JP2006077072A - Adhesive tape and method for mounting of image sensor using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat-resistant adhesive tape having high visibility and a method for the mounting of an image sensor by using the tape as a protection adhesive tape for a solid-state image sensing device. <P>SOLUTION: The adhesive tape has an adhesive layer on at least one surface and has a chroma of ≤5.0 in terms of b* in the L*a*b* color specification system in conformity to JIS Z 8729 after heating at 180°C for 1 hr. The invention further provides an adhesive tape containing an oxidation inhibitor in the adhesive layer in an amount of 0.1-10 wt.% (solid basis) based on the total solid component of the adhesive agent. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat-resistant adhesive tape and a mounting method of a video sensor using the same.

  In recent years, image sensors using solid-state imaging devices have been widely used in digital cameras, video cameras, and the like. In the manufacturing process including mounting of the image sensor on the substrate side, scratches on the surface of the image sensor and adhesion of dust are highly likely to directly affect imaging. In view of this, a technique is adopted in which an adhesive tape is used as a surface protection tape and is attached to the light receiving portion side of the image sensor to avoid scratches and dust from being attached in the mounting and manufacturing process.

  On the other hand, the component mounting process for mounting the video sensor on a substrate or the like includes a process in a high temperature region such as soldering. However, many of the current surface protective adhesive tapes do not have heat resistance corresponding to the above process. Therefore, conventionally, in the component mounting process, the bonded protective tape is peeled off once before the process in the high temperature region, and the protective tape is bonded again after the component mounting process.

  At present, as an improvement method, a method using a surface protection tape based on a film having a high heat resistance mainly composed of polyimide is employed. However, since the polyimide film has a brownish brown hue, the visibility is poor, and the total light transmittance of the film is low. Therefore, it is difficult to inspect the tape attached in the optical inspection after mounting the components.

  In addition, for adhesive tapes using films with excellent transparency, such as polyethylene terephthalate and polyethylene naphthalate, the hue of the adhesive tape changes when the adhesive tape turns yellow at 180 ° C (yellowing). In addition, since the visibility is lowered, a defect may occur in the optical inspection after component mounting.

  Furthermore, there is a demand for an adhesive tape with high visibility not only in the above-described image sensor but also in the mounting process of various members. The request is strong. In addition, such characteristics are very useful, and there is a strong demand from applications that are generally used for the purpose of protecting the display on the surface of a high-temperature member.

  Accordingly, an object of the present invention is to provide a heat-resistant adhesive tape with high visibility. Moreover, it exists in using in the mounting process of the image | video sensor used for the solid-state imaging device as an adhesive tape for protection. In other words, it is possible to perform processing in a high temperature region with the adhesive tape pasted to the light receiving side of the image sensor, and to protect the light receiving side of the image sensor during the processing. An object of the present invention is to provide a video sensor mounting method capable of maintaining a state with excellent overall visibility.

  As a result of intensive studies, the present inventors have found that the object can be achieved by the following adhesive tape and a video sensor mounting method using the same, and have completed the present invention.

  The present invention is a tape having an adhesive layer on at least one side, and the chromaticity of the tape after heating at 180 ° C. for 1 hour is L * a * b * b in the color system according to JIS Z 8729 The value of * is 5.0 or less.

  As described above, there is a strong demand for an adhesive tape having predetermined visibility even under high temperature conditions. The present invention has found that it is preferable to set the chromaticity of the pressure-sensitive adhesive tape after heating within the above-mentioned range in response to such a request, and in the application of various base materials or pressure-sensitive adhesives, the pressure-sensitive adhesive having such chromaticity. By selecting a tape, it became possible to objectively ensure visibility. In particular, in the video sensor mounting process, by using an adhesive tape that satisfies such a standard, very high work efficiency can be ensured.

  The present invention is the above-mentioned pressure-sensitive adhesive tape, which is a pressure-sensitive adhesive tape containing an antioxidant in the pressure-sensitive adhesive layer, wherein the proportion of the antioxidant in the pressure-sensitive adhesive layer is based on the total amount of solid components of the pressure-sensitive adhesive It is 0.1 to 10 wt%.

  One of the factors that reduces the visibility of adhesive tape under high temperature conditions is that the effect of oxidation of the adhesive layer that constitutes the adhesive tape is large. By adding an appropriate amount of antioxidant in the adhesive layer, visibility at high temperatures is increased. Can be secured. On the other hand, since excessive addition affects the adhesive function of the adhesive layer, the present invention clarifies the range of the optimum addition amount of such an antioxidant.

