JP4563711B2 - Substrate film for dicing - Google Patents

Description

  The present invention relates to a substrate film for dicing effective for dicing a semiconductor wafer or the like into chips.

For example, a semiconductor wafer made in advance with a large area is diced (cut) into chips, and it is necessary to fix the wafer during dicing. A dicing board is used for this fixing and dicing.
The mount is basically composed of an adhesive layer for fixing the wafer and a resin layer (dicing base layer) for receiving a cut by a dicing cutter. As the resin layer, a polyolefin film or a polyvinyl chloride film is generally used. However, the polyvinyl chloride film is in a decline due to environmental problems.

Problems that arise in the dicing of a semiconductor wafer (hereinafter simply referred to as a wafer) include, for example, chips from a dicing board (dicing waste) generated during dicing, and wafer notches (in the industry, this is called chipping). ), Expansion (extensibility) of the mount after dicing, and static electricity generated when dicing or after dicing and picking up a cut wafer.
Concerning this static electricity, especially in the recent trend of gathering more information in smaller wafer chips, it has become a bigger issue.
That is, there is a very high risk that the occurrence of static electricity leads to the destruction of information accumulated on the wafer. There are many patent technologies that address these various problems, and many improved technologies have been published.

For example, the following is disclosed as a patented technique that aims to prevent generation of static electricity along with improvement of chips and expandability, for example.
Antistatic layer with surfactant such as acrylic amphoteric or cationic surfactant, maleic anhydride-styrene anion, or antistatic layer with this surfactant, between base sheet and adhesive layer made of polyethylene, polypropylene, etc. In which a heat-curing type antistatic layer is laminated (for example, see Patent Documents 1 and 2), polypropylene (specifically, a blended polypropylene resin with a polyethylene resin) in 100 parts by weight of a polyoxyethylene chain A film formed by mixing 10 to 200 parts by weight of an antistatic agent obtained by copolymerizing a monomer having butadiene and butadiene, and a layer formed of a radiation-polymerizable pressure-sensitive adhesive layered thereon (see, for example, Patent Document 3) .), An adhesive layer made of a radiation-polymerizable adhesive, and an antistatic material in which a peeling film is laminated on the adhesive layer. A body adhesive sheet for processing, which withstand voltage of the adhesive face of the sheet at the time of peeling the peeling film is to be less than 200V (e.g. see Patent Document 4.), And the like.
The pressure-sensitive adhesive sheet for semiconductor processing described in Reference 4 is obtained by laminating the pressure-sensitive adhesive layer and the peeling film on a base film provided with antistatic properties. As the base film, a polyethylene-based film is used. In addition, the anionic and cationic nonionic surfactants generally known for polypropylene resins and the like are kneaded and molded, and in Example 1, An example of kneading a polymer-type antistatic agent with a polyether / polyolefin block polymer (Perestat 300), which is different from general surfactants, is described. Specifically, 15 parts by weight of the polymer type antistatic agent is kneaded with 100 parts by weight of polypropylene with a twin-screw kneading extruder, and then pressed with an extruder to obtain a sheet having a thickness of 150 μm. A sticky adhesive layer is laminated, and a release film is laminated thereon to form an adhesive sheet for semiconductor processing. After aging at room temperature for 7 days or more, the withstand voltage when the peelable film is peeled off is measured. That's what it says.
Japanese Patent Laid-Open No. 9-190990 JP 2000-178516 A JP 2003-147302 A Japanese Patent Laid-Open No. 2003-282489

The present invention is a result of diligent investigation to find a substrate film for dicing which is excellent in the dicing waste and chipping, and has improved expandability and information destruction of the chip based on the generation of static electricity and does not cause trouble in each process. , That is what has been reached.
The expandability here means that, for example, when dicing mount (substrate film) is expanded, control expansion can be performed with a necessary width uniformly in any direction without a necking phenomenon. This necking is a phenomenon that occurs suddenly due to a neck shape at the corner of the cradle when the dicing cradle is raised and the dicing board is expanded after dicing. When this occurs, the chip cannot be picked up.

First, in the present invention, a semiconductive layer A formed from the resin A described below and a layer B formed from the resin B are laminated in the order of layer B / semiconductive layer A / layer B, and The three layers have a volume resistivity of 10 ⁹ to 10 ¹³ Ω · cm when 500 V is applied, and are characterized by a substrate film for dicing.
<Resin A>
Polypropylene thermoplastic elastomer having a melting point peak temperature of 125 to 148 ° C., 40 to 75% by mass, and a hydrophilic polyethylene resin or hydrophilic polypropylene resin 60 to 25 in which a polyoxyalkylene chain is block-bonded to a polyethylene chain or a polypropylene chain Blend resin with mass%.
<Resin B>
Low density polyethylene resin .

