JP2008153412A - Method of breaking substrate into pieces, manufacture method of image sensor, and thermosetting adhesive sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of breaking substrate into pieces, a manufacturing method of an image sensor and thermosetting adhesive sheet for preventing bad influence caused by the adhesive layer remaining on the substrate and the like while both chip jump and pick-up property related under tradeoff can be both satisfied. <P>SOLUTION: An adhesive layer laminated on a base film is stuck on a glass substrate, and the glass substrate is mounted on a dicing tape so that the glass substrate is covered with the base film. At least the glass substrate and the adhesive layer are diced and the divided glass substrate is picked up so that the base film remains at the dicing tape and the adhesive layer is applied to the glass substrate in the singulation method of the substrate. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a substrate dividing method, an image sensor manufacturing method, and a thermosetting adhesive sheet.

  Conventionally, in the process of separating the substrate with the adhesive layer, the surface of the adhesive layer is directly mounted on a dicing tape, and dicing and pickup are performed. At this time, if the adhesive force between the adhesive layer and the dicing tape is too weak, so-called chip jumping occurs in which chips separated during dicing are detached from the dicing tape, resulting in a defect. On the other hand, if the adhesive force between the adhesive layer and the dicing tape is too strong, it cannot be peeled off between the adhesive layer and the dicing tape at the time of picking up, which is also defective. Therefore, the adhesive force between the adhesive layer and the dicing tape needs to be controlled so that there is no chip skip and stable pickup can be performed. However, normally, both are in a trade-off relationship, and it is difficult to satisfy both chip skipping and pick-up properties.

Therefore, it is conceivable to reduce the adhesion between the adhesive layer and the dicing tape at the time of picking up by using a dicing tape having an ultraviolet curable adhesive layer. If it does not decrease, a pick-up failure may occur as a result.
In addition, as a method for manufacturing a semiconductor device, an adhesive layer is coated on a base film, the adhesive layer is attached to a wafer together with the base film, and further attached to a dicing sheet together with the base film, and the wafer is formed on a semiconductor element. There has been proposed a method of picking up semiconductor elements by separating them into pieces and separating them between a base film and an adhesive layer (for example, Patent Document 1). In this method, the adhesive layer remaining on the entire surface of the wafer may be effectively used for mounting on a circuit board or the like to be mounted thereafter, but depending on the type of semiconductor element, this adhesive layer May adversely affect the application of the semiconductor device or its own characteristics.
JP-A-2005-203401

  The present invention has been made in view of the above-mentioned problems, and can satisfy both of the prevention of chip jump and the pickup property that are in a trade-off relationship, and avoids adverse effects due to the adhesive layer remaining on the substrate and the like. It is an object of the present invention to provide a method for separating a substrate, a method for manufacturing an image sensor, and a thermosetting adhesive sheet.

The substrate singulation method of the present invention includes a step of attaching an adhesive layer laminated on a base film to a glass substrate;
Mounting the glass substrate on the dicing tape so that the base film is attached to the adhesive surface of the dicing tape;
Dicing at least the glass substrate and the adhesive layer;
And picking up the separated glass substrate so that the base film remains on the dicing tape and the adhesive layer adheres to the glass substrate.

In this substrate singulation method, the adhesive layer attached to the glass substrate preferably has a lattice pattern.
Moreover, it is preferable that an adhesive bond layer is a thermosetting adhesive bond layer containing an epoxy resin.
Furthermore, it is preferable to satisfy a relationship of (adhesion force between the adhesive layer and the base film) <(adhesion force between the base film and the dicing tape).
The base film is preferably a polyester-based, polyolefin-based, or polyvinyl chloride-based film.

The image sensor manufacturing method of the present invention is a method in which the glass substrate singulated by the above-described singulation method is pasted so as to cover the surface of the light receiving part in the image sensor, and is adhered to the glass substrate. Is used as a gap adjustment layer between the light receiving portion surface and the glass substrate.
The thermosetting adhesive sheet of the present invention is characterized in that a release film, an epoxy thermosetting adhesive layer, and a dicing substrate film are laminated in this order.