  This invention is the said adhesive tape, Comprising: The heat shrink rate of the said adhesive tape after implementing a heating at 180 degreeC for 1 hour is 1.0% or less, It is characterized by the above-mentioned.

  As described above, in the adhesive tape used for the high temperature member in various uses including the mounting of the image sensor including the process in the high temperature region such as soldering, it is preferable that the shrinkage rate of the base material is small. The present invention clarifies the standard of usefulness as a pressure-sensitive adhesive tape with respect to the shrinkage ratio of the substrate under high temperature conditions. By clarifying these additional conditions, the working efficiency is further increased.

  This invention is the said adhesive tape, Comprising: The adhesive force of the said adhesive tape after implementing a heating at 180 degreeC for 1 hour is 0.1-8.0N / 19mm width, It is characterized by the above-mentioned.

  That is, in order to prevent peeling of the adhesive tape, an adhesive force of a predetermined level or more is required. On the other hand, in order to prevent the adhesive layer from remaining after the tape is peeled from the adherend, it is necessary to have an adhesive force of a predetermined level or less. is there. In particular, in the case of including a mounting process in a high temperature region, it has been found that the adhesive strength of the adhesive tape under heating conditions is preferably within the above range. The work efficiency is increased without deteriorating the function of the tape and without leaving the adhesive on the surface of the adherend when the tape is peeled off after mounting the components.

  The present invention is a video sensor mounting method, characterized in that, in a video sensor mounting process using a solid-state imaging device, the adhesive tape according to any one of the above is bonded to a light receiving portion side of the video sensor. To do.

  Since the above adhesive tape has a high transmittance, the inspection can be performed without peeling the adhesive tape even when performing an internal inspection after mounting the component by using it in the mounting process of the image sensor. . Therefore, it is possible to reduce the obstacle due to the attenuation of the transmittance of the adhesive tape in the inspection process after mounting the components of the conventional solid-state imaging device, and to perform the inspection with the adhesive tape attached. As a result, it is possible to ship in a state where the adhesive tape is bonded to the post-inspection transport process and the like without going through the steps of peeling the adhesive tape before the inspection and re-attaching the adhesive tape after the inspection. . In this way, safety is ensured, and an integrated process in a state where the adhesive tape is bonded is possible, so that productivity can be improved.

  In addition, since the above adhesive tape has excellent heat resistance, heat shrinkability, and adhesiveness, it can protect the surface from contamination and scratches due to foreign matters during component transportation by using it in the mounting process of the image sensor. it can. Further, the film shrinkage due to heat in the component mounting process is small, and the work can be performed without peeling the adhesive tape before mounting, and the peeling due to the heat shrinkage can be prevented. Therefore, it becomes possible to design an adhesive tape having a lower adhesive strength than the conventional one, and it is possible to prevent the adhesive from remaining on the adherend surface when peeling the tape after mounting the components, and to improve the peeling work efficiency. .

  As described above, according to the present invention, it is possible to ensure the heat resistance and visibility under high temperature conditions as well as the function of protecting the adherend. In particular, in the mounting process or inspection process of components of solid-state imaging devices, etc., an integrated process is possible with the adhesive tape attached, so that the image with high workability and productivity can be obtained while protecting the image sensor surface. It is possible to provide a sensor mounting method.

Hereinafter, embodiments of the present invention will be described.
The pressure-sensitive adhesive tape of the present invention is basically formed from a tape base material and a pressure-sensitive adhesive layer provided on one or both surfaces of the base material. Moreover, the release film may be bonded together with respect to the base material of an adhesive tape. That is, by attaching a release film having a release treatment on at least one surface to a base material of an adhesive tape via an adhesive layer, the adhesive layer can be protected and the image sensor surface can be protected.

  The pressure-sensitive adhesive tape according to the present invention is characterized by having visibility under high temperature conditions as a basic characteristic. Specifically, the chromaticity of the tape after heating at 180 ° C. for 1 hour is 5.0 or less as the b * value of the L * a * b * color system according to JIS Z 8729. Is preferable, more preferably 4.0 or less, and still more preferably 3.0 or less. That is, if it exceeds 5.0, the entire pressure-sensitive adhesive tape is yellowish and the visibility is lowered.

