Bonded wafer, process for producing same and substrate

Details Bonded wafer, process for producing same and substrate Bonded wafer, process for producing same and substrate

1998-03-17

2001-03-06

Whitehead, Jr., Carl (Department: 2822)

Active solid-state devices (e.g., transistors, solid-state diode

With means to control surface effects

Insulating coating

C257S347000, C257S642000

Reexamination Certificate

active

06198159

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a bonded wafer in which a polyimide is used as a joining agent, a process for producing the same, and a substrate using the same.
2. Description of the Related Art
Direct bonding, electrostatic joining, soot glass joining, etc. have been proposed as methods for producing a bonded wafer.
All these methods require a joining temperature exceeding 1,000° C., and a joining time of several to several tens of hours.
Furthermore, all these methods require a production apparatus on a large scale, namely a heat treatment furnace to a diffusion furnace specification.
On the other hand, although an aromatic polyimide film is excellent in heat resistance, mechanical strength, electrical properties, etc., it shows poor adhesion to glass as is evident from the production of the film by casting on a glass support. The aromatic polyimide film has been considered inappropriate as a joining agent for the wafers.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a bonded wafer in which a polyimide is used as a joining agent and the polyimide and wafers are joined together under relatively mild conditions and with uniformity, a process for producing the same, and a substrate derived from the same.
That is, the present invention relates to a bonding wafer comprising at least two wafer layers and a joining agent which joins the wafer layers together, the joining agent being an amorphous, heat fusion bonding aromatic polyimide (X) layer alone or a heat fusion bonding aromatic polyimide material comprising a substrate polyimide (Y) layer and an amorphous, heat fusion bonding aromatic polyimide (X) layer on each side of the substrate polyimide (Y) layer.
The present invention also relates to a process for producing a bonded wafer comprising the steps of
sandwiching, as a joining agent, an amorphous, heat fusion bonding aromatic polyimide (X) layer alone or a heat fusion bonding aromatic polyimide film comprising a substrate polyimide (Y) layer and an amorphous, heat fusion bonding aromatic polyimide (X) layer on each side of the substrate polyimide layer, between at least two wafer layers, and
joining the wafer layers together at a temperature of from the glass transition temperature of the aromatic polyimide (X) to the deterioration temperature thereof under a pressure of 0.1 to 100 kg/cm
2
, or a process for producing a bonding wafer comprising the steps of
coating one side of a wafer with a solution of a polyamic acid for forming an amorphous, heat fusion bonding aromatic polyimide (X) as a joining agent,
heating the coated solution for the purpose of removing the solvent and causing imidation to form a heat fusion bonding aromatic polyimide layer,
stacking another wafer on the wafer, and
joining the wafer layers together at a temperature of from the glass transition temperature of the aromatic polyimide (X) to the deterioration temperature thereof under a pressure of 0.1 to 100 kg/cm
2
.
Furthermore, the present invention relates to a substrate prepared by subjecting one surface of a bonded wafer to at least one processing selected from grinding, polishing and etching or a substrate prepared by removing one surface of a bonded wafer so that the wafer has a SOI structure, the bonded wafer comprising at least two wafer layers and a joining agent which joins the wafer layers together, the joining agent being an amorphous, heat fusion bonding aromatic polyimide (X) layer alone or a heat fusion bonding aromatic polyimide material comprising a substrate polyimide (Y) layer and an amorphous, heat fusion bonding aromatic polyimide (X) layer on each side of the substrate polyimide (Y) layer.


REFERENCES:
patent: 3759913 (1973-09-01), Blackley
patent: 4523976 (1985-06-01), Bukhman
patent: 4561726 (1985-12-01), Goodby et al.
patent: 4596069 (1986-06-01), Bayraktaroglu
patent: 4713438 (1987-12-01), Harris et al.
patent: 4931531 (1990-06-01), Tamai et al.
patent: 4978379 (1990-12-01), Sawada et al.
patent: 4978712 (1990-12-01), Bair et al.
patent: 5077244 (1991-12-01), Iyori et al.
patent: 5236118 (1993-08-01), Bower et al.
patent: 5502143 (1996-03-01), Oie et al.
patent: 5691876 (1997-11-01), Chen et al.
patent: 56-36136 (1981-04-01), None
patent: 4-132258 (1992-05-01), None
patent: 6-18234 (1994-03-01), None
Kakao, Relationship Between Bond Strength and Crystallinity of High Polymers—Polyethylene, Polyethyleneterephthalate, and Nylon, 1971, Recent Advances in Adhesion, Gorden and Breach Science Pulishers: New York, p. 453-457, TP 967 .A56 1971.

Affiliated with

Also associated with

Rating

Bonded wafer, process for producing same and substrate does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Bonded wafer, process for producing same and substrate, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Bonded wafer, process for producing same and substrate will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2547794