JP2007258437A - Die bond dicing laminate film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminate film for bonding a semiconductor chip manufacturing dicing die bond film which changes the mutual bonding temperature between a dicing tape and the die bond film. <P>SOLUTION: The laminate film is used after mutually bonding adhesive layers of a dicing tape mainly using a side chain crystalline polymer as the adhesive and a die bond film nonadhesive at room temperature, using an adhesive of a shear viscosity of 10-100,000 Pa s in a temperature range of 40-80°C. The mutually bonding temperature is over the adhesive of either the die bond film or the dicing tape but lower than the setting temperature of the adhesive of the die bond film. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a die-bonded dicing laminated film used when dicing a wafer or picking up a semiconductor chip.

  In recent years, the types of semiconductor chips have been diversified. In particular, the thickness and size of the semiconductor chips vary depending on the electronic component on which the semiconductor chip is mounted and are various.

  From the above background, in the manufacturing process of a semiconductor chip, a construction method corresponding to the size and thickness of each semiconductor chip is required. In particular, the dicing tape used in the wafer dicing process for determining the size of the semiconductor chip and the subsequent pick-up process plays an important role.

  The dicing process is a process that uses a dicing blade to cut a thin back-grinded wafer into a predetermined size, but the wafer is strongly affected by the impact of the dicing blade, causing chipping and cracking. This is an easy process. Depending on the thickness of the wafer that is normally diced and the size of the chip, the dicing tape to be used is also used in various ways.

  Moreover, the semiconductor chip cut | disconnected small needs to peel from a dicing tape after a dicing process. Usually, the needle is pressed from below the dicing tape and peeled off from the dicing tape while being sucked from the surface of the semiconductor chip with a suction collet (pickup process). Even in this pick-up process, since the thickness and size of the cut semiconductor chip are various, a method suitable for each thickness and size is required so that the chip and crack of the semiconductor chip do not occur. In particular, the peeling force when peeling the semiconductor chip from the dicing tape needs to be individually changed depending on the size of each chip, and various dicing tapes corresponding to that need to be prepared.

  In recent years, a die-bonded dicing film in which a dicing tape and a die-bonded laminated film are integrally laminated has been invented, and is currently commonly used in the dicing process and pick-up process of semiconductor chips because of the simplification of the process.

  Usually, the die bond dicing laminated film is used by adhering the die bond film side to a wafer while heating (usually 70 ° C. or higher) before the dicing step. After the dicing process is completed, the adhesive force at the interface between the dicing tape and the die bond film is reduced, and then the semiconductor chip is picked up in the vertical direction together with the die bond film, transferred to the support, and then the die bond film is cured and fixed.

  For example, Patent Document 1 discloses a film in which a dicing tape having an adhesive layer obtained by adding a radiation curing agent to a normal adhesive and a die bond film are integrally laminated. After the wafer is diced, the wafer is irradiated with radiation, the adhesive of the dicing tape is cured to reduce the adhesiveness, and then the semiconductor chip is peeled off and picked up at the interface between the die bond film and the dicing tape.

JP 2003-301148 A

  The die bond dicing film as disclosed above is intended to reduce the adhesive strength of the dicing tape adhesive by radiation curing. The decrease in the adhesive strength is performed after the dicing cut process that requires the adhesive strength, and until then, the die bond film is bonded in a state where the adhesive strength is always generated. Bonding in a state where the adhesive force is generated causes an increase in the adhesive force over time, and greatly reduces the decrease in the adhesive force during pickup after radiation irradiation. If the adhesive force is not reduced during pick-up, a pick-up mistake that does not peel off the chip from the dicing tape occurs.

  Using a dicing tape whose adhesive strength has decreased due to UV irradiation from the beginning or using a dicing tape with slight adhesiveness to weaken the adhesive strength at the time of pick-up means that the wafer fixing force when dicing the wafer Leads to a decrease.

  Thus, it can be said that with these die-bonded dicing films, it is difficult to balance the wafer fixing force during dicing and the adhesive force during pickup. In particular, it is not easy to change the adhesive force between a dicing tape and a die bond film of a die bond dicing laminated film according to various semiconductor chip sizes with an adhesive having the same composition.

