JP6029544B2 - Adhesive composition, adhesive sheet, and method for manufacturing semiconductor device - Google Patents

Description

  The present invention has an adhesive composition particularly suitable for use in a step of bonding (die bonding) a semiconductor chip to an organic substrate, a lead frame or another semiconductor chip, and an adhesive layer made of the adhesive composition. The present invention relates to an adhesive sheet and a method for manufacturing a semiconductor device using the adhesive sheet.

  A semiconductor wafer made of silicon, gallium arsenide or the like is manufactured in a large diameter state, and this wafer is cut and separated (diced) into element pieces (semiconductor chips) and then transferred to the next mounting step. At this time, the semiconductor wafer is subjected to dicing, cleaning, drying, expanding, and pick-up processes in a state where the semiconductor wafer is previously adhered to the adhesive sheet, and then transferred to the next bonding process.

  In order to simplify the processes of the pick-up process and the bonding process among these processes, various dicing / die-bonding adhesive sheets having both a wafer fixing function and a die bonding function have been proposed (Patent Document 1, etc.) ). The adhesive sheet disclosed in Patent Document 1 enables so-called direct die bonding, and the application process of the die bonding adhesive can be omitted. This adhesive contains an acrylic polymer, a reactive double bond group-containing epoxy resin and a thermosetting agent, and optionally contains a filler such as silica.

  The required physical properties of semiconductor devices in recent years have become very strict. For example, in the connection of electronic components, a surface mounting method (reflow) is performed in which the entire package is exposed to a high temperature equal to or higher than the solder melting point. Furthermore, in recent years, the mounting temperature has increased to about 260 ° C. due to the shift to lead-free solder. For this reason, the stress generated inside the semiconductor package at the time of mounting becomes larger than before, and there is a high possibility of causing problems such as peeling at the adhesive interface and package cracks. Therefore, in Patent Document 1, the adhesive reliability is improved by using a reactive double bond group-containing epoxy resin as the epoxy resin and improving the compatibility between the acrylic polymer and the epoxy resin. .

  For high-density mounting, a package structure in which chips are stacked in multiple stages has been proposed. This package structure requires not only adhesion between the substrate and the chip but also adhesion between the chip and the chip. In a multi-stage package, a chip is stacked on the chip via an adhesive layer, and after the adhesive layer is cured, wire bonding is performed, and further, chip stacking, adhesive layer curing, and wire bonding are sequentially performed. Laminate.

  In manufacturing a semiconductor device having a package structure in which the above-described chips are stacked in multiple stages, lamination and wire bonding are performed with the adhesive layer in an uncured or semi-cured state. It has been studied to fully cure the adhesive layer in a lump by using exposure to a high temperature for a long time during the stopping process. However, when this manufacturing method is employed, the adhesive layer is in an uncured or semi-cured state during wire bonding. For this reason, the chip may vibrate and displace during wire bonding, and the position of the wire may become inaccurate or wire bonding may not be performed. In order to eliminate this inconvenience, when adopting the above production method, a relatively hard adhesive is used even in an uncured state. As a means for increasing the hardness of the uncured adhesive layer, it can be considered that a relatively large amount of filler is added to the adhesive.

JP 2008-133330 A

  However, it is not always easy to uniformly mix the filler with the adhesive. If the dispersibility of the filler in the adhesive is poor, the filler aggregates to increase the apparent particle size, thereby reducing the thickness accuracy of the adhesive layer and reducing the adhesiveness and adhesion to the semiconductor wafer. There was a cause. In particular, when the blending amount of the filler is increased, the above-described problem becomes remarkable. In addition, when a large amount of filler is blended in the adhesive, the amount of the curable component (epoxy resin or the like) is relatively decreased, and the reliability of the adhesive layer after curing may be decreased.

  Further, even when the process of collectively curing the adhesive layer as described above is employed, the adhesive layer may be partially cured because a high temperature of 150 ° C. or higher is required during wire bonding. It was. In this undesired curing, no pressure is applied, so when the adhesive layer is cured, the adhesive force is simply lost, leading to a decrease in adhesive strength. When the adhesive layer is partially cured, the followability with respect to the uneven surface is particularly lowered, and the adhesiveness with respect to the substrate surface and the die pad having relatively large unevenness is remarkably deteriorated.

  Therefore, the present invention can uniformly mix the filler in the adhesive layer, and even when adopting a process of collectively curing the adhesive layer in the production of the multi-stage package, the wire bonding is stably performed before curing. An adhesive composition having an adhesive layer made of the adhesive composition, and a semiconductor using the adhesive sheet, which can be used and exhibits excellent adhesive strength after curing, and in particular, can achieve high package reliability in a semiconductor device It is an object of the present invention to provide a device manufacturing method.

The present invention for solving the above problems includes the following gist.
(1) An acrylic polymer (A), a thermosetting resin (B) having a reactive double bond group, and a filler (C) having a reactive double bond group on the surface,
The average particle size of the filler (C) is in the range of 0.01 to 0.2 μm,
The thermosetting resin (B) is composed of an epoxy resin and a thermosetting agent,
An adhesive composition in which one or both of the epoxy resin and the thermosetting agent have a reactive double bond group.

  (2) The adhesive composition according to (1), wherein the content of the acrylic polymer (A) is 50 to 90% by mass in the total weight of the adhesive composition.

  (3) The adhesive composition according to (1) or (2), wherein the acrylic polymer (A) has a hydroxyl group.

  (4) A single-layer adhesive film comprising the adhesive composition according to any one of (1) to (3) above.

  (5) The single-layer adhesive film according to (4), wherein the shear strength after curing at 250 ° C. is 60 N / 5 mm □ or more.

  (6) An adhesive sheet in which an adhesive layer made of the adhesive composition according to any one of (1) to (3) is formed on a support.

  (7) The adhesive sheet according to (6), wherein the shear strength of the adhesive layer after curing at 250 ° C. is 60 N / 5 mm □ or more.

  (8) The adhesive sheet according to (6) or (7), wherein the support is a resin film.

  (9) The adhesive sheet according to (6) or (7), wherein the support is an adhesive sheet.

  (10) A semiconductor wafer is affixed to the adhesive layer of the adhesive sheet according to any one of (6) to (9), the semiconductor wafer and the adhesive layer are diced to form a semiconductor chip, and the semiconductor chip is bonded to the semiconductor chip. A method of manufacturing a semiconductor device, comprising a step of leaving an adhesive layer to remain and peeling from a support, and bonding the semiconductor chip onto a die pad portion or another semiconductor chip via the adhesive layer.

(11) A groove is formed on the surface of the semiconductor wafer in accordance with the outline of the shape of the semiconductor chip to be separated, a protective sheet is pasted on the surface of the semiconductor wafer, and then thinning is performed until the groove reaches from the back side. A step of dividing the semiconductor wafer into semiconductor chips by performing
The semiconductor chip is affixed to the adhesive layer of the adhesive sheet according to any one of the above (6) to (9), the adhesive layer remains fixed on the semiconductor chip and peeled off from the support, and the semiconductor chip is removed from the die pad. A method of manufacturing a semiconductor device, comprising a step of bonding to a part or another semiconductor chip via the adhesive layer.

  According to the present invention, by using an acrylic polymer, a thermosetting resin having a reactive double bond group, and a filler having a reactive double bond group on the surface and having a predetermined average particle size, The compatibility of the acrylic polymer, thermosetting resin and filler in the adhesive composition is improved, and the dispersibility of the filler in the adhesive composition is improved. In addition, the reactive double bond groups are subjected to addition polymerization to form a three-dimensional network structure in the adhesive composition. As a result, a semiconductor chip can be bonded to another semiconductor chip or a substrate with excellent adhesive strength, and a semiconductor device exhibiting high package reliability can be obtained even in a harsh environment. Further, since the uncured or semi-cured adhesive layer has a certain degree of hardness, wire bonding can be stably performed on the adhesive layer.

  Hereinafter, the adhesive composition of the present invention, the adhesive sheet, and a method for producing a semiconductor device using the sheet will be described more specifically.

