JP3321827B2 - Supporting device for forming bonded substrate and method for forming bonded substrate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a support device for forming a bonded substrate. INDUSTRIAL APPLICABILITY The present invention can be generally used as a supporting device when two substrates are joined to form a bonded substrate. For example, the present invention can be used as a supporting device when two semiconductor wafers are bonded to form a bonded semiconductor substrate. Also, an SOI (Sinlicon on Insulator) structure used as a structure of an electronic component such as a semiconductor device (this is a method in which a silicon portion is present on an insulating portion and various semiconductor elements are formed on the silicon portion, (Used mainly in the field of electronic materials) is to bond another substrate to the side of the insulating portion of the silicon substrate on which the insulating portion is formed, and polish the silicon substrate. There is known a technology for forming a structure in which a silicon portion exists on an insulating portion, and this technology is generally called a bonded SOI or the like, but is also used as a substrate support device for forming such a bonded SOI. it can.

The present invention also provides a method for forming a bonded substrate.
About. This invention is also used in the same fields as described above.
it can.

2. Description of the Related Art A conventional method for forming such a bonded SOI structure will be described with reference to FIG.

A silicon substrate 1 as shown in FIG.
(In general, a high flatness silicon wafer is used. This is referred to as a substrate A). One surface of the surface is patterned by using a photolithography technique or an etching technique, and an SiO ₂ film is formed on this surface. The insulating part 2 is formed. Thereby, as shown in FIG. 3B, a structure in which the insulating portion 2 is formed on one side of the silicon substrate 1 is obtained. The insulating portion 2 is formed as a film having irregularities as shown in the figure according to the surface shape of the patterned silicon substrate 1. FIG. 3B shows a state in which a polysilicon film 3 is further formed on the insulating portion 2. The polysilicon film 3 is formed on another substrate (FIG.
This is for forming a highly smooth bonding surface when bonding substrates 4) indicated by.

Next, the surface of the polysilicon film 3 is flattened and polished to obtain a highly smooth surface (FIG. 3C).

[0005] Another substrate 4 (hereinafter referred to as substrate B) is brought into close contact with the polished surface of the polysilicon film 3. The two surfaces are joined by close compression bonding, and as a result, a joined structure as shown in FIG. 3D is obtained. It is generally said that a firm bond is achieved by hydrogen bonding due to OH groups interposed on both surfaces. This is usually heated and thermally bonded to achieve a very strong bond. The bonding strength is generally 200 kg / cm ² or more, and in some cases, 2,000
kg / cm ² . Another substrate 4 to be bonded (substrate B)
Usually, a silicon substrate similar to the substrate 1 (substrate A) is used. This is because a heating step is often performed after bonding, and if the physical properties such as thermal expansion are not equal, inconvenience may occur. If there is no such problem, for example, in the illustrated technique, another substrate 4 only plays a role of a support, so that it is not necessarily a silicon substrate. However, when an element is also formed on another substrate 4 (substrate B) to be bonded, it is necessary that the semiconductor substrate be a semiconductor substrate on which the element can be formed.

Next, the side peripheral portion is chamfered, and FIG.
Structure. FIG. 3 (e) is upside down from FIG. 3 (d) because the substrate 1 is turned upside down for this chamfering and subsequent grinding.

Thereafter, the surface of the substrate 1 is ground, and FIG.
The structure shown in FIG. This surface grinding is stopped before the insulating portion 2 is exposed.

Next, selective polishing is performed. Here, the polishing is performed by precise finishing until the insulating portion 2 is just exposed.
As a result, as shown in FIG. 3G, a structure is obtained in which the silicon portion 10 exists on the insulating portion 2 surrounded by the insulating portion 2 having irregularities. As described above, for the structure in which the silicon portion 10 exists on the insulating portion 2 (SOI structure), various elements are formed in the silicon portion 10. In the structure shown in FIG. 3G, since each silicon portion 10 is surrounded by the insulating portion 2, the element is isolated from the beginning.

FIG. 3 shows one silicon part for clarity of illustration.
Although FIG. 10 is shown large, in reality, many such fine silicon portions 10 are gathered.

[0010]

In the formation of the bonded SOI structure as described above, bubbles may be formed at the bonded interface. Referring to FIG. 3, FIG.
In this case, when the surface of the silicon film 3 on the substrate 1 is bonded to the substrate 4, air bubbles may be generated at this interface. Bubbles may be generated at a size of, for example, about 0.5 mm to 5 mm.

