JP6883019B2 - Semiconductor processing sheet - Google Patents

Description

The present invention relates to a semiconductor processing sheet.
The present application claims priority based on Japanese Patent Application No. 2016-069603 filed in Japan on March 30, 2016, the contents of which are incorporated herein by reference.

The dicing sheet is used when a semiconductor wafer is diced into semiconductor chips. The dicing sheet is, for example, configured to include an adhesive layer on a base material, and is used by being attached to a semiconductor wafer by the adhesive layer. After dicing, for example, the semiconductor chip is separated from the cured pressure-sensitive adhesive layer by reducing the adhesive strength of the pressure-sensitive adhesive layer by curing by irradiation with energy rays such as ultraviolet rays, and is easily picked up.

On the other hand, the semiconductor chip after pickup is die-bonded to the circuit surface of the substrate by, for example, a film-like adhesive, and if necessary, one or more other semiconductor chips are laminated on the semiconductor chip and wire-bonded. After that, the whole is sealed with a resin.
Finally, the target semiconductor device is manufactured using the semiconductor package thus obtained. Therefore, the semiconductor chip may be configured to be picked up with a film-like adhesive on the surface to be die-bonded.

When a film-like adhesive is used in this way, a dicing die-bonding sheet in which an uncut film-like adhesive is provided on the pressure-sensitive adhesive layer of the dicing sheet described above may be used. On the other hand, a plurality of semiconductor chips that have been individually separated may be provided on the film-like adhesive, and in this case as well, a processing sheet having the same configuration as the dicing die bonding sheet is used. To. When such a processing sheet is used, for example, a plurality of semiconductor chips that have been individually separated are provided on the film-like adhesive, and the processing sheet is expanded at a low temperature. As a result, the film-like adhesive may be cut according to the outer shape of the semiconductor chip to manufacture a semiconductor chip having the cut film-like adhesive on a target surface.

As a processing sheet (wafer processing tape) suitable for cutting the film-like adhesive by expanding, for example, the shearing force of the pressure-sensitive adhesive layer and the film-like adhesive (adhesive layer) at 25 ° C. and a 0.2 N / mm ² or more, 200 mJ / cm ² post-energy ray irradiation JIS-Z0237 peel rate 300 mm / min in a standard state that conforms to the the film-like adhesive and the pressure-sensitive adhesive layer at peel angle 180 ° Those having an agent peeling force of 0.3 N / 25 mm or less are disclosed (see Patent Document 1).

International Publication No. 2013/103116

However, the processing sheet disclosed in Patent Document 1 has a problem that energy ray irradiation is required at the time of use. In this processing sheet, when the film-like adhesive is cut by expanding, the pressure-sensitive adhesive layer before the energy ray irradiation is used in order to suppress the floating and scattering of the semiconductor chip provided with the film-like adhesive from the pressure-sensitive adhesive layer. Designed for high adhesive strength, while low adhesive strength of the adhesive layer after energy ray irradiation to facilitate picking up of semiconductor chips with film-like adhesive. There is.

Therefore, the present invention has a configuration in which an adhesive layer is provided on a base material, and is a semiconductor processing sheet for use when cutting a film-like adhesive attached to a semiconductor chip, and is irradiated with energy rays during use. Is unnecessary, and when the film-like adhesive is cut by expanding, it is possible to suppress floating and scattering of the semiconductor chip having the film-like adhesive from the adhesive layer, and it is easy to make the semiconductor chip with the film-like adhesive. It is an object of the present invention to provide a sheet for semiconductor processing that can be picked up.

In order to solve the above problems, the present invention provides a pressure-sensitive adhesive layer on a base material, and the storage elastic modulus of the pressure-sensitive adhesive layer having a thickness of 200 μm at 0 ° C. is 1000 MPa or less, and a mirror surface of a semiconductor wafer. Provided is a semiconductor processing sheet in which the adhesive strength of the pressure-sensitive adhesive layer is 200 mN / 25 mm or less.
In the semiconductor processing sheet of the present invention, it is preferable that the pressure-sensitive adhesive layer is non-energy ray-curable.
The semiconductor processing sheet of the present invention may be formed by further providing a film-like adhesive on the pressure-sensitive adhesive layer.

[1] An adhesive layer is provided on the base material, and the adhesive layer is provided.
The pressure-sensitive adhesive layer contains the pressure-sensitive adhesive resin (i) and the cross-linking agent (ii).
In the pressure-sensitive adhesive layer, the content of the cross-linking agent (ii) is 10 to 50 parts by mass with respect to 100 parts by mass of the content of the pressure-sensitive adhesive resin (i).
Semiconductor processing sheet with the following characteristics:
When the thickness of the pressure-sensitive adhesive layer is 200 μm, the storage elastic modulus of the pressure-sensitive adhesive layer having a thickness of 200 μm at 0 ° C. is 1000 MPa or less, and the semiconductor processing sheet is attached to the mirror surface of the semiconductor wafer. The adhesive strength of the pressure-sensitive adhesive layer to the mirror surface is 200 mN / 25 mm or less.
[2] A semiconductor processing sheet having one adhesive layer on a base material and having the following characteristics:
When the thickness of the pressure-sensitive adhesive layer is 200 μm, the storage elastic modulus of the pressure-sensitive adhesive layer having a thickness of 200 μm at 0 ° C. is 1000 MPa or less, and
When the semiconductor processing sheet is attached to the mirror surface of the semiconductor wafer, the adhesive force of the pressure-sensitive adhesive layer on the mirror surface is 200 mN / 25 mm or less.
[ 3 ] The semiconductor processing sheet according to [1] or [2] , wherein the pressure-sensitive adhesive layer is non-energy ray-curable.
[ 4 ] The semiconductor processing sheet according to any one of [1] to [3] , further comprising a film-like adhesive on the pressure-sensitive adhesive layer.

According to the present invention, it is a structure provided with an adhesive layer on a base material, and is a semiconductor processing sheet for use when cutting a film-like adhesive attached to a semiconductor chip, and is an energy ray at the time of use. Irradiation is not required, and when cutting by expanding the film-like adhesive, it is possible to suppress floating and scattering of the semiconductor chip having the film-like adhesive from the adhesive layer, and the semiconductor chip having the film-like adhesive can be used. A sheet for semiconductor processing that can be easily picked up is provided.

It is sectional drawing which shows typically one Embodiment of the semiconductor processing sheet of this invention. It is sectional drawing for schematically explaining one Embodiment of the manufacturing method of the semiconductor device when the semiconductor processing sheet of this invention is used. It is sectional drawing for schematically explaining one Embodiment of the method of forming a groove in a semiconductor wafer and obtaining a semiconductor chip. It is sectional drawing for schematically explaining one Embodiment of the method of forming a modified layer on a semiconductor wafer and obtaining a semiconductor chip. It is sectional drawing which shows typically the state of the semiconductor chip at the time of expansion of the film-like adhesive when the conventional semiconductor processing sheet is used. It is sectional drawing which shows typically the state at the time of trying to pick up a semiconductor chip with a film-like adhesive when the conventional semiconductor processing sheet is used.

<< Sheet for semiconductor processing >>
The semiconductor processing sheet of the present invention has an adhesive layer on a base material, and the adhesive layer having a thickness of 200 μm has a storage elastic modulus at 0 ° C. of 1000 MPa or less, and is said to have a storage elastic modulus with respect to a mirror surface of a semiconductor wafer. The adhesive strength of the pressure-sensitive adhesive layer is 200 mN / 25 mm or less.
As another aspect, the semiconductor processing sheet of the present invention is a semiconductor processing sheet having an adhesive layer on a base material and having the following characteristics:
When the thickness of the pressure-sensitive adhesive layer is 200 μm, the storage elastic modulus of the pressure-sensitive adhesive layer having a thickness of 200 μm at 0 ° C. is 1000 MPa or less, and the semiconductor processing sheet is attached to the mirror surface of the semiconductor wafer. The adhesive force of the pressure-sensitive adhesive layer on the mirror surface is 200 mN / 25 mm or less.
The sheet for semiconductor processing of the present invention has a structure in which a film-like adhesive is provided on the pressure-sensitive adhesive layer, and a plurality of pre-divided semiconductor chips are provided on the film-like adhesive, and then the semiconductor processing is performed. By performing so-called expanding at a low temperature, the film-like adhesive is expanded together with the sheet for use in the surface direction thereof (the direction along the surface, that is, the direction horizontal to the surface of the film-like adhesive). It is suitable for use in the step of cutting the film-like adhesive according to the outer shape of the semiconductor chip. A semiconductor chip having the film-like adhesive after cutting on a surface (back surface) opposite to the surface on which the circuit is formed (hereinafter, may be abbreviated as "circuit forming surface") (in the present specification). Is sometimes referred to as a "semiconductor chip with a film-like adhesive") is used in the manufacture of semiconductor devices after being picked up.