In addition to the features of the above-mentioned three-layer dicing substrate film, in order to further firmly adhere the layers and to perform dicing more safely and reliably, the layer for dicing consisting of the following layers C is laminated. Also featured is a substrate film.
That is, the semiconductive layer A formed from the resin A described below, the layer B formed from the resin B, and the layer C formed from the resin C are layer B / layer C / semiconductive layer A / layer C /. Layer B is laminated in this order, and the volume resistivity of the five layers is 109 to 1013 Ω · cm when 500 V is applied.
<Resin A>
Polypropylene thermoplastic elastomer having a melting point peak temperature of 125 to 148 ° C., 40 to 75% by mass, and a hydrophilic polyethylene resin or hydrophilic polypropylene resin 60 to 25 in which a polyoxyalkylene chain is block-bonded to a polyethylene chain or a polypropylene chain Blend resin with mass%.
<Resin B>
Low density polyethylene resin .
<Resin C>
Linear low density polyethylene resin.

  The polypropylene-based thermoplastic elastomer is the dicing substrate film comprising a blend of a non-elastic soft copolymer obtained by copolymerizing propylene with butene 1 as a main component and a crystalline polypropylene resin. And

  The layer A formed by mixing the hydrophilic polyethylene resin or the hydrophilic polypropylene resin is also characterized in that it is the dicing substrate film in which the resin is finely dispersed in a layer shape.

  Moreover, since it is also preferable to impart semiconductivity to the resin B and / or resin C as appropriate, hydrophilicity in which a polyoxyalkylene chain is block-bonded to a polyethylene chain or a polypropylene chain with respect to 100 parts by mass of the resin. The substrate film for dicing is also characterized by containing 10 to 35 parts by mass of a conductive polyethylene resin or a hydrophilic polypropylene resin.

  The present invention, which is configured as described above, has the following effects.

  By using the substrate film for dicing according to the present invention as a dicing mount, there is no occurrence of dicing waste, chipping and necking, and the film can be further smoothly expanded and picked up easily.

  A substrate film for dicing with extremely excellent static elimination properties can be obtained, so there is no risk of chip information destruction caused by the occurrence of static electricity, and the problem of static electricity trouble in each process is also solved. Became.

First, the case where the substrate film for dicing (hereinafter referred to as “D substrate film”) of the present invention comprises three layers will be described.
These three layers are formed by laminating a semiconductive layer A formed of resin A and a layer B formed of resin B in the order of layer B / semiconductive layer A / layer B. Resin A is the following.
That is, the melting point peak temperature is preferably 125 to 148 ° C., more preferably 130 to 144 ° C., polypropylene-based thermoplastic elastomer (hereinafter referred to as p · TEP) 40 to 75% by mass, preferably 45 to 70%. 60-25% by mass of a hydrophilic polyethylene resin (hereinafter referred to as hydrophilic PE resin) or a hydrophilic polypropylene resin (hereinafter referred to as hydrophilic PP resin) in which a polyoxyalkylene chain is block-bonded to a polyethylene chain or a polypropylene chain. The blend resin is preferably 55 to 30% by mass.
First, p · TEP is particularly selected here because it is excellent in maintaining a good balance between wafer chipping, dicing waste and expandability, and is semiconductive with hydrophilic PE resin or hydrophilic PP resin ( This is because, for example, it is very easy to impart (static elimination), and cutting with a dicer is performed smoothly and smoothly. In other words, it acts as a central layer that expresses characteristics in a well-balanced manner as a 3-layer to 5-layer film for dicing.

The p · TEP is the following resin.
This is because polypropylene becomes a hard segment chain (a small amount of ethylene may be copolymerized within a range that does not lose this segment characteristic), and at least a two-component copolymer polyolefin mainly composed of an olefin monomer is a soft segment chain. And is a resin having thermoplastic elastomeric properties.
Here, the soft segment chain is, for example, a copolymer polymer chain of ethylene and C4 to C8 α-olefin, a random copolymer polymer chain of ethylene and acrylic acid ester, propylene and C4 to C8, preferably C4 to C5. And a copolymer polymer chain with an α-olefin. Among these, a copolymer polymer chain of the latter propylene and C4 to C8 is preferable. This is because the p · TEP is mainly composed of a propylene component, so that the obtained D-base film has appropriate support (hard, soft and easy to handle), and maintains the chipping characteristics without losing them. Because it also works.
In addition to the α-olefin, a random copolymer polymer chain with a small amount of aromatic monomer such as styrene or diene monomer may be used. Furthermore, p · TEP including a crosslinked structure may be used as long as the thermoplastic elastomer characteristics are not largely lost.

  Further, even in the case of p · TEP, it is necessary to select and use a melting point peak temperature (hereinafter referred to as “mp temperature”) in the range of 125 to 148 ° C., preferably 130 to 145 ° C. This is because when the temperature is lower than 125 ° C., the rigidity is particularly insufficient and chipping occurs, and when the temperature exceeds 148 ° C., the expansion accompanying the necking phenomenon is particularly easily performed.

The p · TEP can also be formed by mutual bonding in one resin, but also by blending p · TEP and non-p · TEP resin, and also by blending soft non-p · TEP and polypropylene resin. p · TEP can be made. New p · TEP by these blends is preferable because the mp temperature can be freely changed relatively and characteristics such as rigidity are easily changed.
In p · TEP in the above three cases, more preferred is p · TEP obtained by blending soft non-p · TEP and polypropylene resin.