  According to the present invention, since there is no chip jump and chip chipping, and dicing is possible and pick-up property is good, a glass substrate with an adhesive layer can be easily separated into individual pieces with a high yield. Furthermore, since a general-purpose tape can be used as the dicing tape without using an expensive ultraviolet curable tape, the ultraviolet irradiation step and the apparatus can be omitted, which can greatly reduce the process cost. .

According to the image sensor manufacturing method of the present invention, the glass substrate with the adhesive layer obtained by the above-described substrate dividing method can be used as it is, and the image sensor can be used by the adhesive layer itself. It is possible to easily form a gap between the surface of the light receiving part and the glass substrate.
Furthermore, the thermosetting adhesive sheet of the present invention can be suitably used for the above-described substrate singulation method and image sensor manufacturing method, and these methods can be performed more easily and reliably. .

In the substrate singulation method of the present invention, a so-called adhesive sheet is applied to a glass substrate in advance before the glass substrate is attached to a dicing tape.
The adhesive sheet used here is not particularly limited as long as it has a base film and an adhesive layer laminated thereon, and a thermosetting, photocurable adhesive sheet, or the like may be used. it can. In particular, a thermosetting adhesive sheet is preferable. This is because the adhesive layer can be cured by a simple method of heating.

  The base film used for such an adhesive sheet is not particularly limited, and any film can be used. For example, acrylic resin, polyurethane resin, polynorbornene resin, polyalkylene glycol resin, polyolefin resin (polystyrene resin, polyethylene resin, etc.), polyimide resin, polyester resin (PET, etc.), epoxy resin , Polyamide-based resin, polycarbonate-based resin, silicone-based resin, polymer film made of fluorine-based resin (fluorinated polyethylene such as PTFE and ETFE), etc .; copper, aluminum, stainless steel and other metal sheets; PP, PVC, PE, Polymer fibers such as PU, PS, PO or PET, synthetic fibers such as rayon or cellulose acetate, natural fibers such as cotton, silk or wool and non-woven fabrics composed of inorganic fibers such as glass fibers or carbon fibers; Physics by impregnation Sheet with functional or optical function; diene (styrene-butadiene copolymer, butadiene, etc.), non-diene (isobutylene-isoprene, chlorinated polyethylene, urethane, etc.), thermoplastic resin (nylon, polyimide) And a sheet containing a rubber component such as a thermoplastic elastomer; or a combination of one or more of these. Of these, organic films are preferable, and polyester-based, polyolefin-based, and polyvinyl chloride-based films are particularly preferable. This is because they have suitable strength, transparency and flexibility.

  The thickness of the base film is not particularly limited, and for example, it is suitable to have a thickness of about 1 μm or more, and preferably has a thickness of about 1 to 100 μm, or about 20 to 80 μm. Thereby, the operativity and workability | operativity in each process, such as bonding to a board | substrate and a cutting | disconnection of a board | substrate, are securable.

  Moreover, it is preferable that the release property is provided to the adhesive layer lamination surface according to the material, the material which comprises an adhesive layer, etc. as for a base film. The releasability may be provided in the base film itself. For example, a release agent represented by silicone oil, silicone resin, etc. is included in the base film or applied to the base film surface. It may be. In particular, when a separate release treatment is performed, it is preferable to perform only one surface of the base film on which the adhesive layer is disposed. As will be described later, the adhesive force between the adhesive layer and the base film can be made smaller than the adhesive force between the base film and the dicing tape, and only the adhesive layer is securely attached to the glass substrate. This is because the unnecessary base film and dicing tape can be easily removed from the glass substrate while remaining.

The adhesive layer is not particularly limited as long as it can constitute an adhesive sheet used for adhering a semiconductor wafer or the like in the field, and is preferably an adhesive containing an epoxy resin, for example. .
The adhesive containing an epoxy resin can be constituted using, for example, an epoxy resin (A component), a curing agent (B component), and optionally a curing accelerator (C component).
The epoxy resin is not particularly limited. For example, various epoxy resins such as dicyclopentadiene type, cresol novolak type, phenol novolak type, bisphenol type, biphenyl type, trishydroxyphenylmethane type, and the like are used. Can do. These may be used alone or in combination of two or more.