As described above, the semiconductor processing sheet of the present invention is suitable as a so-called expanding sheet that expands and cuts a film-like adhesive.
Further, the semiconductor processing sheet of the present invention is also suitable for being used alone as a dicing sheet.

According to the semiconductor processing sheet of the present invention, when the film-like adhesive provided on the semiconductor processing sheet is cut by expanding, the pressure-sensitive adhesive layer of the semiconductor chip with the film-like adhesive (in other words, the semiconductor processing sheet). ) Can be suppressed from floating and scattering, and a semiconductor chip with a film-like adhesive can be easily picked up without any process abnormality.

The expansion cutting of the film-like adhesive as described above is suitable for application, for example, when manufacturing a semiconductor chip with a film-like adhesive including a semiconductor chip having a thin thickness.
The plurality of divided semiconductor chips form a groove from the circuit forming surface (front surface) opposite to the film-like adhesive sticking surface (back surface) of the semiconductor wafer, and the groove is reached until the groove is reached. It can be manufactured by grinding the back surface. The operation of cutting the semiconductor wafer so as to leave the bottom of the groove without dividing the semiconductor wafer in this way is called a half cut. However, in the present invention, "half-cut" does not mean only the operation of cutting the semiconductor wafer so that the groove depth becomes a specific value such as half the thickness of the semiconductor wafer. It means the whole operation of cutting the semiconductor wafer so as to leave the bottom of the groove as in.

Examples of the method of forming the groove include a method of forming a groove by cutting a semiconductor wafer with a blade (that is, blade dicing) and a method of forming a groove by cutting a semiconductor wafer by laser irradiation (that is, that is). Laser dicing), a method of forming a groove by cutting a semiconductor wafer by spraying water containing an abrasive (that is, water dicing) and the like. However, when a semiconductor chip is manufactured by scraping a part of the semiconductor wafer as described above, if the thickness of the semiconductor wafer is thin, a broken semiconductor chip is likely to be obtained and the yield is likely to decrease. In addition, whisker-like shavings remain on the semiconductor chip, and shavings from the semiconductor wafer adhere to the semiconductor chip, causing an abnormality in the pickup of the semiconductor chip with a film-like adhesive, or the obtained semiconductor. The performance of the device deteriorates.

On the other hand, the plurality of divided semiconductor chips are irradiated with laser light in the infrared region so as to be focused on the focal point set inside the semiconductor wafer to form a modified layer inside the semiconductor wafer. The semiconductor wafer is also manufactured by grinding the back surface of the semiconductor wafer and further dividing the semiconductor wafer at the formation site of the modified layer by applying a force at the time of grinding to the semiconductor wafer whose back surface is being ground. it can. In this method, since there is no step of scraping a part of the semiconductor wafer, even if the thickness of the semiconductor wafer is thin, the semiconductor chip is cracked as described above, the uncut portion of the semiconductor chip remains, and the semiconductor wafer is scraped. Adhesion of debris is suppressed.
As described above, the method of dividing the semiconductor wafer at the formation site of the modified layer is suitable when the thickness of the semiconductor wafer is thin, and the thin semiconductor chip obtained from such a semiconductor wafer is formed into a film. The semiconductor processing sheet of the present invention is suitable for picking up together with the state adhesive.

<Base material>
The constituent material of the base material is preferably various resins, and specifically, for example, polyethylene (low density polyethylene (sometimes abbreviated as LDPE), linear low density polyethylene (sometimes abbreviated as LLDPE)). , High density polyethylene (sometimes abbreviated as HDPE), polypropylene, polybutene, polybutadiene, polymethylpentene, styrene / ethylenebutylene / styrene block copolymer, polyvinyl chloride, vinyl chloride copolymer, polyethylene terephthalate, poly Butylene terephthalate, polyurethane, polyurethane acrylate, polyimide, ethylene vinyl acetate copolymer, ionomer resin, ethylene / (meth) acrylic acid copolymer, ethylene / (meth) acrylic acid ester copolymer, polystyrene, polycarbonate, fluororesin, Examples thereof include water additives, modified products, cross-linked products, copolymers and the like of any of these resins.
Among the above, low density polyethylene (LDPE) is preferable.

In addition, in this specification, "(meth) acrylic acid" is a concept including both "acrylic acid" and "methacrylic acid". The same applies to terms similar to (meth) acrylic acid, for example, "(meth) acrylate" is a concept that includes both "acrylate" and "methacrylate", and is a "(meth) acryloyl group". Is a concept that includes both an "acryloyl group" and a "methacryloyl group".

The resin constituting the base material may be only one type, may be two or more types, and when there are two or more types, the combination and ratio thereof can be arbitrarily selected.

The base material may be composed of one layer (single layer) or may be composed of two or more layers. When the base material is composed of a plurality of layers, the plurality of layers may be the same or different from each other, and the combination of the plurality of layers is not particularly limited as long as the effects of the present invention are not impaired.
In the present specification, not only in the case of a base material, "a plurality of layers may be the same or different from each other" means "all layers may be the same or all layers are different". It means that only some of the layers may be the same, and further, "multiple layers are different from each other" means that "at least one of the constituent materials and thicknesses of each layer is different from each other". Means.

The thickness of the base material can be appropriately selected depending on the intended purpose, but is preferably 50 to 300 μm, more preferably 70 to 150 μm.
Here, the "thickness of the base material" means the thickness of the entire base material, and for example, the thickness of the base material composed of a plurality of layers means the total thickness of all the layers constituting the base material. means.
In addition, in this specification, "thickness" means the value represented by the average of the thickness measured by the contact type thickness gauge at arbitrary 5 places.

In order to improve the adhesion of the base material to other layers such as the pressure-sensitive adhesive layer provided on the base material, the base material is subjected to sandblasting treatment, solvent treatment or other unevenness treatment, corona discharge treatment, electron beam irradiation treatment, plasma treatment. , Ozone / ultraviolet irradiation treatment, flame treatment, chromic acid treatment, hot air treatment and other oxidation treatments may be applied to the surface.
Further, the base material may have a surface surface that has been subjected to a primer treatment.
Further, the base material is a layer for preventing the base material from adhering to another sheet or adhering to the adsorption table when the antistatic coat layer and the semiconductor processing sheet are stacked and stored. It may have.

<Adhesive layer>
The pressure-sensitive adhesive layer preferably satisfies the conditions of storage elastic modulus shown below and is non-energy ray-curable.
In the present invention, "non-energy ray curable" means a property that does not cure even when irradiated with energy rays. On the contrary, the property of being cured by irradiating with energy rays is called "energy ray curability".
In the present invention, the "energy ray" means an electromagnetic wave or a charged particle beam having an energy quantum, and examples thereof include ultraviolet rays and electron beams.
Ultraviolet rays can be irradiated by using, for example, a high-pressure mercury lamp, a fusion H lamp, a xenon lamp, a light emitting diode, or the like as an ultraviolet source. The electron beam can be irradiated with an electron beam generated by an electron beam accelerator or the like.

The pressure-sensitive adhesive layer may be only one layer (single layer), may be a plurality of layers of two or more layers, and when there are a plurality of layers, the plurality of layers may be the same or different from each other, and the combination of the plurality of layers may be used. There is no particular limitation.

The thickness of the pressure-sensitive adhesive layer can be appropriately selected depending on the intended purpose, but is preferably 1 to 100 μm, more preferably 1 to 60 μm, and particularly preferably 1 to 30 μm.
Here, the "thickness of the pressure-sensitive adhesive layer" means the thickness of the entire pressure-sensitive adhesive layer, and for example, the thickness of the pressure-sensitive adhesive layer composed of a plurality of layers is the sum of all the layers constituting the pressure-sensitive adhesive layer. Means the thickness of.

The pressure-sensitive adhesive layer for which the storage elastic modulus is to be obtained may be a single-layer pressure-sensitive adhesive layer having a thickness of 200 μm, or a pressure-sensitive adhesive layer having a thickness of less than 200 μm and having a total thickness of 200 μm. It may be a laminated body obtained by laminating two or more layers so as to be.
In this specification, regardless of whether the pressure-sensitive adhesive layer for which the storage elastic modulus is to be obtained is a single-layer pressure-sensitive adhesive layer or the above-mentioned laminated body, it may be simply referred to as "stick-bond layer". ..
Further, in the present specification, the above-mentioned "storage elastic modulus of the pressure-sensitive adhesive layer" and "storage elastic modulus of the laminated body" are "unless otherwise specified" when the pressure-sensitive adhesive layer is curable. It means "the storage elastic modulus of the pressure-sensitive adhesive layer before curing" and "the storage elastic modulus of the laminate before the pressure-sensitive adhesive layer is cured".