  In use under a high temperature condition, since discoloration is usually accelerated at a high temperature, it is preferable to check the chromaticity after a predetermined time has passed under a heating condition. The chromaticity is preferably expressed by a symbol or a numerical value in order to ensure its objectivity, and is expressed by an L * a * b * color system that conforms to JIS Z 8729, which is the most general expression method. Details of the chromaticity measurement method will be described later.

  At this time, the pressure-sensitive adhesive tape contains an antioxidant in the pressure-sensitive adhesive layer provided on one or both sides of the tape substrate, and the proportion of the antioxidant in the pressure-sensitive adhesive layer is the total amount of the solid component of the pressure-sensitive adhesive. It is preferably 0.1 to 10 wt%, more preferably 0.3 to 7 wt%, and still more preferably 0.5 to 5 wt%. That is, when the addition amount of the antioxidant is less than 0.1 wt%, the effect of preventing discoloration of the adhesive layer cannot be expected. If it exceeds 10 wt%, the composition of the pressure-sensitive adhesive in the pressure-sensitive adhesive layer may become brittle, and the pressure-sensitive adhesive may remain on the surface of the adherend when peeled off after heating. May bleed out and contaminate the surface of the adherend. Furthermore, if the oxidation is promoted, there is a possibility that the adhesive force and the cohesive force are reduced.

  The antioxidant used in the present invention is not particularly limited, but has hydrogen that easily reacts with a radical such as phenolic —OH or —NH— in the molecule, and reacts with the radical to make it a stable substance. Two types are available: phenolic and amine-based.

  Examples of phenolic antioxidants include 4-hydroxymethyl-2,6-di-t-butylphenol, 2,4-dimethyl-6-t-butylphenol, 2,6-di-t-butyl-p-cresol, 4,4'-methylene-bis- (6-t-butyl-o-cresol), 4,4-dioxydiphenyl, hydroquinone monobenzyl ether, 2,6-diamilhydroquinone, tetrakis [methylene-3 (3 , 5-t-butyl-4-hydroxyphenyl) propionate] methane, etc., specifically, trade name Irganox (manufactured by Ciba Specialty) and the like can be used.

  Examples of amine-based antioxidants include p, p'-diaminodiphenylmethane, phenyl-α-naphthylamine, and dialkyldiphenylamine.

  The base material of the adhesive tape used for this invention will not be specifically limited if it is a film which has heat resistance in 180 degreeC temperature conditions. For example, polyethylene terephthalate (PET) film, polyethylene naphthalate (PEN) film (PEN), polyethersulfone (PES) film, polyetherimide (PEI) film, polysulfone (PSF) film, polyphenylene sulfide (PPS) film, It is preferably made of a polyether ether ketone (PEEK) film, a polyarylate (PAR) film, an aramid film, a polyimide film, or a liquid crystal polymer (LCP) film. In particular, in view of the shrinkage rate of the base material and bonding to the image sensor, the base material is preferably made of a base material mainly composed of polyethylene naphthalate having both the heat resistance and the visibility at the time of bonding.

  Further, the thickness of the pressure-sensitive adhesive tape used in the present invention is preferably at least 5 μm or more in order to prevent breakage or tearing, and more preferably 10 to 100 μm in view of suitable handling properties.

  About the adhesive used for this invention, if it has heat resistance, it will not specifically limit. Specifically, an acrylic pressure-sensitive adhesive or a silicone pressure-sensitive adhesive can be used. In particular, the acrylic pressure-sensitive adhesive has relatively high heat resistance and can be said to be the most suitable pressure-sensitive adhesive material for the present invention.

  For example, the acrylic pressure-sensitive adhesive is a pressure-sensitive adhesive made of an acrylic copolymer obtained by copolymerization of a monomer containing at least an alkyl (meth) acrylate. Examples of the alkyl (meth) acrylate herein include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isoamyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) ) Acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, and the like. Further, these acrylic pressure-sensitive adhesives can contain an appropriate crosslinking agent. For example, an isocyanate crosslinking agent, an epoxy crosslinking agent, an aziridine-based compound, a chelate-based crosslinking agent and the like are examples.

  Furthermore, as necessary, various additives such as a filler, an anti-aging agent, a pigment, a dye, and a silane coupling agent can be added as necessary.