Specifically, the case of blending the soft non-p · TEP and polypropylene resin is as follows.
First, the soft non-p · TEP is copolymerized (randomly) with propylene mainly containing an α-olefin of C4 to C5, more preferably C4 (that is, butene 1). It has a low softening point of about 110 ° C. and a low melt viscosity of about 1.5 to 8 Pa · s (190 ° C.), and is soft at room temperature but has no elastic properties.
The polypropylene resin blended therein is preferably a crystalline polypropylene resin having a crystallinity of 40% or more.
This combination is also effective in creating p · TEP with mp temperatures of 125-148 ° C.

One hydrophilic PP resin or hydrophilic PE resin is a semiconductive resin having the following structure, but this resin does not impair the action and effect of p · TEP. Dispersibility with TEP (also layered dispersibility which will be described later) is very good, and a great effect that there is no bleeding out phenomenon is exhibited. This is the reason for selection.
First, a polyolefin chain, preferably a polyethylene chain or a polypropylene chain, is bonded as a block to a polyoxyalkylene chain. This mediation of bonding is performed by an ester group, an amide group, an ether group, a urethane group or the like, but it is preferable from the viewpoint of blendability that it is based on an ester group or an ether group. When this polyethylene chain or polypropylene chain is present as a block, it is considered that the bleed-out phenomenon seen in the other surfactants mentioned above is not observed.
In addition, it is not preferable to use the above-mentioned conventionally known surfactant or the like in combination because the risk of bleeding out is high even if the amount added is small.

  The presence of one polyoxyalkylene chain as a block eliminates the accumulation of static electricity by performing a higher static elimination action. Therefore, it is not preferable that each of these chains has a low molecular weight and the bond thereof is random, since the compatibility and the static elimination action tend to decrease.

  The hydrophilic PE resin or hydrophilic PP resin is nonionic. This is because the above-mentioned effects are exhibited both anionic and cationic, but these ionic ones are preferable because metal ions can easily enter and adhere to a wafer or the like.

The polyethylene chain or the polypropylene chain has a high molecular weight as described above, and its molecular weight is, for example, about 1200 to 6000 in a molecular weight range lower than the molecular weight generally called a polymer. In this molecular weight range, in order to block-bond polyethylene or polypropylene to the polyoxyalkylene chain, the reaction operation is performed in the previous stage, and the acid modification of polyethylene or polypropylene is about 1200 to 6000 molecular weight polyethylene or polypropylene. It depends on what is easy to do.
The molecular weight of one polyoxyalkylene chain is preferably about 1000 to 15000 in terms of heat resistance and reactivity (with this acid-modified polyethylene or polypropylene).
This polyoxyalkylene chain has semiconductivity, but its volume resistivity is about 10 ⁵ to 10 ¹⁰ Ω · cm. By being in this range, the balance with the blend ratio described later is The volume resistivity (hereinafter referred to as ρv) referred to in the invention can be expressed as 10 ⁹ to 10 ¹³ Ω · cm.

  The method for producing hydrophilic PE resin or hydrophilic PP resin is, for example, that the molecular weight polyethylene or polypropylene is acid-modified and reacted with polyalkylene glycol. For more details, see FIG. For example, since it is described in JP-A-2001-278985 or JP-A-2003-48990, it is omitted.

The p · TEP and the hydrophilic PE resin or the hydrophilic PP resin are used after being blended in a predetermined amount. In order to provide effective semiconductivity while maintaining the various required properties described above, the predetermined blend amount is also important, here achieved by the above proportions. This means that when the hydrophilic PE resin or hydrophilic PP resin exceeds 60% by mass and p · TEP is less than 40% by mass, the expression of each characteristic by the p · TEP is suppressed. When the hydrophilic PE resin or the hydrophilic PP resin is less than 25% by mass and the p · TEP exceeds 75% by mass, the required semiconductivity is not exhibited.
There is no particular limitation on which of the hydrophilic PE resin and the hydrophilic PP resin to be blended, but it is a hydrophilic PP resin if preferably selected. This is because it is particularly good for chipping.

Next, the resin B forming the layer B will be described.
As the resin B, a low-density polyethylene resin (hereinafter referred to as LDPE resin) is particularly selected. This resin is a polymer made of ethylene alone, and can be mentioned as having a density in the range of about 0.85 to 0.92.
Here, the reason why such an LDPE resin is particularly selected is as follows.
First, the insufficient expandability of the layer A as the central layer is improved to a higher level at once, and further, the cut impact caused by the dicer is alleviated, and the incision can be performed more smoothly. . Therefore, extensibility at a higher level cannot be obtained even in the case of, for example, a single or copolymerized polypropylene resin other than the LDPE resin, as well as a medium density to high density polyethylene resin.

  The layer B is formed of the same or different LDPE resin and is laminated on both sides of the semiconductive layer A. In use (actual dicing operation), both layers B are Different roles. In other words, an adhesive layer is further provided on one side, and the product to be cut is attached and fixed on this side, and a dicer is inserted and cut. It also serves as a stopper that prevents the notch from reaching the dicing table surface. Therefore, in consideration of these different roles, it is also preferable to use a low density LDPE resin for the layer B on the side where the adhesive layer is provided, and use a high density LDPE resin for the layer B on the side in contact with the dicing surface. That is.

