JP5799993B2 - Substrate bonding apparatus and substrate bonding method - Google Patents

Description

The present invention relates to a substrate bonding apparatus and a substrate bonding how are bonded by aligning a plurality of substrates.

In recent years, notebook computers and mobile phones that use semiconductor integrated circuits have become increasingly sophisticated. As a result, there is an increasing demand for higher density and higher functionality of semiconductor integrated circuits.

One method for increasing the density and functionality of semiconductor integrated circuits is to bond substrates such as wafers and stack the substrates.

In the case of bonding the substrates, for example, since it is necessary to bond the electrodes of the wafer, they need to be aligned and bonded to each other. To align and bond the substrates,
A substrate bonding apparatus provided with a pair of substrate holding means is used. Here, the substrates to be bonded are first and second substrates. First, the first and second substrates are respectively positioned and held by a pair of substrate holding means. Next, with the pair of substrate holding means aligned, at least one of the pair of substrate holding means is moved to join the first and second substrates.

  Such a substrate bonding apparatus is described in Patent Document 1, for example.

JP 2005-302858 A

However, when the substrate is bonded by the substrate bonding apparatus as described above, the substrate (for example,
Due to variations in the flatness of the wafer surface and uneven thickness of the applied resin, air pockets (voids) may be generated between the bonded substrates. There is known a bonding method in which the substrate is brought into contact with the substrate so that the central portion of the substrate surface is convex so as to prevent such air accumulation and the contact area is gradually increased from the central portion. However, when bonding is performed in such a way that the central portion of the substrate surface is convex, the force applied for bonding is concentrated only on the central portion (contact portion), and bonding is performed uniformly over the entire surface of the substrate. There was no problem.

Therefore, there is a need for a substrate bonding apparatus, a substrate bonding method, and a substrate holder that can perform bonding uniformly over the entire surface of the substrate while preventing air accumulation between the bonded substrates.

The substrate bonding apparatus according to the present invention is a bonding apparatus for bonding two substrates to each other, and includes a first substrate holding unit that holds one of the substrates, and a second substrate holding unit that holds the other substrate. The space including at least the two substrates is evacuated, and at least the first substrate holding means is configured such that when the two substrates are joined to each other, a part of the one substrate is the other substrate. The substrate is first contacted, and at least a part of the one substrate is convex so that a contact area of the two substrates extends from the part of the one substrate .

According to the substrate bonding apparatus of the present invention, the control means controls the force acting on the first and second substrate holding means according to the contact area of the substrate, so that the force applied for bonding is concentrated only on the contact portion. The bonding can be performed uniformly over the entire surface of the substrate.

A substrate bonding method according to the present invention is a bonding method for bonding two substrates to each other, wherein at least a part of at least one of the substrates is convex, and the part of the one substrate is made to be the other substrate. A step of bringing the two substrates into contact with each other, a step of evacuating a space including at least the two substrates, and a contact area of the two substrates extending from the part of the one substrate in a state where the space is evacuated. Joining the two substrates to each other .

According to the substrate bonding method of the present invention, since the force applied to the first and second substrate holding means is controlled according to the contact area of the substrate, the force applied for bonding does not concentrate only on the contact portion. The bonding can be performed uniformly over the entire surface of the substrate.

A substrate holder for a substrate bonding apparatus according to a reference embodiment of the present invention has a convex portion in a region excluding at least a part of a peripheral portion of a surface that holds a substrate, and includes an elastic material on the surface that holds the substrate. Features.

The substrate holder for a substrate bonding apparatus according to the reference embodiment of the present invention includes an elastic material on the surface that holds the substrate. Therefore, when only a part of the substrate surface comes into contact, the elastic material is deformed and the shape of the substrate is changed. Since it changes, it can prevent that excessive force acts only on the part which the substrate surface contacted.

A substrate holder for a substrate bonding apparatus according to a reference embodiment of the present invention has a hollow portion having a convex portion in a region excluding at least a part of a peripheral portion of a surface holding a substrate and filled with gas or liquid. It is characterized by.

Since the substrate holder for a substrate bonding apparatus according to the reference embodiment of the present invention includes a hollow portion filled with gas or liquid, when only a part of the substrate surface is in contact, the pressure of the gas or liquid in the hollow portion is Since it becomes uniform, it is possible to prevent the pressure from becoming excessive only at the contacted portion of the substrate surface.

According to the present invention, the air reservoir between the joined substrates while not occurred, the substrate bonding apparatus and a substrate bonding how that can be performed uniformly bonding over the entire surface of the substrate is obtained.