  Although the thickness of the adhesive layer of an adhesive tape is not specifically limited, It is 1-50 micrometers or less, Preferably they are 3 micrometers or more and 30 micrometers or less, More preferably, they are 5 micrometers or more and 20 micrometers or less. In order to secure the pressure-sensitive adhesive layer, it is effective if even a slight level difference is generated on the surface of the base material. On the other hand, a thin layer is preferable in consideration of permeability, that is, visibility. When the thickness is less than 1 μm, the surface protection tape may be bent due to contact with the light receiving portion, and the pasting property is also deteriorated. Further, the adhesive tape may be peeled off due to heat shrinkage of the film being heated. If it exceeds 50μm, deformation of the adhesive during slitting and punching of the tape, or pressure applied to the tape during tape application, transportation, etc., and deformation of the adhesive due to heating during mounting This may cause the adhesive to be applied to the light receiving portion.

  In the present invention, the heat shrinkage rate of the pressure-sensitive adhesive tape after heating at 180 ° C. for 1 hour is 1.0% or less, more preferably 0.5% or less, and still more preferably 0.3% or less. desired. This is to further improve the working efficiency by clarifying additional conditions regarding the shrinkage ratio of the substrate under high temperature conditions. The heat shrinkage referred to here is based on the value after bonding to a BA plate in the form of an adhesive tape and leaving it at 180 ° C. for 1 hour. A specific method for measuring the thermal shrinkage will be described later in [Example] <Evaluation method>.

  Moreover, in this invention, it is preferable that the adhesive force of the adhesive tape after implementing a heating at 180 degreeC for 1 hour is 0.1-8.0N / 19mm width, More preferably, it is 0.2N-5. A width of 0 N / 19 mm, more preferably a width of 0.3 N to 4.0 N / 19 mm is desired. With an adhesive force exceeding 8.0 N / 19 mm, tape peeling from the adherend may be difficult in the process. In addition, there is a possibility that an adhesive layer may remain on the surface of the adherend, and a treatment layer (for example, an IR treatment layer (infrared treatment layer) on the surface of the solid-state imaging device) or an AR treatment layer (antireflection treatment layer) on the surface of the adherend. ) And the like) may be peeled off. On the other hand, when it is less than 0.1 N / 19 mm, the adhesive tape may be peeled off due to the heat shrinkage of the film being heated. The adhesive force here is based on a value measured according to JIS Z0237.

  Moreover, when using a release film for an adhesive tape, you may use any well-known thing as a release film. Specifically, a release coating layer, for example, a silicone layer formed on the bonding surface of the release film with the adhesive layer of the base material can be used. Examples of the substrate for the release film include paper materials such as glassine paper and resin films made of polyethylene, polypropylene, polyester, and the like.

  Moreover, this adhesive tape may be processed according to the use, for example, the size of the target solid-state imaging device. The processing method is not particularly limited as long as it is a method that maintains a uniform shape and does not leave a pressure-sensitive adhesive in the processed cross section, but punching is preferable in view of productivity.

In the mounting process of the image sensor using the solid-state imaging device, the present invention can effectively utilize the function by using any one of the above adhesive tapes attached to the light receiving part side of the image sensor. it can. That is, by the operation illustrated below, it is possible to effectively utilize the excellent characteristics such as high heat resistance and visibility of the pressure-sensitive adhesive tape of the present invention, thereby enabling a very efficient mounting process.
(1) Adhesive tape is bonded in advance to the light receiving part side of the image sensor for protection (2) Attached to the substrate in that state (3) Introduced and mounted in solder reflow etc. (5) Video sensor breakage and foreign matter inspection (6) Proceed to the next step with the adhesive tape peeled off or bonded

  Examples and the like specifically showing the configuration and effects of the present invention will be described below. Moreover, the evaluation method in an Example etc. was performed as follows. The present invention is not limited to such examples or evaluation methods.