The storage elastic modulus of the pressure-sensitive adhesive layer or laminate at 0 ° C. is 1000 MPa or less, preferably 996 MPa or less. When the storage elastic modulus is not more than the upper limit value, as will be described later, floating and scattering of the semiconductor chip with the film-like adhesive from the pressure-sensitive adhesive layer at the time of cutting by expanding the film-like adhesive is suppressed. ..
The lower limit of the storage elastic modulus of the pressure-sensitive adhesive layer or laminate at 0 ° C. is not particularly limited and may be, for example, 100 MPa, 300 MPa, or 500 MPa, but these are examples.
That is, as one aspect, the storage elastic modulus of the pressure-sensitive adhesive layer or laminate at 0 ° C. is 100 MPa to 1000 MPa, preferably 300 MPa to 1000 MPa, more preferably 500 MPa to 996 MPa, and particularly preferably 533 MPa to 994 MPa.

In the present invention, the storage elastic modulus (MPa) is such that the pressure-sensitive adhesive layer or laminate to be measured is heated at a temperature rising rate of 10 ° C./min and a frequency of 11 Hz, for example, from −50 ° C. to 50 ° C. It is obtained by measuring the storage elastic modulus (MPa) when the temperature is raised in a specific temperature range.
More specifically, when the thickness of the pressure-sensitive adhesive layer was 200 μm, the temperature was raised by a dynamic viscoelasticity measuring device under the conditions of a temperature rising rate of 10 ° C./min, a frequency of 11 Hz, and a temperature of -50 to 50 ° C. It can be obtained by measuring the storage elastic modulus (MPa) at 0 ° C.

The storage elastic modulus can be appropriately adjusted by, for example, adjusting the type and amount of the components contained in the pressure-sensitive adhesive layer.
For example, the storage elastic modulus of the pressure-sensitive adhesive layer and the storage elastic modulus of the laminate can be adjusted by adjusting the ratio of the monomers constituting the adhesive resin described later, the blending amount of the cross-linking agent, the content of the filler, and the like. Can be easily adjusted.
However, these adjustment methods are only an example.

The adhesive force of the pressure-sensitive adhesive layer on the semiconductor wafer (adhesive force on the mirror surface of the semiconductor wafer) in the semiconductor processing sheet of the present invention is 200 mN / 25 mm or less, preferably 196 mN / 25 mm or less. When the adhesive strength is not more than the upper limit value, the semiconductor chip with a film-like adhesive can be easily picked up without curing the adhesive layer by energy ray irradiation or the like, as will be described later.
The lower limit of the adhesive force of the pressure-sensitive adhesive layer on the semiconductor wafer is not particularly limited, and may be, for example, 10 mN / 25 mm, 30 mN / 25 mm, or 50 mN / 25 mm, but these are examples.
That is, as one aspect, the adhesive force of the pressure-sensitive adhesive layer on the semiconductor processing sheet of the present invention is 10 to 200 mN / 25 mm, preferably 30 to 200 mN / 25 mm, more preferably 50 to 196 mN / 25 mm. It is preferable, and 55 to 194 mN / 25 mm is particularly preferable.

In the present specification, "adhesive strength of the pressure-sensitive adhesive layer on the semiconductor wafer" means "the pressure-sensitive adhesive layer on the semiconductor wafer before curing" when the pressure-sensitive adhesive layer is curable, unless otherwise specified. It means "adhesive strength". Further, the measurement of the adhesive strength is the measurement of the adhesive strength in the standard state specified in JIS Z0237 2008 unless otherwise specified.

In the present invention, the adhesive strength (mN / 25 mm) can be measured by the following method. That is, the semiconductor processing sheet having a width of 25 mm and an arbitrary length is produced. Next, the semiconductor processing sheet is attached to the semiconductor wafer (that is, the mirror surface of the semiconductor wafer) by the pressure-sensitive adhesive layer at room temperature (for example, 23 ° C.). Then, at this temperature, the semiconductor processing sheet is peeled off from the semiconductor wafer at a peeling speed of 300 mm / min so that the surfaces of the pressure-sensitive adhesive layer and the semiconductor wafer in contact with each other form an angle of 180 °. Perform 180 ° peeling. The peeling force at this time is measured, and the measured value is defined as the adhesive force (mN / 25 mm). The length of the semiconductor processing sheet used for measurement is not particularly limited as long as the peeling force can be stably measured. For example, the length of the semiconductor processing sheet used for measurement may be 150 mm.
Examples of the semiconductor wafer include a silicon wafer and the like.

The adhesive strength of the pressure-sensitive adhesive layer on the semiconductor wafer can be appropriately adjusted by, for example, adjusting the type and amount of the components contained in the pressure-sensitive adhesive layer.
For example, the adhesive strength of the pressure-sensitive adhesive layer can be easily adjusted by adjusting the combination of monomers constituting the adhesive resin described later, the ratio of the monomers, the blending amount of the cross-linking agent, the content of the filler, and the like. it can.
However, these adjustment methods are only an example.

Semiconductor wafers such as silicon wafers are different from the pressure-sensitive adhesive layer if the same pressure-sensitive adhesive layer is attached to the same part even if the types are different or the production lots are different for the same type. The variation in adhesive strength is small. Therefore, the adhesive strength of the pressure-sensitive adhesive layer can be specified with high accuracy by selecting a semiconductor wafer as the measurement target. In the present invention, when a semiconductor chip with a film-like adhesive is separated from the pressure-sensitive adhesive layer and picked up by selecting a pressure-sensitive adhesive layer having an adhesive force against the mirror surface of the semiconductor wafer of 200 mN / 25 mm or less. In addition, the adhesive force of the adhesive layer to the film-like adhesive can be adjusted so that the occurrence of process abnormalities can be suppressed and picked up easily. Such effects of the present invention are exhibited in all film-like adhesives used in this field.

The pressure-sensitive adhesive layer can be formed from a pressure-sensitive adhesive composition containing a pressure-sensitive adhesive. For example, the pressure-sensitive adhesive layer can be formed on a target portion by applying the pressure-sensitive adhesive composition to the surface to be formed of the pressure-sensitive adhesive layer and drying it if necessary. A more specific method for forming the pressure-sensitive adhesive layer will be described in detail later together with a method for forming the other layers. The ratio of the contents of the components that do not vaporize at room temperature in the pressure-sensitive adhesive composition is usually the same as the ratio of the contents of the components in the pressure-sensitive adhesive layer.

The pressure-sensitive adhesive composition may be applied by a known method, for example, an air knife coater, a blade coater, a bar coater, a gravure coater, a roll coater, a roll knife coater, a curtain coater, a die coater, a knife coater, and a screen coater. , A method using various coaters such as a Meyer bar coater and a kiss coater.

The drying conditions of the pressure-sensitive adhesive composition are not particularly limited, but when the pressure-sensitive adhesive composition contains a solvent described later, it is preferably heat-dried. In this case, for example, at 70 to 130 ° C. for 10 seconds to dry. It is preferable to dry under the condition of 5 minutes.

[Adhesive composition]
The pressure-sensitive adhesive composition is preferably non-energy ray-curable.
Examples of the non-energy ray-curable pressure-sensitive adhesive composition include a pressure-sensitive adhesive resin such as an acrylic resin, a urethane-based resin, a rubber-based resin, a silicone-based resin, an epoxy-based resin, a polyvinyl ether, or a polycarbonate (hereinafter, “adhesive”). The one containing (referred to as "sexual resin (i)") can be mentioned.

(Adhesive resin (i))
The adhesive resin (i) is preferably an acrylic resin.
Examples of the acrylic resin in the adhesive resin (i) include acrylic polymers having at least a structural unit derived from (meth) acrylic acid alkyl ester.
The structural unit of the acrylic resin may be only one type, may be two or more types, and when there are two or more types, the combination and ratio thereof can be arbitrarily selected.
Here, "origin" means that the chemical structure is changed due to polymerization.

Examples of the (meth) acrylic acid alkyl ester include those in which the alkyl group constituting the alkyl ester has 1 to 20 carbon atoms, and the alkyl group is linear or branched. Is preferable.
More specifically, as the (meth) acrylic acid alkyl ester, methyl (meth) acrylic acid, ethyl (meth) acrylic acid, n-propyl (meth) acrylic acid, isopropyl (meth) acrylic acid, (meth) acrylic acid. n-butyl, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-Ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, n-octyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, (meth) ) Undecyl acrylate, dodecyl (meth) acrylate (also called (meth) lauryl acrylate), tridecyl (meth) acrylate, tetradecyl (meth) acrylate (also called myristyl (meth) acrylate), (meth) acrylic Pentadecyl acid, hexadecyl (meth) acrylate (also called palmityl (meth) acrylate), heptadecyl (meth) acrylate, octadecyl (meth) acrylate (also called stearyl (meth) acrylate), nonadecil (meth) acrylate , (Meta) icosyl acrylate and the like.
Among the above, 2-ethylhexyl (meth) acrylate is preferable.