Moreover, a hardening | curing agent will not be specifically limited if the said epoxy resin is hardened, For example, a phenol resin can be used.
The phenol resin is not particularly limited, and examples thereof include dichloropentadiene type phenol resin, phenol novolac resin, cresol novolac resin, and phenol aralkyl resin. These may be used alone or in combination of two or more.

  The blending ratio of the epoxy resin and the curing agent is preferably set to an amount sufficient to cure the epoxy resin when a phenol resin is used as the curing agent. For example, it is preferable that the total of hydroxyl groups in the phenol resin is 0.7 to 1.5 equivalents relative to 1 equivalent of epoxy groups in the epoxy resin, more preferably 0.9 to 1.2 equivalents. preferable.

Examples of the curing accelerator include amines (primary amines, tertiary amines, hydrazides, urea derivatives, imidazoles, azabicyclo compounds, etc.), organic phosphoruss (phosphine, phosphorane, phosphorus imide, etc.) ) And onium salt systems (phosphonium salt systems, sulfonium salt systems, etc.). These may be used alone or in combination of two or more.
The mixing ratio of the curing accelerator (component C) is suitably set in the range of 0.05 to 10% by weight of the total adhesive layer, preferably in the range of 0.1 to 3% by weight, 0.3 More preferred is ˜2% by weight.

  The adhesive layer may contain an inorganic filler as necessary. The inorganic filler is not particularly limited, and various conventionally known fillers can be used. Examples thereof include quartz glass powder, talc, silica powder (fused silica powder, crystalline silica powder, etc.), alumina powder, aluminum nitride powder, silicon nitride powder and the like. These may be used alone or in combination of two or more. Among these, from the viewpoint that the linear expansion coefficient of the obtained cured product can be reduced, it is preferable to use silica powder. Among silica powders, it is preferable to use fused silica powder from the viewpoint of high filling property and high fluidity. Is particularly preferred.

  Examples of the fused silica powder include spherical fused silica powder and crushed fused silica powder. From the viewpoint of fluidity, it is preferable to use spherical fused silica powder. In particular, it is preferable to use those having an average particle diameter in the range of 0.2 to 30 μm, and more preferably in the range of 0.5 to 15 μm. In addition, an average particle diameter can be measured using a laser diffraction scattering type particle size distribution measuring apparatus, for example.

In the adhesive layer of the present invention, in addition to the above components, other additives such as an elastomer component, a flame retardant, a release agent, and a pigment such as carbon black can be appropriately blended as necessary.
The elastomer component is not particularly limited and may be any component as long as it can impart flexibility and flexibility to the epoxy resin composition. Examples include various acrylic ester polymers such as polyacrylic acid esters, polymers made of polybutadiene, SBR, EVA, polyisoprene, polyacrylonitrile, and the like.
Examples of the flame retardant include organic phosphorus compounds, antimony oxide, aluminum hydroxide, magnesium hydroxide and the like.

The adhesive layer used in the present invention is not particularly limited and can be produced by a production method known in the art. Among these, a varnish coating method is preferable because it can easily control the film thickness uniformly. For example, in this varnish coating method, first, each component and optional components or additives are mixed in a desired blending amount and dissolved or dispersed in an organic solvent such as methyl ethyl ketone to prepare a varnish. This varnish is applied onto a substrate film and dried to form an adhesive layer. Subsequently, a release film separate from the base film (including the same material as the base film) may be bonded to the adhesive layer and wound, or the resulting adhesive layer was formed. It may be laminated and wound so that the adhesive layer is in contact with the back surface of the base film. Although the total sheet thickness after drying is not particularly limited, it is usually 5 to 100 μm, preferably 20 to 50 μm, from the viewpoint of thickness uniformity and the amount of residual solvent. The sheet thus obtained may be laminated and used so as to have a desired thickness, if necessary.
Moreover, each component and arbitrary components or additives may be directly kneaded with a kneader to form a solid resin layer, or the obtained solid resin layer may be extruded into a sheet shape to form a film.

