate.

7. The method of claim 1 wherein the substrate is transparent.

8. The method of claim 1 wherein etching the first portion of the substrate comprises exposing the substrate to acid.

9. The method of claim 1 further comprising:
etching the second portion of the substrate, wherein the first portion of the substrate etches at a faster rate than the second portion of the substrate.

10. The method of claim 1 wherein the mask is patterned using photolithography.

11. The method of claim 1 wherein the mask comprises a hard mask.

12. The method of claim 1 wherein the mask comprises a photoresist.

13. The method of claim 1 wherein after the first portion of the substrate is separated from the second portion of the substrate, edges of the first and second portion have a smooth curved surface.

14. The method of claim 1 wherein the substrate is glass.

15. The method of claim 1 wherein the laser beam has a collimated portion that is collimated in a focal region and the collimated portion is focused on the substrate.

16. The method of claim 1 further comprising, after the mask is removed from the substrate:
applying force to the substrate at a location within the patterned area to remove a section of the substrate corresponding to the hole.

17. The method of claim 1 wherein the mask comprises a photoresist layer and the patterning comprises a photolithography process.

18. A method of forming a hole in a substrate comprising material transparent to a laser, the method comprising:
forming a modulated area in the substrate according to a first predetermined pattern that defines a perimeter of the hole by exposing the substrate to laser beam pulses from a picosecond laser according to the first predetermined pattern, wherein the laser pulses are shaped with optics into an elongated beam shape focused within the substrate and wherein a wavelength, power and pulse duration of the laser beam are selected to modify properties of the substrate in the modulated area without ablating the substrate;
depositing a mask over the substrate including the modulated area, the first portion of the substrate and a second portion of the substrate that surrounds the modulated area;
patterning the mask according to a second predetermined pattern that corresponds with the first predetermined pattern to form a patterned mask area;
etching through the substrate in the modulated area; and
separating the first portion of the substrate from the second portion of the substrate.

19. The method of claim 18 wherein the laser beam is collimated in a depth of focus between 0.1 to 3 mm.

20. The method of claim 19 wherein forming the modulated region is done with a single pass of the laser along the first predetermined pattern.

21. The method of claim 19 wherein forming the modulated region is done with multiple passes of the laser along the first predetermined pattern, wherein in each of the multiple passes the laser is focused at a different depth of the substrate.

Assignees

• Apple Inc

Inventors

• Gupta Nathan K
• Lancaster-Larocque Simon R
• Sharma Prithu
• Cheng Weibo
• Kangude Abhijit A
• Posner Bryan W
• Jinasundera Sudirukkuge T
• Bir Karan

Classifications

• B23K26/08

  Devices involving relative movement between laser beam and workpiece · CPC title

• B23K26/53 Primary

  for modifying or reforming the material inside the workpiece, e.g. for producing break initiation cracks · CPC title

• B23K26/0622

  by shaping pulses · CPC title

• B23K2103/54

  Glass · CPC title

• B23K26/36 Primary

  Removing material (B23K26/55, B23K26/57 take precedence) · CPC title