From the viewpoint of improving the adhesive strength of the pressure-sensitive adhesive layer, the acrylic polymer preferably has a structural unit derived from a (meth) acrylic acid alkyl ester having 4 or more carbon atoms in the alkyl group. The alkyl group preferably has 4 to 12 carbon atoms, and more preferably 4 to 8 carbon atoms, from the viewpoint of further improving the adhesive force of the pressure-sensitive adhesive layer. The (meth) acrylic acid alkyl ester having 4 or more carbon atoms in the alkyl group is preferably an acrylic acid alkyl ester.

The acrylic polymer preferably has a structural unit derived from a functional group-containing monomer in addition to the structural unit derived from the (meth) acrylic acid alkyl ester.
The functional group-containing monomer may be, for example, a starting point of cross-linking when the functional group reacts with a cross-linking agent described later, or when the functional group reacts with an unsaturated group in an unsaturated group-containing compound. Examples thereof include those capable of introducing an unsaturated group into the side chain of the acrylic polymer.

Examples of the functional group in the functional group-containing monomer include a hydroxyl group, a carboxy group, an amino group, an epoxy group and the like.
That is, examples of the functional group-containing monomer include a hydroxyl group-containing monomer, a carboxy group-containing monomer, an amino group-containing monomer, and an epoxy group-containing monomer.

Examples of the hydroxyl group-containing monomer include hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and (meth). Hydroxyalkyl (meth) acrylates such as 2-hydroxybutyl acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate; non- (meth) acrylics such as vinyl alcohol and allyl alcohol. Saturated alcohol (unsaturated alcohol having no (meth) acrylic skeleton) and the like can be mentioned.
Among the above, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and the like are preferable.

Examples of the carboxy group-containing monomer include ethylenically unsaturated monocarboxylic acids (monocarboxylic acids having ethylenically unsaturated bonds) such as (meth) acrylic acid and crotonic acid; fumaric acid, itaconic acid, maleic acid, and citracon. Ethylene unsaturated dicarboxylic acids such as acids (dicarboxylic acids having ethylenically unsaturated bonds); anhydrides of the ethylenically unsaturated dicarboxylic acids; (meth) acrylic acid carboxyalkyl esters such as 2-carboxyethyl methacrylate and the like. Be done.

As the functional group-containing monomer, a hydroxyl group-containing monomer and a carboxy group-containing monomer are preferable, and a hydroxyl group-containing monomer is more preferable.

The functional group-containing monomer constituting the acrylic polymer may be only one type, may be two or more types, and when there are two or more types, the combination and ratio thereof can be arbitrarily selected.

In the acrylic polymer, the content of the structural unit derived from the functional group-containing monomer is preferably 1 to 35% by mass with respect to the total amount (total mass) of the structural units constituting the acrylic polymer. It is more preferably 3 to 32% by mass, and particularly preferably 5 to 30% by mass.

The acrylic polymer may further have a structural unit derived from another monomer in addition to the structural unit derived from the (meth) acrylic acid alkyl ester and the structural unit derived from the functional group-containing monomer.
The other monomer is not particularly limited as long as it can be copolymerized with a (meth) acrylic acid alkyl ester or the like.
Examples of the other monomer include styrene, α-methylstyrene, vinyltoluene, vinyl formate, vinyl acetate, acrylonitrile, acrylamide and the like.

The other monomer constituting the acrylic polymer may be only one kind, may be two or more kinds, and when there are two or more kinds, the combination and ratio thereof can be arbitrarily selected.

It is preferable that the adhesive resin (i) other than the acrylic polymer also has a structural unit derived from the functional group-containing monomer, like the acrylic polymer.

The pressure-sensitive adhesive resin (i) contained in the pressure-sensitive adhesive composition may be only one type, may be two or more types, and when there are two or more types, the combination and ratio thereof can be arbitrarily selected.

The content of the pressure-sensitive adhesive resin (i) is 45 to 90% by mass with respect to the total mass of the components other than the solvent constituting the pressure-sensitive adhesive composition (that is, with respect to the total mass of the pressure-sensitive adhesive layer). It is more preferably 55 to 87% by mass, further preferably 65 to 84% by mass, and particularly preferably 72 to 81% by mass. When the ratio of the content of the adhesive resin (i) is in such a range, the adhesiveness of the adhesive layer becomes better.

(Crosslinking agent (ii))
The pressure-sensitive adhesive composition preferably contains a cross-linking agent (ii).
The cross-linking agent (ii) is, for example, one that reacts with the functional group to cross-link the adhesive resins (i) with each other.
Examples of the cross-linking agent (ii) include isocyanate-based cross-linking agents such as tolylene diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, and adducts of these diisocyanates (that is, cross-linking agents having an isocyanate group); ethylene glycol glycidyl ether and the like. Epoxy-based cross-linking agents (ie, cross-linking agents having a glycidyl group); azilysin-based cross-linking agents such as hexa [1- (2-methyl) -aziridinyl] triphosphatriazine (ie, cross-linking agents having an aziridinyl group); aluminum chelate And the like (that is, a cross-linking agent having a metal chelate structure); an isocyanurate-based cross-linking agent (that is, a cross-linking agent having an isocyanurate skeleton) and the like.
The cross-linking agent (ii) is preferably an isocyanate-based cross-linking agent from the viewpoints of improving the cohesive force of the pressure-sensitive adhesive to improve the adhesive force of the pressure-sensitive adhesive layer and being easily available. Examples thereof include a tolylene diisocyanate trimer adduct of methylolpropane.

The cross-linking agent (ii) contained in the pressure-sensitive adhesive composition may be only one type, may be two or more types, and when there are two or more types, the combination and ratio thereof can be arbitrarily selected.

When the pressure-sensitive adhesive composition contains a cross-linking agent (ii), the content of the cross-linking agent (ii) in the pressure-sensitive adhesive composition is 5 to 50 with respect to 100 parts by mass of the content of the pressure-sensitive adhesive resin (i). It is preferably parts by mass, more preferably 10 to 45 parts by mass, and particularly preferably 15 to 40 parts by mass. As another aspect, the content of the cross-linking agent (ii) may be 22 to 38 parts by mass with respect to 100 parts by mass of the content of the adhesive resin (i), and 22.62 to 37. It may be 70 parts by mass. When the content of the cross-linking agent (ii) is at least the lower limit value, the effect of using the cross-linking agent (ii) can be obtained more remarkably. Further, when the content of the cross-linking agent (ii) is not more than the upper limit value, it becomes easier to adjust the adhesive force of the pressure-sensitive adhesive layer to the film-like adhesive.

(Other additives)
The pressure-sensitive adhesive composition may contain other additives that do not fall under any of the above-mentioned components as long as the effects of the present invention are not impaired.
Examples of the other additives include antioxidants, antioxidants, softeners (plasticizers), fillers (fillers), rust inhibitors, colorants (pigments, dyes), sensitizers, and tackifiers. , Known additives such as reaction retarders and cross-linking accelerators (catalysts).
The "reaction retarder" is, for example, a substance that suppresses the progress of an unintended cross-linking reaction in the pressure-sensitive adhesive composition during storage due to the action of a catalyst mixed in the pressure-sensitive adhesive composition. is there. Examples of the reaction retarder include compounds that form a chelate complex by chelating to a catalyst, and more specifically, compounds having two or more carbonyl groups (-C (= O)-) in one molecule. Can be mentioned.

The other additives contained in the pressure-sensitive adhesive composition may be only one kind, two or more kinds, and when two or more kinds, the combination and ratio thereof can be arbitrarily selected.

The content of the other additives in the pressure-sensitive adhesive composition is not particularly limited, and may be appropriately selected depending on the type thereof.

(solvent)
The pressure-sensitive adhesive composition may contain a solvent. Since the pressure-sensitive adhesive composition contains a solvent, the suitability for coating on the surface to be coated is improved.

The solvent is preferably an organic solvent. Examples of the organic solvent include ketones such as methyl ethyl ketone and acetone; esters such as ethyl acetate (for example, carboxylic acid esters); ethers such as tetrahydrofuran and dioxane; aliphatic hydrocarbons such as cyclohexane and n-hexane; toluene and xylene. Aromatic hydrocarbons such as 1-propanol, alcohols such as 2-propanol and the like.

As the solvent, for example, the solvent used in the production of the adhesive resin (i) may be used as it is in the adhesive composition without removing it from the adhesive resin (i), or the adhesive resin (i) may be used as it is. A solvent of the same or different type as the solvent used in the production may be added separately in the production of the pressure-sensitive adhesive composition.

The solvent contained in the pressure-sensitive adhesive composition may be only one type, may be two or more types, and when there are two or more types, the combination and ratio thereof can be arbitrarily selected.

In the pressure-sensitive adhesive composition, the content of the solvent is not particularly limited and may be appropriately adjusted.