It is a figure which shows the structure of the board | substrate bonding apparatus by one Embodiment of this invention. It is a figure which shows the detailed structure of a pressurization apparatus and a control apparatus by one Embodiment of this invention. It is a figure which shows the structure of the 1st substrate holder and 2nd substrate holder by one Embodiment of this invention. It is a figure which shows the structure of the 1st board | substrate holder and 2nd board | substrate holder by other embodiment of this invention. 3 is a flowchart illustrating a substrate bonding method according to an embodiment of the present invention.

FIG. 1 is a diagram illustrating a configuration of a substrate bonding apparatus according to an embodiment of the present invention. The substrate bonding apparatus according to the present embodiment includes an upper frame 301 and a lower frame 303. The first plate 103 is installed on the upper frame 301, and the first substrate holder 101 is installed on the first plate 103. The first substrate holder 101 holds the first substrate W1. A pressure device 250 is installed on the lower frame 303, the pressure device 250 is provided with a second plate 203, and a second substrate holder 201 is installed on the second plate 203. The second substrate holder 201 holds the second substrate W2.

The pressurizing device 250 raises the second plate 203, so that the second substrate holder 2
01 rises, and the first substrate W1 held by the first substrate holder 101 and the second substrate W2 held by the second substrate holder 201 are joined. When the substrate is a wafer, the wafer may be bonded by previously applying a resin to the bonding surface of the wafer and sandwiching the resin between the wafers. In the present specification and claims, “pressurization” means applying a force to the substrate in order to join the substrates first.

Furthermore, the substrate bonding apparatus according to the present embodiment includes a control device 300 for controlling the pressure device 250.

The space S including the first substrate holder 101 and the second substrate holder 201 of the substrate bonding apparatus may be sealed to increase the degree of vacuum. If the degree of vacuum is increased, air accumulation between the substrates is less likely to occur during bonding.

FIG. 2 is a diagram illustrating a detailed configuration of the pressurizing device 250 and the control device 300 according to an embodiment of the present invention. The pressurizing device 250 includes a base part 251 and an elevating part 253, and the elevating part 253 is provided with a second plate 203. The control device 300 includes an electropneumatic regulator 3
01 and a pressure setting device 303. The pressure inside the base portion 251 of the pressurizing device 250 is changed, and the elevating unit 253 is moved up and down. The pressure inside the base portion 251 is controlled by the control device 300. Specifically, the electropneumatic regulator 301 of the control device 300 controls the pressure inside the base portion 251 so as to realize the pressurization set by the pressurization setting device 303 of the control device 300.

The elevating unit 253 is configured to move up and down along the stroke guide 207, and the stroke guide 207 includes a position measuring device (for example, a position measuring device for detecting the position of the elevating unit 253).
305) is installed. The position measurement value measured by the position measuring device 305 is sent to the pressure setting device 303 of the control device 300. Pressure setting device 303
Will be described in detail later.

The load cell 307 may be installed so as to support the base portion 251 of the pressurizing device 250, and the pressure applied by the pressurizing device 250 may be measured. The electropneumatic regulator 301 may control the applied pressure using the measured value of the applied pressure measured by the load cell 307.

The drive source of the pressurizing device 250 may be other such as a motor. Moreover, you may comprise so that the 1st substrate holder 101 may be raised / lowered with a pressurization apparatus.

FIG. 3 is a diagram showing the configuration of the first substrate holder 101A and the second substrate holder 201A according to an embodiment of the present invention. First substrate holder 101A and second substrate holder 20
1A may be configured to hold the substrate by an electrostatic chuck or a vacuum chuck.

The surface of the first substrate holder 101A that holds the substrate is a plane, but the second substrate holder 10
The surface holding the 2A substrate is configured so that the central portion is convex. For this reason, when the substrates are joined, the central portion of the second substrate W2 held by the second substrate holder 102A becomes convex, so the central portion of the second substrate W2 and the center of the first substrate W1 It joins so that a part may contact initially and a contact area may spread gradually. It is preferable that the curvature of the surface of the second substrate holder 102 that holds the substrate does not change significantly over the entire surface so that the substrates can be joined smoothly. The curvature of the surface holding the substrate is determined so that the substrates can be smoothly joined without causing air accumulation.

In another embodiment, the first substrate holder 101A may be configured such that the central portion of the surface that holds the substrate is convex. Or you may comprise so that the center part of the surface holding the board | substrate of both board | substrate holders may become convex.

Further, the portion of one or both of the substrate holders is configured such that a portion excluding at least a part of the peripheral portion of the surface holding the substrate is convex, and the substrate portion corresponding to the convex portion when the substrates are joined May be contacted first and air may be removed from at least a portion of the non-convex periphery.