Next, the case of five layers of layer B / layer C / semiconductive layer A / layer C / layer B will be described.
This five-layer film is preferable in order to maintain the effects of the three layers, strengthen the interlayer adhesion, eliminate the risk of delamination due to impact during dicing, and more safely and reliably. Yes, this is achieved by laminating between layer B and semiconductive layer A as layer C.
As the resin forming the layer C, a linear low density polyethylene resin (hereinafter referred to as LLDPE resin) is particularly selected. This is because the resin components of the semiconductive layer A and the layer B are well known. They are laminated with high adhesion, and have no adverse effects on chipping, dicing waste, etc., as well as expandability. Therefore, it is not preferable whether this is another resin, for example, a low to high density polyethylene resin or a low density PP resin.

The LLDPE resin is generally a resin in which a small amount of α-olefin such as butene 1 is branched and introduced into a polyethylene chain, but there are differences in characteristics depending on whether the polymerization catalyst is Ziegler-Natta or metallocene. Here, any catalyst may be used.
Further, the LLDPE resin may be modified by grafting with a reactive carboxylic acid such as maleic anhydride.

And, the resin component of the above layer B and / or layer C is basically necessary for the three-layer or five-layer film without blending the hydrophilic PE resin or hydrophilic PE resin. Semi-conductivity (10 ⁹ to 10 ¹³ Ω · cm in ρv) is imparted. However, for example, when the thickness of each layer is set, that is, when the layer thickness of the layer A is set to be thin and the layer thickness of the layer B and / or the layer C is set to be thick, However, it may not be easy to impart the necessary semiconductivity.
Therefore, a hydrophilic PE resin or a hydrophilic PE resin is blended with the layer B and / or the layer C in advance so that the necessary semiconductivity can be easily imparted even with such setting of each layer thickness. It is also a good thing to keep.
In this case, the blend amount may basically be such that the semiconductivity of the layer A is promoted on the premise that the characteristics of the layer B and / or the layer C are not lost. Therefore, basically, the amount may be smaller than the blend amount in the semiconductive layer A. When this quantitative ratio is illustrated, it is 10-35 mass parts with respect to 100 mass parts of resin B and resin C used for the said layer B and / or layer C, Preferably it is 15-30 mass parts.
If the amount is less than 10 parts by mass, the layer A does not actively support the semiconductivity of the layer A. On the other hand, if it exceeds 35 parts by mass, it is difficult to perform smooth expansion without necking.
The layer B may be blended with a smaller amount of hydrophilic PE resin or hydrophilic PE resin than the layer C. This is because a separate adhesive layer is provided on one surface of the layer B, and the other surface does not lose its smoothness with the dicing table.

The layer thickness of layer B / semiconductive layer A / layer B or layer B / layer C / semiconductive layer A / layer C / layer B is as follows.
Basically, the semiconductive layer A is the thickest, the layer C is the thinnest, and the layer B is set between both layers. As described above, the semiconductive layer A becomes a central layer of the D base film, and is a base for developing the above functions (especially chipping, dicing waste, necessary semiconductive properties, support as a film). This function becomes more effective by making it thickest. As described above, the layer B is provided with excellent extensibility and further functions such as cutting control of the dicer to the dicing table. This is because the layer A may be thinner than the layer A, and the layer C basically has only an adhesive function between the layer A and the layer B, and therefore it should be made the thinnest.
Specifically, first, the total thickness is about 80 to 250 μm. If it is too thin, the depth of cut by the dicer will be insufficient, and it will be difficult to handle without waist. Conversely, if it is too thick, the waist becomes too strong and difficult to handle. Among them, the layer A is preferably set to 40 to 190 μm, the layer B to 10 to 35 μm, and the layer C to 5 to 10 μm.

The three-layer or five-layer D-substrate film thus constructed is also provided with the necessary semiconductivity as described above, so that it has the property of quickly eliminating static electricity generated in the handling process, including information destruction of the wafer. However, this characteristic is more effectively present in the film, particularly in ρv10 ⁹ to 10 ¹³ Ω · cm, preferably 10 ¹⁰ to 10 ¹² Ω · cm.
This electrical resistance is a volume resistivity measured by applying a DC voltage of 500 V to both sides of the film, not a surface resistivity. Therefore, even if the surface resistivity is in the range of 10 ⁹ to 10 ¹³ Ω / □ or even less, it does not essentially solve the charge removal. In other words, for the fundamental solution of static electricity generation, the static electricity generated on the surface must be immediately grounded and escape from the system. For this purpose, the entire D substrate film must be semiconductive, that is, ρv. I have to. In particular, in a dicing board having a predetermined resistivity only on the surface or having a semiconductive layer interposed in multiple layers, since all of the inside is not in a semiconductive state, it is in an electrically insulated state. Yes. In a film having electrical resistance only on this surface, charged static electricity flows for a moment, but it does not flow out of the system. As a result, the electric charge is increasingly stored inside, and the film itself has a risk of causing dielectric breakdown.
Here, the lower limit of ρv is set to 10 ⁹ Ω · cm. However, as described above, from the balance with the expression of other effects, this is the minimum resistance limit and 10 ⁹ Ω · cm is sufficient to solve at least the problem of static electricity generation at the time of pickup. It depends. Conversely, the upper limit of 10 ¹³ Ω · cm is an upper limit for eliminating the trouble caused by the generated static electricity.

