JP2008118029A - Semiconductor device manufacturing method and semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor device manufacturing method that enables to avoid troubles such as substrate breakage in a post-step and intrusion of chemicals while allowing excellent junction between a semiconductor substrate and a transparent substrate even if an edge bead occurs when joining the semiconductor substrate with the transparent substrate via adhesive layers. <P>SOLUTION: The semiconductor device manufacturing method is used for manufacturing a semiconductor device composed by joining the semiconductor substrate with the transparent substrate via adhesive layers. The method is successively provided with the following steps, that is, a step for forming a first adhesive layer by spin-coating a first adhesive resin on one face of the semiconductor substrate, a step for exposing a part of the outer peripheral part and a prescribed portion in the semiconductor substrate by partially removing the first adhesive layer, a step for forming a second adhesive layer only on the exposed parts in the outer peripheral part by spin-coating a second adhesive resin on the semiconductor substrate, and a step for joining the semiconductor substrate and the transparent substrate with each other while pressurizing them after arranging the transparent substrate on the semiconductor substrate via the first/second adhesive layers. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a semiconductor device manufacturing method and a semiconductor device.

Conventionally, in order to seal a functional element such as a solid-state imaging device mounted on a semiconductor substrate, a technique has been proposed in which a cap substrate (light transmissive protective member) made of a glass substrate or the like is bonded and fixed to the semiconductor substrate via an adhesive layer (For example, Patent Document 1).
In this case, as a method of bonding the glass substrate to the semiconductor substrate, an adhesive resin is selectively applied on the semiconductor substrate so as to surround the functional element, and after the glass substrate is pressure-bonded to the adhesive resin, A method of curing by applying ultraviolet rays or the like is used.

At this time, as a method for selectively applying the adhesive resin, a method combining spin coating and exposure development is the easiest. However, in the method using spin coating, there is a problem that a bulge called an edge bead can be formed on the outer peripheral portion of the formed adhesive layer. Specifically, as shown in FIG. 3, when the semiconductor substrate 30 and the glass substrate 31 are bonded, the outer peripheral portion of the substrate is hindered by the rising (edge bead 32 ′) of the adhesive layer 32, and cannot be bonded well. As a result, there is a risk of causing fatal problems such as cracking of the substrate in a later process or infiltration of a chemical solution.
JP 2004-207461 A

The present invention has been devised in view of such a conventional situation, and even when an edge bead occurs when a semiconductor substrate and a transparent substrate are bonded via an adhesive layer, the semiconductor substrate and the transparent substrate It is a first object of the present invention to provide a method of manufacturing a semiconductor device that can satisfactorily bond the substrate and avoid inconveniences such as substrate cracking and chemical solution intrusion in a subsequent process.
A second object of the present invention is to provide a semiconductor device in which the semiconductor substrate and the transparent substrate are favorably bonded via an adhesive layer without an edge bead.

A method for manufacturing a semiconductor device according to claim 1 of the present invention is a method for manufacturing a semiconductor device in which a semiconductor substrate and a transparent substrate are bonded via an adhesive layer, and includes a first adhesive property on one surface of the semiconductor substrate. Forming a first adhesive layer by spin-coating a resin; removing a part of the first adhesive layer to expose an outer peripheral portion of the semiconductor substrate and a predetermined portion; and the semiconductor substrate A step of forming a second adhesive layer only on the exposed portion of the outer peripheral portion by spin-coating a second adhesive resin thereon, and the semiconductor through the first adhesive layer and the second adhesive layer A step of arranging the transparent substrate on the substrate and bonding them together while applying pressure.
According to a second aspect of the present invention, there is provided a method for manufacturing a semiconductor device according to the first aspect, wherein the same material is used as the first adhesive resin and the second adhesive resin.
A semiconductor device according to claim 3 of the present invention is a semiconductor device in which a semiconductor substrate provided with a functional element and a transparent substrate are bonded via an adhesive layer, and the adhesive layer surrounds the functional element. The first adhesive layer made of the first adhesive resin arranged as described above and the second adhesive layer made of the second adhesive resin arranged on the outer peripheral portion of the semiconductor substrate.
According to a fourth aspect of the present invention, in the semiconductor device according to the third aspect, the first adhesive resin and the second adhesive resin are the same material.

In the present invention, the edge bead can be removed by removing the outer peripheral portion of the first adhesive layer formed on one surface of the semiconductor substrate. After that, by forming the second adhesive layer only on the outer peripheral portion, when joining the semiconductor substrate and the transparent substrate via the adhesive layer, it can be satisfactorily joined without being hindered, and thus It is possible to provide a method for manufacturing a semiconductor device that can avoid inconveniences such as substrate cracking and chemical solution intrusion in a subsequent process.
In the present invention, the adhesive layer includes a first adhesive layer disposed so as to surround the functional element and a second adhesive layer disposed on the outer peripheral portion of the semiconductor substrate, thereby providing the functional element. Thus, a semiconductor device can be provided in which the semiconductor substrate and the transparent substrate are satisfactorily bonded to each other through the adhesive layer, and problems such as cracking of the substrate and infiltration of a chemical solution are avoided.

