Apparatus for molecular adhesion bonding with compensation for radial misalignment

• US 9,818,614 B2
• Filed: 08/07/2015
• Issued: 11/14/2017
• Est. Priority Date: 07/07/2010
• Status: Active Grant

• Current Assignee: Sony Semiconductor Solutions Corporation (Sony Group Corp.)
• Original Assignee: Sony Semiconductor Solutions Corporation (Sony Group Corp.)
• Inventors: Gaudin, Gweltaz
• Primary Examiner(s): Koch, George
• Application Number:
  US14/820,729
• Publication Number:
  US 20150348933A1
• Time in Patent Office: 830 Days
• Field of Search: 156297, 156299, 156 64, 438 14, 438 16, 438457
• CPC Class Codes: B32B 2041/04 Detecting wrong registration, misalignment, deviation, failure
• CPC Class Codes: B32B 2307/202 Conductive
• CPC Class Codes: B32B 2309/72 For measuring or regulating, e.g. systems with feedback loops
• CPC Class Codes: B32B 2457/14 Semiconductor wafers
• CPC Class Codes: B32B 37/144 using layers with different mechanical or chemical conditions or properties, e.g. layers with different thermal shrinkage, layers under tension during bonding constructional features for tensioning B32B38/1825
• CPC Class Codes: B32B 37/18 involving the assembly of discrete sheets or panels only
• CPC Class Codes: B32B 38/1808 characterised by the laying up of the layers
• CPC Class Codes: B32B 38/1866 conforming the layers or laminate to a convex or concave profile
• CPC Class Codes: B32B 41/00 Arrangements for controlling or monitoring lamination processes; Safety arrangements
• CPC Class Codes: H01L 21/185 Joining of semiconductor bodies for junction formation
• CPC Class Codes: H01L 21/187 by direct bonding
• CPC Class Codes: H01L 2224/08146 the bonding area connecting to a via connection in the body
• CPC Class Codes: H01L 2224/75702 in the upper part of the bonding apparatus, e.g. in the bonding head
• CPC Class Codes: H01L 2224/75703 Mechanical holding means
• CPC Class Codes: H01L 2224/75756 in the upper part of the bonding apparatus, e.g. in the bonding head
• CPC Class Codes: H01L 2224/75901 using a computer, e.g. fully- or semi-automatic bonding
• CPC Class Codes: H01L 2224/80 Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
• CPC Class Codes: H01L 2224/80006 being a temporary or sacrificial substrate
• CPC Class Codes: H01L 2224/80357 being flush with the surface
• CPC Class Codes: H01L 2224/80895 between electrically conductive surfaces, e.g. copper-copper direct bonding, surface activated bonding
• CPC Class Codes: H01L 2224/80896 : between electrically insulating surfaces, e.g. oxide or nitride layers
• CPC Class Codes: H01L 2224/80948 : Thermal treatments, e.g. annealing, controlled cooling
• CPC Class Codes: H01L 2224/94 : at wafer-level, i.e. with connecting carried out on a wafer comprising a plurality of undiced individual devices
• CPC Class Codes: H01L 24/75 : Apparatus for connecting with bump connectors or layer connectors
• CPC Class Codes: H01L 24/80 : Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
• CPC Class Codes: H01L 24/94 : at wafer-level, i.e. with connecting carried out on a wafer comprising a plurality of undiced individual devices
• CPC Class Codes: H01L 25/0657 : Stacked arrangements of devices
• CPC Class Codes: H01L 25/50 : Multistep manufacturing processes of assemblies consisting of devices, each device being of a type provided for in group H01L27/00 or H01L29/00 H01L21/50 takes precedence
• CPC Class Codes: H01L 2924/3511 : Warping
• CPC Class Codes: Y10T 156/10 : Methods of surface bonding and/or assembly therefor
• CPC Class Codes: Y10T 156/1089 : of discrete laminae to single face of additional lamina
• CPC Class Codes: Y10T 156/1092 : All laminae planar and face to face

Abstract

A method for bonding a first wafer onto a second wafer by molecular adhesion where the wafers have an initial radial misalignment between them. The method includes bringing the two wafers into contact so as to initiate the propagation of a bonding wave between the two wafers while a predefined bonding curvature is imposed on at least one of the two wafers during the contacting step as a function of the initial radial misalignment.

Claims

1. An apparatus for bonding a first wafer onto a second wafer by molecular adhesion, the apparatus comprising:

a microprocessor for calculating a predefined bonding curvature of the first wafer as a function of an initial radial misalignment between the first wafer and the second wafer, wherein the initial radial misalignment occurs as a result of different radial expansions of the first and second wafers;

a first holding support for holding the first wafer, wherein the first holding support comprises a jack for imposing the predefined bonding curvature on the first wafer;

a second holding support for holding the second wafer; and

a microcontroller for controlling the apparatus so that the second wafer is released from the second support before or while being brought in contact with the first wafer, so that the second wafer adapts to the bonding curvature imposed on the first wafer during the propagation of a bonding wave.

2. The apparatus of claim 1, wherein the microprocessor calculates a radius of curvature corresponding to the predefined bonding curvature as the function of the initial radial misalignment.