  The present invention has been made to solve the above-described problems, and provides a die-bonded dicing laminated film that can easily change the fixing force and adhesive force between a dicing tape and a die-bonding film and can cope with various semiconductor chip sizes. The purpose is to do.

  The present invention is a dicing tape mainly composed of a pressure-sensitive adhesive layer composed of a side chain crystalline polymer and a support film, and has non-adhesiveness at room temperature, and has a shear viscosity of 10 Pa · in a temperature range of 40 ° C. or higher and 80 ° C. or lower. In a laminated film obtained by laminating and integrating a die bond film having an adhesive layer exhibiting s to 100000 Pa · s on the adhesive layer surface, the temperature of the laminated integration is 40 ° C. or higher or the melting point of the adhesive layer of the dicing tape or higher. A laminated film used for manufacturing a semiconductor chip, wherein the temperature is lower than the curing temperature of the adhesive layer of the die bond film.

  Moreover, this invention is the said laminated | multilayer film whose temperature of lamination | stacking integration is the range which is the range of 40-80 degreeC, or the shear viscosity of the adhesion layer of a die-bonding film is 10 Pa.s or more and 100000 Pa.s or less. . Furthermore, the present invention provides the above laminated film, wherein the melting point of the adhesive layer of the dicing tape is higher than the tackiness expression temperature of the die bond film, and the temperature of lamination integration is 40 ° C. or higher or the melting point of the adhesive layer of the dicing tape. It is.

Hereinafter, the present invention will be described in more detail.
The die bond film used in the present invention is preferably composed of a resin component and a filler. As the filler, for example, gold, silver, copper, nickel, aluminum, carbon, silica, quartz and the like are used, and spherical silica is preferable. Such a filler is used in a ratio of about 100 to 1000 parts by weight with respect to 100 parts by weight of the resin component. The resin component is preferably made of a thermoplastic resin, a thermosetting resin, and a curing agent. Examples of the thermoplastic resin include thermoplastic resins such as phenoxy resin, polycarbonate resin, and polystyrene resin. Examples of the thermosetting resin include thermosetting resins such as epoxy, phenol, and urea. As a preferable epoxy resin, there is a glycidyl ether type epoxy resin, which can be used alone or as a mixture thereof. The curing agent can be selected from various types, but as the epoxy curing agent, general curing agents such as amines, acid anhydrides and polyhydric phenols and latent curing agents such as dicyandiamide, imidazoles and hydrazides Can be used. A latent curing agent that exhibits curability at a predetermined temperature above room temperature, for example, at or above the temperature at which the resin component exhibits the necessary tackiness, and is capable of long-term storage at room temperature is desirable.

  Although the die-bonding film obtained by mix | blending these is non-adhesive at normal temperature, a shear viscosity will be 10 Pa.s-100,000 Pa.s by heating at 40 to 80 degreeC. Here, if it is lower than 10 Pa · s, the fluidity will flow out and cannot be bonded to the dicing tape. If it is higher than 100000 Pa · s, the fluidity will be insufficient and good adhesion cannot be obtained.

  The dicing tape used in the present invention comprises at least two layers of a base support film and an adhesive layer mainly composed of a side chain crystalline polymer. The support film is preferably one that does not impair mechanical properties by heat treatment from room temperature to 90 ° C., for example, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene film, polypropylene film, polyvinyl chloride film, polycarbonate film, polyamide film. A plastic film such as a polyimide film is used. The thickness is desirably 50 to 250 μm. The surface of the plastic film is chemically and physically treated with surface treatments such as corona discharge treatment, plasma treatment, blast treatment, sand mat treatment, primer chemical treatment, etc. in order to increase the adhesion to the adhesive layer of the side chain crystalline polymer. Processing can also be performed. Furthermore, by coating an adhesive layer such as an acrylic, rubber, or silicon adhesive layer on top of that, it is possible to further improve the adhesion or impart adhesive force to the metal dicing ring used during dicing cut. You can go.