  Hereinafter, an embodiment of a semiconductor device according to the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view showing an example of a semiconductor device of the present invention.
The semiconductor device 1 of the present invention is a semiconductor device in which a semiconductor substrate 2 provided with a functional element 3 and a transparent substrate 7 are bonded via an adhesive layer 6, and the adhesive layer 6 includes the functional element 3. It is comprised from the 1st adhesive layer 4 which consists of the 1st adhesive resin 4a distribute | arranged so that it may surround, and the 2nd adhesive layer 5 which consists of the 2nd adhesive resin 5a distribute | arranged to the outer peripheral part of the said semiconductor substrate 2 It is characterized by.

  In the present invention, the adhesive layer 6 includes the first adhesive layer 4 disposed so as to surround the functional element 3 and the second adhesive layer 5 disposed on the outer peripheral portion of the semiconductor substrate 2. It is possible to provide the semiconductor device 1 in which the semiconductor substrate 2 including the element 3 and the transparent substrate 7 are satisfactorily bonded via the adhesive layer 6 and inconveniences such as cracking of the substrate and infiltration of a chemical solution are avoided.

  The semiconductor substrate 2 is made of, for example, silicon, and a large number of functional elements 3 are formed on the surface. In the semiconductor substrate 2, although not shown, a boron diffusion layer for electrically connecting the functional element 3 to an external electronic circuit or the like, or a penetration penetrating the front surface 2 a and the back surface 2 b of the semiconductor substrate 2. An electrode or the like is provided.

The functional element 3 is an element having a fine three-dimensional structure, for example, an image sensor such as a solid-state imaging element (CCD), a MEMS device (MEMS = Micro Electro Mechanical System), or the like.
Examples of the MEMS device include a micro relay, a micro switch, a pressure sensor, an acceleration sensor, a high frequency filter, and a micro mirror.

The transparent substrate 7 is disposed above the functional element 3 with an interval, and has a role of protecting the functional element 3. As the transparent substrate 7, a plate material made of a transparent material such as resin or glass can be used.
The adhesive layer 6 includes a first adhesive layer 4 disposed so as to surround the functional element 3 and a second adhesive layer 5 disposed on the outer peripheral portion of the semiconductor substrate 2, and the semiconductor substrate 2 and the transparent substrate 7. Between the semiconductor substrate 2 and the transparent substrate 7. The adhesive layer 6 can be formed by applying an adhesive resin to the surface 2 a of the semiconductor substrate 2.

As the adhesive resin used for the adhesive layer 6, for example, an epoxy resin, a photosensitive BCB resin, or the like can be used. The thickness of the adhesive layer 6 is set to a thickness that provides sufficient adhesive strength depending on the type of adhesive resin, but is preferably about 10 μm to 100 μm.
The first adhesive resin 4a and the second adhesive resin 5a are preferably the same material. Thereby, the curvature of the board | substrate etc. resulting from the difference of contraction rate of both can be prevented.

Next, a method for manufacturing the semiconductor device shown in FIG. 1 will be described.
The method for manufacturing a semiconductor device of the present invention is a method for manufacturing a semiconductor device in which a semiconductor substrate 2 and a transparent substrate 7 are bonded via an adhesive layer 6, and the first adhesive resin 4 a is formed on one surface of the semiconductor substrate 2. A step of forming the first adhesive layer 4 by spin coating, a step of removing a part of the first adhesive layer 4 to expose the outer peripheral portion of the semiconductor substrate 2 and a predetermined portion, A step of forming the second adhesive layer 5 only on the exposed portion of the outer peripheral portion by spin-coating the second adhesive resin 5a on the semiconductor substrate 2, and the first adhesive layer 4 and the second adhesive layer A step of arranging the transparent substrate 7 on the semiconductor substrate 2 via 5 and bonding them together under pressure.

In the present invention, by removing the outer peripheral portion of the first adhesive layer 4 formed on one surface of the semiconductor substrate 2, the edge bead 4 ′ (swelling of the outer peripheral portion) can be removed. After that, by forming the second adhesive layer 5 only on the outer peripheral portion, when the semiconductor substrate 2 and the transparent substrate 7 are bonded via the adhesive layer 6, they are bonded well without being disturbed by the rise. As a result, inconveniences such as cracking of the substrate in the subsequent process and infiltration of the chemical solution can be avoided.
Hereinafter, each step will be described in detail.

  First, as shown in FIG. 2A, the first adhesive layer 4 is formed by spin-coating the first adhesive resin 4 a on one surface of the semiconductor substrate 2. A photosensitive resin is used as the first adhesive resin 4a. At this time, a rise (edge bead 4 ') as shown in the figure is generated on the outer peripheral portion of the substrate due to the influence of the surface tension and the like. The range where the edge bead can be formed is in the range of 2 to 8 mm from the outermost periphery of the substrate, although it depends on the spin conditions and the viscosity of the resin.