(Adhesive composition)
The adhesive composition according to the present invention is an acrylic polymer (A) (hereinafter also referred to as “component (A)”. The same applies to other components), a thermosetting resin (B), and a filler (C). In order to improve various physical properties, other components may be included as necessary. Hereinafter, each of these components will be described in detail.

(A) Acrylic polymer The acrylic polymer (A) preferably has a weight average molecular weight (Mw) of 500,000 or more. Preferably it is 500,000-2 million, More preferably, Mw is 500,000-1.5 million, More preferably, Mw is 500,000-800,000. When the weight average molecular weight of the acrylic polymer (A) is less than 500,000, the cohesive force of the adhesive layer may be reduced, and the package reliability of a semiconductor device manufactured using the adhesive layer may be reduced. If the weight average molecular weight of the acrylic polymer (A) is too high, the adherence to an adherend (semiconductor wafer, chip, substrate, etc.) may be reduced, which may cause transfer defects or voids.
Moreover, the molecular weight distribution (Mw / Mn, Mn is a number average molecular weight) of an acrylic polymer (A) becomes like this. Preferably it is 1-5, More preferably, it is 1-3. By setting the molecular weight distribution of the acrylic polymer (A) within the above range, the effect of improving the package reliability of the present invention is further enhanced. The acrylic polymer (A) having a molecular weight distribution exceeding 3 contains a large amount of low molecular weight components having high fluidity even if the weight average molecular weight is high, and this low molecular weight component causes a decrease in package reliability. There is.
In addition, the value of the weight average molecular weight (Mw), the number average molecular weight (Mn), and the molecular weight distribution (Mw / Mn) of the acrylic polymer (A) is measured by a gel permeation chromatography (GPC) method. Value (polystyrene equivalent value).

  The glass transition temperature (Tg) of the acrylic polymer is preferably -20 ° C to 50 ° C, more preferably -10 ° C to 40 ° C, and further preferably 0 ° C to 30 ° C. When the Tg of the acrylic polymer is within such a range, the package reliability tends to be improved. Examples of the method for adjusting the glass transition temperature of the acrylic polymer (A) include the following methods. For example, as a method of increasing the glass transition temperature, when a (meth) acrylic acid alkyl ester having 1 to 18 carbon atoms in the alkyl group described later is used as the monomer constituting the acrylic polymer (A), alkyl is used. Examples thereof include a method for selecting a (meth) acrylic acid alkyl ester having a small group carbon number and a method for increasing the content ratio of a (meth) acrylic acid alkyl ester having a small carbon number in the alkyl group. In addition, the glass transition temperature of an acrylic polymer (A) is the value calculated | required from the formula of FOX.

  The monomer constituting the acrylic polymer (A) includes at least a (meth) acrylic acid ester monomer or a derivative thereof. (Meth) acrylic acid ester monomers or derivatives thereof include (meth) acrylic acid alkyl esters having an alkyl group having 1 to 18 carbon atoms, (meth) acrylic acid esters having a cyclic skeleton, and (meth) acrylic having a hydroxyl group. Examples include acid esters, (meth) acrylic acid esters having a glycidyl group, (meth) acrylic acid esters having an amino group, and (meth) acrylic acid esters having a carboxyl group.

Examples of the (meth) acrylic acid alkyl ester having 1 to 18 carbon atoms of the alkyl group include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, Pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, (meth) acrylic acid Examples include decyl, lauryl (meth) acrylate, tetradecyl (meth) acrylate, octadecyl (meth) acrylate, and the like.
Examples of (meth) acrylic acid ester having a cyclic skeleton include (meth) acrylic acid cycloalkyl ester, (meth) acrylic acid benzyl ester, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl ( Examples thereof include (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, and imide (meth) acrylate.
Examples of the (meth) acrylic acid ester having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate and the like.
Examples of the (meth) acrylic acid ester having a glycidyl group include glycidyl (meth) acrylate.
Examples of the (meth) acrylic acid ester having an amino group include monoethylamino (meth) acrylate and diethylamino (meth) acrylate.
Examples of the (meth) acrylic acid ester having a carboxyl group include 2- (meth) acryloyloxyethyl phthalate and 2- (meth) acryloyloxypropyl phthalate.

  In addition, the acrylic polymer (A) includes monomers having a carboxyl group other than (meth) acrylic acid esters such as (meth) acrylic acid and itaconic acid, (meth) such as vinyl alcohol and N-methylol (meth) acrylamide. Monomers having a hydroxyl group other than acrylic ester, (meth) acrylamide, vinyl acetate, styrene and the like may be copolymerized.

  When the adhesive composition contains a crosslinking agent (G) described later, the acrylic polymer (A) has a functional group (hydroxyl group, amino group, glycidyl group, carboxyl group, etc.) that reacts with the crosslinking agent (G). In particular, an acrylic polymer (A) having a hydroxyl group is preferable because it is easy to produce and it is easy to introduce a crosslinked structure using a crosslinking agent (G). Moreover, the acrylic polymer which has a hydroxyl group has good compatibility with the thermosetting resin (B) mentioned later.

  When a functional group that reacts with the crosslinking agent (G) is introduced into the acrylic polymer (A) by using a monomer having a functional group that reacts with the crosslinking agent (G) as a monomer constituting the acrylic polymer (A). The proportion of the monomer having a functional group that reacts with the crosslinking agent (G) in the total mass of the monomer constituting the acrylic polymer (A) is preferably about 1 to 20% by mass, and 3 to 15% by mass. More preferred. By setting the structural unit derived from the monomer having a functional group that reacts with the crosslinking agent (G) in the acrylic polymer (A) within the above range, the functional group that reacts with the crosslinking agent (G) and the crosslinking agent (G). React with each other to form a three-dimensional network structure, and the crosslinking density of the acrylic polymer (A) can be increased. As a result, the adhesive composition of the present invention can form a single-layer adhesive film or an adhesive layer having excellent shear strength. Further, since the water absorption of the adhesive composition is reduced, a semiconductor device having excellent package reliability can be obtained.

  The acrylic polymer (A) is preferably contained in a proportion of 50% by mass or more in the total weight of the adhesive composition. By adopting such a configuration, it becomes a preferable property when used in a process of collectively curing the adhesive layer. This is because a certain degree of hardness can be maintained even when the adhesive before curing is exposed to a high temperature, and wire bonding can be performed. That is, when the content of the acrylic polymer (A) in the adhesive composition is relatively large, the storage elastic modulus of the adhesive layer can be increased even before thermosetting. For this reason, even when the adhesive layer is uncured or semi-cured, the vibration and displacement of the chip during wire bonding are suppressed, and wire bonding can be performed stably. Thus, when the content of the acrylic polymer (A) is increased in order to ensure process suitability, the amount of the thermosetting resin (B) is relatively reduced. For this reason, the curing may be insufficient, but the adhesive composition of the present invention is capable of binding the thermosetting resin (B) and the filler (C) via a reactive double bond. Such a problem of insufficient curing can be solved. The acrylic polymer (A) is more preferably contained in a proportion of 50 to 90% by mass and more preferably in a proportion of 50 to 80% by mass in the total weight of the adhesive composition. . By making the ratio of the acrylic polymer (A) in the adhesive composition within the above range, the effect of improving the package reliability of the present invention becomes more remarkable.

(B) Thermosetting resin having a reactive double bond group The thermosetting resin (B) is composed of an epoxy resin and a thermosetting agent. In the present invention, either or both of the epoxy resin and the thermosetting agent are used. Has a reactive double bond group. The epoxy resin includes an epoxy resin (B1) having a reactive double bond group and an epoxy resin (B1 ′) having no reactive double bond group, and the thermosetting agent includes a reactive double bond group. There is a thermosetting agent (B2) having no thermosetting agent (B2) and a reactive double bond group. The thermosetting resin (B) of the present invention contains either an epoxy resin (B1) having a reactive double bond group or a thermosetting agent (B2) having a reactive double bond group as an essential component. . Moreover, any one of an epoxy resin (B1) and an epoxy resin (B1 ') is included as an essential component, and either one of a thermosetting agent (B2) and a thermosetting agent (B2') is included as an essential component. However, when both the epoxy resin and the thermosetting agent do not have a reactive double bond group, that is, the combination of only the component (B1 ′) and the component (B2 ′) is excluded.