  In addition, the semiconductivity of the D substrate film composed of ρv is semiconducting for its proper expression (no unevenness in ρv, expressed by a relatively small amount of hydrophilic PE resin or blend of hydrophilic PE resins). It is also influenced by the dispersion state of the conductive layer A. In general, it is ideal that any blend is in the form of extremely fine particles and independently finely dispersed. However, in the present invention, this dispersed state is not good for this proper expression. For proper expression, it is preferable that the layer is finely dispersed. Of course, this layered dispersion state does not suppress the other effects described above, and may act in a good direction in some cases.

In order to confirm this lamellar dispersion state, a three-layer film obtained as Example 1 (simply using raw materials by dry blending) and Reference Example 1 (raw materials that were further biaxially melt-kneaded after driving) was used. Then, the cross section was enlarged by a scanning electron microscope (5000 times) and a photograph was taken. The results are shown in FIGS. Example 1 is shown in FIG. 1, and Reference Example 1 is shown in FIG. In the figure, the whitish part is Pereztat 300 corresponding to the hydrophilic PP resin, and the blackish part is p · TEP of the matrix resin. In Example 1, many hydrophilic PP resins are finely dispersed in a continuous layer, whereas in Reference Example 1, there is a layer, but it is small and insignificant, mostly granular and in an independent dispersion state. Can understand well.
Further, in Example 1, the gap between the electrically insulating p · TEP layers is very narrow and both are dense, whereas in Reference Example 1, the gap between the p · TEP layers is very wide. It can also be seen that is separated.
This can also be seen by comparing ρv, which is one of the effects. Compared to Reference Example 1, Example 1 is much smaller in electrical resistance, that is, it is in a state where electricity flows easily. This is caused by the difference in the dispersion state of the hydrophilic PP resin described above. It is believed that there is. By the way, the samples of both cases were left in an atmosphere of 23 ° C. and 50% RH for 48 hours, and then the charge half-life (seconds) was measured using an Honest meter. The charge was halved in 4 seconds. It also shows that the film of the present invention can be discharged much faster even when charged.

Next, the means for producing each D base film will be described.
Although there are various types of manufacturing means, an example of a manufacturing method in which the dispersion of the hydrophilic PE resin or the hydrophilic PP resin described above easily adopts a layered dispersion state will be exemplified.
First, the three-layer D substrate film of layer B / semiconductive layer A / layer B will be described.
Although there are various laminating means, simultaneous molding by three-layer coextrusion is desirable, and will be described below based on this.

  First, as a raw material for the semiconductive layer A, p · TEP and hydrophilic PE resin or hydrophilic PP resin are simply dry blended (for example, a dumble mixer) at the above blend ratio. This is because further melt-kneading is not preferable because the layered dispersion becomes difficult to take. Then, the moisture content of the dry blend is adjusted to 500 to 3000 ppm. If it is less than 500 ppm, the required semiconductive property does not appear smoothly, and if it exceeds 3000 ppm, irregularities (whether due to bubbles) are easily formed in the layer.

Then, the dry blend raw material for the layer A is supplied to one single screw extruder, and the screw of the extruder has a measuring section groove depth of 3.5 to 7.5 mm, preferably 4. It is preferable to use a full flight gradually decreasing deep screw (hereinafter referred to as FF screw) in a range of 0 to 6.5 mm, a compression ratio of 1.5 to 2.5, preferably 1.6 to 2.0 mm (hereinafter referred to as FF screw). There are other types of screw type dalmerged type screws, both of which are not preferred because high shear stress is easily applied to the molten resin).
Here, when the groove depth of the measuring portion is less than 3.5 mm, shear stress is easily applied more than necessary, and as a result, it is difficult to obtain the ρv, and when it exceeds 7.5 mm, an excessive resin pressure is applied, This is because the residence time becomes long and there is a risk that the hydrophilic PE resin or the hydrophilic PP resin may be decomposed.
On the other hand, if the compression ratio is less than 1.5, it is difficult to stably supply the raw material drene resin, and if it exceeds 2.5, melt kneading action tends to be added.
The length L / D of the screw is preferably 35, preferably not exceeding 30. This is also because the molten resin is not retained for a long time. This is because a long stay may cause a decomposition of the hydrophilic PE resin or the hydrophilic PP resin.

  The temperature of the resin in the barrel is 145 (inlet) to 235 ° C. (outlet), preferably 150 to 230 ° C., and is adjusted under gradually increasing high temperature. It is because it will lead to decomposition | disassembly of hydrophilic PE resin or hydrophilic PP resin when it exceeds 235 degreeC.

  On the other hand, each of the other two single-screw extruders is supplied with LDPE resin, which is resin B for layer B. First, the water content of the resin is, in particular, hydrophilic PE resin or hydrophilic PP resin. In the case of blending, the same management as in the case of the layer A is performed. Then, when blending a hydrophilic PE resin or a hydrophilic PP resin, simply dry-blend as in the case of the layer A.

