Methods of forming a TSV wafer with improved fracture strength

Patent metadata

Field	Value
Publication number	US-9312205-B2
Application number	US-201414195940-A
Country	US
Kind code	B2
Filing date	Mar 4, 2014
Priority date	Mar 4, 2014
Publication date	Apr 12, 2016
Grant date	Apr 12, 2016

Abstract

A method including forming a through-substrate via through a thickness of a substrate, the thickness of the substrate is measured from a front side of the substrate to a back side of the substrate, removing a first portion of the substrate to form an opening in the back side of the substrate such that a second portion of the substrate remains in direct contact surrounding a vertical sidewall of the through-substrate via, and filling the opening with an alternate material having a lower modulus of elasticity than the substrate.

First claim

What is claimed is:

1. A method comprising:
forming through-substrate vias through a thickness of a substrate and forming semiconductor devices on a front side of the substrate, the thickness of the substrate being measured from the front side of the substrate to a back side of the substrate;
removing a first portion of the substrate to form an opening that extends a predetermined depth into the back side of the substrate and that defines a second portion of the substrate, the second portion remaining in direct contact with and laterally surrounding a vertical sidewall of one of the through-substrate vias;
filling the opening with an alternate material having a lower modulus of elasticity than the substrate such that the alternate material extends laterally between adjacent second portions that laterally surround adjacent through-substrate vias, the alternate material being at least as thermally conductive as the substrate; and
polishing the back side of the substrate so that an exposed surface of the alternate material is essentially co-planar with the back side of the substrate.

2. The method of claim 1 , the filling of the opening with the alternate material being carried out at a process temperature less than or equal to 400° C.

3. The method of claim 1 , the alternate material comprising silicon or germanium and being polycrystalline or amorphous.

4. The method of claim 1 , the second portion extending laterally from the vertical sidewall of the one of the through-substrate vias to the alternate material by a distance greater than or equal to a diameter or a width of the through-substrate via.

5. The method of claim 1 , the removing of the first portion of the substrate to form the opening in the back side of the substrate being performed such that the opening has a depth that is less than or equal to approximately 50% of the thickness of the substrate.

6. The method of claim 1 , further comprising: forming metal contacts on the back side of the substrate in direct contact with the through-substrate vias.

7. A method comprising:
forming an array of through-substrate vias through a thickness of a single crystal silicon substrate and forming semiconductor devices on a front side of the single crystal silicon substrate, the through-substrate vias extending vertically from the front side of the substrate to a back side of the substrate;
removing a first portion of the substrate to form an opening that extends a predetermined depth into the back side of the substrate and that defines a second portion of the substrate, the second portion containing the array and remaining in direct contact with and laterally surrounding vertical sidewalls of the through-substrate vias;
filling the opening with an alternate material to improve a durability of the single crystal silicon substrate and reduce a potential for cracking during fabrication, the alternate material having a lower modulus of elasticity than the single crystal silicon substrate; and
polishing the back side of the substrate so that an exposed surface of the alternate material is essentially co-planar with the back side of the substrate.

8. The method of claim 7 , the filling of the opening with the alternate material being carried out at a process temperature less than or equal to 400° C.

9. The method of claim 7 , the alternate material comprising silicon or germanium and being polycrystalline or amorphous.

10. The method of claim 7 , the alternate material being at least as thermally conductive as the single crystal silicon substrate.

11. The method of claim 7 , the alternate material being physically separated from any of the through-substrate vias by a distance greater than or equal to a diameter or a width of the through-substrate vias.

12. The method of claim 7 , further comprising:
forming metal contacts on the back side of the substrate in direct contact with the through-substrate vias.

13. A method comprising:
forming through-substrate vias through a thickness of a substrate and forming semiconductor devices on a front side of the substrate, the thickness of the substrate being measured from the front side of the substrate to a back side of the substrate;
removing a first portion of the substrate to form an opening that extends a predetermined depth into the back side of the substrate and that defines a second portion of the substrate,
the second portion remaining in direct contact with and laterally surrounding a vertical sidewall of one of the through-substrate vias such that the vertical sidewall is physically separated from the opening by a distance that is at least equal to a width of the through-substrate via, and
the predetermined depth being approximately one-half the thickness of the substrate;

filling the opening with an alternate material having a lower modulus of elasticity than the substrate such that the alternate material extends laterally between adjacent second portions that laterally surround adjacent through-substrate vias, the alternate material being at least as thermally conductive as the substrate; and
polishing the back side of the substrate so that an exposed surface of the alternate material is essentially co-planar with the back side of the substrate.

14. The method of claim 13 , the filling of the opening with the alternate material being carried out at a process temperature less than or equal to 400° C.

15. The method of claim 13 , the alternate material comprising silicon and being polycrystalline or amorphous.

16. The method of claim 13 , the alternate material comprising aerogel.

17. The method of claim 13 , the alternate material comprising a metal.

18. The method of claim 13 , further comprising: forming metal contacts on the back side of the substrate in direct contact with the through-substrate vias and physically separated from the alternate material.

Assignees

• IBM

Inventors

• Adkisson James W
• Amoah Yoba
• Gambino Jeffrey P
• Leggett Christine A
• Lifson Max L
• Musante Charles F
• Samala Sruthi
• Thomas David C

Classifications

• H10W20/0245

  comprising use of blind vias during the manufacture · CPC title

• H10W20/2125

  Top-view shapes · CPC title

• H10W20/217

  comprising ring-shaped isolation structures outside of the via holes · CPC title

• H10W42/121

  protecting against mechanical damage (H10W76/00, H10W74/00 take precedence) · CPC title

• H10W20/425

  Barrier, adhesion or liner layers · CPC title