WO2013099778A1

WO2013099778A1 - Substrate for stealth dicing film, film for stealth dicing, and method for manufacturing electronic component

Info

Publication number: WO2013099778A1
Application number: PCT/JP2012/083154
Authority: WO
Inventors: 中野　重則; 雅弘錦織; 芳恵橋本; 雄介宮下
Original assignee: 三井・デュポンポリケミカル株式会社
Priority date: 2011-12-26
Filing date: 2012-12-20
Publication date: 2013-07-04
Also published as: KR101832297B1; KR20160086989A; JPWO2013099778A1; TW201600582A; KR20160049041A; JP6247733B2; CN107057594A; CN104011836A; JP6073810B2; KR20140102756A; TWI500731B; TW201333152A; KR101742647B1; JP2017063210A; TWI563061B; CN107057594B; CN104011836B

Abstract

Provided is a substrate for stealth dicing film in which the thickness is within the range of 50 µm to 200 µm inclusive, the initial stress is within the range of 9 MPa to 19 MPa inclusive, the expansion rate is within the range of 102 % to 120 % inclusive, the haze value is 10 or less, and the total light transmittance is 90 % or more.

Description

[Name of invention determined by ISA based on Rule 37.2] Laser dicing film substrate, laser dicing film, and electronic component manufacturing method

The present invention relates to a stealth dicing film substrate, and a stealth dicing film and an electronic component manufacturing method using the same.

When dicing a semiconductor wafer, the wafer is cut by a dicing blade while using cooling water and cleaning water, and in the next expansion process, the dicing film corresponding to the cut wafer is expanded to form small chips. It was done. At this time, the semiconductor wafer was fixed with a dicing film to prevent chips from being scattered.

On the other hand, as a semiconductor wafer dicing method, a method of dicing a semiconductor wafer with a laser beam has been proposed (see, for example, Japanese Patent Application Laid-Open No. 2007-245173). As a dicing method using laser light, a surface ablation method in which a laser is focused on a wafer surface and absorbed to dig a groove has been known for a long time. In recent years, after forming a modified region by condensing laser light inside the wafer, a method of dividing the wafer from the modified region as a starting point by pulling a dicing film corresponding to the wafer (for example, stealth dicing) Law) has been proposed.

In the dicing method using laser light, when the laser light is irradiated through the dicing film, the dicing film has high transparency in order to divide the wafer without hindering the irradiated laser light. It is required to do. In addition, the dicing film is required to have a property that allows good division of the wafer after laser irradiation.

In relation to the above circumstances, as a technique related to the dicing method using laser light, for example, including an adhesive layer having a predetermined tensile elastic modulus and adhesive force, and a base material layer having a predetermined tensile elastic modulus, A dicing film having an expansion ratio and a haze in a predetermined range is disclosed (for example, see JP 2011-61097 A). According to this dicing film, it is said that a high division rate can be obtained.

As a dicing technique using an ionomer, a substrate for a dicing tape provided with a layer containing a potassium ionomer has been disclosed (for example, see JP2011-40449A). According to this base material for dicing tape, it is said that it is excellent in antistatic performance. Also disclosed is a semiconductor wafer sheet having a base material sheet containing an ionomer resin as a base polymer and a predetermined crystal dispersant blended therein, and an adhesive layer (for example, JP 2000-273416 A). And JP 2000-345129 A). According to this semiconductor wafer sheet, it is said that expanded uniformity can be obtained.

In addition, as a dicing technique using a cross-linked resin containing an ionomer, the base film does not cause problems due to loosening after the heat shrinking step by setting the Vicat softening point and the stress increase due to heat shrinkage to a predetermined range. A dicing film is described (for example, see JP 2011-216508 A). In addition, from the viewpoint of preventing thread-like shavings from being threaded, it is disclosed to use an ionomer resin crosslinked with a metal ion such as zinc or magnesium (see, for example, Japanese Patent Application Laid-Open No. 2011-210887).