  In such an adhesive sheet, it is preferable that at least the adhesive layer has a lattice pattern. That is, it is preferably a pattern in which holes having a predetermined size of rectangle, polygon, or a shape approximately similar to these are punched regularly. By having such a pattern, the substrate is mounted on a dicing tape with the adhesive sheet attached to the glass substrate, and after dicing, together with the glass substrate and the adhesive layer, the base film is peeled off. Since the contact area of the adhesive layer to the material film can be reduced, the glass substrate with the adhesive layer can be picked up with a smaller force. In addition, a punching pattern is arranged on a glass substrate in a region where the adhesive layer is not allowed to remain or a region where it is not desired to remain, and a lattice pattern is arranged on the outer periphery of the region. The sheet can be attached to the glass substrate. Thereby, it is possible to prevent an adhesive layer that is considered to affect the light reception from adhering to and remaining in a region located on the surface of the light receiving unit in the image sensor described later. Further, by arranging an adhesive layer on the outer peripheral portion of the light receiving portion, the adhesive layer can function as a gap adjustment layer between the surface of the light receiving portion and the glass substrate, which is a simpler method. The gap can be formed by a simple method of controlling the film thickness of the adhesive layer.

  The size of the lattice pattern is not particularly limited, and can be appropriately adjusted according to the size of the image sensor that uses the glass substrate, particularly the size of the light receiving portion. For example, the size of the punched hole is about 1 to 5 mm × 2 to 15 mm, and the width of the lattice is about 0.5 to 3.0 mm.

  The glass substrate used in the present invention is usually a plate-like glass substrate on which a semiconductor element or the like is not mounted on the substrate, and the type thereof is not particularly limited, and quartz glass, soda lime glass, borosilicate Various things, such as acid glass, lead glass, fluoride glass, are mentioned. Of these, quartz glass is preferable. From another point of view, it is preferable that the glass substrate is precisely controlled to have a predetermined refractive index, thickness, light transmittance, etc. in order to cover the light receiving portion of the image sensor. Although the thickness of a glass substrate is not specifically limited, For example, about 300-700 micrometers is mentioned.

First, as shown in FIG. 1A, the substrate dividing method according to the present invention includes an adhesive sheet 10 in which a release film 13 is laminated on a base film 12 on which the above-described adhesive layer 11 is formed. As shown in FIG. 1 (c), the release film 13 of the adhesive sheet 10 is peeled off, and the exposed adhesive layer 11 is attached to the glass substrate 14. Thereby, the adhesive bond layer 11 and the base film 12 are laminated | stacked on the glass substrate 14 in this order.
In addition, as shown in FIG.1 (b), before sticking the adhesive bond layer 11 of the adhesive sheet 10 to the glass substrate 14, at least the adhesive bond layer 11 of the adhesive sheet 10 may be formed in the grid | lattice-like pattern 10a. preferable.

  Next, as shown in FIG. 1D, the glass substrate 14 is mounted on a dicing tape 15 so that the base film 12 is attached. That is, the substrate film 12, the adhesive layer 11, and the glass substrate 14 are mounted on the dicing tape 15 so as to be laminated in this order. As the dicing tape 15 used here, any of those usually used in the field can be used.

  Subsequently, as shown in FIG. 1E, the glass substrate 14 and the adhesive layer 11 are diced from above the dicing tape 15. Dicing in this case can be performed using a dicing apparatus that is normally used in this field. Further, the glass substrate 14 needs to be completely cut, and the adhesive layer 11 is also preferably cut completely. However, the glass substrate 14 is cut to such an extent that the force applied to the pickup of the glass substrate 14 is not greatly affected. There may be parts that are not. Moreover, although the base film 12 may be cut | disconnected completely, it is preferable not to be carried out. As will be described later, since the base film 12 is not completely cut, the entire base film 12 can be kept in a state of being covered with the dicing tape 15 with a large area. 11 can be separated.