  The screw of the two extruders for the layer B may be a screw specification generally used for film forming of polyethylene, but a hydrophilic PE resin or a hydrophilic PP resin may be blended. In the case of the semiconductive layer A, it is preferable to be as close as possible. From this point, using a full-flight gradually decreasing deep screw with a depth of 1.5 to 3.0 mm in the measuring section groove and a compression ratio of 2.5 to 3.5, the barrel extrusion temperature is gradually increased at 150 to 210 ° C. It should be under high temperature adjustment.

The molten resin extruded from the three extruders is sent to a three-layer T die and laminated at the same time, and the temperature of the T die is 235 ° C. or lower, preferably 210 to 225 ° C.
The extruded melt-laminated film is first cooled through a cooling roll at 40 to 100 ° C., preferably 60 to 90 ° C., but is not substantially stretched. This is because it is not preferable in terms of expandability.
The withdrawal rate should be about 5 to 10% so as not to increase. This is because when the film is discharged from the T-die, the film is soft and the neck-in is large, so this is prevented in advance. Therefore, the cooling roll is placed close to the T die so as to be in this range.

On the other hand, in the case of a five-layer film of layer B / layer C / semiconductive layer A / layer C / layer B, it is preferably produced under the following conditions.
First, lamination is preferably performed by simultaneous coextrusion from a five-layer coextrusion T-die, as in the case of the three-layer film.
In the blending of hydrophilic PE resin or hydrophilic PP resin, each extrusion raw material is also prepared by dry blending, and the moisture content is the same as in the case of the three layers.

  The screw conditions of each single screw extruder may be the same as those for the three layers for the layer B and the semiconductive layer A. The resin in the case of layer C is LLDPE, which is different from the LDPE of layer B, but may be the same as the screw in the case of layer B.

The resin temperature in the barrel, the temperature of the five-layer T die, the cooling temperature, the stretching conditions, and the drawing conditions may be the same.
In each of the layers, the resin of the layer B and the semiconductive layer A may be added with a small amount of generally known olefin resin additives (for example, antioxidants, weathering agents, lubricants, etc.). good.

The obtained D substrate film cannot be used as it is. An adhesive layer for adhering and fixing the member to be diced is provided on one surface of the outer layer B to form a dicing mount. As the resin for the adhesive layer, for example, acrylic resins, rubber resins, electron beam irradiation acrylic resins and the like that are generally used are used, but the layer thickness should be as thin as possible. It is also for avoiding an electrical insulating layer effect.
When the member to be diced is a wafer, the dicing board is used after being processed into a tape-shaped roll wound with a release paper (film).

Hereinafter, examples will be described in detail together with comparative examples and reference examples.
The expandability, ρv, delamination strength, and necking phenomenon in the text and in the following examples are
It is measured as follows.

● Scalability,
The (D substrate) film obtained in each example is used as a sample, and 10 × 10 mm squares are drawn in advance on this film. Then, it is cut into a circle having a diameter of 300 mm, and this is brought into contact with the surface of a cylindrical body having an outer diameter of 150 mm (automatically moves up and down), and the entire periphery of the end of the film is chucked. Next, the cylinder is pushed up by 20 mm at a speed of 200 cm / min, and the film is expanded in all directions. Then, the vertical and horizontal expansion of the grid located at the center is measured. If the lengths in the vertical and horizontal directions are both 110% or more, the film is excellent as expandable film, and if at least one of the stretches is less than 110%, the film is inferior in expandability.

● ρv (Ω ・ cm),
The film obtained in each example was cut into A3 size, DC voltage 500V was applied to both sides of the film, and the resistance measuring instrument “HIRESTA IP / HR Blob” manufactured by Mitsubishi Chemical Corporation was applied to 10 locations. ρv is measured.
The measurement is performed after 10 seconds, and the value is shown as an average value.

● Delamination strength,
The film obtained in each example is cut to a width of 10 mm and subjected to a 180 ° peel test at a peel rate of 200 mm / min using a peel tester HEIDON-17 manufactured by Shinto Kagaku Co., Ltd. A result is shown by N / 10mm, 60N / 10mm or more is written as ◎, less than 40-60N / 10mm is marked as ◯, and less than 40N / 10mm is marked as x.

● Necking phenomenon,
The film obtained in each example was cut to a width of 10 mm, and using a tensile tester AGS100A manufactured by Shimadzu Corporation, the necking was performed at a distance of 40 mm between the marked lines and at a pulling speed of 200 mm / min. It was confirmed by visual observation whether or not there was a neck-like extension. “X” indicates presence of necking and “O” indicates absence of necking.