Furthermore, three layers in which a 40 μm thick intermediate layer containing crystalline polypropylene is disposed between a 30 μm thick adhesive coating layer using EMAA and a 30 μm thick expanding ring contact layer using low density polyethylene A substrate for a wafer dicing tape having a structure has been disclosed (for example, see Japanese Patent Application Laid-Open No. 2003-158098). According to this wafer dicing tape substrate, it is said that it has excellent uniform expandability. In addition, a three-layer structure in which a central layer using an ethylene-methacrylic acid- (2-methyl-propyl acrylate) terpolymer or its zinc ionomer resin is disposed between two layers using low-density polyethylene. An adhesive tape for fixing a semiconductor wafer having a structure is disclosed (for example, see Japanese Patent Application Laid-Open No. 7-230972). According to this adhesive tape for fixing a semiconductor wafer, it is said that necking during expansion and adhesion to a pickup pin are prevented.

However, the dicing film described in Japanese Patent Application Laid-Open No. 2011-61097 has a certain degree of suitability in that the substrate is efficiently divided, and the substrate for dicing tape described in Japanese Patent Application Laid-Open No. 2011-40449 is disclosed. As for the materials, the use of potassium ionomer is expected to improve the antistatic performance, but none of the materials necessarily meet the market demands in terms of transparency or wafer fragmentation. In addition, the sheets described in Japanese Patent Laid-Open Nos. 2000-273416 and 2000-345129 are assumed to be diced with a dicing blade, and are difficult to apply to dicing with a laser beam. Furthermore, Japanese Patent Application Laid-Open No. 2011-216508 discloses a technique for applying an ionomer to an adhesive tape for wafer processing, but it is a technique for solving the problem at the time of dicing with a blade, up to the workability at the time of laser dicing. Is not planned.

Japanese Patent Application Laid-Open No. 2011-210887 also discloses the application of an ionomer to an adhesive tape for wafer processing. This disclosure is also a technique for solving the problem at the time of dicing with a blade, and the workability at the time of laser dicing is also disclosed. Until is not planned.
As described above, further improvement is expected for the laser processability of the dicing film.

In the substrate for wafer dicing tape described in JP-A-2003-158098, polyolefin such as polypropylene is used for the intermediate layer constituting the laminated structure. In general, polypropylene or the like has an extremely large stress when it is stretched. Therefore, when a dicing film is expanded after laser irradiation by a stealth dicing method, whitening is likely to occur when the dicing film is expanded. On the contrary, in the technique described in Japanese Patent Laid-Open No. 7-230972, which has a three-layer structure in which a layer using a terpolymer is an intermediate layer, the stress at the initial stage of elongation becomes too small, so that the wafer is divided. It is difficult to do well. In this case, it is necessary to increase the amount of expansion of the tape in order to improve the dividing property of the wafer. However, if the amount of expansion of the tape is increased, the amount of tape deflection increases, which may adversely affect the transport process and the like.

As described above, in the conventional dicing technology using laser light, when the laser light is irradiated through the dicing film, the irradiated laser light is collected inside the wafer without being affected by absorption or scattering. From the viewpoint of making it light, it is the actual situation that sufficient transparency cannot be ensured. Furthermore, from the viewpoint of determining the laser beam irradiation position, transparency in the visible region is required.

Also, in the stealth dicing method using laser light, the dicing film is expanded after the laser irradiation to uniformly expand the dicing film, and the cracks in the wafer corresponding to the dicing film are divided as starting points. In order to improve the division property at this time, it is required that the stress required for the dicing film satisfies a predetermined range that does not adversely affect other properties such as whitening. In particular, when the stress of the dicing film is insufficient, sufficient splitting properties cannot always be obtained. Further, the dicing film is required to have antistatic properties.

The present invention has been made in view of the above circumstances, is suitable for stealth dicing by laser light, and has excellent transparency and wafer division properties, and a stealth dicing film substrate and a stealth dicing film, and wafer division. The present invention provides a method for manufacturing an electronic component having excellent properties.

Wafer splitting is the ease of division in a modified region inside a wafer formed using laser light. The film substrate for dicing has good extensibility that it has expandability (expansion rate) of 102% or more while having a stress of 9 MPa or more and 19 MPa or less (preferable lower limit is a range exceeding 10 MPa). It is preferable in terms of obtaining.

The inventors of the present invention provide a wafer cutting property of the base material (hereinafter sometimes referred to as “stealth dicing film base material”) provided when producing a stealth dicing film including an adhesive layer and a base material. Studies were repeated to improve (ie initial stress) and expandability. The present invention maintains the thickness of the film base material at an appropriate thickness, and adjusts the initial stress and the expansion rate of the film base material to a predetermined range, so that the balance between the splitting property and the expandability of the film base material is achieved. It has been achieved based on such knowledge.