[Manufacturing method of adhesive composition]
The pressure-sensitive adhesive composition is obtained by blending each component for constituting the pressure-sensitive adhesive composition.
The order of addition of each component at the time of blending is not particularly limited, and two or more kinds of components may be added at the same time.
When a solvent is used, the solvent may be mixed with any of the ingredients other than the solvent to dilute the ingredients in advance, or any of the ingredients other than the solvent should be diluted in advance. Instead, the solvent may be mixed with these ingredients.

The method of mixing each component at the time of blending is not particularly limited, and from known methods such as a method of rotating a stirrer or a stirring blade to mix; a method of mixing using a mixer; a method of adding ultrasonic waves to mix. It may be selected as appropriate.
The temperature and time at the time of adding and mixing each component are not particularly limited as long as each compounding component does not deteriorate, and may be appropriately adjusted, but the temperature is preferably 15 to 30 ° C.
FIG. 1 is a cross-sectional view schematically showing an embodiment of a semiconductor processing sheet of the present invention. In addition, in the figure used in the following description, in order to make it easy to understand the features of the present invention, the main part may be enlarged and shown, and the dimensional ratio of each component is the same as the actual one. Is not always the case.

The semiconductor processing sheet 1 shown in FIG. 1 is a sheet in which the pressure-sensitive adhesive layer 12 is provided on the base material 11. In the semiconductor processing sheet 1, the pressure-sensitive adhesive layer 12 is laminated on one surface 11a of the base material 11.

The semiconductor processing sheet of the present invention is not limited to the one shown in FIG. 1, and a part of the structure shown in FIG. 1 has been changed, deleted or added within the range not impairing the effect of the present invention. It may be a thing.

<< Manufacturing method of semiconductor processing sheet >>
The semiconductor processing sheet of the present invention can be produced by laminating an adhesive layer on a base material. The method for forming the pressure-sensitive adhesive layer is as described above.
For example, the pressure-sensitive adhesive composition is applied onto the release film and dried as necessary to form a pressure-sensitive adhesive layer on the release film in advance, and the release film in the formed pressure-sensitive adhesive layer is used. The semiconductor processing sheet can be obtained by laminating the exposed surface on the side opposite to the contacting side with one surface of the base material. The release film may be removed at an arbitrary timing after the semiconductor processing sheet is obtained. The pressure-sensitive adhesive composition is preferably applied to the peel-treated surface of the release film.

The semiconductor processing sheet is usually stored in a state where a release film is attached to the surface of the outermost layer (that is, the pressure-sensitive adhesive layer) on the side opposite to the base material. Therefore, after the pressure-sensitive adhesive layer is formed on the release film by the above-mentioned method, even after the pressure-sensitive adhesive layer is bonded to the base material, the release film may be left in the bonded state without being removed.

<< Manufacturing method of semiconductor devices >>
As a method for manufacturing a semiconductor device when the semiconductor processing sheet of the present invention is used, for example, a film-like adhesive is provided on the surface of the pressure-sensitive adhesive layer in the semiconductor processing sheet, and the pressure-sensitive adhesive in the film-like adhesive is provided. A step of forming a laminated structure in which a plurality of divided semiconductor chips are provided on a surface opposite to the side on which the agent layer is provided (hereinafter, abbreviated as "laminated structure forming step"). The step of cutting the film-like adhesive by expanding toward the surface of the film-like adhesive while cooling the film-like adhesive in the laminated structure (hereinafter, "cutting step"). A step of picking up (pulling) the semiconductor chip (that is, a semiconductor chip with a film-like adhesive) provided with the film-like adhesive after cutting from the pressure-sensitive adhesive layer (hereinafter, "pulling away"). It may be abbreviated as "process"), and a manufacturing method including.

By using the semiconductor processing sheet of the present invention, the film-like adhesive is used when the film-like adhesive is cut by expanding the semiconductor processing sheet, in other words, expanding the film-like adhesive in the cutting step. Floating and scattering from the adhesive layer of the attached semiconductor chip are suppressed. Further, in the peeling step, the semiconductor chip with a film-like adhesive can be easily pulled away from the pressure-sensitive adhesive layer and picked up without curing the pressure-sensitive adhesive layer by irradiation with energy rays or the like. As described above, when the semiconductor processing sheet of the present invention is used, the semiconductor chip with a film-like adhesive can be picked up without curing the pressure-sensitive adhesive layer, which simplifies the manufacturing process of the semiconductor device. it can.

Hereinafter, the manufacturing method will be described with reference to FIG. FIG. 2 is a cross-sectional view for schematically explaining an embodiment of a method for manufacturing a semiconductor device when the semiconductor processing sheet of the present invention is used. Here, a manufacturing method when the semiconductor processing sheet shown in FIG. 1 is used will be described. In FIG. 2, the same components as those shown in FIG. 1 are designated by the same reference numerals as those in FIG. 1, and detailed description thereof will be omitted. Further, in FIG. 2, only the configurations related to the semiconductor processing sheet, the film-like adhesive, and the semiconductor chip are shown in cross section. These are the same in the figures after FIG.

<Laminate structure forming process>
The laminated structure 101 shown in FIG. 2A is adhered to the surface 12a of the pressure-sensitive adhesive layer 12 of the semiconductor processing sheet 1 (the surface of the pressure-sensitive adhesive layer 12 opposite to the side on which the base material is provided) in the form of a film. This is a laminated structure in which the agent 9 is provided, and a plurality of divided semiconductor chips 8 are provided on the surface 9a of the film-shaped adhesive 9 on the side opposite to the side provided with the pressure-sensitive adhesive layer 12. The semiconductor processing sheet 1 is the semiconductor processing sheet of the present invention in which the pressure-sensitive adhesive layer 12 is laminated on the surface 11a of the base material 11.
In FIG. 2, the gaps (derived from the grooves) between the plurality of semiconductor chips 8 are highlighted.

In the laminated structure forming step, for example, one film-like adhesive 9 is attached to the back surface 8b (the surface of the semiconductor chip 8 opposite to the circuit forming surface) of the plurality of divided semiconductor chips 8. After that, the pressure-sensitive adhesive layer 12 of the semiconductor processing sheet 1 of the present invention is attached to the surface 9b of the film-like adhesive 9 on the side opposite to the side provided with the semiconductor chip 8, whereby the laminated structure 101 Can be formed. Further, after attaching one film-like adhesive 9 to the surface 12a of the pressure-sensitive adhesive layer 12 in the semiconductor processing sheet 1 of the present invention, what is the side of the film-like adhesive 9 provided with the pressure-sensitive adhesive layer 12? The laminated structure can also be formed by attaching the surface 9a on the opposite side to the back surface 8b of the plurality of divided semiconductor chips 8.

As described above, the plurality of divided semiconductor chips 8 form grooves from the circuit forming surface (front surface) opposite to the film-like adhesive 9 sticking surface (back surface) on the semiconductor wafer, and form grooves in the grooves. It can be manufactured by grinding the back surface until it reaches the point. The groove can be formed by a method such as blade dicing, laser dicing, or water dicing.

FIG. 3 is a cross-sectional view for schematically explaining an embodiment of a method of forming a groove in such a semiconductor wafer to obtain a semiconductor chip.
In this method, as shown in FIG. 3A, a groove 80'is formed on the semiconductor wafer 8'by a method such as blade dicing, laser dicing, or water dicing from one surface 8a' which is the circuit forming surface thereof. ..
Next, as shown in FIG. 3B, the surface (back surface) 8b'opposite of the front surface (circuit forming surface) 8a'of the semiconductor wafer 8'is ground. Grinding of the back surface 8b'can be performed by a known method, for example, using a grinder 62. As shown here, the back surface 8b'is preferably ground by attaching the back grind tape 63 to the surface 8a'of the semiconductor wafer 8'.
Then, by grinding the back surface 8b'until the groove 80'is reached, a plurality of semiconductor chips 8 can be obtained from the semiconductor wafer 8'as shown in FIG. 3C. The back surface 8b'of the semiconductor wafer 8'is a back surface 8b of the semiconductor chip 8, that is, a surface for providing the film-like adhesive 9.

However, in the above-mentioned manufacturing method of the semiconductor device, a modified layer is formed inside the semiconductor wafer as described above, and the modified layer is formed at a site where the modified layer is formed, instead of a method of scraping a part of these semiconductor wafers. It is preferable to adopt a method of dividing the semiconductor wafer.

That is, in the manufacturing method of the semiconductor device, before the step of forming the laminated structure, the semiconductor is further irradiated with a laser beam in an infrared region so as to focus on a focal point set inside the semiconductor wafer. The step of forming a modified layer inside the wafer (hereinafter, may be abbreviated as "modified layer forming step") and the semiconductor wafer on which the modified layer is formed are provided with the film-like adhesive. A step of dividing the semiconductor wafer at a portion of the modified layer by applying a grinding force to the semiconductor wafer while grinding the surface to obtain a plurality of semiconductor chips (hereinafter, "division step"). It is preferable that a plurality of semiconductor chips obtained in the dividing step are used in the laminated structure forming step.
FIG. 4 is a cross-sectional view for schematically explaining an embodiment of a method of forming a modified layer on such a semiconductor wafer to obtain a semiconductor chip.