  Thereafter, as shown in FIG. 1 (f), the separated glass substrate 14 is picked up. The pickup here peels between the base film 12 and the adhesive layer 11 so that the base film 12 remains on the dicing tape 15 and the adhesive layer 11 adheres to the glass substrate 14. Is done. Therefore, it is preferable to satisfy the relationship of (adhesion force between the adhesive layer 11 and the base film 12) <(adhesion force between the base film 12 and the dicing tape 15). Thereby, unnecessary base film 12 and dicing tape 15 can be easily peeled from glass substrate 14 while only adhesive layer 11 remains reliably on glass substrate 14.

  Then, an image sensor can be manufactured by sticking the picked-up glass substrate with an adhesive layer so that the light-receiving part surface in an image sensor may be coat | covered. In this case, it is preferable to leave the adhesive layer attached to the glass substrate only in a desired region, that is, the outer periphery of the glass substrate or the peripheral region thereof, with a uniform film thickness. Thereby, it can prevent that an adhesive bond layer arrange | positions with a glass substrate in the light-receiving part of an image sensor. In addition, the thickness of the adhesive layer makes it possible to function as a gap adjustment layer that controls the gap width between the light receiving surface and the glass substrate, making the image sensor manufacturing method simpler and better yield. An image sensor can be manufactured.

  In addition, the kind, form, etc. of the image sensor in the present invention are not particularly limited, and examples thereof include an image pickup device such as a CMOS and a CCD, and arbitrarily, on a semiconductor substrate / wafer on which these are formed, For example, it is preferable to attach the glass substrate with an adhesive layer described above via a color filter, a microlens, or the like.

Hereinafter, embodiments of the substrate singulation method, the image sensor manufacturing method, and the thermosetting adhesive sheet of the present invention will be described in detail.
Example 1
First, each component shown below was prepared.

Epoxy resin 1 (Trishydroxyphenylmethane type epoxy resin, Nippon Kayaku, EPPN-501HY) 4.3 parts by weight Epoxy resin 2 (Bisphenol A type epoxy resin, Japan Epoxy Resin, Epocol YL-828) 4.3 weights Part,
Curing agent (Novolac type phenolic resin, Meiwa Kasei, DL-65) 5.2 parts by weight,
Acrylic resin (acrylic copolymer, manufactured by Nagase ChemteX, Teisan Resin SG-P3) 14.4 parts by weight Curing accelerator (tetraphenylphosphonium tetraphenylborate (manufactured by Hokuko Chemical, TPP-K) 0.9 parts by weight)
70.9 parts by weight of silica powder (spherical fused silica powder having an average particle size of 5.5 μm, manufactured by Denki Kagaku Kogyo Co., Ltd., FB-7SDC) These were dispersed and mixed to prepare a sheet coating varnish.

Next, this varnish was coated on a 50 μm thick polyester film A (Mitsubishi Chemical Polyester, MRF-50) with a comma coater, dried, and polyester film B (Mitsubishi Chemical Polyester, MRX-38). Was bonded to obtain a thermosetting adhesive sheet. The adhesive layer here was 30 μm, and the total thickness of the adhesive sheet was 118 μm.
The obtained thermosetting adhesive sheet was punched into a lattice shape by a punching die to obtain a patterned adhesive sheet. The pattern at this time had a punched hole size of about 2.0 × 2.5 mm and a lattice pattern width of about 0.7 mm.

Next, the polyester film A on the adhesive sheet was peeled off, and the adhesive layer was stuck on the glass wafer using a roll laminator. The glass substrate thus obtained was mounted on a dicing tape with the polyester film B on the adhesive layer attached thereto, and diced from the glass substrate by a dicer. For dicing, for example, a DISC DFG-651 dicer is used, a resin blade with a rotation speed of 38000 rpm and a blade thickness of 300 μm is used, and the total amount of cut with the adhesive layer and the substrate is about 50 μm, and the speed is 40 mm / Cutting was carried out under the conditions of sec, water amount at cutting: 1.5 L / min. At this time, chip skipping and chip chipping were counted. The results are shown in Table 1.
As is clear from Table 1, no chip skipping, chip chipping or the like occurred, and the pick-up property was good.