  Since the thermosetting resin (B) has a reactive double bond group, the acrylic polymer (A) and a filler (C described later) are compared with a thermosetting resin having no reactive double bond group. ) With high compatibility. Further, the reactive double bond groups in the adhesive composition undergo addition polymerization to form a three-dimensional network structure in the adhesive composition. For this reason, the adhesive composition of this invention can improve the reliability of a semiconductor device rather than the adhesive composition containing only the thermosetting resin which does not have a reactive double bond group as a thermosetting resin. it can.

  The reactive double bond group is a functional group having a polymerizable carbon-carbon double bond, and specific examples include a vinyl group, an allyl group, a (meth) acryloyl group, and a (meth) acryloxy group. Preferably, an acryloyl group is mentioned. Therefore, the reactive double bond group in the present invention does not mean a double bond having no polymerizability. For example, the component (B) may contain an aromatic ring, but the unsaturated structure of the aromatic ring does not mean the reactive double bond group in the present invention.

  As the epoxy resin (B1) having a reactive double bond group, a resin having an aromatic ring is preferable because the strength and heat resistance of the adhesive after thermosetting are improved. Moreover, as the epoxy resin (B1) having such a reactive double bond group, for example, a compound obtained by converting a part of the epoxy group of a polyfunctional epoxy resin into a group containing a reactive double bond group Is mentioned. Such a compound can be synthesized, for example, by addition reaction of acrylic acid to an epoxy group. Or the compound etc. which the group containing a reactive double bond group directly couple | bonded with the aromatic ring etc. which comprise an epoxy resin are mentioned.

  Here, as an epoxy resin (B1) which has a reactive double bond group, the compound represented by following formula (1), the compound represented by following formula (2), or the reactive double bond group mentioned later And compounds obtained by addition reaction of a part of the epoxy group heacrylic acid of the epoxy resin (B1 ′) having no alkenyl.

[R is H- or _CH 3 -, n is an integer of 0. ]

R is H- or _CH 3 -, n is an integer of 0. ]

  The epoxy resin (B1) having a reactive double bond group obtained by reacting an epoxy resin (B1 ′) having no reactive double bond group with acrylic acid is completely unreacted or epoxy group. Although it may be a mixture with the consumed compound, in this invention, what is necessary is just to contain the said compound substantially.

  A conventionally well-known epoxy resin can be used as an epoxy resin (B1 ') which does not have a reactive double bond. Specific examples of such epoxy resins include polyfunctional epoxy resins, biphenyl compounds, bisphenol A diglycidyl ether and hydrogenated products thereof, cresol novolac type epoxy resins, dicyclopentadiene type epoxy resins, and biphenyl type epoxy resins. Examples thereof include epoxy compounds having two or more functional groups in the molecule, such as resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, and phenylene skeleton type epoxy resin. These can be used individually by 1 type or in combination of 2 or more types.

  The number average molecular weights of the epoxy resins (B1) and (B1 ′) are not particularly limited, but are preferably 300 to 30000, more preferably 400 to 10000 from the viewpoints of curability of the adhesive, strength after curing, and heat resistance. Especially preferably, it is 500-30000. The content of reactive double bond groups in the total amount of the epoxy resin [(B1) + (B1 ′)] is 0.1 to 1000 mol with respect to 100 mol of epoxy groups in the total amount of the epoxy resin. The amount is preferably 1 to 500 mol, more preferably 10 to 400 mol. If the amount is less than 0.1 mol, the package reliability may not be improved. If the amount exceeds 1000 mol, the thermosetting property may be insufficient.

  The thermosetting agent functions as a curing agent for the epoxy resins (B1) and (B1 '). In the present invention, one or both of a thermosetting agent (B2) having a reactive double bond group and a thermosetting agent (B2 ') having no reactive double bond group are used as the thermosetting agent. When the epoxy resin consists only of an epoxy resin (B1 ') having no reactive double bond group, a thermosetting agent (B2) having a reactive double bond group is used as an essential component. When the epoxy resin has a reactive double bond group, either the thermosetting agent (B2) or the thermosetting agent (B2 ') may be used, or both may be used.

The thermosetting agent (B2) having a reactive double bond group is a thermosetting agent having a polymerizable carbon-carbon double bond group. As the reactive double bond group, a vinyl group, an allyl group, a (meth) acryloyl group, a (meth) acryloxy group, and the like are preferable, and a methacryloyl group is more preferable.
Moreover, in addition to said reactive double bond group, a thermosetting agent (B2) contains the functional group which can react with an epoxy group. The functional group capable of reacting with the epoxy group preferably includes a phenolic hydroxyl group, an alcoholic hydroxyl group, an amino group, a carboxyl group, and an acid anhydride. Among these, a phenolic hydroxyl group, an alcoholic hydroxyl group, and an amino group are more preferable. Particularly preferred is a phenolic hydroxyl group.

Examples of the thermosetting agent (B2) having a reactive double bond group include a compound obtained by substituting a part of the hydroxyl group of a phenol resin with a group containing a reactive double bond group, or an aromatic ring of the phenol resin. And a compound in which a group containing a reactive double bond group is directly bonded. Here, as the phenol resin, a novolak type phenol resin represented by the following formula (Formula 3), a dicyclopentadiene type phenol resin represented by (Formula 4), a polyfunctional phenol resin represented by (Formula 5), and the like In particular, a novolac type phenol resin is preferable. Therefore, as the thermosetting agent (B2) having a reactive double bond group, a compound obtained by substituting a part of the hydroxyl group of the novolac type phenol resin with a group containing a reactive double bond group, or a novolac type phenol A compound in which a group containing a reactive double bond group is directly bonded to the aromatic ring of the resin is preferable.

  As a particularly preferred example of the thermosetting agent (B2) having a reactive double bond group, a reactive double bond group is introduced into a part of a repeating unit containing a phenolic hydroxyl group such as the following formula (a). And a compound containing a repeating unit having a group containing a reactive double bond group such as the following formula (b) or (c). The thermosetting agent (B2) having a particularly preferable reactive double bond group includes a repeating unit of the following formula (a) and a repeating unit of the following formula (b) or (c).

(Wherein n is 0 or 1)

(In the formula, n is 0 or 1, R ¹ is an optionally substituted hydrocarbon group having 1 to 5 carbon atoms, X is —O—, —NR ² — (R ² is hydrogen or Methyl) or R ¹ X is a single bond, and A is a (meth) acryloyl group)

The phenolic hydroxyl group contained in the repeating unit (a) is a functional group that can react with the epoxy group, and has a function as a curing agent that reacts and cures with the epoxy group of the epoxy resin when the adhesive composition is thermally cured. The reactive double bond group contained in the repeating units (b) and (c) improves the compatibility between the acrylic polymer (A) and the thermosetting resin (B), and the reactive double bond group. By mutual addition polymerization, a three-dimensional network structure is formed in the adhesive composition. As a result, the hardened | cured material of adhesive composition becomes a tougher property, and, thereby, the reliability as an adhesive agent improves. Further, the reactive double bond group contained in the repeating units (b) and (c) is polymerized and cured at the time of energy ray curing of the adhesive composition, and acts to reduce the adhesive force between the adhesive layer and the support. Also have.
The ratio of the repeating unit represented by the formula (a) in the thermosetting agent (B2) is 5 to 95 mol%, more preferably 20 to 90 mol%, particularly preferably 40 to 80 mol%, The ratio of the repeating units represented by the formula (b) or (c) is 5 to 95 mol% in total, more preferably 10 to 80 mol%, and particularly preferably 20 to 60 mol%.

As a thermosetting agent (B2 ') which does not have a reactive double bond group, the compound which has 2 or more of functional groups which can react with an epoxy group in 1 molecule is mentioned. Examples of the functional group include a phenolic hydroxyl group, an alcoholic hydroxyl group, an amino group, a carboxyl group, and an acid anhydride. Of these, phenolic hydroxyl groups, amino groups, acid anhydrides and the like are preferable, and phenolic hydroxyl groups and amino groups are more preferable.
An adhesive layer containing a thermosetting agent having an amino group (amine-based thermosetting agent) has higher hygroscopicity than an adhesive layer containing a thermosetting agent having a phenolic hydroxyl group (phenolic thermosetting agent). Therefore, the adhesive layer has a large decrease in adhesiveness after the introduction of wet heat conditions, but the adhesive layer containing a phenolic thermosetting agent has high moist heat resistance. Is small. Therefore, as the thermosetting agent (B2 ′), a compound having two or more phenolic hydroxyl groups capable of reacting with an epoxy group in the molecule is particularly preferable.

