JP2765466B2 - Substrate bonding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joining method for directly joining dissimilar materials and a joining method for fabricating a device using the same.

[0002]

2. Description of the Related Art In recent years, there has been an increasing interest in optoelectronic integrated circuits. By integrating an optical device made of GaAs or InP and an electronic device made of Si or GaAs, a dramatic improvement in operating characteristics and realization of new functions are expected. In order to realize such an opto-electronic integrated circuit, a technique for directly crystal-growing materials having different lattice constants such as Si, GaAs, and InP has been actively studied. For example, Journal of Crystal Grouse by Akiyama et al.
f Crystal Growth) Vol. 68, 21-2
This is described in detail in a six-page paper. In recent years, there has been remarkable progress in the crystal growth technology of the lattice mismatch system. However, this type of crystal growth film has a problem that dislocations due to lattice mismatch and differences in thermal expansion coefficients are introduced, and it is necessary to insert a thick buffer layer to alleviate these problems.

[0003] Apart from such crystal growth of different materials, direct bonding of substrates has been widely performed, and attempts for practical use have been made. These descriptions are described, for example, in Furukawa et al., Applied Physics Vol. 60, No. 8, 790-793, 1991.
On the page. Substrate bonding technology requires relatively few steps,
The conditions for the interface are relatively mild. Therefore,
It is thought that in the future, it will be possible to bond devices optimized on individual substrates or transfer devices optimized on each substrate directly to a substrate on which electronic circuits are integrated by bonding. Expectations from applications are gathered.

[0004]

However, when the device is transferred onto a certain substrate, there is a problem of coordination as to where to join the substrate to which the device is to be transferred. As a method of alignment, there was a method of matching an alignment pattern using infrared light. However, various devices were required, and the joining was complicated. In addition, there is a problem that it takes a considerable time to separate only the substrate after device transfer.

In view of the above circumstances, it is an object of the present invention to provide a joining method that satisfies both simple alignment at the time of joining and reduction of required time at the time of separation.

[0006]

Means for Solving the Problems In order to solve the above-mentioned problems, a means provided by the present invention has a registration pattern.
To be formed on the substrate via a hole and a separation layer
The substrate having the element having the
The substrates are joined together by matching the pattern
The separation layer is selectively etched to form the separation layer.
A substrate having the alignment pattern
To a substrate bonding method, characterized in that bonding the element.

[0007]

According to the present invention, simple alignment can be performed only by adding a simple cutting technique such as providing a hole in a substrate, and the etching solution is removed from the hole (hole) at the time of separation. Are easily permeated, and the separation time is shortened.
As a result, device fabrication using a series of substrate bonding is simple,
And it can be done in a short time.

[0008]

Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing the shape of a substrate used in the present invention. FIG. 2 is a cross-sectional view showing an example of a substrate bonding method using the present invention. First S
An i-substrate 1 is prepared, and a registration pattern 2 is formed thereon. Separately, for example, a second InP substrate 3 is prepared. The holes 4 are formed in the InP substrate 3 according to the joint alignment. Next, on the InP substrate 3, a long-wave device (element) 5 such as a laser is separated from the separation layer 6 to a thickness of 0.5.
It is produced after forming about μm. In this case, as the separation layer 6, for example, _{In X Al 1 - X As (} x is 0 to 0.5)
Is used.

The InP substrate 3 and the Si substrate 1 are aligned from the hole 4 while observing the alignment pattern 2 of the Si substrate 1.
Annealing is performed in an H ₂ atmosphere at 00 ° C. for 60 minutes. Thereby, both can be joined. Further, if it is desired to transfer an element separately manufactured on a different third InP substrate onto the first Si substrate 1, the same steps may be repeated.

Next, the separation layer 6 is formed using phosphoric acid as an etchant.
Only selective removal. At this time, since the etchant wraps around the holes 4 to etch the separation layer 6, the time required for separation is reduced. Thus, various optical devices can be formed on the first Si substrate 1. Here, the materials of the individual substrates may be changed according to the purpose, and are not limited to those shown here. Then, a separation layer and an etchant thereof may be appropriately selected in accordance therewith. In addition, some elements may be already formed on the first substrate. The element is not limited to a laser, but can be applied to optical devices such as a light receiver in general.

[0011]

According to the present invention, alignment can be easily performed when a device (element) is directly joined to a substrate, and the separation time can be reduced when the substrate is separated.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing the shape of a substrate using the present invention.

FIG. 2 is a cross-sectional view showing a substrate bonding method using the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Matching pattern 3 Substrate 4 Void part 5 Device 6 Separation layer

Claims (1)

(57) [Claims] A substrate having a 1. A pitch alignment pattern, a substrate having an element which is formed via the the pores part separating layer on a substrate, and combined eye the eye alignment pattern from the pore portion Bonding the substrates to each other, selectively etching the separation layer to separate the substrate on which the separation layer is formed, and bonding the element to a substrate having the alignment pattern. Method.