JPH1187201A - Method for bonding anode and device thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for bonding an anode and a device thereof, without receiving influences from Na ions in a glass substrate so as to prolong anode life, and to shorten bonding time thereof in the course of bonding the anode, wherein the glass substrate is interposed between a plurality of Si silicon substrates. SOLUTION: A plate electrode 13 is provided on a heater 11, which has been heated to approximately 400 deg.C via an insulator 12 interposed therebetween. Further, three substrates, i.e., a first Si substrate 14, a glass substrate 15 and a second Si substrate 16 are successively laid on the plate electrode 13. Positive voltage is impressed on the first Si substrate 14 and the second Si substrate 16, and a negative voltage is impressed on the glass substrate 15. The negative voltage is impressed from an electrode portion of the glass substrate 15 which is outside the superposition of the first Si substrate 14 and the second Si substrate 16. Therefore, Na ions in the glass substrate, which affects adversely bonding, are concentrated on the electrode portion which is located at the outer portion of the glass substrate 15. Thus, it is possible to perform anode bonding, wherein the overlapped portions of the first Si substrate 14, the glass substrate 15 and the second Si substrate 16 are not at all affected by the Na ions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for anodic bonding of a silicon substrate (hereinafter referred to as "Si substrate") to a glass substrate in the manufacture of a semiconductor device or a spectroscope utilizing emitted light.

[0002]

2. Description of the Related Art Conventionally, as a method of bonding a plurality of Si substrates or glass substrates in a manufacturing process of a semiconductor device or a spectroscope, an anodic bonding method shown in FIG.
No. 544. This anodic bonding method will be described with reference to the cross-sectional view of FIG.

First, a Si substrate 10 heated to 400 ° C.
1 and the first glass substrate 105 by the needle electrode 110
Anode bonding is performed by applying C200V. Next, the second glass substrate 106 is placed on the opposite surface of the Si substrate 101 joined to the first glass substrate 105, and the needle electrode 11 is formed as described above.
0, DC200V is applied, and the first glass substrate / Si
The anodic bonding of the substrate / second glass substrate is performed stepwise.

At this time, the needle electrode 111 is connected to the ground electrode 107.
If the same potential (200V DC) is applied, the ground electrode 1
07 enables selective electrostatic bonding in which the electrostatic attraction is canceled and the Si substrate and the glass substrate are not bonded.

On the other hand, as a bonding apparatus in the above-described anodic bonding method, an anodic bonding apparatus as shown in the front views of FIGS. 8A and 8B is conventionally used.
First, referring to FIG. 8A, a plate electrode 43 is provided on a heater 41 via an insulating plate 42,
After placing the first Si substrate 44 thereon,
A glass substrate 45 (having a coefficient of thermal expansion close to that of the Si substrate and made of Pyrex glass containing Na ions) is overlaid on the substrate 44, and a needle electrode 46 is brought into contact with the glass substrate 45 from above.

[0006] By using such a bonding apparatus, Si
To join the substrate and the glass substrate, first, the first Si substrate 44 and the glass substrate 45 are positioned and fixed.
Is heated to about 400 ° C. Next, the plate electrode 43 in contact with the first Si substrate 44 serves as an anode, and the needle electrode 46 in contact with the glass substrate 45 serves as a cathode,
00V is applied.

At this time, ions in the glass move to form a space charge layer of negative charges near the interface between the first Si substrate 44 and the glass substrate 45, and when a large electrostatic attraction occurs, the needle-like electrode 46 The joining starts around the contact portion, and the joining between the first Si substrate 44 and the glass substrate 45 is completed as time passes.

[0008]

In the anodic bonding method shown in FIG. 7, the anodic bonding of a plurality of substrates, such as a first glass substrate / Si substrate / second glass substrate, is performed stepwise, and only at an arbitrary portion. Although selective bonding can be performed, bonding requires a great deal of man-hours because of the stepwise bonding with a single needle electrode. Further, the bonding between the Si substrate and the glass substrate, which are the objects to be bonded, is a combination of a first Si substrate / a glass substrate / a second Si substrate configured when a spectroscope is manufactured, and the steps shown in FIG. When joining is performed, although apparent joining is obtained, the following problems have occurred.