Example 2
Instead of using the polyester film B, the dicing property was evaluated substantially in the same manner as in Example 1 except that a polyolefin film was used. The results are shown in Table 1.
As is clear from Table 1, no chip skipping, chip chipping or the like occurred, and the pick-up property was good.

Example 3
The dicing property was evaluated in substantially the same manner as in Example 1 except that polyvinyl chloride (manufactured by Mitsubishi Chemical MKV, KM film) was used instead of the polyester film B. The results are shown in Table 1.
As is clear from Table 1, no chip skipping, chip chipping or the like occurred, and the pick-up property was good.

Comparative Example 1
When the glass substrate was bonded onto the dicing tape, the dicing property was evaluated in substantially the same manner as in Example 1 except that the mounting was performed with the polyester film B peeled off. The results are shown in Table 1.
As is apparent from Table 1, 35 out of 100 chips had a strong adhesive force between the adhesive layer / dicing tape and could not be picked up.

Comparative Example 2
Dicing properties were evaluated in substantially the same manner as Comparative Example 1 except that a UV curable dicing tape was used as the dicing tape. The results are shown in Table 1.
As is clear from Table 1, the adhesion between the adhesive layer / dicing tape was strong with 5 out of 100 chips, and pickup could not be performed.

Example 4
The glass substrate obtained in Example 1 has a size of 2.35 × 2.85 mm, and an adhesive layer having a width of about 0.35 mm is formed on the outer periphery thereof. This glass substrate was pasted so as to cover the surface of the light receiving portion of the CCD element formed on the silicon wafer, and an image sensor was manufactured.
In the image sensor obtained in this way, a hollow whose gap was easily controlled as the thickness of the adhesive layer could be secured on the surface of the light receiving part without passing through a special process.

  The present invention can be preferably used for a glass substrate constituting an image sensor or the like, but is not limited to a glass substrate, but also a semiconductor wafer such as a silicon wafer, a germanium wafer, a gallium arsenide wafer, a circuit substrate, a ceramic. It can be used for all of a wide range of processing such as substrates, metal substrates, plastic substrates, and sealing resin substrates sealed with these sealing resins.

It is a schematic sectional process drawing for demonstrating the board | substrate individualization method of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Adhesive sheet 11 Adhesive layer 12 Base film 13 Release film 14 Glass substrate 15 Dicing tape

Claims (7)

A step of attaching an adhesive layer laminated on a base film to a glass substrate;
Mounting the glass substrate on the dicing tape so that the base film is attached to the adhesive surface of the dicing tape;
Dicing at least the glass substrate and the adhesive layer;
Picking up the glass substrate separated so that the base film remains on the dicing tape and the adhesive layer adheres to the glass substrate.   The singulation method according to claim 1, wherein the adhesive layer attached to the glass substrate has a lattice pattern.   The singulation method according to claim 1 or 2, wherein the adhesive layer is a thermosetting adhesive layer containing an epoxy resin.   The singulation method according to claim 1, which satisfies a relationship of (adhesion force between the adhesive layer and the base film) <(adhesion force between the base film and the dicing tape).   The singulation method according to claim 1, wherein the base film is a polyester-based, polyolefin-based, or polyvinyl chloride-based film.   The glass substrate singulated by the singulation method according to claim 1 is attached so as to cover a light receiving portion surface in an image sensor, and an adhesive layer attached to the glass substrate is attached to the light receiving portion surface. A manufacturing method of an image sensor used as a gap adjustment layer between a glass substrate.   A thermosetting adhesive sheet obtained by laminating a release film, an epoxy thermosetting adhesive layer, and a substrate film for dicing in this order.

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