[0011] Since the bonding surface is not in close contact with the portion where bubbles are generated, sufficient bonding is not performed and the portion is easily peeled off.
For example, after the surface grinding shown in FIG. 3F, the film thickness t ₁ of the film of the substrate 1 on the substrate 4 becomes a thin film of 4 to 20 μm, usually about 5 to 10 μm. , It easily peels off. This can be a source of contamination and can have a significant effect on device formation. For example, polishing may cause scratches on the wafer. As described above, the peeling due to the air bubbles causes contamination, and impairs the reliability of the device. 3 If it is the state of (g), thinner film thickness t ₂ of the silicon portion 10 side of the film on the substrate 4 is made approximately 3 to 4 [mu] m, the peel where to the same source of contamination, Furthermore, the device may be defective.

For this reason, it is necessary to prevent air bubbles from being generated at the bonding portion between the two substrates.

Conventionally, when forming a bonded SOI,
As shown in FIGS. 4 (A) to 4 (C), in order to prevent air bubbles from being generated between the two substrates to be bonded, a first support portion 13 for supporting one substrate 4 and another substrate 1 are used. For example, a second support jig 14 for supporting a semiconductor wafer is used, and the second support jig 14 is configured such that the surface of the supported substrate 1 is convex, and the second support jig 14 is convex toward the substrate 4. Techniques such as matching are adopted.

[0014]

However, in the above-described technique, even if the second support jig 14 is configured as, for example, a vacuum chuck, it is not always possible to support the substrate 1 in a good convex shape. Also, when a flat bonded substrate is formed by bonding, that is, when bonding is performed from the state of FIG. 4B to the state of FIG. May occur.

The present invention solves the above-mentioned problem, and even when the supported substrate is supported in a convex shape, the substrate is supported in a good convex shape.
It is an object of the present invention to provide a bonded substrate forming support device that enables bonding in a good state and does not cause inconvenience such as expansion and contraction of a pattern.

The present invention also provides the above-described disadvantages.
Not to provide a method of forming a bonded substrate
I do.

According to a first aspect of the present invention, there is provided a supporting apparatus for joining two substrates to form a bonded substrate, comprising: a first supporting portion for supporting one substrate; A second support portion capable of supporting the substrate in a convex state with respect to the one substrate, wherein the second support portion is a bend jig for supporting the central portion of the supported substrate in a convex shape, A holding jig for supporting a peripheral portion of the supported substrate, wherein the holding jig has a holding portion formed so as to be able to move in and out according to the shape of the supported substrate. a device is intended to achieve the above object by this configuration.

According to a second aspect of the present invention, at least one of the two substrates is a semiconductor wafer and forms a bonded semiconductor substrate. a device is intended to achieve the above object by this configuration.

According to a third aspect of the present invention, in the supporting apparatus for forming a bonded substrate according to the first or second aspect, the holding jig is made of a material that does not cause metal contamination and carbon contamination. With this configuration, the above object is achieved.

According to a fourth aspect of the present invention, there is provided a supporting device for joining two substrates to form a bonded substrate, wherein the first supporting portion supports one substrate and the other substrate is connected to the one substrate. a second supporting portion capable of supporting in the form of convex with respect to the substrate, the second support portion is configured to have a holding member capable of supporting the entire of the supported substrate to a convex shape, the second Support
Is a bend jig for supporting the central portion of the supported substrate in a convex shape,
Around a member on which a holding member for supporting the supported substrate is placed
And a holding jig for engaging and supporting the portion.
This is a supporting device for forming a bonded substrate, and achieves the above object by this configuration.

According to a fifth aspect of the present invention, two substrates are joined together.
A support device for forming a bonded substrate, wherein one of the substrates
A first supporting portion for supporting a plate, and the other substrate
A second supporting portion capable of supporting the substrate in a convex state;
The second support portion supports the entire supported substrate in a convex shape.
Having a holding member capable of holding the two substrates.
At least one of which is a semiconductor wafer and is bonded
A beam characterized by forming a semiconductor substrate
This is a supporting device for forming a laminated substrate, and achieves the above object by this configuration.

According to a sixth aspect of the present invention, two substrates are joined together.
A support device for forming a bonded substrate, wherein one of the substrates
A first supporting portion for supporting a plate, and the other substrate
A second supporting portion capable of supporting the substrate in a convex state;
The second support portion supports the entire supported substrate in a convex shape.
A holding member that can be held, and the holding member
Of materials that do not cause metal and carbon contamination.
The present invention is a supporting device for forming a bonded substrate, and achieves the above object by this configuration.

