JP2008130705A - Method of manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that, after a carrier substrate is bonded on a semiconductor substrate with an adhesive layer disposed therebetween and then subjected to predetermined treatment, a residue of an adhesive remains on the semiconductor substrate when the carrier substrate is peeled from the semiconductor substrate. <P>SOLUTION: A method of manufacturing a semiconductor device includes a first step of forming adhesive layers (6A, 6B) formed of a photosensitive material on the first surface of a semiconductor substrate 1 including effective element regions 2 for forming an element circuit and ineffective regions 3 surrounding the effective element regions, a second step of exposing the adhesive layers with light and developing the adhesive layers with the adhesive layers removed from the effective element regions 2 and with the adhesive layer 6A remaining on the ineffective regions 3, a third step of bonding the carrier substrate on the first surface of the semiconductor substrate 1 with the adhesive layer 6A disposed therebetween, a fourth step of subjecting the semiconductor substrate 1 to predetermined treatment with the carrier substrate bonded thereon, and a fifth step of cutting the effective element regions 2 and the ineffective regions 3 into the individual semiconductor substrates 1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a semiconductor device applied when a support substrate is attached to a semiconductor substrate and a predetermined process is performed.

  When manufacturing a 3D stacked type SIP (System in Package) with a chip-on-chip structure using a through electrode to a semiconductor chip represented by an LSI (Large Scale Integration) chip, the semiconductor chip In order to efficiently and easily form through electrodes and backside wiring, it is necessary to reduce the thickness of the semiconductor substrate (wafer). However, if the thickness of the semiconductor substrate is reduced, the risk of warping and cracking increases, and handling becomes difficult.

  For this reason, conventionally, for example, as shown in FIG. 10, a reinforcing support substrate 53 is attached to the main surface (bump forming surface) of the semiconductor substrate 51 on which the bumps 50 are formed via an adhesive layer 52. In this state, the back surface of the semiconductor substrate 51 is ground by a grinder 54 to reduce the thickness. In addition, the semiconductor substrate 51 is subjected to a predetermined process with the support substrate 53 attached, and then the support substrate 53 is peeled off from the semiconductor substrate 51 together with the adhesive layer 52, and then the semiconductor substrate 51 is removed by a dicing apparatus (not shown). It is singulated.

  In relation to such a semiconductor device manufacturing technology, for example, Patent Document 1 discloses a material such as alumina, aluminum nitride, boron nitride, or silicon carbide having a thermal expansion coefficient substantially the same as that of a semiconductor substrate as a support substrate. And a thermoplastic resin such as polyamide is used as an adhesive for bonding the support substrate and the semiconductor substrate, and as a method of applying this adhesive, a method of forming a film having a thickness of 10 to 100 μm, or an adhesive resin solution is used. A method has been proposed in which a film of 20 μm or less is formed by spin coating and drying.

  In Patent Document 2, a step of fixing a semiconductor substrate to a support substrate via a support tape formed from an adhesive sheet that generates gas from at least one surface by stimulation, and fixing the semiconductor substrate to the support substrate A technique relating to a method of manufacturing an IC chip is disclosed which includes a step of processing in a state, a step of stimulating the support tape, and a step of peeling the support tape from the semiconductor substrate.

JP 2001-77304 A JP 2004-186282 A

  However, in the technique described in Patent Document 1, since the semiconductor substrate and the support substrate are bonded using a thermoplastic resin such as polyamide, the semiconductor substrate is exposed to a high-temperature atmosphere in a processing step after thinning the semiconductor substrate. Then, the adhesive may be dissolved and the semiconductor substrate and the support substrate may be separated. In addition, since the adhesive is applied to the main surface of the semiconductor substrate on which the bumps are formed, when the support substrate and the semiconductor substrate are peeled off, the adhesive is bonded onto the semiconductor substrate by, for example, the composition change of the adhesive by heating in the previous process. The residue of the agent may remain, resulting in poor bonding.