<Modified layer forming process>
In this method, as shown in FIG. 4A, in the modified layer forming step, laser light in the infrared region is irradiated so as to be focused on the focal point set inside the semiconductor wafer 8'. The modified layer 81'is formed inside the semiconductor wafer 8'.
In the modified layer forming step, for example, in order to form the modified layer 81'while minimizing the damage to the surface of the semiconductor wafer 8'and the region near the surface due to the irradiation of the laser beam, the opening degree (NA) is formed. ) Is preferably irradiated with a large laser beam.

<Division process>
Next, in the dividing step, as shown in FIG. 4B, the surface (back surface) 8b'opposite of the front surface (circuit forming surface) 8a'of the semiconductor wafer 8'is ground. The grinding at this time can be performed by the same method as the grinding of the back surface of the semiconductor wafer having the grooves, which has been described with reference to FIG. 3 above. For example, the grinding of the back surface 8b'at this time is preferably performed by attaching the back grind tape 63 to the front surface 8a'of the semiconductor wafer 8'.

Then, by grinding the back surface 8b'of the semiconductor wafer 8'and further applying a force at the time of grinding to the semiconductor wafer 8'during grinding, the semiconductor wafer is formed at the formed portion of the modified layer 81'. By dividing the 8', as shown in FIG. 4C, a plurality of semiconductor chips 8 can be obtained from the semiconductor wafer 8'. In this case as well, the back surface 8b'of the semiconductor wafer 8'is the back surface 8b of the semiconductor chip 8, that is, the surface for providing the film-like adhesive 9, as in the case described with reference to FIG.

In any of the above methods, when the back grind tape 63 is used, the obtained plurality of semiconductor chips 8 are held in an aligned state on the back grind tape 63.

The thickness of the semiconductor chip 8 is not particularly limited, but is preferably 5 to 60 μm, and more preferably 10 to 55 μm. When such a thin semiconductor chip is used, the effect of using the semiconductor processing sheet of the present invention can be obtained more remarkably.

In the above-mentioned method for manufacturing a semiconductor device, the film-like adhesive 9 may be a known one, and examples thereof include those having curability, preferably those having thermosetting property, and those having pressure-sensitive adhesive property. preferable. The film-like adhesive 9 having both thermosetting property and pressure-sensitive adhesive property can be attached by lightly pressing against various adherends in an uncured state. Further, the film-like adhesive 9 may be one that can be attached to various adherends by heating and softening. The film-like adhesive 9 finally becomes a cured product having high impact resistance by curing, and this cured product can maintain sufficient adhesive properties even under severe high temperature and high humidity conditions.

The thickness of the film-like adhesive 9 is not particularly limited, but is preferably 1 to 50 μm, and more preferably 3 to 40 μm. When the thickness of the film-shaped adhesive 9 is at least the above lower limit value, a higher adhesive force to the adherend (semiconductor chip) can be obtained. Further, when the thickness of the film-like adhesive 9 is not more than the upper limit value, the film-like adhesive 9 can be cut more easily by the expansion described later.

<Cutting process>
In the cutting step, after the laminated structure forming step, as shown in FIG. 2B, while cooling the film-like adhesive 9 of the laminated structure 101, the surface 9a direction of the film-like adhesive 9 (FIG. The film-like adhesive 9 is expanded in the direction indicated by the arrow I in 2 (b), that is, the horizontal direction with respect to the surface of the film-like adhesive 9, and the film-like adhesive 9 is cut. The film-like adhesive 9 may be expanded together with the base material 11 and the pressure-sensitive adhesive layer 12 (that is, the semiconductor processing sheet 1). Here, the film-like adhesive after cutting is indicated with reference numeral 9', but such a film-like adhesive 9'after cutting may be simply referred to as "film-like adhesive 9'". is there. Further, the direction of expansion of the film-like adhesive 9 is indicated by an arrow I.

The cooling temperature of the film-like adhesive 9 in the cutting step is not particularly limited, but is preferably -15 to 3 ° C. from the viewpoint that the film-like adhesive 9 can be cut more easily.

The expanding speed (expansion speed) of the film-like adhesive 9 in the cutting step is not particularly limited as long as it does not impair the effects of the present invention, but is preferably 0.5 to 100 mm / sec, and is 0. It is more preferably 5 to 60 mm / sec, and may be, for example, 1 to 50 mm / sec. When the expanding rate is within such a range, the effect of the present invention can be obtained more remarkably. Further, when the expanding speed is equal to or less than the upper limit value, the semiconductor chip 8 is less likely to be damaged when the film-like adhesive 9 is expanded.

In the cutting step, since the semiconductor processing sheet 1 is used, the semiconductor chip 8 in a state where the film-like adhesive 9'after cutting is provided on the back surface 8b is not lifted or scattered from the pressure-sensitive adhesive layer 12. It is suppressed.

On the other hand, FIG. 5 is a cross-sectional view schematically showing the state of the semiconductor chip at the time of expanding the film-like adhesive when a conventional semiconductor processing sheet is used.
The pressure-sensitive adhesive layer 72 shown here has been used conventionally, and when a semiconductor processing sheet 7 having the pressure-sensitive adhesive layer 72 provided on the base material 11 is used, it adheres in the form of a film after cutting. The semiconductor chip 8 provided with the agent 9'may be lifted from the pressure-sensitive adhesive layer 72 or may be peeled off from the pressure-sensitive adhesive layer 72 and scattered. Such floating and scattering of the semiconductor chip with a film-like adhesive is typically obtained, for example, when the storage elastic modulus at 0 ° C. of the pressure-sensitive adhesive layer having a thickness of 200 μm described above is less than 1000 MPa. Can be seen.
Further, such floating and scattering of the semiconductor chip with a film-like adhesive tends to occur when the thickness of the semiconductor chip 8 is thin.

<Pulling process>
In the separating step, after the cutting step, as shown in FIG. 2C, the semiconductor chip 8 and the film-like adhesive 9'after cutting attached to the semiconductor chip 8 are attached to the semiconductor processing sheet 1 (adhesive). It is separated from the layer 12) and picked up.

In the pulling step, the semiconductor chip 8 is pulled up by the pulling-up portion 61 of the semiconductor device manufacturing apparatus, so that the film-like adhesive 9'after cutting, which is attached to the back surface 8b of the semiconductor chip 8, is applied to the pressure-sensitive adhesive layer. Peel from 12. The method of pulling up the semiconductor chip 8 may be a known method, and examples thereof include a method of adsorbing and pulling up the surface of the semiconductor chip 8 with a vacuum collet. Here, the pulling direction of the semiconductor chip 8 is indicated by an arrow II.

By using the semiconductor processing sheet 1 in the pulling step, the semiconductor chip 8 is cut together with the film-like adhesive 9'after cutting, without curing the pressure-sensitive adhesive layer 12 by energy ray irradiation or the like. The film-like adhesive-attached semiconductor chip can be easily pulled away from the adhesive layer 12 and picked up.

On the other hand, FIG. 6 is a cross-sectional view schematically showing a state when an attempt is made to pick up a semiconductor chip with a film-like adhesive when a conventional semiconductor processing sheet is used.
Among them, in FIG. 6A, when the semiconductor chip 8 is pulled up as in the case of FIG. 2C, the film-like adhesive 9'after cutting is peeled off from the semiconductor chip 8 and the film after cutting. The state adhesive 9'remains laminated on the pressure-sensitive adhesive layer 72, indicating a state in which only the semiconductor chip 8 is pulled up.
On the other hand, in FIG. 6B, when the semiconductor chip 8 is pulled up as in the case of FIG. 2C, the semiconductor chip 8 passes through the film-like adhesive 9'after cutting and the pressure-sensitive adhesive layer 72 is used. It shows a state in which the semiconductor chip 8 could not be pulled up.
The process abnormalities as shown in FIGS. 6 (a) and 6 (b) are typically seen when the adhesive force of the pressure-sensitive adhesive layer 72 to the semiconductor wafer is a large value exceeding 200 mN / 25 mm. Be done. The state of FIG. 6A is likely to occur when the adhesive force of the film-like adhesive 9'to the semiconductor wafer is relatively small, and the state of FIG. 6B is the state of the film-like adhesive 9'. It tends to occur when the adhesive force to the semiconductor wafer is relatively large.

