Wafer to Wafer Bonding Process and Structures

Patent metadata

Field	Value
Publication number	US-2016190089-A1
Application number	US-201514712729-A
Country	US
Kind code	A1
Filing date	May 14, 2015
Priority date	Dec 26, 2014
Publication date	Jun 30, 2016
Grant date	—

Abstract

Bonded structures and method of forming the same are provided. A conductive layer is formed on a first surface of a bonded structure, the bonded structure including a first substrate bonded to a second substrate, the first surface of the bonded structure being an exposed surface of the first substrate. A patterned mask having first openings and second openings is formed on the conductive layer, the first openings and the second openings exposing portions of the conductive layer. First portions of first bonding connectors are formed in the first openings and first portions of second bonding connectors are formed in the second openings. The conductive layer is patterned to form second portions of the first bonding connectors and second portions of the second bonding connectors. The bonded structure is bonded to a third substrate using the first bonding connectors and the second bonding connectors.

First claim

What is claimed is:

1 . A method comprising:
forming a conductive layer on a first surface of a bonded structure, the bonded structure comprising a first substrate bonded to a second substrate, the first surface of the bonded structure being an exposed surface of the first substrate; forming a patterned mask on the conductive layer, the patterned mask comprising first openings and second openings, the first openings and the second openings exposing portions of the conductive layer; forming first portions of first bonding connectors in the first openings and first portions of second bonding connectors in the second openings; patterning the conductive layer to form second portions of the first bonding connectors and second portions of the second bonding connectors, wherein the first portions of the first bonding connectors and the first portions of the second bonding connectors are used as a mask; and bonding the bonded structure to a third substrate using the first bonding connectors and the second bonding connectors, wherein the first bonding connectors and the second bonding connectors extend through third openings formed on a front side of the third substrate and contact conductive features exposed by the third openings.

2 . The method of claim 1 , wherein the first substrate is a MEMS wafer and the second substrate is a cap wafer.

3 . The method of claim 2 , wherein the third substrate is a CMOS wafer.

4 . The method of claim 1 , wherein the first bonding connectors form a bond ring.

5 . The method of claim 4 , wherein the second bonding connectors are enclosed by the bond ring.

6 . The method of claim 1 , wherein after bonding the bonded structure to the third substrate, the first portions of the first bonding connectors extend along sidewalls of respective second portions of the first bonding connectors.

7 . The method of claim 1 , wherein a thickness of the first bonding connectors is substantially same as a thickness of the second bonding connectors.

8 . A method comprising:
forming first protruding features and second protruding features on a backside of a first substrate; forming a first conductive material on the first protruding features and the second protruding features; forming first portions of first bonding connectors on the first protruding features; forming first portions of second bonding connectors on the second protruding features; patterning the first conductive material to form second portions of the first bonding connectors and second portions of the second bonding connectors, wherein the first portions of the first bonding connectors and the first portions of the second bonding connectors are used as a mask; and bonding a second substrate to the first substrate using the first bonding connectors and the second bonding connectors.

9 . The method of claim 8 , wherein forming the first portions of the first bonding connectors comprises:
forming a first patterned mask on the first conductive material, the first patterned mask having first openings therein, the first openings exposing portions of the first conductive material disposed on the first protruding features; forming a second conductive material in the first openings, the second conductive material being different from the first conductive material; and removing the first patterned mask.

10 . The method of claim 9 , wherein forming the first portions of the second bonding connectors comprises:
forming a second patterned mask on the first conductive material, the second patterned mask having second openings therein, the second openings exposing portions of the first conductive material disposed on the second protruding features; forming the second conductive material in the second openings; and removing the second patterned mask.

11 . The method of claim 8 , wherein the first bonding connectors form a bond ring.

12 . The method of claim 11 , wherein the second bonding connectors are enclosed by the bond ring.

13 . The method of claim 8 , further comprising, before bonding the second substrate to the first substrate, forming third openings and fourth openings on a front surface of the second substrate, the third openings exposing first conductive features and the fourth openings exposing second conductive features.

14 . The method of claim 13 , wherein the first bonding connectors extend into the third openings and contact the first conducive features, and wherein the second bonding connectors extend into the fourth openings and contact the second conducive features.

15 . A method comprising:
patterning a back surface of a first substrate to form first protruding features and second protruding features; forming second portions of first bonding connectors on the first protruding features and second portions of second bonding connectors on the second protruding features; forming first portions of the first bonding connectors on the second portions of the first bonding connectors and first portions of the second bonding connectors on the second portions of the second bonding connectors; and bonding a second substrate to the first substrate using the first bonding connectors and the second bonding connectors.

16 . The method of claim 15 , wherein forming the second portions of the first bonding connectors and the second portions of the second bonding connectors comprises:
sputtering a first conductive material on the first protruding features and the second protruding features; and patterning the first conductive material.

17 . The method of claim 16 , wherein forming the first portions of the first bonding connectors and the first portions of the second bonding connectors comprises forming a second conductive material on the first conductive material by an electroless plating method, the second conductive material being different from the first conductive material.

18 . The method of claim 15 , wherein a thickness of the first bonding connectors is substantially same as a thickness of the second bonding connectors.

19 . The method of claim 15 , wherein the first bonding connectors form a bond ring.

20 . The method of claim 19 , wherein the second bonding connectors are bond pads, the bond pads being enclosed by the bond ring.

Assignees

• Taiwan Semiconductor Mfg

Inventors

• Yu Chen-Hua
• Chen Ming-Fa
• Tsai Wen-Ching

Classifications

• H10W99/00

  Subject matter not provided for in other groups of this subclass · CPC title

• H10W90/794

  between a chip and a stacked insulating package substrate, interposer or RDL · CPC title

• H10W90/734

  between a chip and a stacked insulating package substrate, interposer or RDL · CPC title

• H10W90/732

  between stacked chips · CPC title

• H10W90/722

  between stacked chips · CPC title