According to a seventh aspect of the present invention, at least two substrates are used.
One is a semiconductor wafer, and the bonded semiconductor substrate
5. The method according to claim 4, wherein the plate is formed.
Is a supporting device for forming a bonded substrate described in 6, which achieves the above object by this configuration.

The invention according to claim 8 is a bonding base for forming a bonded substrate by directly bonding the polished surfaces of two substrates.
A method for forming a plate, comprising: a bend jig having a convexly curved support surface, wherein one of the substrates is supported by a first support portion and an outer peripheral portion of the other substrate placed on a flat surface is held. and performing bonding at the substrate of the curved convex by mechanically pressing the substrate against the said other by the
This is a method for forming a bonded substrate, and achieves the above object by this configuration.

Regarding the configuration of the invention of claim 1 of the present application,
The following is a description with reference to the example of FIG. 1 showing one embodiment of the present invention described in detail below.

The supporting device for forming a bonded substrate according to the present invention is a supporting device for forming a bonded substrate by joining two substrates 1 and 4 as shown in FIG. And a second support portion 5 that can support the other substrate 1 in a convex state with respect to the one substrate 4, wherein the second support portion 5 is It has a bend jig 14 for supporting the central portion of the support substrate 1 in a convex shape, and a holding jig 52 for sucking and supporting the peripheral portion of the supported substrate 1. It has a holding portion 51 that can be freely moved in and out according to the shape.

Particularly, in this embodiment, at least one of the two substrates (especially, the substrate 1; however, in the illustrated example, both are Si semiconductor substrates) is a semiconductor wafer, and forms a bonded semiconductor substrate. The present invention according to claim 2 is embodied.

Further, in this embodiment, the holding jig 52 is made of a material that does not cause metal contamination and carbon contamination (for example, a so-called fluororesin such as Teflon).
The present invention according to claim 3 is embodied.

According to the first aspect of the present invention, the substrate 1 is held in a convex shape with respect to the substrate 1 by the bend jig 14 so as to be joined (FIG. 1B). As the joining progresses, the movable holding portion 51 is displaced in the vertical direction in the drawing to realize a smooth joining operation, and good bonding is achieved without bubbles. Problems such as pattern expansion and contraction can be suppressed.

According to the third aspect of the present invention, since the holding jig is made of a material which does not cause metal contamination or carbon contamination, the substrate can be prevented from being contaminated.

Next, the structure of the invention of claim 4 of the present application will be described with reference to FIG. 2 showing an embodiment of the present invention which will be described in detail later.

As shown in FIG. 2, the supporting device for forming a bonded substrate according to the present invention is a supporting device for bonding two substrates 1 and 4 to form a bonded substrate. And a second support portion 5 that can support the other substrate 1 in a convex state with respect to the one substrate 4, wherein the second support portion 5 is It has a holding member 7 that can support the entire support substrate 1 in a convex shape.

Example of Further Figure 2, the bend jig 14 in which the second supporting section 5 to support the central portion of the support substrate 1 in a convex shape,
Member 9 on which holding member 7 for supporting substrate 1 is placed
And a holding jig 8 for engaging and supporting the peripheral portion of
You.

Further, in the embodiment shown in FIG. 2, at least one of the two substrates (particularly, substrate 1; however, in the illustrated example, both are Si semiconductor substrates) is a semiconductor wafer, and forms a bonded semiconductor substrate. This embodies the invention of claim 5 .

Further, in this embodiment, since the holding member 7 is made of a material (for example, a so-called fluororesin such as Teflon) which does not cause metal contamination and carbon contamination, the invention according to claim 6 is embodied. is there.

According to the fourth aspect of the present invention, when the substrate 1 held by the holding member 7 is joined, the substrate 1 is held by the holding member 7 and supported in a convex shape with respect to the substrate 4 to perform joining (FIG. 9). 2 (b)), smooth joining is achieved, and good bonding is achieved without bubbles. Problems such as pattern expansion and contraction can be suppressed.

According to the sixth aspect of the present invention, since the holding member is made of a material which does not cause metal contamination and carbon contamination, it is possible to prevent the substrate from being contaminated.