  In particular, when manufacturing a stacked type SIP in which chips are mounted at a high density, a semiconductor substrate is formed at a process temperature of about 300 ° C. in order to form a through electrode and a backside wiring on a semiconductor substrate with a support substrate attached thereto. Since it is necessary to process, adhesive residue is likely to be generated. In addition, at present, there is no material that simultaneously satisfies the characteristics such as heat resistance, chemical resistance, and peelability required for an adhesive for attaching a support substrate (for temporary fixing).

  In the method for manufacturing a semiconductor device according to the present invention, an adhesive layer made of a photosensitive material is formed on a first surface of a semiconductor substrate including an effective element region in which an element circuit is formed and an ineffective region surrounding the effective element region. A first step of removing the adhesive layer from the effective element region and a second step of exposing and developing the adhesive layer with the adhesive layer left in the ineffective region, and an adhesive layer on the first surface of the semiconductor substrate The third step of attaching the support substrate via the step, the fourth step of applying a predetermined process to the semiconductor substrate with the support substrate attached, and separating the semiconductor substrate by separating the effective element region and the invalid region Including a fifth step.

  In the method for manufacturing a semiconductor device according to the present invention, the adhesive layer formed using a photosensitive material on the first surface of the semiconductor substrate is exposed and developed to remove the adhesive layer from the effective element region in advance. In addition, since the support substrate is attached using the adhesive layer left in the ineffective region, the semiconductor substrate can be separated into pieces while the support substrate is attached to the semiconductor substrate.

  According to the method for manufacturing a semiconductor device according to the present invention, it is not necessary to peel the support substrate from the semiconductor substrate, so that it is possible to eliminate problems caused by adhesive residues. Further, in the method using the existing support substrate, when the support substrate is attached to the semiconductor substrate with an adhesive and the through electrode, the back surface wiring, the bump, and the like are formed on the semiconductor substrate, the process temperature is as high as about 300 ° C. Then, the support substrate cannot be peeled from the semiconductor substrate due to the thermal denaturation of the adhesive. As a result, it becomes impossible to use the semiconductor substrate as a semiconductor device. However, if the method of the present invention is used, there is no need to peel the support substrate from the semiconductor substrate, so that the process temperature becomes as high as about 300 ° C. Electrodes, backside wiring, bumps, and the like can be formed on the semiconductor substrate.

  Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
1 to 6 are process diagrams showing a method of manufacturing a semiconductor device according to the first embodiment of the present invention. First, a semiconductor substrate is prepared in which element circuits such as LSI, wiring, bumps (for example, solder bumps) to be protruding electrodes are formed on the first surface (main surface). For example, a silicon wafer can be used as the semiconductor substrate. The bump is formed on the first surface of the semiconductor substrate as a connection terminal.

  As shown in FIGS. 1A and 1B, the semiconductor substrate 1 has a plurality of effective element regions 2 cut out as chips (semiconductor elements) to be cut out finally. The effective element area 2 is an area in which element circuits such as LSI, wiring, electrode portions, and the like are formed, and is partitioned in a lattice shape according to the chip size. The chip is cut out from the semiconductor substrate in a square or rectangular planar shape. Therefore, the effective element region 2 is divided into a square or a rectangle according to the shape of the chip.

  The semiconductor substrate 1 has an ineffective region 3 in addition to the effective element region 2. The invalid region 3 is a region where an element circuit or the like is not formed, and is positioned so as to surround the effective element region 2. The invalid area 3 is an area that is excised when cutting a chip in a subsequent process. A plurality of bumps 4 are formed in the effective element region 2, but no bumps 4 are formed in the invalid region 3. The number and arrangement of the bumps 4 in the effective element region 2 can be arbitrarily changed. For example, the bumps 4 may be disposed only on the outer periphery of the effective element region 2, or the bumps 4 may be disposed on the entire effective element region 2. The invalid region 3 is a region excluding the effective element region 2 in the entire region of the semiconductor substrate 1. For this reason, the ineffective region 3 exists not only in the rectangular frame-shaped portion surrounding each effective element region 2 but also in the peripheral portion of the semiconductor substrate 1. In addition, in a portion surrounding the effective element region 2 (portion called a street), the ineffective region 3 is partitioned in a line shape having a predetermined width vertically and horizontally.