Also, as shown in FIG. 3, the first substrate holder 101A and the second substrate holder 201A
The surface holding the substrate includes elastic materials 1011 and 2011. According to this embodiment, when only a part of the substrate surface comes into contact, the elastic material 1011 of the first substrate holder 101A and the elastic material 2011 of the second substrate holder 201A are deformed, and the shape of the substrate changes. Therefore, it is possible to prevent an excessive force from acting only on the contacted portion of the substrate surface. The elastic materials 1011 and 2011 are conductive metal, soft metal foil such as resin, copper, or the like. The material and thickness of the elastic materials 1011 and 2111 are determined so that an excessive force is not applied to the contacted portion of the substrate surface in a state where only a portion of the substrate surface is in contact with the elastic modulus.

  In other embodiments, only one substrate holder may comprise an elastic material.

In this way, if the center part of the surface holding the substrate is configured to be convex and bonding is performed using a substrate holder provided with an elastic material on the surface holding the substrate, only a part of the substrate surface is formed. In the case of contact, the elastic material of the substrate is deformed and the shape of the substrate changes, so that it is possible to prevent an excessive force from acting only on the contacted portion of the substrate surface.

FIG. 4 is a diagram showing the configuration of the first substrate holder 101B and the second substrate holder 201B according to another embodiment of the present invention. Similar to the embodiment shown in FIG. 3, the first substrate holder 1
The surface for holding the 01B substrate is a flat surface, but the center portion of the surface for holding the substrate of the second substrate holder 201B is configured to be convex. In the present embodiment, the second substrate holder 201 </ b> B includes a hollow portion 2013. The hollow portion 2013 is filled with gas or liquid so as to have a predetermined pressure. According to the present embodiment, when only a part of the substrate surface is in contact, the pressure of the gas or liquid in the hollow portion 2013 becomes uniform, so that the pressure is excessive only at the contacted portion of the substrate surface. Is prevented.

In another embodiment, the first substrate holder 101B may be configured such that the central portion of the surface that holds the substrate is convex. Or you may comprise so that the center part of the surface holding the board | substrate of both board | substrate holders may become convex.

Further, the portion of one or both of the substrate holders is configured such that a portion excluding at least a part of the peripheral portion of the surface holding the substrate is convex, and the substrate portion corresponding to the convex portion when the substrates are joined May be contacted first and air may be removed from at least a portion of the non-convex periphery.

Moreover, you may comprise so that the 1st board | substrate holder 101B may be provided with a hollow part. Or
You may comprise so that both board | substrate holders may be provided with a hollow part.

As described above, if a substrate holder having a hollow portion, which is configured so that the central portion of the surface holding the substrate is convex and is filled with a gas or liquid having a predetermined pressure, is joined, Since the pressure of the gas or fluid in the part becomes uniform, it is possible to prevent the pressure from becoming excessive in the local area of the contact surface.

  FIG. 5 is a flowchart illustrating a substrate bonding method according to an embodiment of the present invention.

In step S5010 of FIG. 5, the first substrate holder 101 and the second substrate holder 201 hold the first substrate W1 and the second substrate W2. Here, each of the first substrate W1 and the second substrate W2 may be a set of a plurality of substrates already bonded. The substrate holder and the substrate may be aligned in advance using a fiducial mark or the like.

In step S5020 of FIG. 5, the first substrate holder 101 and the second substrate holder 201 are driven until the control device 300 drives the pressure device 250 and the first substrate W1 and the second substrate W2 come into contact with each other. Approach.

In step S5030 of FIG. 5, a target value of a force that is applied to the first substrate holder 101 and the second substrate holder 201 by the pressure setting device 303 of the control device 300 is obtained. First
The target value of the force applied to the substrate holder 101 and the second substrate holder 201 is determined so that the applied pressure (pressure) per unit area always becomes a desired value while the contact area of the substrate changes. In order to achieve the desired pressure, the contact area of the substrate is estimated, and the applied pressure is determined by multiplying the estimated contact area by the desired pressure value. Here, the desired pressure value may be determined from experience values.

  The function of the pressure setting device 303 will be described in detail below.

The pressure setting device 303 may estimate the contact area from the position of the second substrate holder 201 when determining the target value of the force to be applied to the first substrate holder 101 and the second substrate holder 201. The position of the first substrate holder 101 is fixed and known. Also, the physical properties such as the first and second substrate holders and the dimensions and elastic modulus of the substrate are known. Therefore, if the position of the second substrate holder 201 is known, the deformation of the substrate due to contact and the contact area can be estimated.

Specifically, the pressurizing force setting device 303 is installed on the stroke guide 207, and the elevating unit 2.
The position of the second substrate holder 201 is obtained from the position measurement value from a position detector (for example, a linear guide) 305 for detecting the position 53, and the substrate contact is determined from the position of the second substrate holder 201. Estimate the area.