[0037]

Embodiments of the present invention will be described below with reference to the drawings. Of course, the invention of the present application is not limited by the embodiments.

Embodiment 1 In this embodiment, the invention according to claim 1 of the present invention, particularly the invention according to claim 2 and the invention according to claim 3 when forming a bonded semiconductor wafer when forming a transistor having an SOI structure. Is applied. That is, in this embodiment, when two semiconductor wafers are used as two substrates 1 and 4 to be bonded, and the polished surfaces are directly bonded to each other to obtain a bonded wafer, the two semiconductor wafers are placed on a flat surface. Holding the outer peripheral portion of the semiconductor wafer (substrate 1) (in this example, vacuum suction,
Using a bend jig 14 machined into a convex or curved surface such as a spherical surface or a convex shape, the mirror side of the semiconductor wafer (substrate 1) can be curved (spherical or convex) by mechanically pressing. (A convex shape such as a mold)
The invention of the present application was embodied in such a manner as to achieve bonding without bubbles by performing the bonding of No. 4, and to prevent undesired deformation such as pattern expansion and contraction by performing smooth support and bonding. It is an example.

Referring to FIGS. 1 (a) to 1 (c). In FIGS. 1A and 1B, reference numerals 1 and 4 denote two substrates to be bonded, here semiconductor wafers, and their bonding surfaces are mirror-polished. Reference numeral 13 denotes a holding jig serving as a first supporting portion for supporting one substrate 1 flat. Reference numeral 5 denotes a supporting portion for supporting the other substrate 1, a bend jig 14 for supporting the central portion of the substrate 1 in a convex shape, and holding jigs 51, 52 for supporting the peripheral portion of the substrate 1 by suction.
have. The holding jig has a ring-shaped holding portion 51 which is slidably provided so as to be able to slide in and out of the annular recess and which supports the lower portion of the peripheral portion of the substrate 1 in contact therewith. In this embodiment,
The holding part 51 and the holding jig 52 were formed of Teflon (fluororesin). Further, the vacuum chuck as the first support portion 13 was also formed of Teflon. In addition, ceramic, Delrin, and Duracon can also be used.

FIG. 1A shows that the semiconductor wafers as substrates 1 and 4 are respectively held by holding jigs as first support portions 13 and holding jigs 51 and 52 as second support portions 5. This shows a state in which a flat surface is sucked and held by vacuum. In this embodiment, one substrate 4 is supported by suction on the entire surface, and the other substrate 1 is suctioned only around the wafer.
Support.

Next, FIG. 1B shows that the semiconductor wafer, which is the substrate 1 at the bottom of the figure, is pushed up by the bend jig 14 in the direction of the arrow to make the mirror surface convex (spherical or other curved convex). 2 shows a state in which the substrate 4 is brought into contact with a semiconductor wafer which is a substrate 4 above. At that time, the ring-shaped holding portion 51 moves upward in the figure together with the substrate 1 and holds the substrate 1 while maintaining a vacuum state. In this state, the two substrates 1 and 4 are mechanically joined together with the joining force (hydrogen bonding force) between the substrates 1 and 4.

Next, FIG. 1C shows that the bend jig 14 is lowered in the direction of the arrow, and at the same time, the support portion which is a vacuum chuck.
13 is also down. Holder 51 that forms a vacuum ring
And the substrate 1 which is a semiconductor wafer is also lowered, and the substrates 1, 4
Are completely adhered.

According to this embodiment, the mirror side of the semiconductor wafer substrate can be easily made into a spherical or curved convex shape, so that air bubbles are pushed out from the central portion of the convex curved surface toward the periphery. Since bonding can be achieved, the remaining of bubbles is reduced, and good bonding is performed, so that pattern expansion and contraction is reduced. Further, since the holding jig is formed of a material (fluorine resin or the like) which does not cause metal contamination or carbon contamination, unlike the case where carbon contamination such as a rubber material is caused, contamination is prevented and back surface contamination is reduced.

Embodiment 2 Next, a second embodiment will be described with reference to FIGS. 2 (a) and 2 (b). In this embodiment, the entire surface of the substrate 1 is adsorbed and supported by the holding member 7, and the holding member 7
The holding jig 8 is placed on the spring member 9 which is engaged and held around the notch 81.

FIG. 2A shows a state in which substrates 1 and 4, which are semiconductor wafers, are suction-supported on a flat surface by a holding member 7 and a first support portion 13 which are vacuum chucks, respectively.