Specific examples of the phenolic curing agent include polyfunctional phenolic resins, biphenols, novolac-type phenolic resins, dicyclopentadiene-based phenolic resins, and aralkylphenolic resins.
A specific example of the amine curing agent is DICY (dicyandiamide). These can be used individually by 1 type or in mixture of 2 or more types.

  The number average molecular weight of the thermosetting agents (B2) and (B2 ′) described above is preferably 40 to 30000, more preferably 60 to 10000, and particularly preferably 80 to 30000.

  The content of the thermosetting agent [(B2) and (B2 ′)] in the adhesive composition is 0.1 to 500 parts by mass with respect to 100 parts by mass of the epoxy resin [(B1) and (B1 ′)]. It is preferably 1 to 200 parts by mass. When the content of the thermosetting agent is small, the adhesiveness may not be obtained due to insufficient curing, and when it is excessive, the moisture absorption rate of the adhesive layer increases and the package reliability may be lowered. Moreover, it is preferable that content of a thermosetting agent [(B2) and (B2 ')] is 5-50 mass parts with respect to 100 mass parts of acrylic polymers (A), and is 10-40 mass parts. It is more preferable. When the content of the thermosetting agent is small, the adhesiveness may not be obtained due to insufficient curing, and when it is excessive, the moisture absorption rate of the adhesive layer increases and the package reliability may be lowered.

  Thermosetting resin (B) (total of epoxy resin and thermosetting agent [(B1) + (B1 ′) + (B2) + (B2 ′)]) is preferably 50% in the total mass of the adhesive composition. It is contained in a proportion of less than mass%, more preferably 1 to 30 mass%, still more preferably 5 to 25 mass%. In the adhesive composition, the thermosetting resin (B) is preferably 1 part by mass or more and less than 100 parts by mass, more preferably 3 to 60 parts by mass with respect to 100 parts by mass of the acrylic polymer (A). More preferably, it is contained in the range of 3 to 40 parts by mass. If the content of the thermosetting resin (B) is too low, sufficient adhesiveness may not be obtained, and if it is too high, the peeling force between the adhesive layer and the support may be increased, resulting in pickup failure. .

(C) Filler having a reactive double bond group on the surface The filler (C) having a reactive double bond group on the surface is not particularly limited as long as it has a reactive double bond group on the surface. The reactive double bond group is preferably a vinyl group, an allyl group, a (meth) acryloyl group, or a (meth) acryloxy group.

  The filler is preferably a filler surface-treated with a compound having a reactive double bond group.

  Examples of the material of the filler (untreated filler) include silica, alumina, calcium carbonate, calcium silicate, magnesium hydroxide, aluminum hydroxide, titanium oxide, carbon black, talc, mica, and clay. Of these, silica is preferable. Silanol groups possessed by silica effectively act on bonding with the silane coupling agent.

  The filler having a reactive double bond group on the surface can be obtained, for example, by surface-treating the surface of an untreated filler with a coupling agent having a reactive double bond group.

  The coupling agent having the reactive double bond group is not particularly limited. As the coupling agent, for example, a coupling agent having a vinyl group, a coupling agent having a styryl group, and a coupling agent having a (meth) acryloxy group are preferably used. The coupling agent is preferably a silane coupling agent.

  Specific examples of the coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and 3-methacryloxypropyltriethoxy. Examples thereof include silane, 3-methacryloxypropylmethyldiethoxysilane, and 3-acryloxypropyltrimethoxysilane. Examples of these commercially available products include KBM-1003, KBE-1003, KBM-1403, KBM-502 and KBM-503, KBE-502, KBE-503, and KBM-5103 (all manufactured by Shin-Etsu Chemical Co., Ltd.). Can be mentioned.

  The method for surface-treating the filler with the coupling agent is not particularly limited. As this method, for example, an untreated filler is added to a mixer capable of high-speed stirring such as a Henschel mixer or a V-type mixer, and the coupling agent is dissolved directly or in an alcohol aqueous solution, an organic solvent or an aqueous solution while stirring. -The dry method of adding dispersedly is mentioned. Further, a slurry method in which a coupling agent is added to a slurry of untreated filler, a direct treatment method such as a spray method in which a coupling agent is sprayed after drying the untreated filler, or preparation of the above composition In some cases, an unprocessed filler and an acrylic polymer are mixed, and an integral blend method or the like in which a coupling agent is directly added at the time of mixing.

  A preferable lower limit of the amount of the coupling agent for surface-treating 100 parts by mass of the untreated filler is 0.1 parts by mass, and a preferable upper limit is 15 parts by mass. If the amount of the coupling agent is less than 0.1 parts by mass, the untreated filler may not be sufficiently surface-treated by the coupling agent, and the effect may not be exhibited. When the amount of the coupling agent exceeds 15 parts by mass, a large amount of unreacted coupling agent may remain, causing a decrease in package reliability.

The average particle size of the filler is in the range of 0.01 to 0.2 μm. When the average particle diameter of the filler is within the above range, the adhesiveness can be exhibited without impairing the sticking property with the semiconductor wafer. In particular, when the chip is used for mounting on an adherend such as a substrate or another chip, the effect of improving the reliability of the adhesive composition of the present invention is remarkably obtained. If the average particle size is too large, there may be a problem that the surface state of the sheet deteriorates and the in-plane thickness of the adhesive layer varies. The “average particle size” is determined by a particle size distribution meter (manufactured by Nikkiso Co., Ltd., device name: Nanotrac 150) using a dynamic light scattering method.
By making the average particle diameter of the filler within the above range, the effect of improving the reliability of the adhesive composition can be remarkably obtained due to the following reasons.
When the particle size of the filler is large, the structure formed from components other than the filler filling between the fillers also becomes large. Components other than the filler are less cohesive than the filler. If the structure formed from components other than the filler is large, the fracture may spread over a wide range when the component other than the filler breaks. On the other hand, when the filler is fine, the structure formed from components other than the filler is also fine. Then, even if a fracture occurs in components other than the filler, the filler taken into the fine structure prevents the progress of the fracture. As a result, the fracture tends not to spread over a wide area. Furthermore, in this invention, reactive double bond groups, such as a methacryloxy group which a filler has, and reactive double bond groups, such as B1 component contained in components other than a filler, may produce a coupling | bonding. If the filler is fine, the contact area between the filler and components other than the filler increases. As a result, the bond between the filler and the B1 component tends to increase.

  The filler (C) having a reactive double bond group on the surface is excellent in affinity with the acrylic polymer (A) and the thermosetting resin, and can be uniformly dispersed in the adhesive composition.

  The filler (C) is contained in a proportion of preferably less than 50% by mass, more preferably 1 to 30% by mass, and further preferably 5 to 25% by mass in the total mass of the adhesive composition. The filler (C) is preferably 5 parts by mass or more and less than 100 parts by mass, more preferably 8 to 60 parts by mass with respect to 100 parts by mass in total of the acrylic polymer (A) and the thermosetting resin (B). More preferably, it is contained in the range of 10 to 40 parts by mass. If the amount of the filler is too large, adhesion to the wafer and adhesion to the substrate may be deteriorated. If the amount of the filler particles is too small, the effect of filler addition may not be sufficiently exhibited.

  In such a range, when the adhesive layer contains the filler (C), the adhesive layer exhibits an elastic modulus enough to withstand vibration during wire bonding even in an uncured or semi-cured state. For this reason, the effect of the present invention that the wire bonding can be performed stably without the vibration and displacement of the chip during the wire bonding is enhanced.