Specific means for solving the above problems are as follows.
<1> Used as the base material of a stealth dicing film provided with an adhesive layer and a base material. It is a film substrate for stealth dicing having a range of 102% to 120%, a haze value of 10 or less, and a total light transmittance of 90% or more.
<2> Selected from magnesium ionomer of ethylene / (meth) acrylic acid copolymer and zinc ionomer of ethylene / (meth) acrylic acid copolymer, derived from (meth) acrylic acid alkyl ester in the copolymer It is a film base material for stealth dicing as described in <1> containing the ionomer resin whose structural unit copolymerization ratio is less than 7 mass%.
<3> The copolymerization ratio in the copolymer of the structural unit derived from (meth) acrylic acid of at least one of the magnesium ionomer and the zinc ionomer is more than 10% by mass and 30% by mass or less. <2> The film substrate for stealth dicing described in 1.
<4> The stealth dicing film substrate according to <2> or <3>, wherein at least one of the magnesium ionomer and the zinc ionomer has a degree of neutralization of more than 0% and 60% or less.
<5> At least one of the magnesium ionomer and the zinc ionomer is the film substrate for stealth dicing according to <2> or <3>, which has a degree of neutralization of 10% to 40%.

<6> A multilayer structure in which the layer X, the first layer Y, and the second layer Z in contact with the adhesive layer are sequentially stacked, or the layer X, the second layer Z, and the first layer in contact with the adhesive layer The film substrate for stealth dicing according to <1>, wherein Y has a multilayer structure in which layers are sequentially stacked, and the thickness of the layer X, the layer Y, and the layer Z is in the range of 10 μm to 100 μm. .
<7> The layer X in contact with the adhesive layer contains the resin A, the bending rigidity of the resin A is in the range of 100 MPa to 350 MPa, the first layer Y contains the resin B, and the bending of the resin B The rigidity is in the range of 5 MPa to 350 MPa, the second layer Z includes the resin C, and the bending rigidity of the resin C is in the range of 50 MPa to 350 MPa.
Stealth according to <6>, wherein the larger absolute value of the difference obtained by subtracting the bending rigidity of the resin B from the bending rigidity of the resin A or the resin C is in the range of 50 MPa to 345 MPa. It is a film substrate for dicing.
<8> The stealth dicing film according to <6> or <7>, wherein the layer X in contact with the adhesive layer contains a resin A, and the resin A is an ionomer of an ethylene / unsaturated carboxylic acid binary copolymer. It is a substrate.
<9> The stealth dicing film substrate according to <8>, wherein the content of the structural unit derived from the unsaturated carboxylic acid in the binary copolymer is 1% by mass or more and 35% by mass or less.

<10> The first layer Y includes a resin B, and the resin B is a low density polyethylene, a linear low density polyethylene, an ethylene vinyl acetate copolymer, an ethylene / unsaturated carboxylic acid binary copolymer, and <6> to <6> which is at least one selected from the ionomer, the ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid terpolymer and the ionomer, and the ethylene / unsaturated carboxylic acid terpolymer 9> The film substrate for stealth dicing according to any one of 9>.
<11> The second layer Z includes a resin C, and the resin C is an ethylene / unsaturated carboxylic acid binary copolymer and its ionomer, and an ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester ternary. The film substrate for stealth dicing according to any one of <6> to <10>, which is at least one selected from a copolymer and an ionomer thereof.
<12> The film substrate for stealth dicing according to any one of <1> to <11>, comprising an antistatic agent having a melting point of 155 ° C. or higher and 185 ° C. or lower.
<13> The film substrate for stealth dicing according to any one of <1> to <12>, which has a surface resistivity of 1 × 10 ⁹ Ω / sq to 1 × 10 ¹² Ω / sq.

<14> A stealth dicing film comprising an adhesive layer and the stealth dicing film substrate according to any one of <1> to <13>.
<15> The step of attaching the stealth dicing film according to <14> to the back surface of the wafer, and the wafer to which the stealth dicing film is attached is irradiated with laser light from the stealth dicing film side, And a step of dicing the wafer with a laser beam through a stealth dicing film.