FIG. 2B shows a state in which the bend jig 14 is pushed up in the direction of the arrow so as to be brought into contact with the substrate 1 and the substrate 4 and adhered thereto. At this time, the holding member 7 which is a vacuum chuck and the member 9 which is a leaf spring are
However, only the periphery of the member 9 is held by the holding jig 8, and the holding of the convex curved surface is achieved.

In this embodiment, by lowering the bend jig 14 (in the direction opposite to the arrow), the first support portion 13 which is a vacuum chuck is also lowered, and the holding member 7 and the substrate 1 returns to the flat state.

In this embodiment, the material of the first support portion 13, the holding member 7 and the holding jig 8 which is a vacuum chuck uses ceramic, Teflon, Delrin, Duracon or the like to prevent contamination by metal or carbon. It is.

According to this example, the two semiconductor wafers as the substrates 1 and 4 were completely bonded to each other, and bonding with little bubbles, little expansion and contraction of the pattern, and no contamination of the back surface could be achieved.

[0050]

As described above, according to the present invention, even when the substrate to be supported is supported in a convex shape, it can be supported with a good convex curved surface, so that the bonding can be performed in a good state, and the expansion and contraction of the pattern can be achieved. It is possible to form a bonded substrate free from such disadvantages.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment.

FIG. 2 is a diagram showing a second embodiment.

FIG. 3 is a view showing a step of forming a bonded SOI structure.

FIG. 4 is a diagram showing a background art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Insulating part 4 Substrate 5 Second supporting part 51 Holding part 52 Holding jig 10 Silicon part 13 First supporting part 14 Bend jig 7 Holding member 8 Holding jig 9 Mounting member

Claims (8)

(57) [Claims] 1. A supporting device for joining two substrates to form a bonded substrate, comprising: a first supporting portion for supporting one of the substrates; and a projecting portion for projecting the other substrate to the one of the substrates. And a bend jig for supporting a central portion of the supported substrate in a convex shape, and a holding member for supporting a peripheral portion of the supported substrate. A supporting device for forming a substrate, comprising: a jig; and the holding jig includes a holding portion formed so as to be able to move in and out according to the shape of the supported substrate. 2. The supporting apparatus for forming a bonded substrate according to claim 1, wherein at least one of the two substrates is a semiconductor wafer and forms a bonded semiconductor substrate. 3. The supporting apparatus for forming a bonded substrate according to claim 1, wherein the holding jig is made of a material that does not cause metal contamination and carbon contamination. 4. A supporting device for joining two substrates to form a bonded substrate, wherein the first supporting portion supports one substrate and the other substrate is convex with respect to the one substrate. a second supporting portion capable of supporting at state, the second support portion is configured to have a holding member capable of supporting the entire of the supported substrate to a convex shape, the second support portion, the Support the center of the support substrate in a convex shape
And a holding member for supporting the supported substrate.
Holding jig for engaging and supporting the peripheral portion of the member to be placed
A supporting device for forming a bonded substrate. 5. A bonded substrate formed by joining two substrates.
A supporting device for supporting one substrate and a first substrate supporting the other substrate.
The second support capable of supporting the one substrate in a convex state.
Comprising a part, the second supporting section supports the entire of the supported substrate to a convex shape
Together with the obtained holding member, at least one of the two substrates is a semiconductor wafer, bonding the substrate forming support apparatus, characterized in that to form a bonding semiconductor substrate. 6. A bonded substrate formed by joining two substrates.
A supporting device for supporting one substrate and a first substrate supporting the other substrate.
The second support capable of supporting the one substrate in a convex state.
Comprising a part, the second supporting section supports the entire of the supported substrate to a convex shape
Together with the obtained holding member, the holding member is metal contamination and bonding the substrate forming support apparatus characterized by comprising a material that does not result in carbon contamination. 7. The supporting device for forming a bonded substrate according to claim 4, wherein at least one of the two substrates is a semiconductor wafer and forms a bonded semiconductor substrate. 8. A method for forming a bonded substrate in which polished surfaces of two substrates are directly bonded to each other to form a bonded substrate, wherein one of the substrates is supported by a first support portion and a flat substrate is formed. By holding the outer peripheral portion of the other substrate placed on the surface and mechanically pressing the other substrate with a bend jig having a convexly curved support surface, the other substrate is bonded to the curved surface convex shape. How to form a bonded substrate
Law .