The other component adhesive composition may contain the following components in addition to the above components.
(D) It is preferable that a photoinitiator adhesive composition contains a photoinitiator. By containing a photopolymerization initiator, for example, when the adhesive sheet of the present invention is used as a dicing die bonding sheet, it is applied to the wafer and then irradiated with ultraviolet rays before the dicing process, thereby thermosetting resin (B ) And the reactive double bond group of the filler (C) can be reacted and precured. By pre-curing, the adhesive layer is relatively soft before curing, so it has good adhesion to the wafer, and has an appropriate hardness during dicing, and adhesion of the adhesive to the dicing blade and other problems Can be prevented. In addition, the peelability at the interface between the support (resin film or pressure-sensitive adhesive sheet) and the adhesive layer can be controlled. Furthermore, since the hardness is higher in the precured state than in the uncured state, stability during wire bonding is improved.

Specific examples of the photopolymerization initiator (D) include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, methyl benzoin benzoate, benzoin dimethyl ketal, 2, 4-diethylthioxanthone, α-hydroxycyclohexyl phenyl ketone, benzyldiphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, 1,2-diphenylmethane, 2-hydroxy-2-methyl -1- [4- (1-Methylvinyl) phenyl] propanone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide and β-chloran Examples include suraquinone.
A photoinitiator (D) can be used individually by 1 type or in combination of 2 or more types.

  When the photopolymerization initiator (D) is used, the blending ratio is appropriately set based on the total amount of the reactive double bond groups on the filler surface and the reactive double bond groups of the thermosetting resin. do it. Although it is not limited at all, for example, with respect to a total of 100 parts by mass of the thermosetting resin (B) and the filler (C), the photopolymerization initiator (D) is usually 0.1 to 10 parts by mass, Preferably it is 1-5 mass parts. When the content of the photopolymerization initiator (D) is lower than the above range, a satisfactory reaction may not be obtained due to insufficient photopolymerization, and when it exceeds the above range, a residue that does not contribute to photopolymerization is generated, and the adhesive. The curability of the composition may be insufficient.

(E) Curing accelerator The curing accelerator (E) is used to adjust the curing rate of the adhesive composition. Preferred curing accelerators include tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, tris (dimethylaminomethyl) phenol; 2-methylimidazole, 2-phenylimidazole, 2-phenyl- Imidazoles such as 4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole; Organic phosphines such as tributylphosphine, diphenylphosphine, triphenylphosphine; And tetraphenylboron salts such as tetraphenylphosphonium tetraphenylborate and triphenylphosphinetetraphenylborate. These can be used individually by 1 type or in mixture of 2 or more types.

  When the curing accelerator (E) is used, the curing accelerator (E) is added to 100 parts by mass of the total of the thermosetting resin (B) [(B1) + (B1 ′) + (B2) + (B2 ′)]. On the other hand, it is preferably contained in an amount of 0.01 to 10 parts by mass, more preferably 0.1 to 1 part by mass. By containing the curing accelerator (E) in an amount within the above range, it has excellent adhesive properties even when exposed to high temperatures and high humidity, and high package reliability even when exposed to severe reflow conditions. Sex can be achieved. If the content of the curing accelerator (E) is small, sufficient adhesive properties cannot be obtained due to insufficient curing, and if it is excessive, the curing accelerator having a high polarity will pass through the adhesive layer under high temperature and high humidity. The reliability of the package is lowered by segregation and segregation.

(F) Coupling agent The coupling agent (F) has a functional group that reacts with an inorganic substance and a functional group that reacts with an organic functional group, and improves the adhesiveness and adhesiveness of an adhesive layer to an adherend. You may use for. Moreover, the water resistance can be improved by using a coupling agent (F), without impairing the heat resistance of the hardened | cured material obtained by hardening | curing an adhesive bond layer.

As the coupling agent (F), a silane coupling agent is desirable. Such coupling agents include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethyl. Trimethoxysilane, γ- (methacryloxypropyl) trimethoxysilane, γ-aminopropyltrimethoxysilane, N-6- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-6- (aminoethyl) -γ -Aminopropylmethyldiethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, methyltrimethoxysilane, methyl Torie Toki Silane, 2 or 3 having a low molecular silane coupling agent alkoxy group such as vinyltrimethoxysilane, bis (3-triethoxysilylpropyl) tetrasulfane, vinyltriacetoxysilane, etc. imidazole silane. Further, an oligomer which is a product obtained by condensing the low molecular silane coupling agent having two or three alkoxy groups or the low molecular silane coupling agent having four alkoxy groups by hydrolysis and dehydration condensation of alkoxy groups There are types. In particular, among the above low molecular silane coupling agents, a low molecular silane coupling agent having two or three alkoxy groups and a low molecular silane coupling agent having four alkoxy groups are condensed by dehydration condensation. Preferably, the oligomer is a compound having a high reactivity of alkoxy groups and a sufficient number of organic functional groups. For example, 3- (2,3-epoxypropoxy) propylmethoxysiloxane and dimethoxysiloxane The oligomer which is a polymer is mentioned.
These can be used individually by 1 type or in mixture of 2 or more types. Of these, compounds having a group that reacts with a functional group of the acrylic polymer (A), the thermosetting resin (B) and the like are preferably used.

  When using a coupling agent (F), a coupling agent is 0.1-20 mass parts normally with respect to a total of 100 mass parts of an acrylic polymer (A) and a thermosetting resin (B), Preferably it is 0. 2 to 10 parts by mass, more preferably 0.3 to 5 parts by mass. If the content of the coupling agent (F) is less than 0.1 parts by mass, the above effect may not be obtained, and if it exceeds 20 parts by mass, it may cause outgassing.

(G) A crosslinking agent (G) can be added to the crosslinking agent adhesive composition in order to adjust the initial adhesive force and cohesive strength of the adhesive layer. In addition, when mix | blending a crosslinking agent, the functional group which reacts with a crosslinking agent is contained in the said acrylic polymer (A).
Examples of the crosslinking agent (G) include organic polyvalent isocyanate compounds and organic polyvalent imine compounds.

  Examples of the organic polyvalent isocyanate compound include aromatic polyvalent isocyanate compounds, aliphatic polyvalent isocyanate compounds, alicyclic polyvalent isocyanate compounds, trimers of these organic polyvalent isocyanate compounds, and these organic polyvalent isocyanate compounds. And a terminal isocyanate urethane prepolymer obtained by reacting a polyol compound with a polyol compound.

  Examples of organic polyvalent isocyanate compounds include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylene diisocyanate, diphenylmethane-4,4′-diisocyanate, diphenylmethane. -2,4'-diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, trimethylolpropane adduct tolylene diisocyanate and lysine Isocyanates.

  When using an isocyanate-based crosslinking agent, it is preferable to use an acrylic polymer having a hydroxyl group as the acrylic polymer (A). When the crosslinking agent has an isocyanate group and the acrylic polymer (A) has a hydroxyl group, a reaction between the crosslinking agent and the acrylic polymer (A) occurs, and a crosslinked structure can be easily introduced into the adhesive.

  Examples of the organic polyvalent imine compound include N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane-tri -Β-aziridinylpropionate and N, N′-toluene-2,4-bis (1-aziridinecarboxyamide) triethylenemelamine can be exemplified.

  When using a crosslinking agent (G), a crosslinking agent (G) is 0.01-20 mass parts normally with respect to 100 mass parts of acrylic polymers (A), Preferably it is 0.1-10 mass parts, More preferably, it is 0. Used at a ratio of 5 to 5 parts by mass.

(H) The energy beam polymerizable compound may be blended in the energy beam polymerizable compound adhesive composition. The energy beam polymerizable compound (H) contains a reactive double bond group, and is polymerized and cured when irradiated with energy rays such as ultraviolet rays and electron beams. Specific examples of the energy ray polymerizable compound (H) include trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, and 1,4. Examples include acrylate compounds such as butylene glycol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, oligoester acrylate, urethane acrylate oligomer, epoxy-modified acrylate, polyether acrylate, and itaconic acid oligomer. Such a compound has at least one polymerizable carbon-carbon double bond in the molecule, and usually has a weight average molecular weight of about 100 to 30,000, preferably about 300 to 10,000. When the energy ray polymerizable compound (H) is used, the blending amount thereof is not particularly limited, but it is used at a ratio of about 1 to 50 parts by mass with respect to 100 parts by mass of the total solid content of the adhesive composition. preferable.