In another embodiment, the pressure setting device 303 is configured such that the first substrate holder 101 includes a distance sensor such as a laser distance meter attached to one or both of the first substrate holder 101 and the second substrate holder 201. The distance between the second substrate holder 201 and the second substrate holder 201 may be measured, and the contact area of the substrate may be estimated from the distance.

Further, in another embodiment in which the substrate is a transparent substrate such as a glass substrate, the material of the first substrate holder 101 and the second substrate holder 201 is also a transparent material, and the pressure setting device 303 is configured to contact the substrate. You may measure a direct contact area by acquiring the image of a part.

The pressurizing force setting device 303 multiplies the estimated contact area by a desired pressure value to obtain a target value of the pressurizing force and sets it in the electropneumatic regulator 301. Here, the desired pressure value may be constant regardless of the contact area. Or you may change according to a contact area.

In step S5040 of FIG. 5, the electropneumatic regulator 301 of the control device 300 controls the force applied to the first substrate holder 101 and the second substrate holder 201 according to the target value of the applied pressure.

According to the substrate bonding method of the present embodiment, since a desired pressure value can be applied to the contact surface of the substrate, only a part of the substrate is first contacted so as not to generate air pockets, thereby reducing the contact area. Even if the substrates are joined so as to be spread out, excessive pressure is prevented from acting on the contact surface of the substrate.

As described above, according to the present invention, it is possible to obtain a substrate bonding apparatus, a substrate bonding method, and a substrate holder capable of uniformly bonding the entire surface of the substrate while preventing air accumulation between the bonded substrates. .

One embodiment of the present invention is characterized in that a central portion of a surface for holding at least one of the first and second substrate holding means is convex.

According to this embodiment, it is possible to perform bonding so that the contact area is gradually increased from the central portion of the substrate and no air pool is generated between the substrates.

Another embodiment of the present invention is characterized in that at least one of the first and second substrate holding means includes an elastic material.

According to this embodiment, when only a part of the substrate surface comes into contact, the elastic material is deformed and the shape of the substrate changes, so that an excessive force is prevented from acting only on the contacted part of the substrate surface. it can.

Another embodiment of the present invention is characterized in that at least one of the first and second substrate holding means includes a hollow portion.

According to this embodiment, when only a part of the substrate surface is in contact, the pressure of the gas or liquid in the hollow portion becomes uniform, so that it is prevented that the pressure is excessive only in the contacted part of the substrate surface. The

Another embodiment of the present invention is characterized in that the contact area of the substrate surface is estimated according to the positions of the first and second substrate holding means.

According to the present embodiment, the contact area of the substrate surface is reliably and easily estimated according to the positions of the first and second substrate holding means.

101, 101A, 101B ... first substrate holder, 201, 201A, 201B ... second substrate holder, 250 ... pressure device, 300 ... control device

Claims (7)

A joining method for joining two substrates together,
Making at least a portion of at least one of the substrates convex;
Contacting the portion of the one substrate with the other substrate;
The two substrates in contact with each other are pressurized so that the applied pressure per unit area applied to the two substrates in a region in contact with each other is a predetermined target value, and the part of the one substrate is applied by the applied pressure. Bonding the two substrates together so that the contact area of the two substrates extends from the part of the one substrate by changing the shape of
A joining method including: Vacuuming a space containing at least the two substrates;
The bonding method according to claim 1, wherein the two substrates are bonded to each other so that a contact area of the two substrates extends from the part of the one substrate in a state where the space is evacuated. Measuring the contact area;
Controlling the force acting on the substrate holding means for holding at least one of the two substrates according to the contact area;
The joining method according to claim 1 or 2, wherein   The bonding method according to claim 3, wherein the contact area is measured by acquiring images of the two substrates.   The bonding method according to claim 3, wherein the contact area is estimated based on a distance between the two substrates.   The contact area is estimated based on at least one position of a first substrate holding unit that holds one of the two substrates and a second substrate holding unit that holds the other substrate. Joining method. A joining device for joining two substrates together,
First substrate holding means for holding one of the substrates;
Second substrate holding means for holding the other substrate;
An elevating part for moving at least one of the first substrate holding means and the second substrate holding means;
With
At least the first substrate holding means moves at least the portion of the one substrate so that the portion of the one substrate first contacts the other substrate when the two substrates are bonded to each other. Convex,
The elevating unit moves at least one of the first substrate holding unit and the second substrate holding unit, so that a pressing force per unit area applied to the two substrates in a region in contact with each other is predetermined. By pressurizing the two substrates in contact with each other so as to be a target value, and changing the shape of the part of the one substrate by the applied pressure, the contact area of the two substrates becomes the one of the one substrate A bonding apparatus for bonding the two substrates to each other so as to spread from the part.

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