<16> The thickness is in the range of 50 μm to 200 μm, the initial stress is in the range of 9 MPa to 19 MPa, the expansion rate is in the range of 102% to 120%, the haze value is 10 or less, the total light In this method, a film substrate having a transmittance of 90% or more is used as a substrate for a stealth dicing film.
<17> Use of a film base material for producing a film for stealth dicing, wherein the thickness is in the range of 50 μm to 200 μm, the initial stress is in the range of 9 MPa to 19 MPa, and the expansion rate is 102% or more This is the use of a film substrate having a range of 120% or less, a haze value of 10 or less, and a total light transmittance of 90% or more.

In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

According to the present invention, there are provided a stealth dicing film base material and a stealth dicing film which are suitable for dicing with a laser beam and which are excellent in transparency and wafer cutting property. In addition, according to the present invention, a method for manufacturing an electronic component excellent in wafer cutting property is provided.

It is a schematic sectional drawing which shows the structural example of the film for stealth dicing which concerns on one Embodiment of this invention. It is a schematic sectional drawing which shows the other structural example of the film base material for stealth dicing of FIG. It is the schematic which shows the place which has irradiated the laser beam through the film for stealth dicing in the case of dicing of a wafer. It is the schematic which shows the state in which the modification part was formed in the wafer in the case of dicing of a wafer. It is the schematic which shows the place which gives external stress to the film for stealth dicing, and isolate | separates a wafer into a some chip | tip.

Hereinafter, a stealth dicing film substrate of the present invention, and a stealth dicing film and an electronic component manufacturing method using the same will be described with reference to the drawings.

[Stealth dicing film substrate and stealth dicing film]
The stealth dicing film 1 will be described with reference to FIGS. 1 to 4, and the stealth dicing film substrate of the present invention will be described in detail through the description. FIG. 1 is a schematic cross-sectional view showing a configuration example of a stealth dicing film.

Stealth dicing is a dicing method in which a laser is focused inside a silicon wafer to form a modified layer (crack or the like) in the wafer and external stress is applied by tape expanding or the like to divide the chip.

As shown in FIG. 1, the stealth dicing film 1 includes a stealth dicing film base material 11 (hereinafter referred to as a base material 11) and an adhesive layer 12 provided on the base material 11.
The substrate 11 may be configured as either a single layer or a multilayer. When the base material 11 is configured in multiple layers, for example, as shown in FIG. 2, the base material 11 includes a layer 11 </ b> X, an intermediate layer 11 </ b> Y (or 11 </ b> Z), and an inner layer 11 </ b> Z (in contact with the adhesive layer 12 constituting the stealth dicing film). Alternatively, a structure including a three-layer structure in which 11Y) is stacked may be used.

In the stealth dicing method, the wafer is made into chips by utilizing the extension force of the dicing film. In the stealth dicing method which has been attracting attention in recent years, dicing sheets used for blade dicing and laser dicing which have been widely used in the past have been used as they are when producing micro-sized semiconductor chips. However, when such a conventional dicing sheet is used, the initial expansion strength (initial stress) may be too low. If the initial stress of the film is too low, the extension force is not sufficiently transmitted to the modified portion formed inside the wafer, so that it becomes difficult to chip the wafer. That is, in a film in which initial stress cannot be obtained sufficiently, each chip cannot be divided by a dicing line, and a plurality of chips are connected, which may reduce the production yield of semiconductor chips. Therefore, in the present invention, in order to improve the wafer severability (that is, initial strength (also referred to as initial stress)) and expandability of the film substrate for stealth dicing, the thickness of the substrate is maintained at a predetermined thickness, By adjusting the initial stress and the expansion rate of the base material to a predetermined range, a balance between breakability and expandability is achieved.
In particular, when the substrate is composed of multiple layers, the layer 11Y (first layer Y) and the layer 11Z with respect to the layer X in contact with the adhesive layer in order to improve the wafer severability (initial strength) and expandability as described above. By balancing the (second layer Z) and adjusting the initial stress of the base material to a range of 9 MPa or more and 19 MPa or less, a balance between the breakability and the expandability can be achieved. In addition, the film substrate of the present invention has a multi-layer structure, but the transparency of the layer is maintained, laser diffusion and absorption are small, and the processing suitability by stealth dicing is excellent.