(I) The thermoplastic resin adhesive composition may contain a polymer other than the acrylic polymer (A). As such a polymer, thermoplastic resin (I) can be used. Thermoplastic resin (I) is mix | blended in order to maintain the flexibility of the adhesive bond layer after hardening. The thermoplastic resin (I) preferably has a weight average molecular weight of 1,000 to 100,000, more preferably 3,000 to 80,000. By containing the thermoplastic resin (I), the delamination between the support and the adhesive layer in the pick-up process of the semiconductor chip can be easily performed, and the adhesive layer follows the unevenness of the substrate, and voids, etc. Occurrence can be suppressed.

  The glass transition temperature of the thermoplastic resin (I) is preferably -30 to 150 ° C, more preferably -20 to 120 ° C. If the glass transition temperature of the thermoplastic resin (I) is too low, the peeling force between the adhesive layer and the support may increase and chip pick-up failure may occur. If the glass transition temperature is too high, the adhesive force for fixing the wafer will be high. May be insufficient.

  Examples of the thermoplastic resin (I) include polyester resin, urethane resin, phenoxy resin, polybutene, polybutadiene, and polystyrene. These can be used individually by 1 type or in mixture of 2 or more types.

  When the thermoplastic resin (I) is used, the blending amount is preferably 1 to 300 parts by mass, more preferably 2 with respect to 100 parts by mass in total of the acrylic polymer (A) and the thermosetting resin (B). It is in the range of ˜100 parts by mass. When the content of the thermoplastic resin (I) is in this range, the above effect can be obtained.

(J) Other inorganic fillers In addition to the filler (C), the adhesive composition may contain an inorganic filler (J) as a filler having no reactive double bond group. . Examples of the inorganic filler include silica, talc, calcium carbonate, titanium white, bengara, silicon carbide, boron nitride, and the like, beads formed by spheroidizing these, single crystal fibers, glass fibers, and the like.

(K) In addition to the above, various additives may be added to the general-purpose additive adhesive composition as necessary. Various additives include plasticizers, antistatic agents, antioxidants, pigments, dyes, gettering agents and the like.

(Adhesive sheet)
An adhesive layer made of an adhesive composition containing each component as described above has adhesiveness (for example, thermal adhesiveness or pressure-sensitive adhesiveness) and heat curable properties. When the adhesive layer has pressure-sensitive adhesiveness, it can be applied to the adherend by pressing in an uncured state. Moreover, when an adhesive bond layer has heat adhesiveness, when pressing to a to-be-adhered body, an adhesive bond layer can be heated and stuck. The thermal adhesiveness in the present invention means that there is no pressure-sensitive adhesiveness at room temperature, but it is softened by heat and can adhere to an adherend.
Further, since the filler is uniformly dispersed in the adhesive layer, the deformation of the adhesive layer is small and the wire bonding can be stably performed even at a high temperature at which the semiconductor chip is bonded and wire bonding is performed. Finally, a cured product having high impact resistance can be obtained through heat curing, and it has excellent shear strength and can maintain sufficient adhesive properties even under severe high temperature and high humidity conditions. When the photopolymerization initiator (D) is included, it also has energy ray curability and can be precured by irradiation with energy rays before the main curing. Pre-curing increases the hardness of the adhesive layer and improves the stability during wire bonding.

  The adhesive sheet may be a single-layer adhesive film formed by forming the above-mentioned adhesive composition, but preferably an adhesive layer made of the above-mentioned adhesive composition is formed on the support so as to be peelable. This is an adhesive sheet. The single layer adhesive film of the present invention preferably has a shear strength after curing at 250 ° C. of 60 N / 5 mm □ or more, more preferably in the range of 70 N / 5 mm □ to 150 N / 5 mm □, and even more preferably 80 N. The range is from / 5 mm □ to 120 N / 5 mm □. The adhesive sheet of the present invention preferably has a shear strength of the adhesive layer after curing at 250 ° C. of 60 N / 5 mm □ or more, more preferably in the range of 70 N / 5 mm □ to 150 N / 5 mm □, More preferably, it is the range of 80N / 5mm □-120N / 5mm □.

  Hereinafter, taking an adhesive sheet in which an adhesive layer is formed so as to be peelable on a support as an example, preferred embodiments and usage embodiments thereof will be described. When using an adhesive sheet in which the adhesive layer is formed to be peelable on the support, the adhesive layer is affixed to an adherend such as a wafer or chip, the support is peeled off, and the adhesive layer is attached. Transfer to the body. The shape of the adhesive sheet according to the present invention can take any shape such as a tape shape. The support may be a resin film having no tack on the surface, or may be a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer on the resin film.

  Examples of the resin film used as the support for the adhesive sheet include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate. Phthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate copolymer film, ionomer resin film, ethylene / (meth) acrylic acid copolymer film, ethylene / (meth) acrylic acid ester copolymer film, polystyrene film Transparent films such as polycarbonate film, polyimide film, and fluororesin film are used. These crosslinked films are also used. Furthermore, these laminated films may be sufficient. Moreover, the film which colored these, an opaque film, etc. can be used.

  The adhesive sheet according to the present invention is affixed to various adherends, and after subjecting the adherend to necessary processing, the adhesive layer is peeled off from the support in a state where the adhesive layer remains fixed to the adherend. That is, it is used for a process including a step of transferring an adhesive layer from a support to an adherend. For this reason, the surface tension of the surface in contact with the adhesive layer of the support (resin film) is preferably 40 mN / m or less, more preferably 37 mN / m or less, and particularly preferably 35 mN / m or less. The lower limit is usually about 25 mN / m. Such a resin film having a low surface tension can be obtained by appropriately selecting the material, and can also be obtained by applying a release agent to the surface of the resin film and performing a release treatment.

  As the release agent used for the release treatment of the resin film, alkyd, silicone, fluorine, unsaturated polyester, polyolefin, wax, etc. are used, and in particular, alkyd, silicone, and fluorine release agents. Is preferable because it has heat resistance.

  In order to release the surface of the resin film using the release agent described above, the release agent can be applied as it is without solvent, or diluted or emulsified with a solvent, using a gravure coater, Mayer bar coater, air knife coater, roll coater, etc. Then, the release film may be formed by subjecting the resin film coated with the release agent to room temperature or heating, or curing it with an electron beam or ultraviolet rays. Further, the surface tension of the resin film may be adjusted by laminating the films by wet lamination, dry lamination, hot melt lamination, melt extrusion lamination, coextrusion processing, or the like.

  When an adhesive sheet is used as the support, the adhesive sheet may be an adhesive sheet used as a dicing sheet. The dicing sheet has a pressure-sensitive adhesive layer on the resin film as described above, and the adhesive layer is detachably laminated on the pressure-sensitive adhesive layer. Therefore, the pressure-sensitive adhesive layer of the dicing sheet can be composed of a known pressure-sensitive adhesive having removability, and by selecting a pressure-sensitive adhesive such as an ultraviolet curable type, a heat-foaming type, a water swelling type, or a weakly viscous type The adhesive layer can be easily peeled off.

  Further, the adhesive sheet may have a shape in which the support and the adhesive layer are previously punched in the same shape as the adherend (semiconductor wafer or the like). In particular, it is preferable that the laminate composed of the support and the adhesive layer is held on a long release film.

  The thickness of the support is usually 10 to 500 μm, preferably 15 to 300 μm, particularly preferably about 20 to 250 μm. When the support is an adhesive sheet, the layer made of the adhesive usually occupies a thickness of about 1 to 50 μm in the thickness of the support. Moreover, the thickness of an adhesive bond layer is 2-500 micrometers normally, Preferably it is 6-300 micrometers, Most preferably, it is about 10-150 micrometers.

  The production method of the adhesive sheet is not particularly limited. When the support is a resin film, the adhesive composition may be applied and dried on the resin film to form an adhesive layer. Good. Moreover, you may manufacture by providing an adhesive bond layer on another peeling film, and transferring this to the said resin film or an adhesive sheet.

  In addition, in order to protect an adhesive bond layer before using an adhesive sheet, you may laminate | stack a peeling film on the surface of an adhesive bond layer. As the release film, one in which a release agent such as a silicone resin is applied to a plastic material such as a polyethylene terephthalate film or a polypropylene film is used. In addition, a pressure-sensitive adhesive layer or a pressure-sensitive adhesive tape may be separately provided on the outer peripheral portion of the surface of the adhesive layer in the adhesive sheet in order to fix other jigs such as a ring frame.