  The adhesive layer of the side chain crystalline polymer of the dicing tape means an adhesive layer that reversibly causes a crystalline state and an amorphous state corresponding to a temperature change. In the present invention, the transition point between the crystalline state and the amorphous state is referred to as the melting point, which means the temperature at which the specific portion initially matched to the ordered state becomes disordered, and the differential thermal scanning calorific value. It is a value obtained by measuring with a meter (DSC) under measurement conditions of 10 ° C./min.

  The pressure-sensitive adhesive layer of the side chain crystalline polymer comprises 30 to 100 parts by weight of an acrylic ester or methacrylic ester having a linear alkyl group having 16 or more carbon atoms and an acrylic ester having a C 1 to C 6 alkyl group or A polymer obtained by polymerizing 0 to 70 parts by weight of a methacrylic acid ester and 0 to 10 parts by weight of a polar monomer is desirable. This side chain crystalline polymer may be either a homopolymer or a copolymer.

  Examples of the acrylic acid ester and / or methacrylic acid ester (hereinafter also referred to as (meth) acrylate) having a linear alkyl group having 16 or more carbon atoms include cetyl (meth) acrylate, stearyl (meth) acrylate, eicosyl (meta ) One type or two or more types such as (meth) acrylate having a linear alkyl group having 16 to 22 carbon atoms such as acrylate and behenyl (meth) acrylate can be preferably used. This linear alkyl group becomes a side chain when it becomes a polymer.

  Examples of the (meth) acrylate having an alkyl group having 1 to 6 carbon atoms include one or more of methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate and the like. It can be preferably used.

  Examples of polar monomers include carboxyl-containing ethylenically unsaturated monomers such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, and fumaric acid; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meta ) One type or two or more types of ethylenically unsaturated monomers having a hydroxyl group such as acrylate and 2-hydroxyhexyl (meth) acrylate can be preferably used.

  Such a side-chain crystalline polymer can be obtained by a conventionally known method. However, in order to reduce contamination by the pressure-sensitive adhesive, it is desirable not to contain a low molecular weight substance, and the weight average molecular weight of the polymer is 30 in terms of polystyrene. 10,000 to 1,000,000 is desirable. If the molecular weight is less than 300,000, there is a risk of causing contamination such as transfer of an adhesive due to insufficient cohesive force. Moreover, when molecular weight exceeds 1 million, there exists a possibility that solution viscosity may become high and coating may become difficult. The melting point of the obtained polymer is 30 to 70 ° C, preferably 40 to 60 ° C. If the melting point exceeds 70 ° C., the preferred temperature at the time of sticking the adhesive film becomes too high, and if it is lower than 30 ° C., the tackiness is developed at room temperature, and the adhesive force may change over time.

  The pressure-sensitive adhesive layers of the die-bonding film and the dicing tape are not less than the tackiness expression temperature of the pressure-sensitive adhesive layer of the die-bonding film or the melting point of the pressure-sensitive adhesive layer of the dicing tape, and less than the curing temperature of the pressure-sensitive adhesive of the die-bonding film. The die-bonded dicing laminated film of the present invention (hereinafter, also referred to as a laminated film). At least one interface of each pressure-sensitive adhesive layer is in a fluid state by heating to a temperature equal to or higher than the tackiness expression temperature of the die-bonding film or a temperature equal to or higher than the melting point of the dicing tape. Can be adhered and adhered. Even when this laminated film is returned to the pick-up temperature (normally normal temperature) which is lower than the tackiness expression temperature of the die-bonding film and lower than the melting point of the dicing tape, the boundary layer of the adhesive of the laminated film of the present invention is stuck. It is maintained and kept in close contact with each other.

  In addition, for example, when each of the adhesives is bonded at a temperature equal to or higher than the tack development temperature of the die bond film or higher than the melting point of the dicing tape, each adhesive is in a fluid state. The adhesive strength of the adhesive layer interface is improved as compared with the above case. Even in this case, even when the temperature is returned to the pick-up temperature that is not higher than the tackiness expression temperature of the die-bonding film and not higher than the melting point of the dicing tape, the boundary surface of the adhesive layer maintains and maintains the contact state when bonded. Therefore, one side is bonded and held stronger than in the above case where one side is bonded in a state showing fluidity.