The step bonding in the anodic bonding means that the first Si substrate 44 and the glass substrate 45 are bonded as shown in FIG. 8A, and then the second Si substrate is bonded as shown in FIG. The bonding between the glass substrate 47 and the glass substrate 45 is performed. In this case, they are apparently joined as described above. However, FIG.
At the time of bonding, the first Si substrate 44 and the glass substrate 45 are already well bonded because the first Si substrate 44 serves as a negative voltage electrode when bonding the second Si substrate 47. However, since the Na ions in the glass substrate 45 are attracted to and concentrated on the first Si substrate 44 side, the interface of the first Si substrate 44 reacts with the Na ions. (Such as polishing of a Si substrate), the first Si substrate 44 and the glass substrate 45 must be used.
Separation occurs at the interface with the substrate.

Such a phenomenon appears remarkably when the first Si substrate / glass substrate / second Si substrate are simultaneously anodically bonded. For example, if three layers are simultaneously bonded in the configuration of FIG. 8B, the second Si substrate 47 and the glass substrate 45
Although the first Si substrate 44 and the glass substrate 45 can be satisfactorily bonded to each other, the first Si substrate 44 serves as a negative voltage electrode and reacts with Na ions in the glass substrate to cause corrosive damage. Thus, the bonding between the first Si substrate 44 and the glass substrate 45 becomes completely impossible.

[0011] The present invention solves the above-mentioned problems, and when performing anodic bonding with a glass substrate sandwiched between a plurality of Si substrates, a strong bonding not affected by Na ions in the glass substrate can be performed in a short time. It is an object of the present invention to provide an anodic bonding method and an anodic bonding apparatus.

[0012]

According to the present invention, a glass substrate is sandwiched between a plurality of Si substrates, a DC voltage is applied and heated using the Si substrate as an anode and the glass substrate as a cathode,
In the method of anodic bonding a plurality of Si substrates and a glass substrate, the anodic bonding method is such that the cathode is brought into contact with the outside of the glass substrate overlapping the Si substrate to perform bonding. Preferably, at the outer peripheral edge of the glass substrate overlapping with the Si substrate,
This is an anodic bonding method using a Si electrode bonded as a cathode electrode plate.

The present invention also relates to an anodic bonding apparatus used for the anodic bonding, wherein an anode in contact with a plurality of Si substrates is connected to a lower plate electrode and an upper bar electrode by a fixed arm. This is an anodic bonding apparatus in which a mold electrode is used, and a cathode in contact with the outside of the glass substrate is a frame electrode having a plurality of leaf spring portions. Preferably, the plurality of leaf springs are separately manufactured together with coil-shaped springs and pins, and have a structure that can be detachably attached to the frame electrode by screws or fitting. Further preferably, in the vise electrode, a lower plate electrode and an upper bar electrode are connected by a movable arm. Further, preferably, a heater, an insulator, and a plate electrode on which the Si substrate and the glass substrate are mounted are made rotatable.

[0014]

Next, an embodiment of the present invention will be described in detail with reference to FIGS. FIG. 1 is a front view illustrating a first embodiment of the anodic bonding method of the present invention. As shown in FIG. 1, a plate electrode 1 is placed on a heater 11 heated to about 400 ° C. via an insulator 12.
3, a first Si substrate 14, a glass substrate 15, and a second Si substrate 16 are stacked thereon. A positive electrode is connected to the first Si substrate 14 and the second Si substrate 16 side, and a negative electrode is connected to the glass substrate 15 side. When DC 200 V is applied, the first Si substrate 14 and the glass substrate 15 and the second Si substrate
A space charge layer of negative charges is formed near the interface between the substrate 16 and the glass substrate 15, and the contact surfaces of the layers are attracted to each other, and the bonding is started.