  Next, a method of using the adhesive sheet according to the present invention will be described taking as an example the case where the adhesive sheet is applied to the manufacture of a semiconductor device.

(Method for manufacturing semiconductor device)
Hereinafter, an example of a method for manufacturing a semiconductor device according to the present invention will be described in detail.
In a first method of manufacturing a semiconductor device according to the present invention, a semiconductor wafer is attached to the adhesive layer of the adhesive sheet, the semiconductor wafer and the adhesive layer are diced into semiconductor chips, and bonded to the back surface of the semiconductor chip. And a step of adhering the adhesive layer to the support and separating the adhesive layer from the support, and adhering the semiconductor chip on the die pad portion of the organic substrate or the lead frame or on another semiconductor chip via the adhesive layer.

  In the first method for manufacturing a semiconductor device according to the present invention, first, a semiconductor wafer having a circuit formed on the front surface and a ground back surface is prepared.

  The semiconductor wafer may be a silicon wafer or a compound semiconductor wafer such as gallium / arsenic. Formation of a circuit on the wafer surface can be performed by various methods including conventionally used methods such as an etching method and a lift-off method. Next, the opposite surface (back surface) of the circuit surface of the semiconductor wafer is ground. The grinding method is not particularly limited, and grinding may be performed by a known means using a grinder or the like. At the time of back surface grinding, an adhesive sheet called a surface protection sheet is attached to the circuit surface in order to protect the circuit on the surface. In the back surface grinding, the circuit surface side (that is, the surface protection sheet side) of the wafer is fixed by a chuck table or the like, and the back surface side on which no circuit is formed is ground by a grinder. The thickness of the wafer after grinding is not particularly limited, but is usually about 20 to 500 μm.

Next, the back side of the ring frame and the semiconductor wafer is placed on the adhesive layer of the adhesive sheet according to the present invention, and lightly pressed to fix the semiconductor wafer. When the photopolymerization initiator (D) is blended in the adhesive layer, the reactive energy of the thermosetting resin (B) and the filler (C) is obtained by irradiating the adhesive layer with energy rays from the support side. The heavy bond group may be reacted and cured to increase the cohesive force of the adhesive layer and decrease the adhesive force between the adhesive layer and the support. Examples of the energy rays to be irradiated include ultraviolet rays (UV) and electron beams (EB), and preferably ultraviolet rays are used.
Thereafter, the semiconductor wafer is cut to obtain a semiconductor chip by a blade dicing method using a dicing saw or a laser dicing method using laser light. The cutting depth when a dicing saw is used is a depth that takes into account the sum of the thickness of the semiconductor wafer and the adhesive layer and the wear of the dicing saw, and the adhesive layer is also cut to the same size as the chip. . The energy beam irradiation may be performed at any stage after the semiconductor wafer is pasted and before the semiconductor chip is peeled off (pickup). For example, the irradiation may be performed after dicing or after the following expanding step. Good. Further, the energy beam irradiation may be performed in a plurality of times.

  Then, if necessary, when the adhesive sheet is expanded, the interval between the semiconductor chips is expanded, and the semiconductor chips can be picked up more easily. At this time, a deviation occurs between the adhesive layer and the support, the adhesive force between the adhesive layer and the support is reduced, and the pick-up property of the semiconductor chip is improved. When the semiconductor chip is picked up in this manner, the cut adhesive layer can be adhered to the back surface of the semiconductor chip and peeled off from the support.

  Next, the semiconductor chip is placed on the die pad of the lead frame which is the chip mounting portion or on the surface of another semiconductor chip (lower chip) through the adhesive layer, and the chip is temporarily attached. The chip mounting part may be heated before the semiconductor chip is placed, or may be heated immediately after the chip is placed. The heating temperature is usually 80 to 200 ° C., preferably 100 to 180 ° C., and the heating time is usually 0.1 seconds to 5 minutes, preferably 0.5 seconds to 3 minutes. The pressure is usually 1 kPa to 200 MPa.

  Thereafter, it is preferable that the chips are sequentially stacked with the chips temporarily attached, and after the wire bonding, the adhesive layer is fully cured by using heating in resin sealing that is normally performed in package manufacture. By passing through such a process, an adhesive bond layer can be hardened collectively and manufacturing efficiency improves. Moreover, since the adhesive layer has a certain degree of hardness during wire bonding, wire bonding is performed stably. Furthermore, since the adhesive layer is softened under the die bonding condition, it is sufficiently embedded in the unevenness of the chip mounting portion, and generation of voids can be prevented and the reliability of the package is improved.

  In the second method of manufacturing a semiconductor device according to the present invention, first, a groove is formed on the surface of the semiconductor wafer in accordance with the outline of the shape of the semiconductor chip to be separated, and a protective sheet is attached to the surface of the semiconductor wafer. Then, a plurality of chip groups obtained by a so-called first dicing method, in which a semiconductor wafer is divided into semiconductor chips by performing a thinning process until reaching the groove from the back surface side, are prepared.

  Next, as in the first manufacturing method, the ring frame and the back side of the chip group are placed on the adhesive layer according to the present invention, and lightly pressed to fix the chip group. Thereafter, only the adhesive layer is diced to a chip size. A method for dicing only the adhesive layer is not particularly limited, and for example, a laser dicing method can be employed.

  After that, the adhesive sheet is expanded as necessary, and the adhesive layer is fixedly left on the semiconductor chip and peeled off from the support, and the semiconductor chip is placed on the die pad portion or other semiconductor chip via the adhesive layer. The step of bonding is as described in the first manufacturing method.

  The adhesive composition and adhesive sheet of the present invention can be used for bonding semiconductor compounds, glass, ceramics, metals, etc., in addition to the above-described methods of use.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples. In the following examples and comparative examples, <shear strength measurement> and <package reliability evaluation> were performed as follows.

<Measurement of shear strength>
(Evaluation sample preparation)
The adhesive sheets of Examples and Comparative Examples were attached to the polished surface of a # 2000 polished silicon wafer (150 mm diameter, 350 μm thick) using a tape mounter (Adwill RAD2500, manufactured by Lintec Corporation) and fixed to a ring frame for wafer dicing. . Next, dicing was performed using a dicing apparatus (DFD Co., Ltd., DFD651) to a chip size of 5 mm × 5 mm to obtain a chip. The amount of cut during dicing was such that the support was cut by 20 μm.
As an adherend, a CMP-treated chip (size: 10 mm × 10 mm, thickness: 350 μm) was prepared. The chip obtained above and the adherend are pressure-bonded onto the adherend via the adhesive layer under the conditions of 150 ° C. and 100 gf for 1 second, and 175 assuming mold sealing of the semiconductor package. The adhesive layer was thermally cured at 5 ° C. for 5 hours to prepare an evaluation sample.

(Evaluation)
The evaluation sample was placed on a plate at 250 ° C. assuming a temperature during reflow, and the shear strength was measured using a bond tester (dage 4000, manufactured by dage) under an environmental condition of humidity 50% RH. The setting conditions of the bond tester are a head height of 50 μm and a speed of 0.2 mm / second.

<Package reliability evaluation>
(Manufacture of semiconductor chips)
The adhesive sheets of Examples and Comparative Examples were attached to the polished surface of a dry-polished silicon wafer (150 mm diameter, 75 μm thick) with a tape mounter (Adwill RAD2500 manufactured by Lintec Corporation) and fixed to a ring frame for wafer dicing. Next, the wafer was diced into a chip size of 8 mm × 8 mm using a dicing apparatus (DFD651 manufactured by DISCO Corporation). The amount of cut during dicing was such that the support was cut by 20 μm.

(Manufacture of semiconductor packages)
As a substrate, a circuit pattern is formed on a copper foil-clad laminate (CCL-HL830, manufactured by Mitsubishi Gas Chemical Co., Ltd., copper foil thickness: 18 μm), and a solder resist (PSR-4000 AUS303, manufactured by Taiyo Ink) is formed on the pattern. (LN001E-001 PCB (Au) AUS303 manufactured by Chino Giken Co., Ltd.) was used. The chip on the adhesive sheet obtained above was picked up from the support together with the adhesive layer, and pressed onto the substrate under the conditions of 120 ° C., 250 gf, and 0.5 seconds via the adhesive layer.