<Evaluation method>
About the tape produced on the said conditions, the following item was evaluated.
(1) Shape of tape after heating After the samples of the above-mentioned examples and comparative examples were bonded to the glass surface, the shape of the tape after being left for 1 hour at 180 ° C. was visually confirmed.
(2) The state of the glass surface after tape peeling The state of the glass surface after tape peeling was confirmed visually.
(3) Chromaticity Using an integrating sphere type spectral transmittance measuring device (Murakami Color Research Laboratory Co., Ltd., DOT-3C) as a measuring device, cutting into a predetermined sample size, from the base material side of the adhesive tape The measurement was performed and evaluated as the value of b * of the L * a * b * color system in accordance with JIS Z 8729.
(4) Visibility assuming internal optical inspection after package formation A box with a height of 5 mm is formed with an acrylic plate, and a semiconductor element that has undergone a wiring process is placed therein. And the adhesive tape was stuck on the acrylic board upper part, and the presence or absence of the connection of the semiconductor element in an acrylic board was confirmed through the tape. The effect was confirmed by visual observation of five people. The evaluation criteria were classified in the following three stages.
○: A device that can clearly confirm the presence or absence of the wiring process.
Δ: The wire connection process can be barely confirmed.
X: The connection process cannot be confirmed.
(5) Heat shrinkage rate Adhesive tape is cut into 20 mm square, attached to a BA plate, heated under a temperature condition of 180 ° C., and the size of the film before and after the heating is projected by a projector (made by Mitutoyo: PROFILE PROJECTOR PJ-H300F). ) Was used to measure both the MD direction and the TD direction. The BA plate refers to a SUS304 plate (BA5 finish SUS304 manufactured by Nippon Metal Co., Ltd.) surface-finished to BA5 in accordance with JIS “BA finish”.

<Example 1>
An acrylic pressure-sensitive adhesive comprising 0.5 wt% of an antioxidant (manufactured by Ciba Specialty, Irganox) in a pressure-sensitive adhesive composition on a base material made of polyethylene naphthalate having a thickness of 25 μm. A solution of the agent was applied and dried to prepare an adhesive tape having an adhesive layer having a thickness of 10 μm.
After the adhesive tape was heated at 180 ° C. for about 1 hour, the adhesive strength measured according to JIS Z0237 was 2.0 N / 19 mm, the thermal shrinkage was 0.15%, and after heating at 180 ° C. for 1 hour. The chromaticity of the tape was 2.7 as the b * value of the L * a * b * color system.

<Comparative Example 1>
A pressure-sensitive adhesive tape produced in the same manner as in Example 1 was obtained except that no antioxidant was added to the pressure-sensitive adhesive.
After the adhesive tape was heated at 180 ° C. for about 1 hour, the adhesive strength measured according to JIS Z0237 was 2.0 N / 19 mm, the thermal shrinkage was 0.15%, and after heating at 180 ° C. for 1 hour. The chromaticity of the tape was 5.6 as the value of b * in the L * a * b * color system.

<Comparative example 2>
A pressure-sensitive adhesive film produced in the same manner as in Example 1 was obtained except that 15 wt% of an antioxidant (manufactured by Ciba Specialty, Irganox) was added to the total amount of the solid component in the pressure-sensitive adhesive composition. . The light transmittance of this adhesive film was 30.0%. This adhesive film was cut into a predetermined size to obtain an adhesive tape.
After the adhesive tape was heated at 180 ° C. for about 1 hour, the adhesive strength measured according to JIS Z0237 was 2.0 N / 19 mm, the thermal shrinkage was 0.15%, and after heating at 180 ° C. for 1 hour. The chromaticity of the tape was 5.6 as the value of b * in the L * a * b * color system.

<Summary of results>
The evaluation results of visibility are summarized in Table 1.

以上のように、実施例１について、耐熱性かつ、視認性に優れた表面保護粘着テープを提供することができた。ＣＣＤパッケージ成型時に使用すると、特に有用であった。

As mentioned above, about Example 1, the surface protection adhesive tape excellent in heat resistance and visibility was able to be provided. It was particularly useful when used when molding a CCD package.

Claims (5)

  It is a tape having an adhesive layer on at least one side, and the chromaticity of the tape after heating at 180 ° C. for 1 hour is a value of b * in the L * a * b * color system according to JIS Z 8729 Adhesive tape characterized by being 5.0 or less.   The pressure-sensitive adhesive tape contains an antioxidant in the pressure-sensitive adhesive layer, wherein the ratio of the antioxidant in the pressure-sensitive adhesive layer is 0.1 to 10 wt% with respect to the total amount of solid components of the pressure-sensitive adhesive. The pressure-sensitive adhesive tape according to claim 1.   The pressure-sensitive adhesive tape according to claim 1 or 2, wherein a heat shrinkage ratio of the pressure-sensitive adhesive tape after heating at 180 ° C for 1 hour is 1.0% or less.   The pressure-sensitive adhesive tape according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive force of the pressure-sensitive adhesive tape after heating at 180 ° C for 1 hour is 0.1 to 8.0 N / 19 mm width. A mounting method of a video sensor, wherein the adhesive tape according to any one of claims 1 to 4 is bonded to a light receiving portion side of the video sensor in a mounting step of the video sensor using a solid-state imaging device.