  In this way, by simply changing the temperature at which the die bond film and the dicing tape are bonded, the adhesive force at the interface between the adhesive layers at the pick-up temperature that is below the tackiness expression temperature of the die bond film and below the melting point of the dicing tape. Can be changed.

As described above, the adhesive layer of the dicing tape is mainly made of a side chain crystalline polymer, and when the adhesive reaches the melting point, it rapidly undergoes a phase transition from a crystalline state to a state showing a non-crystalline fluidity. It has the property of transferring. Such a rapid phase transition shows that the storage elastic modulus (G ′) of the pressure-sensitive adhesive exhibits 5 × 10 ⁶ Pa or more at a temperature below the melting point, whereas it is less than 1 × 10 ⁵ Pa at a temperature above the melting point. It is clear from the sudden drop.

  In this way, an adhesive capable of reversibly repeating crystallinity and non-crystallinity at the melting point temperature is used for the dicing tape, and the die bond film adhesive is used at a temperature higher than the melting point of the dicing tape adhesive. And then, after returning to a temperature state below the tackiness expression temperature of the die bond film or below the melting point of the dicing tape, the adhesive of the dicing tape instantaneously undergoes a phase transition, and each adhesive when bonded It becomes possible to maintain the state of the interface. When a normal acrylic pressure-sensitive adhesive is used as this pressure-sensitive adhesive, it does not show a rapid phase transition, and it is difficult to generate the above phenomenon.

  Using such a laminated film, the wafer can be sufficiently fixed by dicing the wafer in a state where the dicing die-bonding film is below the tackiness expression temperature of the die-bonding film and below the melting point of the dicing tape. Chip skipping and chipping of the semiconductor chip that occur during dicing can be prevented.

  In the present invention, it is desirable for the die-bonding film pressure-sensitive adhesive to exhibit a phenomenon similar to the phase transition as well as the dicing tape pressure-sensitive adhesive. That is, at the tack development temperature or higher, the shear viscosity rapidly decreases and exhibits fluidity, and at a temperature lower than the tack development temperature, the shear viscosity rapidly increases and is non-adhesive with no fluidity. It is desirable to change to Since the change in this state changes abruptly like the adhesive of the dicing tape, after bonding with the adhesive of the dicing tape, the dicing die bond film is less than the tackiness expression temperature of the die bond film or less than the melting point of the dicing tape. In this temperature state, the pressure-sensitive adhesive instantly changes to a non-sticky state that does not exhibit fluidity, so that the interface state of each pressure-sensitive adhesive when bonded can be maintained.

  In the present invention, as described above, it is desirable that both the dicing tape and the die bond film are adhesives that cause a sudden change in state, and by using this phenomenon, the dicing tape and the die bond film can be used together. This object can be achieved by pasting together.

  Depending on the bonding temperature, only the adhesive of the die bond film can be made into a fluid state, only the adhesive of the dicing tape can be made into a fluid state, or both can be made into a fluid state. It is possible to maintain different adhesive forces at the interfaces of the respective pressure-sensitive adhesives at a temperature at the time of pickup which is not higher than the tackiness expression temperature and not higher than the melting point of the dicing tape. In particular, when the adhesive is bonded at a temperature at which both adhesives exhibit fluidity (above the die bond film tacking temperature and the dicing tape melting point), the die bonding film tacking temperature is below the dicing tape melting point. It can be seen that the die bond dicing film having the strongest adhesive interface at the following pick-up temperature is obtained.

  From the above, the die-bonded dicing laminated film of the present invention can be obtained by changing the temperature at which the respective adhesive layers are bonded to each other, so that the lamination at the time of dicing and at the time of pick-up is lower than the tackiness expression temperature of the die-bonding film and lower than the melting point of the dicing tape. It is possible to change the adhesion between the layers of the film.

  After the wafer is diced to a predetermined size, the semiconductor chip is picked up by a suction collet, or picked up by a needleless pick-up jig (pickup process). Usually, in this step, the semiconductor chip is picked up by a suction collet while pushing up the chip with a needle from below the semiconductor chip.