Then, assuming a heat at the time of wire bonding, heat was applied for 2 hours in an atmosphere of 175 ° C., and a sealing device (Apic Yamada) was formed with a molding resin (KE-1100AS3 manufactured by Kyocera Chemical Co., Ltd.) to a sealing thickness of 400 μm. Sealing was performed using MPC-06M TriAl Press (manufactured by Co., Ltd.). Next, heating and pressing at 6.9 MPa were performed at 175 ° C. for 2 minutes, and then the resin was cured by heating at 175 ° C. for 5 hours.
Then, the sealed substrate is affixed to a dicing tape (Adwill D-510T manufactured by Lintec Corporation), and is subjected to reliability evaluation by dicing to a size of 15 mm × 15 mm using a dicing apparatus (DFD651 manufactured by Disco Corporation). The semiconductor package was obtained.

(Evaluation)
The obtained semiconductor package is allowed to stand for 168 hours under conditions of 85 ° C. and humidity 60% RH for moisture absorption, followed by IR reflow (reflow for 1 minute) with a preheating of 130 ° C. (harsh conditions) and a maximum temperature of 260 ° C. Furnace: WL-15-20DNX type manufactured by Sagami Riko) was performed three times. After that, the presence or absence of floating / peeling of the joints and the occurrence of package cracks were detected by a scanning ultrasonic flaw detector (Hy-Focus manufactured by Hitachi Construction Machinery Finetech Co., Ltd.) and a cross-section polishing machine (Refine Polisher HV manufactured by Refinetech Co., Ltd.). Then, the cross section was cut out and evaluated by cross-sectional observation using a digital microscope (VHX-1000 manufactured by Keyence Corporation).
The case where peeling of 0.5 mm or more in length was observed at the substrate / semiconductor chip junction was judged as peeling, and 27 packages were put into the test, and the number of pieces where peeling did not occur was counted.

<Adhesive composition>
Each component which comprises an adhesive composition is shown below.
(A) Acrylic polymer: copolymer consisting of 95 parts by mass of methyl acrylate and 5 parts by mass of 2-hydroxyethyl acrylate (Mw: 500,000, Mw / Mn: 2.9, Tg: 9 ° C., manufactured by Toyochem)
(B) Thermosetting resin:
(B-1) Acryloyl group-added cresol novolac type epoxy resin (CNA-147 manufactured by Nippon Kayaku Co., Ltd.)
(B-2) Thermosetting agent: Aralkylphenol resin (Mirex XLC-4L manufactured by Mitsui Chemicals, Inc.)
(C) Filler:
(C-1) Silica filler modified with methacryloxy group (average particle diameter 50 nm, manufactured by Admatechs Co., Ltd., 3-methacryloxypropyltrimethoxysilane treated product)
(C-2) Vinyl-modified silica filler (average particle size 50 nm, manufactured by Admatechs, vinyltrimethoxysilane treated product)
(C-3) Silica filler modified with methacryloxy group (average particle size 0.5 μm, SO-C2, manufactured by Admatechs Co., Ltd., 3-methacryloxypropyltrimethoxysilane treated product)
(C-4) Trimethyl group-modified silica filler (average particle size 70 nm, NSS-5N trimethylsilyl treated, manufactured by Tokuyama Corporation)
(F) Silane coupling agent (MKC silicate MSEP2 manufactured by Mitsubishi Chemical Corporation)
(G) Crosslinking agent: aromatic polyisocyanate (Nihon Polyurethane Industry Co., Ltd. Coronate L)

(Examples and Comparative Examples)
(Adhesive layer)
The above components were blended in the amounts (mass ratio) described in Table 1 to obtain an adhesive composition. A methyl ethyl ketone solution (solid concentration 20% by mass) of the obtained composition was applied on the release-treated surface of a release film (SP-PET 381031 manufactured by Lintec Corporation) that was release-treated with silicone so that the thickness was 20 μm after drying. After drying (drying conditions: 100 ° C. for 1 minute in an oven), bonding with a support (polyethylene film, thickness 100 μm, surface tension 33 mN / m) and transferring the adhesive layer onto the support allows adhesion A sheet was obtained. A semiconductor package was created using the obtained adhesive sheet, and its reliability was evaluated. Moreover, the shear strength of the adhesive layer after curing was evaluated. The results are shown in Table 1. In Table 1, PKG reliability means package reliability, and was expressed by the number of peels that did not occur in the above evaluation / 27 (the number of packages put into the test).

  The shear strength of the adhesive layers made of the adhesive compositions of Examples 1 and 2 were both 60 N / 5 mm □ or more. The adhesive compositions of Examples 1 and 2 both have an adhesive composition of Comparative Example 1 that does not contain a filler (C) having an average particle size in the range of 0.01 to 0.2 μm, and reactivity. The reliability of the semiconductor device can be improved as compared with the adhesive composition of Comparative Example 2 that does not contain the filler (C) having a double bond group on the surface.

  According to the present invention, an acrylic polymer (A), a thermosetting resin (B) having a reactive double bond group, and a filler having a reactive double bond group on the surface and a predetermined average particle size By using (C), the filler can be uniformly mixed in the adhesive layer, and a three-dimensional network structure can be introduced into the adhesive layer. For this reason, a semiconductor chip can be bonded to another semiconductor chip or a substrate with excellent adhesive strength, and a semiconductor device exhibiting high package reliability can be obtained even in a harsh environment. In addition, since a certain degree of hardness can be imparted to the uncured or semi-cured adhesive layer, wire bonding can be stable even for a long time when a process is used to collectively cure the adhesive layer in the manufacture of multistage packages. Thus, wire bonding can be performed.

Claims (11)

An acrylic polymer (A), a thermosetting resin (B) having a reactive double bond group, and a filler (C) having a reactive double bond group on its surface;
The average particle size of the filler (C) is in the range of 0.01 to 0.2 μm,
The thermosetting resin (B) is composed of an epoxy resin and a thermosetting agent,
An adhesive composition in which one or both of the epoxy resin and the thermosetting agent have a reactive double bond group.   The adhesive composition according to claim 1, wherein the content of the acrylic polymer (A) is 50 to 90% by mass in the total weight of the adhesive composition.   The adhesive composition according to claim 1 or 2, wherein the acrylic polymer (A) has a hydroxyl group.   The single layer adhesive film which consists of an adhesive composition in any one of Claims 1-3.   The single-layer adhesive film according to claim 4, wherein the shear strength after curing at 250 ° C. is 60 N / 5 mm □ or more.   The adhesive sheet in which the adhesive bond layer which consists of an adhesive composition in any one of Claims 1-3 is formed on a support body.   The adhesive sheet according to claim 6, wherein the adhesive layer after curing at 250 ° C. has a shear strength of 60 N / 5 mm □ or more.   The adhesive sheet according to claim 6 or 7, wherein the support is a resin film.   The adhesive sheet according to claim 6 or 7, wherein the support is an adhesive sheet.   A semiconductor wafer is affixed to the adhesive layer of the adhesive sheet according to claim 6, the semiconductor wafer and the adhesive layer are diced into semiconductor chips, and the adhesive layer is fixedly left on the semiconductor chips. A method of manufacturing a semiconductor device including a step of peeling from a support and bonding the semiconductor chip onto a die pad portion or another semiconductor chip via the adhesive layer. A groove is formed on the surface of the semiconductor wafer in accordance with the outline of the shape of the semiconductor chip to be separated, a protective sheet is pasted on the surface of the semiconductor wafer, and then a thinning process is performed until the groove reaches from the back side. A step of dividing the semiconductor wafer into semiconductor chips by, and
The semiconductor chip is affixed to the adhesive layer of the adhesive sheet according to any one of claims 6 to 9, the adhesive layer is fixedly left on the semiconductor chip and peeled off from the support, and the semiconductor chip is placed on the die pad portion or A method for manufacturing a semiconductor device, comprising a step of bonding to another semiconductor chip via the adhesive layer.