At this time, since the negative electrode is connected to the outside of the glass substrate 15 which overlaps the first Si substrate 14 and the second Si substrate 16, Na ions in the glass which adversely affect the bonding are removed from the glass substrate. 15, the first Si substrate 14, the glass substrate 15, and the second Si substrate.
At the portion where the substrates 16 overlap, anodic bonding can be performed without being affected by Na ions.

According to the first embodiment of the anodic bonding method of the present invention, a negative voltage is applied to the outside of a glass substrate overlapping with a plurality of Si substrates, so that the first necessary for manufacturing a spectroscope is obtained. Simultaneous bonding of a plurality of Si substrates such as a Si substrate / glass substrate / second Si substrate and a glass substrate becomes possible, and the bonding time is reduced to half compared with the conventional step bonding.

Next, a first embodiment of the anodic bonding apparatus of the present invention will be described. FIG. 2 is a front view showing the first embodiment of the anodic bonding apparatus of the present invention. In the anodic bonding apparatus of FIG. 2, a fixed arm 21 incorporated in a vise is attached to one end of the plate electrode 13. A rod electrode 22 is screwed into the tip of the fixed arm 21 so as to be adjustable.
It is in contact with the second Si substrate 16. Therefore, the plate electrode 13 and the rod electrode 22 are electrically connected via the fixed arm 21. On the other hand, a frame-shaped electrode 25 having a plurality of leaf springs 24 is mounted on the tip of a manipulator 23 movable in the X, Y, and Z directions.

Next, the operation of the first embodiment of the anodic bonding apparatus of the present invention will be described with reference to FIG. 2 for the case of simultaneous bonding of the first Si substrate / glass substrate / second Si substrate.
First, the insulator 1 was placed on the heater 11 heated to about 400 ° C.
2 and a plate electrode 13 is provided via the first Si.
The superposition of the three substrates 14, the glass substrate 15, and the second Si substrate 16 is the same as in the first embodiment of the anodic bonding method described with reference to FIG.

Next, the bar electrode 22 screwed into the fixed arm 21 is adjusted, and the bar electrode 22 is brought into contact with the second Si substrate 16. Subsequently, the manipulator 23 is adjusted, and the first S
A plurality of leaf spring portions 24 provided on the frame electrode 25 are brought into contact with the outside of the glass substrate 15 protruding from the i-substrate 14 and the second Si substrate 16. Usually, the glass substrate 15
A thin plate of about 0.2 to 0.5 mm is used. For this reason, a thin plate such as stainless steel or a copper plate having high spring properties is used for the leaf spring portion 24 so that the glass substrate 15 is not damaged by contact pressure.

Thereafter, DC 200 V is applied to the fixed arm 21.
When a positive voltage is applied to the frame type electrode 25 and a negative voltage is applied to the frame type electrode 25, the first Si substrate 14, the glass substrate 15, and the second Si substrate 1
6 and the glass substrate 15 can be simultaneously bonded. Although the plurality of leaf spring portions 24 provided on the frame electrode 25 are manufactured by integral processing, only the leaf spring portion 24 is manufactured as a separate body, and is detachably attached to the frame electrode 25 by screws or fitting. It may have a structure. The same effect can be obtained by attaching a pin to the leaf spring portion 24 if a coiled spring is used or the frame-shaped electrode 25 itself has a spring property.

FIG. 3 is a front view showing a second embodiment of the anodic bonding apparatus of the present invention. In the anodic bonding apparatus shown in FIG. 3, a movable arm 27 having a spring 26 and swinging in the direction of arrow A is attached to one end of the plate electrode 13.
A rod electrode 28 is fixed to the tip of the movable arm 27 and is always in contact with the second Si substrate 16. Other points are the same as those of the first embodiment in FIG. The rod electrode 28 is
As in the anodic bonding apparatus shown in FIG. 2, screwing may be used.

FIG. 4 is a front view showing a third embodiment of the anodic bonding apparatus according to the present invention. In the anodic bonding apparatus in FIG. 4, the fixed arm 21 attached to the plate electrode 13 in FIG. Also, the heater 11, the insulator 1,
2. The plate electrode 13 has a drive system such as a motor outside (not shown) and has a structure rotatable in the direction of arrow B.