Example 1
Resin A for semiconductive layer A (hereinafter simply referred to as layer A resin),
Tumble mixer with 60% by mass of p · TEP (variety F-3740 manufactured by Idemitsu Petrochemical Co., Ltd.) and 40% by mass of hydrophilic PP resin (manufactured by Sanyo Chemical Co., Ltd., product Perestat 300, melting point 135 ° C.) having an mp temperature of 144 ° C. -Blend resin dry blended at-with a moisture content of 1400 ppm.
Resin B for layer B (hereinafter simply referred to as layer B resin),
LDPE with a density of 0.921 (variety F522N manufactured by Ube Industries, Ltd., melting point 109 ° C.) and a moisture content of 180 ppm.
Using each of the above resins as a raw material, this was co-extruded from a three-layer T-die having a slit width of 600 μm and adjusted to a temperature of 225 ° C. by using three extruders and molding conditions having the following contents. A three-layer D substrate film composed of semiconductive layer A / layer B was obtained.

<Extruder and molding conditions for layer A resin>
FF screw type extruder ・ ・ L / D = 28, measuring section groove depth 6.2mm, compression ratio 1.8
◎ Molding conditions: Extrusion temperature is 150-180 ° C at the barrel temperature of the part corresponding to the supply area, 190-215 ° C at the temperature corresponding to the compression area, and 205-230 at the temperature corresponding to the metering area. Gradually increasing high temperature adjustment to 2 ° C., resin pressure 21.5 MPa, drawing rate 7%, cooling roll temperature 80 ° C., non-stretching.
<Layer B resin extruder and molding conditions>
◎ FF screw extruder ・ L / D = 28, groove depth 1.5mm, compression ratio 3.0,
◎ Molding conditions: Extrusion temperature: barrel temperature of 150 to 175 ° C. in the portion corresponding to the supply region, barrel temperature of 185 to 195 ° C. in the portion corresponding to the compression region, and barrel temperature 200 to 205 in the portion corresponding to the metering region Gradually increased high temperature adjustment to 1 ° C., resin pressure 18.5 MPa, draw rate 7%, cooling roll temperature 80 ° C., no stretching.

The total thickness of the three-layer D substrate film obtained above was 90 μm, and each layer was Layer A 70 μm and Layer B 10 μm. Using the film as a sample, expandability, ρv, delamination strength and necking phenomenon were measured and summarized in Table 1.

(Example 2)
◎ Layer A resin,
P · TEP (product type CAP350 manufactured by Ube Industries, Ltd.) having a mp temperature of 135 ° C., which is made by blending a crystalline PP resin with a non-elastic room temperature soft copolymer obtained by copolymerizing butene 1 as a main component with propylene. A blend resin obtained by dry blending 60% by mass and 40% by mass of hydrophilic PP resin (manufactured by Sanyo Chemical Co., Ltd., variety Perestat 300, melting point 135 ° C.) with a tumble mixer, and has a moisture content of 2000 ppm.
◎ Layer B resin,
A blend resin obtained by dry blending 80% by mass of LDPE having a density of 0.921 (product type F522N, manufactured by Ube Industries Co., Ltd.) and 20% by mass of the hydrophilic PP resin of Example 1 with a tumble mixer, and having a moisture content of 2100 ppm.
Resin C for layer C (hereinafter simply referred to as layer C resin),
LLDPE resin (type Evolu-SP2520, metallocene catalyst manufactured by Mitsui Chemicals, Inc.)
A blend resin obtained by dry blending 80% by mass and 20% by mass of the hydrophilic PP resin of Example 1 with a tumble mixer and having a moisture content of 800 ppm.
Using each of the above resins as a raw material, this was co-extruded from a five-layer T die having a slit width of 600 μm and adjusted to a temperature of 225 ° C. by using five extruders and molding conditions having the following contents. A five-layer D substrate film composed of layer C / semiconductive layer A / layer C / layer B was obtained.

<Extruder and molding conditions for layer A resin>
FF screw type extruder ・ ・ L / D = 28, measuring section groove depth 6.2mm, compression ratio 1.8
◎ Molding conditions: Extrusion temperature is 150 to 180 ° C. at the part corresponding to the supply area, 190 to 215 ° C. at the area corresponding to the compression area, and 205 to 235 at the temperature corresponding to the measuring area. Gradually increasing high temperature adjustment to 2 ° C., resin pressure 21.5 MPa, drawing rate 7%, cooling roll temperature 80 ° C., non-stretching.
<Extruder and molding conditions for layer B resin>
◎ FF screw extruder ・ L / D = 28, groove depth 1.5mm, compression ratio 3.0,
◎ Molding conditions: Extrusion temperature: barrel temperature of 150 to 175 ° C. in the portion corresponding to the supply region, barrel temperature of 185 to 195 ° C. in the portion corresponding to the compression region, and barrel temperature 200 to 205 in the portion corresponding to the metering region Gradually increased high temperature adjustment to 1 ° C., resin pressure 18.5 MPa, draw rate 7%, cooling roll temperature 80 ° C., no stretching.
<Extruder and molding conditions for layer C resin>
Same as for layer B resin. However, the resin pressure is 22.5 MPa.

  The total thickness of the 5-layer D substrate film obtained above was 90 μm, and each layer was layer A 50 μm, each layer B 15 μm, and each layer C 5 μm. Using the film as a sample, expandability, ρv, delamination strength and necking phenomenon were measured and summarized in Table 1.