  When dicing using the laminated film (die-bonded dicing film) of the present invention, it is necessary to peel off at the interface between the adhesive of the die-bonding film and the adhesive of the dicing tape. In the dicing process and the pick-up process, each of the pressure-sensitive adhesives is in a crystalline state below the melting point (in the case of a dicing tape pressure-sensitive adhesive) or in a non-adhesive state having a high shear viscosity (in the case of a die-bonding film pressure-sensitive adhesive). Therefore, the semiconductor chip can be easily picked up with a slight force from the starting point of the small peeling made by pushing up the needle.

  The fixing force and adhesive force between the dicing tape and the die bond film can be easily changed, and a die bond dicing film that can correspond to various semiconductor chip sizes can be provided.

  An embodiment of the present invention will be described below with reference to FIG. A die bond film 1 and a dicing tape 2 are prepared. The die bond film 1 and the dicing tape 2 may have any of the above-described adhesive layers, but may have a support (not shown). Next, the pressure-sensitive adhesive layer surfaces of the die bond film 1 and the dicing tape 2 are overlapped and laminated by thermocompression bonding under the above conditions to obtain the die bond dicing film of the present invention.

  Adhesive tape 3 is brought into intimate contact with and fixed to the dicing tape 2 side of the die bond dicing film (after having the support removed). The adhesive tape 3 helps the die bond film 1 and the dicing tape 2 to be peeled off during the pickup operation. Next, the wafer 4 is brought into close contact with the die-bonding film 1 (after peeling off the support, if any), and fixed. Thereafter, the wafer 4 and the die bond dicing film are cut into a predetermined chip size by dicing. Next, the chip is pushed up by the pickup needle 5 and peeled off at the interface between the die bond film 1 and the dicing tape 2 to obtain a chip with a die bond film.

  EXAMPLES Hereinafter, although a reference example and an Example are given and this invention is demonstrated in detail, this invention is not limited to a following example. In addition, a part means a weight part.

Example 1
As a thermosetting resin component, an epoxy resin, a solvent, and a phenoxy resin were mixed, spherical silica was added, and the mixture was kneaded with three rolls. A microcapsule type imidazole-type latent curing agent was added to this mixture to obtain a mixed varnish. This was applied onto a 50 μm release treated PET film and dried to obtain a die bond film.

  45 parts of behenyl acrylate, 50 parts of methyl acrylate, 5 parts of acrylic acid and 0.5 part of azobisisobutyronitrile were mixed with 200 parts of ethyl acetate and polymerized at 55 ° C. to obtain a side chain crystalline polymer A solution. The weight average molecular weight of the obtained polymer was 600,000, and the melting point was 55 ° C. To this, 5 parts of Chemite PZ33 as a cross-linking agent was added to 100 parts of the polymer, applied onto a 50 μm release-treated PET film, and dried to obtain a dicing tape A.

  The pressure-sensitive adhesive layer of the die bond film and the pressure-sensitive adhesive layer of the dicing tape A were laminated at 40 ° C. to obtain a laminated film (laminated film 1). The laminated film 1 was punched into a 21 cmφ circle, and a 100 μm polyethylene film coated with a 10 μm acrylic adhesive layer was bonded to the adhesive side of the dicing tape A to obtain an integrated tape (tape 1). .

Example 2
A die-bonding film having the same composition as in Example 1 and a dicing tape A were used and laminated at 60 ° C. to obtain a laminated film (laminated film 2). This was used as an integrated tape to obtain tape 2.

Example 3
Using a die-bonding film having the same composition as in Example 1 and dicing tape A, lamination was performed at 80 ° C. to obtain a laminated film (laminated film 3). This was used as an integrated tape to obtain tape 3.

Example 4
45 parts of stearyl acrylate, 50 parts of methyl acrylate, 5 parts of acrylic acid and 0.5 part of azobisisobutyronitrile were mixed with 200 parts of ethyl acetate and polymerized at 55 ° C. to obtain a side chain crystalline polymer B solution. The obtained polymer had a weight average molecular weight of 550,000 and a melting point of 35 ° C. To this, 5 parts of Chemite PZ33 as a cross-linking agent was added to 100 parts of the polymer, applied onto a 50 μm release-treated PET film, and dried to obtain a dicing tape B.