  When the semiconductor substrate 1 with such bumps is prepared, as shown in FIG. 2A, for example, the semiconductor substrate 1 is set horizontally on a substrate holding part (for example, a spin chuck) of a coating apparatus such as a spin coater. As shown in FIGS. 2B and 2C, the semiconductor substrate 1 is rotated by driving a motor or the like, and a photosensitive resist material is dropped from above the rotating semiconductor substrate 1 by the nozzle 5. The adhesive layer 6 is formed on the first surface of the semiconductor substrate 1 so as to cover the bumps 4.

  In this case, the adhesive layer 6 may be formed with a uniform thickness by spin coating so as to cover the entire first surface of the semiconductor substrate 1 with the adhesive layer 6. Further, the thickness dimension of the adhesive layer 6 is set larger than the height dimension of the bump 4 so that all the bumps 4 formed on the semiconductor substrate 1 are completely covered with the adhesive layer 6. As the photosensitive resist material, it is preferable to use an epoxy resin having good adhesiveness and excellent heat resistance, chemical resistance, and the like, and a resin mainly composed of epoxy. However, other than epoxy resins, for example, polyimide resins can be used. Further, the adhesive layer 6 is formed in advance in a sheet shape according to the outer shape of the semiconductor substrate 1, and this adhesive sheet is attached to the first surface of the semiconductor substrate 1, whereby the adhesive layer 6 is formed on the semiconductor substrate 1. May be formed.

  Next, if the photosensitive material used for forming the adhesive layer 6 is a negative type, the adhesive located in the ineffective area 3 of the semiconductor substrate 1 through the opening of the mask 7 as shown in FIG. The layer 6A is irradiated with light and shielded with a mask 7 so that the adhesive layer 6B located in the effective element region 2 is not irradiated with light, whereby an adhesive is applied to the developer used in the subsequent development process. The exposed portion 6A of the layer 6 is insolubilized. If the photosensitive material is a positive type, as shown in FIG. 3B, the adhesive layer 6B located in the effective element region 2 of the semiconductor substrate 1 is irradiated with light through the opening of the mask 7, The exposed portion 6B of the adhesive layer 6 is solubilized in the developer used in the subsequent development process by shielding the adhesive layer 6A located in the ineffective area 3 with light so as not to be irradiated with light. .

  Next, the semiconductor substrate 1 that has been subjected to the exposure process using the mask 7 is immersed in a developer, thereby removing the adhesive layer 6 that is soluble in the developer from the first surface of the semiconductor substrate 1. 3A and 3B, in the adhesive layer 6 covering the first surface of the semiconductor substrate 1, the adhesive layer 6B located in the effective element region 2 is against the developer. The adhesive layer 6A that is soluble and is located in the effective area 3 is insoluble in the developer. For this reason, when the exposed adhesive layer 6 is developed with a developer, the adhesive layer 6B covering the effective element region 2 is removed and the ineffective region 3 is covered as shown in FIG. Only the adhesive layer 6A remains without being removed.

  Here, it is necessary to remove the adhesive layer 6B covering the effective element region 2 from the entire region (planar region) of the semiconductor substrate 1 by exposure and development. On the other hand, the adhesive layer 6A covering the invalid area 3 may be left over the entire invalid area 3 as shown in FIG. 4A, or the invalid area 3 as shown in FIG. 4B. You may leave some. Further, it is desirable to leave the adhesive layer 6 </ b> A with a width slightly narrower than the street width in the street portion surrounding the effective element region 2.