(Example 3)
A five-layer D substrate film was obtained under the same conditions except that an acid-modified LLDPE resin (product type AT1535 manufactured by Mitsui Chemicals, Inc.) was used instead of the layer C resin of Example 2. The five-layer thickness configuration was the same as in Example 2. Using the film as a sample, expandability, ρv, delamination strength and necking phenomenon were measured and summarized in Table 1.

(Comparative Example 1)
In Example 2, the layer A resin alone was extruded from a single layer T die (225 ° C., slit width 600 μm) using a layer A resin extruder and molding conditions to obtain a layer A single layer film. However, the resin pressure in this case is 22.0 MPa.
The thickness of the obtained single-layer semiconductive film was 90 μm. The film was used as a sample to measure expandability, ρv, delamination strength, and necking phenomenon, and are summarized in Table 1.

(Comparative Example 2)
A three-layer film was obtained under the same conditions except that the p · TEP resin of layer A of Example 1 was changed to a p.TEP resin having a mp temperature of 152 ° C. (product type E-2710, manufactured by Idemitsu Petrochemical Co., Ltd.). The three-layer thickness configuration was the same as in Example 1. Using the film as a sample, expandability, ρv, delamination strength and necking phenomenon were measured and summarized in Table 1.

(Comparative Example 3)
A five-layer film was obtained under the same conditions except that the layer B resin of Example 2 was changed to a medium density PE with a density of 0.934 (product type Z372, Ube Industries, Ltd., melting point 117 ° C.). The five-layer thickness configuration was the same as in Example 2. Using the film as a sample, expandability, ρv, delamination strength and necking phenomenon were measured and summarized in Table 1.

(Comparative Example 4)
In Example 1, a three-layer film was obtained under the same conditions except that the hydrophilic PP resin in the layer A resin was changed to two types of 20% by mass and 75% by mass. The two types of three-layer thickness configurations were the same as in Example 1. The film of 20% by mass was called 20F and that of 75% by mass was called 75F, and the extensibility, ρv, delamination strength and necking phenomenon were measured for each sample and are summarized in Table 1.

(Reference Example 1)
In the preparation (blending means) of the layer A resin in Example 1, the hydrophilic PP resin blend was first dry blended, and then a biaxial melt kneading extruder (L / D = 7/1, resin rotated in different directions). Were carried inward) (barrel heating temperature gradually increased to 150 to 205 ° C.) and melt kneaded to obtain chips. A three-layer film was obtained by co-extrusion molding with three layers under the same conditions as in this example except that this kneading chip was used. The film thickness configuration obtained was the same as in the example. Using the film as a sample, ρv (expandability, delamination strength and necking phenomenon were not measured) was measured and summarized in Table 1.

A cross section of the three-layer film of Example 1 taken with a scanning electron microscope (5,000 times). A cross section of the three-layer film of Reference Example 1 taken with a scanning electron microscope (5,000 times).

Explanation of symbols

    In each of the photos, the whitish part corresponds to hydrophilic PP resin, and the black part corresponds to p.TEP resin of the matrix

Claims (5)

The semiconductive layer A formed by the resin A described below and the layer B formed by the resin B are laminated in the order of layer B / semiconductive layer A / layer B, and the three layers have A substrate film for dicing having a volume resistivity of 10 ⁹ to 10 ¹³ Ω · cm under application of 500 V.
<Resin A>
Polypropylene thermoplastic elastomer having a melting point peak temperature of 125 to 148 ° C., 40 to 75% by mass, and a hydrophilic polyethylene resin or hydrophilic polypropylene resin 60 to 25 in which a polyoxyalkylene chain is block-bonded to a polyethylene chain or a polypropylene chain Blend resin with mass%.
<Resin B>
Low density polyethylene resin . A semiconductive layer A formed from the resin A described below, a layer B formed from the resin B, and a layer C formed from the resin C are layer B / layer C / semiconductive layer A / layer C / layer. A substrate film for dicing, wherein the substrate is laminated in the order of B, and the volume resistivity of the five layers is 10 ⁹ to 10 ¹³ Ω · cm when 500 V is applied.
<Resin A>
Polypropylene thermoplastic elastomer having a melting point peak temperature of 125 to 148 ° C., 40 to 75% by mass, and a hydrophilic polyethylene resin or hydrophilic polypropylene resin 60 to 25 in which a polyoxyalkylene chain is block-bonded to a polyethylene chain or a polypropylene chain Blend resin with mass%.
<Resin B>
Low density polyethylene resin .
<Resin C>
Linear low density polyethylene resin. The dicing substrate according to claim 1 or 2, wherein the polypropylene-based thermoplastic elastomer is a blend of a non-elastic soft copolymer obtained by copolymerizing propylene with butene 1 as a main component and a crystalline polypropylene resin. Film. The substrate film for dicing according to any one of claims 1 to 3, wherein the hydrophilic polyethylene resin or hydrophilic polypropylene resin present in the semiconductive layer A is finely dispersed in layers. The resin B and / or resin C contains 10 to 35 parts by mass of a hydrophilic polyethylene resin or hydrophilic polypropylene resin in which a polyoxyalkylene chain is block-bonded to a polyethylene chain or a polypropylene chain with respect to 100 parts by mass of the resin. The substrate film for dicing according to any one of claims 1 to 4.