  A laminated film was obtained by laminating the adhesive layer of the die bond film having the same composition as in Example 1 and the adhesive layer of the dicing tape B at 40 ° C. (laminated film 4). The assembly 2 was punched into a 21 cmφ circle, and a 100 μm polyethylene film coated with a 10 μm acrylic pressure-sensitive adhesive layer was bonded to the dicing tape B pressure-sensitive adhesive layer to obtain an integrated tape (tape 4).

Comparative Example 1
Using a commercially available UV tape as the dicing tape, the adhesive layer of this UV tape was bonded to the adhesive layer of the die bond film of Example 1 at 40 ° C. to obtain a laminated film (tape 5). Before picking up (peeling), UV light was irradiated.

Comparative Example 2
Using a slightly adhesive tape as the dicing tape, the adhesive layer of the fine adhesive tape was bonded to the adhesive layer of the die bond film of Example 1 at 40 ° C. to obtain a laminated film (tape 6).

The obtained tapes 1 to 6 are allowed to stand for 48 hours, and then a semiconductor device having a thickness of 100 μm is cut into 2 mm size and 8 mm size to produce a semiconductor device bonded to a circuit board, and dicing suitability (chip skipping, tipping, cut burr) The pick-up property (pick-up mistake) was evaluated.
At the same time, the adhesive properties at the interface between the adhesive of the die bond film used in tapes 1 to 6 and the adhesive of the dicing tape were evaluated by peel peeling and vertical peeling. These are summarized in Table 1. The shear viscosity of the die bond film is at the lamination temperature.

Since the bonding temperature of the tape 1 is as low as 40 ° C., the adhesive force is weak, and a 2 mm semiconductor chip causes a chip jump. However, when the bonding temperature is increased to 60 ° C. and 80 ° C. with the same composition, chip skipping disappears. On the contrary, the tape 3 has a bonding temperature as high as 80 ° C., so that a pickup error may occur with an 8 mm chip. It was shown that the tapes 1 to 3 can be adjusted with a tape having the same composition even if the chip size is changed because the adhesive force can be freely adjusted at the bonding temperature. Similarly, since the melting point of the side chain crystalline polymer is lower than that of the tape 1, the tape 4 has adhesive force without chip skipping and releasability without pick-up error even when the application temperature is as low as 40 ° C. Since the tape 5 has high adhesiveness to the UV tape, there is no chip skipping, but there are many pick-up mistakes during peeling, and the peeling is heavy. Further, the slightly adhesive type tape 6 has a weak adhesive force and causes chip jumping. Since a pick-up error has occurred in the 8 mm size, it is apparent that a material with higher adhesive strength cannot be used, and the balance between adhesive strength and peelability cannot be achieved.

It is process drawing which shows one Embodiment of this invention.

Explanation of symbols

1: Die bond film
2: Dicing tape
3: Adhesive tape
4: Wafer
5: Pickup needle

Claims (3)

  A dicing tape mainly composed of a pressure-sensitive adhesive layer composed of a side chain crystalline polymer and a support film, and non-adhesive at room temperature, and a shear viscosity of 10 Pa · s to 100000 Pa · In a laminated film obtained by laminating and integrating a die bond film having an adhesive layer showing s or less on the adhesive layer surface, the temperature of the laminated integration is 40 ° C. or higher or the melting point of the adhesive layer of the dicing tape, and the die bond A laminated film used for manufacturing semiconductor chips, wherein the temperature is lower than the curing temperature of the adhesive layer of the film.   2. The laminated film according to claim 1, wherein the temperature of the laminated integration is in the range of 40 to 80 ° C. or the temperature range in which the shear viscosity of the pressure-sensitive adhesive layer of the die bond film is 10 Pa · s or more and 100000 Pa · s or less.   The melting point of the pressure-sensitive adhesive layer of the dicing tape is higher than the tackiness expression temperature of the die-bonding film, and the temperature of lamination and integration is 40 ° C. or higher, or higher than the melting point of the pressure-sensitive adhesive layer of the dicing tape. A laminated film according to 1.

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