In the above-mentioned manufacturing method of the semiconductor device, the semiconductor chip 8 (semiconductor chip with the film-like adhesive) separated (picked up) together with the film-like adhesive 9'after cutting is used, and thereafter, the same as the conventional method is used. A semiconductor device is manufactured by the method. For example, the semiconductor chip 8 is die-bonded to the circuit surface of the substrate with a film-like adhesive 9', and if necessary, one or more semiconductor chips are further laminated on the semiconductor chip 8 to perform wire bonding. , The whole is sealed with a resin to form a semiconductor package (not shown). Then, the target semiconductor device may be manufactured using this semiconductor package.

The method for manufacturing a semiconductor device using the semiconductor processing sheet of the present invention is not limited to the above-mentioned method described with reference to FIG. 2, and a part of the above-mentioned method is used as long as the effect of the present invention is not impaired. The configuration of is changed, deleted or added.

The process abnormality described with reference to FIGS. 5 to 6 is an example, and in some cases, another process abnormality may occur.
On the other hand, when the semiconductor processing sheet of the present invention is used, the occurrence of such process abnormalities is suppressed, and as a result, the semiconductor device can be manufactured at low cost by a method simpler than the conventional method.

As one aspect of the semiconductor processing sheet according to one embodiment of the present invention,
A semiconductor processing sheet having an adhesive layer on a base material.
The pressure-sensitive adhesive layer is formed of a pressure-sensitive adhesive composition containing a pressure-sensitive adhesive resin (i) and a cross-linking agent (ii);
The adhesive resin (i) is an acrylic polymer having at least a structural unit derived from (meth) acrylic acid alkyl ester, preferably a structural unit derived from 2-ethylhexyl (meth) acrylic acid, (meth) acrylic acid 2. -Acrylic polymer having at least one structural unit selected from the group consisting of a structural unit derived from hydroxyethyl and a structural unit derived from 4-hydroxybutyl (meth) acrylate;
The cross-linking agent (ii) is an isocyanate-based cross-linking agent, preferably a trimerizing isocyanate trimer adduct of trimethylolpropane;
The content of the adhesive resin (i) is 45 to 90% by mass, preferably 55 to 87% by mass, more preferably 65 to 84% by mass, and particularly preferably 72, based on the total mass of the pressure-sensitive adhesive layer. ~ 81% by mass;
The content of the cross-linking agent (ii) is 5 to 50 parts by mass, preferably 10 to 45 parts by mass, and more preferably 15 to 40 parts by mass with respect to 100 parts by mass of the adhesive resin (i). , Particularly preferably 22-38 parts by mass;
When the thickness of the pressure-sensitive adhesive layer is 200 μm, the storage elastic modulus of the pressure-sensitive adhesive layer having a thickness of 200 μm at 0 ° C. is 100 MPa to 1000 MPa, preferably 300 MPa to 1000 MPa, more preferably 500 MPa to 996 MPa, and particularly preferably 533 MPa. ~ 994 MPa;
When the semiconductor processing sheet is attached to the mirror surface of the semiconductor wafer, the adhesive force of the adhesive layer on the mirror surface is 10 to 200 mN / 25 mm, preferably 30 to 200 mN / 25 mm, more preferably 50 to 196 mN /. 25 mm, particularly preferably 55-194 mN / 25 mm.
A sheet for semiconductor processing, and the like.

As another aspect of the semiconductor processing sheet according to one embodiment of the present invention,
A semiconductor processing sheet having an adhesive layer on a base material.
The pressure-sensitive adhesive layer is formed of a pressure-sensitive adhesive composition containing a pressure-sensitive adhesive resin (i) and a cross-linking agent (ii);
The adhesive resin (i) is an acrylic having at least one structural unit selected from the group consisting of a structural unit derived from 2-ethylhexyl (meth) acrylate and a structural unit derived from 2-hydroxyethyl (meth) acrylate. It is a system polymer;
The cross-linking agent (ii) is a trimerized isocyanate trimer adduct of trimethylolpropane;
The content of the adhesive resin (i) is 76 to 81% by mass;
The content of the cross-linking agent (ii) is 22 to 31 parts by mass with respect to 100 parts by mass of the content of the adhesive resin (i);
When the thickness of the pressure-sensitive adhesive layer is 200 μm, the storage elastic modulus of the pressure-sensitive adhesive layer having a thickness of 200 μm at 0 ° C. is 533 MPa to 873 MPa;
When the semiconductor processing sheet is attached to the mirror surface of the semiconductor wafer, the adhesive force of the pressure-sensitive adhesive layer on the mirror surface is 94 to 194 mN / 25 mm.
A sheet for semiconductor processing, and the like.

As another aspect of the semiconductor processing sheet according to one embodiment of the present invention,
A semiconductor processing sheet having an adhesive layer on a base material.
The pressure-sensitive adhesive layer is formed of a pressure-sensitive adhesive composition containing a pressure-sensitive adhesive resin (i) and a cross-linking agent (ii);
The adhesive resin (i) is an acrylic having at least one structural unit selected from the group consisting of a structural unit derived from 2-ethylhexyl (meth) acrylate and a structural unit derived from 4-hydroxybutyl (meth) acrylate. It is a system polymer;
The cross-linking agent (ii) is a trimerized isocyanate trimer adduct of trimethylolpropane;
The content of the adhesive resin (i) is 70 to 75% by mass;
The content of the cross-linking agent (ii) is 35 to 39 parts by mass with respect to 100 parts by mass of the content of the adhesive resin (i);
When the thickness of the pressure-sensitive adhesive layer is 200 μm, the storage elastic modulus of the pressure-sensitive adhesive layer having a thickness of 200 μm at 0 ° C. is 500 MPa to 994 MPa;
When the semiconductor processing sheet is attached to the mirror surface of the semiconductor wafer, the adhesive force of the adhesive layer on the mirror surface is 50 to 60 mN / 25 mm.
A sheet for semiconductor processing, and the like.

Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the examples shown below.
In the following, the unit of time "msec" means "millisecond".

The components used in the production of the pressure-sensitive adhesive composition are shown below.
-Adhesive resin Adhesive resin (i) -1: -2-ethylhexyl acrylate (hereinafter abbreviated as "2EHA") (80 parts by mass) and -2-hydroxyethyl acrylate (hereinafter "HEA") An acrylic polymer (weight average molecular weight 860000, glass transition temperature −61 ° C.) obtained by copolymerizing (abbreviated) (20 parts by mass).
Acrylic polymer obtained by copolymerizing adhesive resin (i) -2: 2EHA (80 parts by mass) and -4-hydroxybutyl acrylate (hereinafter abbreviated as "4HBA") (20 parts by mass). Weight average molecular weight 430000, glass transition temperature -63 ° C).
Adhesive resin (i) -3: 2 EHA (60 parts by mass), methyl methacrylate (hereinafter abbreviated as "MMA") (30 parts by mass), and HEA (10 parts by mass) are copolymerized with an acrylic system. Polymer (weight average molecular weight 430000, glass transition temperature −31 ° C.).
Adhesive resin (i) -4: Acrylic polymer obtained by copolymerizing lauryl acrylate (hereinafter abbreviated as "LA") (80 parts by mass) and HEA (20 parts by mass) (weight average molecular weight 720000). , Glass transition temperature −27 ° C.).
-Crosslinking agent Crosslinking agent (ii) -1: Trimerizing isocyanate trimer adduct of trimethylolpropane ("Coronate L" manufactured by Tosoh Corporation)
-Photopolymerization initiator Photopolymerization initiator (iii) -1: 1-hydroxycyclohexylphenyl ketone (BASF's "Irgacure (registered trademark) 184""

[Example 1]
<Manufacturing of semiconductor processing sheets>
(Manufacturing of adhesive composition)
A non-energy ray-curable pressure-sensitive adhesive by adding a cross-linking agent (ii) -1 (30.16 parts by mass) to the pressure-sensitive adhesive resin (i) -1 (100 parts by mass) and stirring at 23 ° C. The composition was obtained.
The number of copies shown here is a solid content conversion value.
Table 1 shows each compounding ingredient and the amount thereof. In addition, the description of "-" in the column of the compounding component in Table 1 means that the component is not compounded.

(Manufacturing of semiconductor processing sheets)
The pressure-sensitive adhesive composition obtained above was applied to the peel-treated surface of a peel-off film (“SP-PET38131” manufactured by Lintec Corporation, thickness 38 μm) in which one side of a polyethylene terephthalate film was peel-treated by silicone treatment. A pressure-sensitive adhesive layer having a thickness of 10 μm was formed by heating and drying at 120 ° C. for 2 minutes.
Next, a low-density polyethylene (LDPE) film having a thickness of 110 μm was attached to the exposed surface of the pressure-sensitive adhesive layer as a base material to obtain a semiconductor processing sheet provided with a release film.