3. The apparatus of claim 2, wherein the microprocessor comprises a microprocessor system.

4. The apparatus of claim 1, wherein the jack is driven according to a radius of curvature corresponding to the predefined bonding curvature.

5. The apparatus of claim 1, wherein the first holding support has a curvature corresponding to the predefined bonding curvature.

6. The apparatus of claim 1, further comprising a membrane interposed between the first wafer and the first holding support, the membrane having a curvature corresponding to the predefined bonding curvature.

7. The apparatus of claim 1, wherein the initial radial misalignment is determined by bonding two wafers from a same wafer batch as the first wafer and the second wafer and measuring the misalignment between the two bonded wafers.

8. The apparatus of claim 7, further comprising:

a sensor to measure the misalignment between the two bonded wafers at a plurality of positions on the two bonded wafers using infrared microscopy.

9. The apparatus of claim 8, wherein the sensor carries out the measurement of the misalignment with alignment marks at centers and at peripheral portions of the two bonded wafers.

10. The apparatus of claim 9, wherein the alignment marks at the peripheral portions are about half the distance between the centers and edges of the two bonded wafers.

11. The apparatus of claim 1, further comprising:

a sensor to measure the misalignment between the two bonded wafers, and wherein the microprocessor determines a compensation radial misalignment in dependence at least in part on the initial radial misalignment between the first wafer and the second wafer.

12. The apparatus of claim 1, wherein the predefined bonding curvature is calculated by K_B=(8K_F−

(K₁+K₂))/6, where K_B is the predefined bonding curvature, K_F is a post-bonding curvature of the combined structure of the first and second wafers, K₁ is the initial curvature of the first wafer, and K₂ is the initial curvature of the second wafer.

13. The apparatus of claim 1, wherein the predefined bonding curvature is selected such that a desired post-bonding curvature of the combined structure of the first and second wafers is achieved.

14. The apparatus of claim 13, wherein the desired post-bonding curvature is calculated by K_F=(2(K₁+K₂)+12K_B)/16, where K_F is the desired post-bonding curvature, K₁ is the initial curvature of the first wafer, K₂ is the initial curvature of the second wafer, and K_B is the predefined bonding curvature.

15. An apparatus for bonding a first wafer onto a second wafer by molecular adhesion, the apparatus comprising:

a first holding support for holding the first wafer, wherein the first holding support comprises a jack for imposing a predefined bonding curvature on the first wafer;

a second holding support for holding the second wafer;

a microcontroller or logic elements to control the apparatus so that the second wafer is released from the second support before or while being brought in contact with the first wafer, so that the second wafer adapts to the bonding curvature imposed on the first wafer during the propagation of a bonding wave; and

a microprocessor or microprocessor system for calculating the predefined bonding curvature or a radius of curvature corresponding to the predefined bonding curvature as the function of the initial radial misalignment, wherein the predefined bonding curvature is a function of an initial radial misalignment between the first wafer and the second wafer, wherein the initial radial misalignment occurs as a result of different radial expansions of the first and second wafers,

wherein the microprocessor or microprocessor system receives sensor information that defines radial wafer misalignments between two bonded wafers from a same wafer batch as the first wafer and the second wafer and computes therefrom bonding curvature information and wafer displacement information, which information is sent to the microcontroller or logic elements, and

wherein the microprocessor or the microprocessor system uses the radial wafer misalignments between the two bonded wafers as the initial radial misalignment.

16. A wafer bonding apparatus for bonding a first wafer onto a second wafer by molecular adhesion, the apparatus comprising:

a microprocessor for calculating a predefined bonding curvature of the first wafer as a function of an initial radial misalignment between the first wafer and the second wafer, wherein the initial radial misalignment occurs as a result of different radial expansions of the first and second wafers;

a first holding support assembly including a first holding support configured to hold the first wafer, the first holding support assembly configured to impose the predefined bonding curvature on the first wafer; and

a second holding support configured to hold the second wafer,

wherein the apparatus is configured to release the second wafer from the second support before or while being brought into contact with the first wafer such that the second wafer adapts to the bonding curvature imposed on the first wafer by the first holding support while a bonding wave propagates between the first wafer and the second wafer.

17. The wafer bonding apparatus of claim 16, wherein the first holding support assembly includes a jack, actuation of the jack imposing the predefined bonding curvature on the first wafer held by the first holding support.

18. The wafer bonding apparatus of claim 16, wherein the first holding support assembly includes a membrane interposed between the first wafer and the first holding support, the membrane having a curvature corresponding to the predefined bonding curvature.

19. The wafer bonding apparatus of claim 16, wherein the predefined bonding curvature is imposed on the first wafer by the first holding support, the first holding support having a curvature corresponding to the predefined bonding curvature.

20. The wafer bonding apparatus of claim 16, wherein the wafer bonding apparatus comprises a controller including a microcontroller or logic elements configured to receive sensor information defining radial wafer misalignments between the first wafer and the second wafer, the controller configured to compute bonding curvature information and wafer displacement information at least in part from the sensor information, the controller configured to control at least one of the first holding support and the second holding support using the bonding curvature information and the wafer displacement information.