Precise-Aligned Lock-And-Key Bonding Structures

a lock-and-key bonding and precise alignment technology, applied in the direction of manufacturing tools, non-electric welding apparatus, capacitors, etc., can solve the problems of poor bonding between structures, damage/poor bonding, and weak bonding,

Inactive Publication Date: 2014-03-06
INT BUSINESS MASCH CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

This approach effectively minimizes misalignment and enhances bonding quality by allowing the tapered vias and domed studs to automatically correct positioning, resulting in reliable Cu-to-Cu bonding.

Problems solved by technology

One drawback to conventional Cu-to-Cu bonding techniques is that any amount of misalignment between the Cu interconnect structures can lead to damaged / poor bonding between the structures, and potentially even to failure of the bond.
If the pads are misaligned, e.g., the face of one pad is shifted to the left or to the right relative to the face of the other pad, then the bonding might be adversely affected.
Specifically, the misalignment can cause a portion of the pads to not make contact with each other.
Even worse, if the misalignment is severe enough, then the pads might encounter other structures when being brought together, further compromising the bond.

Method used

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  • Precise-Aligned Lock-And-Key Bonding Structures
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  • Precise-Aligned Lock-And-Key Bonding Structures

Examples

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Embodiment Construction

[0031]Provided herein are techniques for copper (Cu)-to-Cu bonding that involve employing a lock-and-key design between bonding structures (i.e., wafers). FIGS. 1-9 present a first exemplary lock-and-key configuration and illustrate how that configuration can minimize or eliminate misalignment of the bonding structures. For example, FIG. 1 is a cross-sectional diagram illustrating a first bonding structure 102 having Cu pad 104 embedded in an insulator (i.e., in an oxide). As will become apparent from the following description, the techniques presented herein involve the fabrication of two separate bonding structures that are then bonded together using Cu-to-Cu bonding. To schematically illustrate the process, each wafer is considered to have a top surface (or face) that includes Cu structures (i.e., Cu pads / studs) used in the bonding and a bottom surface (or back) opposite the top surface. In some implementations of the present techniques (see, for example, FIGS. 1-9 and 10-16), on...

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Abstract

Copper (Cu)-to-Cu bonding techniques are provided. In one aspect, a bonding method is provided. The method includes the following steps. A first bonding structure is provided having at least one copper pad embedded in a first insulator and at least one via in the first insulator over the copper pad, wherein the via has tapered sidewalls. A second bonding structure is provided having at least one copper stud embedded in a second insulator, wherein a portion of the copper stud is exposed for bonding and has a domed shape. The first bonding structure is bonded to the second bonding structure by way of a copper-to-copper bonding between the copper pad and the copper stud, wherein the via and the copper stud fit together like a lock-and-key. A bonded structure is also provided.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S)[0001]This application is a continuation of U.S. application Ser. No. 12 / 780,086 filed on May 14, 2010, the disclosure of which is incorporated by reference herein.FIELD OF THE INVENTION[0002]The present invention relates to copper (Cu)-to-Cu bonding techniques and more particularly, to Cu-to-Cu bonding techniques that employ a lock-and-key design to minimize or eliminate misalignment during bonding.BACKGROUND OF THE INVENTION[0003]Copper (Cu)-to-Cu bonding is a technique commonly used to form interconnects in electronic device structures. One drawback to conventional Cu-to-Cu bonding techniques is that any amount of misalignment between the Cu interconnect structures can lead to damaged / poor bonding between the structures, and potentially even to failure of the bond.[0004]For example, the Cu interconnect structures can include complementary Cu pads that are brought together and bonded by way of a compression bond. If the pads are misaligned,...

Claims

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Application Information

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Patent Type & AuthorityApplications(United States)
IPC IPC(8): H01L23/00
CPCH01L24/81H01L24/14H01L24/03B23K20/02H01L2224/0401H01L2224/8114B23K2101/38B23K2103/12
InventorCHEN, KUAN-NENGLIU, FEI
OwnerINT BUSINESS MASCH CORP