Process for filling etched holes using photoimageable thermoplastic polymer

Patent metadata

Field	Value
Publication number	US-10329146-B2
Application number	US-201715623267-A
Country	US
Kind code	B2
Filing date	Jun 14, 2017
Priority date	Feb 17, 2015
Publication date	Jun 25, 2019
Grant date	Jun 25, 2019

Abstract

A process for filling one or more etched holes defined in a frontside surface of a wafer substrate. The process includes the steps of: (i) depositing a layer of a photoimageable thermoplastic polymer onto the frontside surface and into each hole; (ii) reflowing the polymer; (iii) selectively removing the polymer from regions outside a periphery of each hole, the selective removing comprising exposure and development of the polymer; (iv) optionally repeating steps (i) to (iii) until each hole is overfilled with the polymer; and (v) planarizing the frontside surface to provide one or more holes filled with a plug of the polymer. Each plug has a respective upper surface coplanar with the frontside surface.

First claim

The invention claimed is:

1. A process for filling one or more etched holes defined in a frontside surface of a wafer substrate, said process comprising the steps of:
(i) depositing a layer of a photoimageable thermoplastic polymer onto the frontside surface and into each hole;
(ii) reflowing the polymer;
(iii) selectively removing the polymer from regions outside a periphery of each hole, the selective removing comprising exposure and development of the polymer;
(iv) optionally repeating steps (i) to (iii) until each hole is overfilled with the polymer; and
(v) planarizing the frontside surface to provide one or more holes filled with a plug of the polymer, each plug having a respective upper surface coplanar with the frontside surface.

2. The process of claim 1 , wherein each hole has a depth of at least 10 microns.

3. The process of claim 1 , wherein each hole has an aspect ratio of >1:1.

4. The process of claim 1 , wherein steps (i) to (iii) are not repeated and each hole is overfilled with the polymer after step (iii).

5. The process of claim 1 , wherein, in step (v), the wafer is planarized by a chemical-mechanical planarization (CMP) process.

6. The process of claim 1 , wherein an extent of overfill of the hole immediately prior to step (v) is less than 12 microns.

7. The process of claim 1 further comprising additional MEMS fabrication steps.

8. The process of claim 7 , wherein the additional MEMS fabrication steps construct inkjet nozzle devices on the planarized surface of the wafer substrate.

9. The process of claim 8 , wherein each nozzle device comprises a nozzle chamber in fluid communication with at least one hole.

10. The process of claim 9 , wherein a respective inlet for each nozzle chamber is defined by one of said holes.

11. The process of claim 10 , further comprising at least one of: wafer thinning and backside etching of ink supply channels.

12. The process of claim 11 , wherein each ink supply channel meets with one or more filled holes.

13. The process of claim 12 , wherein each ink supply channel is relatively wider said one or more holes.

14. The process of claim 13 , further comprising oxidative removal of the polymer from the holes.

15. A process for filling one or more etched holes defined in a frontside surface of a wafer substrate, said process comprising the steps of:
(i) depositing a layer of a photoimageable polymer onto the frontside surface and into each hole;
(ii) selectively removing the polymer from regions outside a periphery of each hole, the selective removing comprising exposure and development of the polymer;
(iii) optionally repeating steps (i) and (ii) until each hole is overfilled with the polymer; and
(iv) planarizing the frontside surface to provide one or more holes filled with a plug of the polymer, each plug having a respective upper surface coplanar with the frontside surface.

16. The process of claim 15 , wherein, in step (iii), the wafer is planarized by a chemical-mechanical planarization (CMP) process.

17. The process of claim 15 , wherein an extent of overfill of the hole immediately prior to step (iii) is less than 12 microns.

18. The process of claim 15 further comprising the step of:
constructing inkjet nozzle devices on the planarized surface of the wafer substrate.

19. The process of claim 18 , wherein each nozzle device comprises a nozzle chamber in fluid communication with at least one hole.

20. The process of claim 19 , wherein a respective inlet for each nozzle chamber is defined by one of said holes.

Assignees

• Memjet Technology Ltd

Inventors

• North Angus
• O'Reilly Ronan
• Mcavoy Gregory

Classifications

• B81C2201/0104

  Chemical-mechanical polishing [CMP] · CPC title

• B81C2201/0121

  involving addition of material followed by removal of parts of said material, i.e. subtractive planarization · CPC title

• B41J2/1639

  sacrificial molding · CPC title

• B81B2203/0353

  Holes · CPC title

• B81C1/00087

  Holes · CPC title