Next, the operation of the third embodiment of the anodic bonding apparatus of the present invention will be described with reference to FIG.
The case of simultaneous bonding of the glass substrate and the second Si substrate will be described. First, a plate electrode 13 is provided on a heater 11 heated to about 400 ° C. via an insulator 12, and a first Si substrate 14, a glass substrate 15, and a second Si substrate 16
And the frame-shaped electrode 25 is placed outside the glass substrate 15.
2 until the plurality of leaf springs 24 provided in FIG.
Is the same as that of the first embodiment.

Next, the bar electrode 22 screwed into the fixed arm 21 is brought into contact with the second Si substrate 16 in an adjustable manner, and the bar electrode 28 also screwed in the fixed arm 21 is brought into contact with the plate electrode 13 in an adjustable manner. Let it. Thereafter, a positive voltage of 200 V DC is applied to the fixed arm 21 and a negative voltage of 200 V DC is applied to the frame electrode 25. When the partial bonding (temporary bonding state) is completed, an external motor is driven and the plate electrode 13 is driven. The upper first Si substrate 14, the glass substrate 15, and the second Si substrate 16 are rotated at a low speed of about 1 rpm. By doing so, the glass substrate 15 and the frame electrode 25
Since the contact point with the leaf spring portion 24 always moves, deterioration of the electrode caused by reacting with Na ions can be avoided as compared with the case where the electrode always contacts the glass substrate.

As described above, the anodic bonding apparatus of the present invention comprises a vice-type anode in which a plate electrode and a bar electrode are connected by a fixed arm or a movable arm, and a frame-type cathode having a plurality of leaf springs. , A plurality of Si substrates and a glass substrate can be simultaneously bonded. Also,
By rotating part of the device, the life of the negative voltage electrode is significantly improved.

Next, a description will be given of a second embodiment of the anodic bonding method according to the present invention. FIG. 5 is a sectional view for explaining the second embodiment, and FIG. 6 is a graph showing the relationship between the electrode area and the bonding time in anodic bonding. In the anodic bonding method of FIG. 5, the Si wafer 31 is anodically bonded to the outer peripheral edge of the glass substrate 15 before performing the simultaneous bonding of the first Si substrate / glass substrate / second Si substrate.

Next, the first electrode S heated to about 400 ° C. is applied to the plate electrode 13 using the anodic bonding apparatus shown in FIG.
The i-substrate 14, the glass substrate 15 with the Si wafer 31, and the second Si substrate 16 are stacked, and the bar electrode 22 is brought into contact with the second Si substrate 16, and the frame-shaped electrode 25 is provided outside the glass substrate 15.
And the anodic bonding is performed. On this occasion,
The leaf spring section 24 is always brought into contact with the Si wafer 31. When a plurality of Si wafers 31 are provided, the plate spring portions 24 corresponding to the number are required. However, when the Si wafer 31 is a single unit, the plate spring unit 24 may be a single unit. The same effect can be obtained even when a thin plate such as stainless steel or a copper plate, a thin metal film such as gold, conductive rubber, or conductive resin is adhered instead of the Si wafer.

In each embodiment of the anodic bonding apparatus of the present invention, a plurality of leaf spring portions 24 are used for the cathode in order to shorten the bonding time by increasing the number of electrodes.
However, the number of leaf springs 24 attached to the frame-shaped electrode 25 is limited, and the electrode installation area cannot be large.
By anodically bonding 1 and using it as a negative electrode,
The electrode area is increased.

FIG. 6 is a graph showing the relationship between the electrode area and the bonding time. For example, 6cm × 7cm (42cm ²⁾
When the Si substrate and the glass substrate are bonded together, when an Si wafer having a different area is bonded to the outer peripheral edge of the glass substrate and used as a negative electrode, the bonding time becomes shorter as the area of the negative electrode is larger. According to the second embodiment of the anodic bonding method of the present invention, when a negative voltage is applied to the outside of a glass substrate overlapping a plurality of Si substrates, the bonding time can be significantly reduced by increasing the electrode area. .