  Subsequently, as shown in FIG. 5A, a support substrate 8 is attached to the first surface of the semiconductor substrate 1 via an adhesive layer 6A. The adhesive strength between the semiconductor substrate 1 and the support substrate 8 using the adhesive layer 6 is desirably 5 MPa (megapascal) or more. The support substrate 8 is a substrate that is bonded to the semiconductor substrate 1 for reinforcement for reducing the thickness of the semiconductor substrate 1. As the support substrate 8, a silicon wafer or a glass substrate can be used.

  Next, as shown in FIG. 5B, the second surface (back surface) of the semiconductor substrate 1 is ground with a support substrate 8 attached, for example, using a grinder (not shown), for example, the semiconductor substrate 1 The thickness of the semiconductor substrate 1 is reduced so that the thickness of the semiconductor substrate 1 is reduced to about 50 to 200 μm.

  Next, as shown in FIG. 5C, through holes are formed in the semiconductor substrate 1 from the second surface side of the semiconductor substrate 1, and the through holes are filled with a conductive material such as a metal, whereby the semiconductor substrate 1 A through electrode 9 is formed on the second surface, and a back surface wiring 10 and a bump 11 are formed on the second surface of the semiconductor substrate 1.

  Next, as shown in FIG. 6A, the semiconductor device 1 is set in a dicing device (not shown) with the dicing tape (or sheet) 12 attached to the second surface of the semiconductor substrate 1, and the semiconductor substrate 1 In addition, the effective substrate region 2 and the ineffective region 3 are separated from each other along the street by cutting a groove into the support substrate 8 attached thereto simultaneously or sequentially with a blade of a dicing apparatus. To do. Thereby, as shown in FIG. 6B, one chip (semiconductor element) 1A is cut out from each effective element region 2 one by one.

  Incidentally, when the semiconductor substrate 1 is cut with a blade of a dicing apparatus, it is desirable to position the semiconductor substrate 1 and the blade so that the cutting edge portion of the blade does not contact the adhesive layer 6A. In addition, it is desirable that the width of the invalid area 3 (street width) in the street portion also secures a dimension that can secure a bonding area necessary for bonding the substrates and avoid contact between the blade and the adhesive layer 6A.

[Second Embodiment]
7 and 8 are process diagrams showing a method of manufacturing a semiconductor device according to the second embodiment of the present invention. In the second embodiment, the through electrode 9, the back surface wiring 10, and the bump 11 are formed on the semiconductor substrate 1 as shown in FIG. 5C in the same procedure as the first embodiment. As shown in FIG. 7A, the semiconductor element (chip) 13 is mounted on the second surface (back surface) of the semiconductor substrate 1 via the bumps 11 by a flip chip method.

  Next, as shown in FIG. 7B, an underfill resin 14 made of, for example, a liquid epoxy resin is injected between the semiconductor substrate 1 and the semiconductor element 13 (gap portion), and this is dried or heat-treated. Harden.

  Subsequently, as shown in FIG. 7C, a dicing tape (or sheet) 15 is attached to the second surface of the semiconductor substrate 1. In this case, the semiconductor element 13 is mounted on the second surface of the semiconductor substrate 1, but since the thickness of the element itself is very thin, the unevenness of the substrate surface by the element is absorbed by the deformation of the dicing tape 15.

  Next, as shown in FIG. 8A, the semiconductor substrate 1 is set in a dicing apparatus (not shown) with the dicing tape 15 attached to the semiconductor substrate 1, and the semiconductor substrate 1 and the support attached to the semiconductor substrate 1 are attached. The semiconductor substrate 1 is separated into pieces by cutting the effective element region 2 and the ineffective region 3 along the street by cutting grooves into the substrate 8 simultaneously or sequentially with a blade of a dicing apparatus. As a result, as shown in FIG. 8B, a semiconductor element 1A having a chip-on-chip structure having a stacked structure with the semiconductor element 13 is cut out one by one from each effective element region 2.