  Next, as shown in FIG. 2B, a part of the first adhesive layer 4 is removed to expose the outer peripheral portion of the semiconductor substrate 2 and a predetermined portion. At this time, the raised portion (edge bead 4 ') of the outer peripheral portion is also simultaneously removed as an unnecessary portion by the exposure mask. Since the adhesive resin is generally a negative type resin, the case where the adhesive resin is a negative type is assumed here. In this case, in order to remove the outer peripheral portion, the outer peripheral portion of the photomask may be covered with Cr or the like so that the outer peripheral portion is not exposed. For example, 2-8 mm with the edge bead 4 ′ is removed by shading. At this time, the exposed portion of the adhesive resin undergoes a crosslinking reaction, and the physical property values inevitably change. Specifically, it becomes harder than before exposure.

Next, as shown in FIG. 2C, the second adhesive layer 5 is formed only on the exposed portion of the outer peripheral portion by spin coating the second adhesive resin 5a on the semiconductor substrate 2. Specifically, the second adhesive resin 5a is selectively dispensed again on the exposed portion of the outer peripheral portion, and then spun for homogenization. At this time, of course, the edge bead 5 ′ is generated again.
The second adhesive resin 5a may be selected from a material different from the first adhesive resin 4a, but the first adhesive resin 4a and the second adhesive resin 5a are preferably the same material. . Thereby, the curvature of the board | substrate etc. resulting from the difference of contraction rate of both can be prevented.

Next, as shown in FIG. 2D, a process such as baking is performed as necessary, and the transparent substrate 7 is bonded. As a bonding method, a method of thermocompression bonding in a vacuum chamber is used. At this time, the second adhesive resin 5a applied to the outer peripheral portion of the substrate is not cross-linked because it does not pass through the exposure process, and is kept soft even if it is a photosensitive resin. Therefore, it can be crushed relatively easily by applying an appropriate weight, and can be bonded without hindering the bonding of the outer peripheral portion. Of course, an adhesive resin that is not a photosensitive resin may be selected and used for recoating.
The semiconductor device 1 shown in FIG. 1 can be obtained by the method as described above.

  In the semiconductor device manufactured in this way, even if edge beads occur in the adhesive layer, the semiconductor substrate provided with the functional element and the transparent substrate are favorably bonded via the adhesive layer. As a result, poor adhesion at the outer peripheral portion and inconveniences resulting therefrom can be greatly reduced, and the yield is improved. For example, even when the bonded substrate is thinned, problems such as chipping of the substrate occur if there are many poor adhesions on the outer peripheral portion, but such a problem can be prevented. Further, since the outer peripheral portion can be effectively sealed, the infiltration of the chemical solution can be prevented.

  As described above, the semiconductor device and the manufacturing method thereof according to the present invention have been described. However, the present invention is not limited to these examples, and various modifications can be made without departing from the spirit of the invention.

  The present invention is widely applicable to semiconductor device manufacturing methods and semiconductor devices.

It is sectional drawing which shows an example of the semiconductor device of this invention. FIG. 2 is a cross-sectional view showing an example of a method for manufacturing the semiconductor device shown in FIG. It is sectional drawing which shows an example of the conventional semiconductor device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Semiconductor device, 2 Semiconductor device, 3 Functional element, 1st contact bonding layer, 4a 1st contact bonding resin, 5 2nd contact bonding layer, 5a 2nd contact bonding resin, 6 contact bonding layer, 7 transparent substrate.

Claims (4)

A method of manufacturing a semiconductor device in which a semiconductor substrate and a transparent substrate are bonded via an adhesive layer,
Forming a first adhesive layer by spin-coating a first adhesive resin on one surface of a semiconductor substrate;
Removing a part of the first adhesive layer to expose an outer peripheral portion and a predetermined portion of the semiconductor substrate;
Forming a second adhesive layer only on the exposed portion of the outer periphery by spin-coating a second adhesive resin on the semiconductor substrate;
Arranging the transparent substrate on the semiconductor substrate through the first adhesive layer and the second adhesive layer, and joining them together while pressing them, in order. .   The method for manufacturing a semiconductor device according to claim 1, wherein the same material is used as the first adhesive resin and the second adhesive resin. A semiconductor device in which a semiconductor substrate provided with a functional element and a transparent substrate are bonded via an adhesive layer,
The adhesive layer includes a first adhesive layer made of a first adhesive resin arranged so as to surround the functional element, and a second adhesive layer made of a second adhesive resin arranged on the outer periphery of the semiconductor substrate, A semiconductor device comprising:   The semiconductor device according to claim 3, wherein the first adhesive resin and the second adhesive resin are made of the same material.

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