As described above, according to the present invention, when anodic bonding is performed with a glass substrate sandwiched between a plurality of Si substrates, the cathode in contact with the glass substrate is positioned outside the glass substrate overlapping the Si substrate. , The Na ions in the glass substrate are dispersed outside the glass substrate, thereby enabling simultaneous bonding without being affected by the Na ions. Furthermore, the rotation of a part of the bonding apparatus constantly changes the position of the negative voltage electrode that is in contact with the glass substrate, thereby avoiding a reaction between the electrode and Na ions in the glass substrate and reducing the life of the electrode. Is greatly extended. Also, by increasing the area of the cathode that contacts the glass substrate,
A large electrostatic force is generated, and the joining time is significantly reduced.

[0031]

As described above, according to the present invention, when anodic bonding is performed with a glass substrate sandwiched between a plurality of Si substrates, simultaneous bonding can be performed without being affected by Na ions in the glass substrate. As a result, it has become possible to realize an anodic bonding method and an apparatus thereof that have a strong bonding force, significantly reduce the bonding time, and extend the life of the electrode.

[Brief description of the drawings]

FIG. 1 is a front view illustrating a first embodiment of an anodic bonding method according to the present invention.

FIG. 2 is a front view showing a first embodiment of the anodic bonding apparatus of the present invention.

FIG. 3 is a front view showing a second embodiment of the anodic bonding apparatus of the present invention.

FIG. 4 is a front view showing a third embodiment of the anodic bonding apparatus of the present invention.

FIG. 5 is a sectional view illustrating a second embodiment of the anodic bonding method according to the present invention.

FIG. 6 is a diagram showing the relationship between electrode area and bonding time in anodic bonding.

FIG. 7 is a cross-sectional view illustrating a conventional anodic bonding method.

FIG. 8 is a view showing a conventional anodic bonding apparatus, wherein FIG.
(B) is a front view, respectively.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Heater 12 Insulator 13 Plate electrode 14 1st Si substrate 15 Glass substrate 16 2nd Si substrate 21 Fixed arm 22 Bar electrode 23 Manipulator 24 Leaf spring part 25 Frame type electrode 26 Spring 27 Movable arm 28 Bar electrode 31 Si wafer 41 Heater 42 Insulating plate 43 Plate electrode 44 First Si substrate 45 Glass substrate 46 Needle electrode 47 Second Si substrate 101 Si substrate 105 First glass substrate 106 Second glass substrate 107 Earth electrode 110 Needle electrode

Claims (6)

[Claims] A glass substrate is interposed between a plurality of Si substrates, a DC voltage is applied and heated using the Si substrate as an anode and the glass substrate as a cathode, and the plurality of Si substrates and the glass substrate are heated. In the anodic bonding method for bonding, the anodic bonding method is characterized in that the bonding is performed by bringing the cathode into contact with the outside of the glass substrate overlapping the Si substrate. 2. The anodic bonding method according to claim 1, wherein an Si wafer is bonded as a cathode electrode plate to an outer peripheral portion of a glass substrate overlapping the Si substrate. 3. A method in which a glass substrate is interposed between a plurality of Si substrates, a DC voltage is applied and heated using the Si substrate as an anode and the glass substrate as a cathode, and the plurality of Si substrates and the glass substrate are heated. In an anodic bonding apparatus for bonding, an anode in contact with a plurality of Si substrates is a vice electrode in which a lower plate electrode and an upper bar electrode are connected by a fixed arm, and a plurality of cathodes in contact with the outside of the glass substrate are provided. An anodic bonding apparatus comprising a frame-shaped electrode having a leaf spring portion. 4. The structure according to claim 2, wherein the plurality of leaf springs are separately manufactured together with coil-shaped springs and pins, and have a structure that can be detachably attached to the frame electrode by screws or fitting. Anodic bonding equipment. 5. The anodic bonding apparatus according to claim 3, wherein said vice electrode has a lower plate electrode and an upper bar electrode connected by a movable arm. 6. The anodic bonding apparatus according to claim 3, wherein a heater, an insulator, and a plate electrode on which the plurality of Si substrates and the glass substrate are mounted are rotatable.