  In the above manufacturing method, the adhesive layer 6B formed from the photosensitive resist material on the first surface of the semiconductor substrate 1 is exposed and developed to remove the adhesive layer 6B from the effective element region 2, Since the support substrate 8 is attached using the adhesive layer 6A left in the ineffective region 3, the support substrate 8 is attached to the semiconductor substrate 1 from the semiconductor substrate 1 before the process of dicing the semiconductor substrate 1 (such as a dicing process). No need to peel. For this reason, an adhesive residue does not remain on the first surface (main surface) of the semiconductor element (chip) 1A cut out from the semiconductor substrate 1.

  In addition, since peelability is not required for the adhesive for pasting the substrate, a material excellent in heat resistance, chemical resistance, etc. (for example, epoxy resin) can be used as the adhesive material. For this reason, when the through electrode 9, the back surface wiring 10, the bump 11, and the like are formed on the semiconductor substrate 1 with the support substrate 8 attached to the semiconductor substrate 1, for example, the process temperature is about 300 ° C. Even when the temperature is high, it is possible to maintain the desired adhesive strength (temporary fixability) while suppressing deterioration and performance deterioration of the adhesive layer 6. For this reason, it becomes possible to prevent peeling of the semiconductor substrate 1 and the support substrate 8 reliably.

  Further, in the state where the support substrate 8 is attached to the semiconductor substrate 1, the thickness dimension T of the adhesive layer 6 is larger than the height dimension H of the bump 4 as shown in FIG. Even if the support substrate 8 is pressed against the adhesive layer 6 in order to obtain strength and adhesion, there is no possibility of damaging the bumps 4. For this reason, it is possible to prevent the bonding failure due to the damage of the bumps 4 and improve the yield.

FIG. 6 is a process diagram (part 1) illustrating the method for manufacturing the semiconductor device according to the first embodiment of the invention; FIG. 6 is a process diagram (part 2) illustrating the method for manufacturing the semiconductor device according to the first embodiment of the present invention; It is process drawing (the 3) which shows the manufacturing method of the semiconductor device which concerns on 1st Embodiment of this invention. FIG. 8 is a process diagram (part 4) illustrating the method for manufacturing the semiconductor device according to the first embodiment of the invention; It is process drawing (the 5) which shows the manufacturing method of the semiconductor device which concerns on 1st Embodiment of this invention. It is process drawing (the 6) which shows the manufacturing method of the semiconductor device which concerns on 1st Embodiment of this invention. It is process drawing (the 1) which shows the manufacturing method of the semiconductor device which concerns on 2nd Embodiment of this invention. It is process drawing (the 2) which shows the manufacturing method of the semiconductor device which concerns on 2nd Embodiment of this invention. It is a figure which shows the relationship between the thickness dimension of an adhesive bond layer, and the height dimension of a bump. It is a figure explaining the manufacturing method of the conventional semiconductor device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Semiconductor substrate, 2 ... Effective element area | region, 3 ... Invalid area | region, 4 ... Bump, 6 ... Adhesive layer, 8 ... Support substrate

Claims (2)

A first step of forming an adhesive layer made of a photosensitive material on a first surface of a semiconductor substrate including an effective element region in which an element circuit is formed and an ineffective region surrounding the effective element region;
A second step of exposing and developing the adhesive layer while removing the adhesive layer from the effective element region and leaving the adhesive layer in the ineffective region;
A third step of attaching a support substrate to the first surface of the semiconductor substrate via the adhesive layer;
A fourth step of applying a predetermined treatment to the semiconductor substrate with the support substrate attached thereto;
And a fifth step of separating the semiconductor substrate by separating the effective element region and the ineffective region from each other. 2. The semiconductor device according to claim 1, wherein in the first step, a thickness dimension of the adhesive layer is made larger than a height dimension of a protruding electrode formed on the first surface of the semiconductor substrate. Production method.

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