<Evaluation of semiconductor processing sheet>
(Effect of suppressing floating / scattering of semiconductor chips with film-like adhesive)
Using a dicing device ("DFD6361" manufactured by Disco Corporation), a depth of 80 μm from the surface of an 8-inch silicon wafer (thickness 720 μm) is drawn so as to draw a square with a size of 10 mm × 10 mm. Half-cut dicing was performed by making a notch with a dicing blade to form a groove. At this time, "27HECC" manufactured by Disco Corporation was used as the dicing blade, and the moving speed of the dicing blade was 50 mm / sec and the rotation speed was 40,000 rpm.
Next, using a tape laminator (“RAD-3510” manufactured by Lintec Corporation), a back grind tape (“ADWILL E-” manufactured by Lintec Corporation) was applied to the mirror surface of the silicon wafer having the above grooves formed at room temperature (23 ° C.). 3125KN ") was attached by the adhesive layer.
Next, a grinder (“DFG8760” manufactured by DISCO Corporation) was used to grind the surface of the silicon wafer opposite to the grooved mirror surface. At this time, grinding was performed so that the thickness of the silicon wafer was 50 μm, and at the same time, the silicon wafer was divided into individual pieces into silicon chips. The obtained silicon chips were fixed on the back grind tape at a distance of about 30 μm from each other.
Next, a film-like adhesive heated to 60 ° C. (“ADWILL LE61-25 *” manufactured by Lintec Corporation, thickness 25 μm) was attached to the ground surface of the obtained silicon chip, and further, the film-like adhesive was further applied. The semiconductor processing sheet obtained above was attached to the pressure-sensitive adhesive layer at room temperature (23 ° C.) to obtain a laminate.
Next, the obtained laminate was attached to and fixed to the dicing ring frame by the exposed surface of the pressure-sensitive adhesive layer, and the back grind tape was peeled off from the silicon chip to provide the pressure-sensitive adhesive layer on the base material. An uncut film-like adhesive is laminated on the pressure-sensitive adhesive layer of the semiconductor processing sheet, and a plurality of semiconductor chips that have been individually separated in advance are arranged and provided on the film-like adhesive. A test piece of the laminated structure was obtained.

The test piece obtained above was placed in the expander (“ME-300B” manufactured by JCM), and the expand amount (expansion amount) was 10 mm and the expand speed (expansion speed) was 10 mm in an environment of 0 ° C. The semiconductor processing sheet and the film-like adhesive were expanded under the condition of / sec, and the film-like adhesive was cut along the outer shape of the silicon chip. That is, here, the semiconductor processing sheet obtained above was used as the expanding sheet.
Next, visually, with respect to the silicon chip (semiconductor chip with film-like adhesive) provided with the cut film-like adhesive, the presence or absence of floating from the adhesive layer and the presence or absence of scattering were confirmed, and these abnormalities were completely observed. If not, the effect of suppressing floating / scattering was judged to be acceptable (A), and if any of these abnormalities were observed, the effect of suppressing floating / scattering was judged to be unacceptable (B). .. The results are shown in the column of "Semiconductor chip floating / scattering suppression" in Table 1.

(Semiconductor chip with film adhesive suitability for pickup)
A film in which no abnormality was observed after evaluating the above-mentioned "effect of suppressing floating / scattering of a semiconductor chip with a film-like adhesive" using a pickup die bonding device ("BESTEM D02" manufactured by Canon Machinery Co., Ltd.). The semiconductor chip with the adhesive was picked up 30 times by the 1-pin push-up method under the conditions of a push-up amount of 200 μm, a push-up speed of 20 mm / sec, and a lifting waiting time of 300 msec. Then, when the pickup was successful all 30 times, the pickup aptitude was determined to be acceptable (A), and when the pickup failed one or more times, the pickup aptitude was determined to be unacceptable (B). The results are shown in the "Pickup aptitude" column in Table 1.

(Storage modulus of the laminate composed of the adhesive layer)
Using the semiconductor processing sheet obtained above, a laminate was prepared by laminating a plurality of layers of the pressure-sensitive adhesive layer from which the base material was peeled off so that the total thickness was 200 μm. Then, using a dynamic viscoelasticity measuring device (“DMA Q800” manufactured by TA instrument), the temperature rise rate is 10 ° C./min, the frequency is 11 Hz, and the temperature is -50 to 50 ° C. at 0 ° C. The storage elastic modulus (MPa) was measured. The results are shown in the "Storage modulus" column in Table 1.

(Adhesive strength of the adhesive layer)
The semiconductor processing sheet obtained above was cut into a size of 25 mm × 150 mm and attached to the mirror surface of the silicon wafer by the adhesive layer at room temperature (23 ° C.). Then, under these temperature conditions, the semiconductor processing sheet is peeled off at a peeling speed of 300 mm / min so that the surfaces of the adhesive layer and the silicon wafer in contact with each other form an angle of 180 °, so-called 180 ° peeling. The peeling force at this time was measured, and the measured value was taken as the adhesive force (mN / 25 mm). The results are shown in the "Adhesive strength" column in Table 1.

[Examples 2 to 4, Comparative Examples 1 to 3]
<Manufacturing and evaluation of semiconductor processing sheets>
A semiconductor processing sheet was produced and evaluated by the same method as in Example 1 except that the compounding components and the blending amount thereof at the time of producing the pressure-sensitive adhesive composition were as shown in Table 1. The results are shown in Table 1.
The pressure-sensitive adhesive layer in Comparative Example 3 is energy ray (ultraviolet) curable, as is clear from the components contained in the pressure-sensitive adhesive composition, but the evaluation of the semiconductor processing sheet is based on the formation of the pressure-sensitive adhesive layer described above. Until then, the curing was not performed by irradiation with energy rays.

As is clear from the above results, in Examples 1 to 4, the storage elastic modulus of the laminate at 0 ° C. was 994 MPa or less, and when the film-like adhesive was cut by expanding, the semiconductor chip with the film-like adhesive was used. Floating and scattering from the pressure-sensitive adhesive layer was completely suppressed. Further, the adhesive force of the adhesive layer to the semiconductor wafer was 194 mN / 25 mm or less, and the semiconductor chip with a film-like adhesive was excellent in pick-up suitability even if it was not cured by energy ray irradiation or the like.

On the other hand, in Comparative Examples 1 and 2, the storage elastic modulus of the laminated body at 0 ° C. was 1218 MPa or more, and the floating and scattering of the semiconductor chip with the film-like adhesive were not suppressed.
Further, in Comparative Example 3, the adhesive force of the adhesive layer on the semiconductor wafer was as large as 534 mN / 25 mm, and the pick-up suitability of the semiconductor chip with the film-like adhesive was poor.

Here, at the time of evaluating the above-mentioned effect of suppressing floating / scattering, a silicon chip obtained by performing half-cut dicing of a silicon wafer using a dicing blade is used. However, instead of such a method of forming a groove on a silicon wafer, for example, a silicon chip obtained by adopting the above-mentioned method of forming a modified layer inside a semiconductor wafer (silicon wafer) may be used. , Similar evaluation results can be obtained. This is because the semiconductor chip manufacturing method (semiconductor wafer dividing method) does not affect the above evaluation process as long as the semiconductor chip used for the evaluation is normal.

Since the present invention can be used in the manufacture of semiconductor devices, it is extremely useful in industry.

1 ... Semiconductor processing sheet, 11 ... Base material, 11a ... Surface of base material, 12 ... Adhesive layer, 12a ... Surface of adhesive layer, 8 ... Semiconductor chip, 8b ... Back side of semiconductor chip

Claims (4)

With an adhesive layer on the substrate,
The pressure-sensitive adhesive layer contains the pressure-sensitive adhesive resin (i) and the cross-linking agent (ii).
In the pressure-sensitive adhesive layer, the content of the cross-linking agent (ii) is 10 to 50 parts by mass with respect to 100 parts by mass of the content of the pressure-sensitive adhesive resin (i).
Semiconductor processing sheet with the following characteristics:
When the thickness of the pressure-sensitive adhesive layer is 200 μm, the storage elastic modulus of the pressure-sensitive adhesive layer having a thickness of 200 μm at 0 ° C. is 1000 MPa or less, and the semiconductor processing sheet is attached to the mirror surface of the semiconductor wafer. The adhesive force of the pressure-sensitive adhesive layer on the mirror surface is 200 mN / 25 mm or less. A semiconductor processing sheet having one adhesive layer on the base material and having the following characteristics:
When the thickness of the pressure-sensitive adhesive layer is 200 μm, the storage elastic modulus of the pressure-sensitive adhesive layer having a thickness of 200 μm at 0 ° C. is 1000 MPa or less, and
When the semiconductor processing sheet is attached to the mirror surface of the semiconductor wafer, the adhesive force of the pressure-sensitive adhesive layer on the mirror surface is 200 mN / 25 mm or less. The semiconductor processing sheet according to claim 1 or 2 , wherein the pressure-sensitive adhesive layer is non-energy ray-curable. The semiconductor processing sheet according to any one of claims 1 to 3, further comprising a film-like adhesive on the pressure-sensitive adhesive layer.

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