The stealth dicing film 1 is used for so-called stealth dicing, in which one surface is formed as an adhesive surface, and the wafer is divided (separated) in a non-contact manner starting from a crack formed in the wafer by laser light irradiation. Specifically, as shown in FIG. 3A, the stealth dicing film 1 is placed on the dicing table 6 and attached to the back surface of the wafer W, and laser is irradiated through the stealth dicing film 1. Laser light L is guided inside the wafer W by laser irradiation, and a plurality of modified regions W1 are formed inside the wafer W by the laser light as shown in FIG. 3B. Thereafter, as shown in FIG. 4, the wafer W is separated into individual chips starting from the modified region W1 by applying an external stress to the stealth dicing film 1 and expanding it in the direction of the arrow.

The stealth dicing film 1 can be applied not only to the above stealth dicing but also to a dicing method using a dicing blade and other dicing methods using laser light.

(Base material)
The substrate may be configured as either a single layer or a multilayer of two or more layers.
~ A. Single layer configuration ~
First, the case where the base material is configured in a single layer structure will be described.
FIG. 1 shows an example in which the substrate 11 is configured in a single layer structure. In FIG. 1, the base material 11 is an ionomer resin base material formed using a magnesium ionomer of an ethylene / (meth) acrylic acid copolymer and / or a zinc ionomer of an ethylene / (meth) acrylic acid copolymer. It is.

The magnesium ionomer includes at least ethylene / (meth) acrylic acid copolymer, ethylene / (meth) acrylic acid alkyl ester copolymer, or ethylene / (meth) acrylic acid / (meth) acrylic acid alkyl ester copolymer. A magnesium ionomer partially neutralized with magnesium is preferred. The copolymer may be any of a block copolymer, a random copolymer, and a graft copolymer, but in consideration of transparency, a binary random copolymer, a ternary random copolymer, a binary It is preferable to use a graft copolymer of a random copolymer or a graft copolymer of a ternary random copolymer, more preferably a binary random copolymer or a ternary random copolymer.

Among the ionomer resins, a preferable magnesium ionomer is based on a copolymer of ethylene and (meth) acrylic acid synthesized by a high-pressure radical polymerization method, and the copolymerization ratio of the (meth) acrylic acid is 10% by mass. In the range of more than 30% by mass and neutralized with magnesium ions. The degree of neutralization with magnesium ions is in the range of more than 0% to 60%, and in this range, extensibility and severability are excellent. The degree of neutralization is preferably in the range of 10% or more and 60% or less, and transparency is excellent in this range. Furthermore, the preferable neutralization degree is in the range of 10% to 40%, and within this range, the balance of expandability, splitting property and transparency is excellent.
Among them, the copolymerization ratio of (meth) acrylic acid in the magnesium ionomer exceeds 10% by mass in terms of excellent balance of expandability, molding processability, fragmentability, and transparency, and is easily available industrially. 20 mass% or less is more preferable.

The zinc ionomer includes at least ethylene / (meth) acrylic acid copolymer, ethylene / (meth) acrylic acid alkyl ester copolymer, or ethylene / (meth) acrylic acid / (meth) acrylic acid alkyl ester copolymer. Zinc ionomers partially neutralized with zinc are preferred. The copolymer may be any of a block copolymer, a random copolymer, or a graft copolymer as in the case of the magnesium ionomer. However, in consideration of transparency, the copolymer is a binary random copolymer or a ternary random copolymer. A copolymer, a graft copolymer of a binary random copolymer, or a graft copolymer of a ternary random copolymer is preferable, and a binary random copolymer or a ternary random copolymer is more preferable.

A suitable zinc ionomer is based on a copolymer of ethylene and (meth) acrylic acid synthesized by a high-pressure radical polymerization method, and the copolymerization ratio of the (meth) acrylic acid exceeds 10% by mass and is 30% by mass. The following range was neutralized with zinc ions. The degree of neutralization with zinc ions is in the range of more than 0% to 60%, and in this range, extensibility and severability are excellent. The degree of neutralization is preferably in the range of 10% or more and 60% or less, and transparency is excellent in this range. Furthermore, the preferable neutralization degree is in the range of 10% or more and 40% or less.
Among them, the copolymerization ratio of (meth) acrylic acid in the zinc ionomer exceeds 10% by mass in terms of excellent balance of expandability, molding processability, fragmentability, and transparency, and is easily available industrially. 20 mass% or less is more preferable.

The ethylene / (meth) acrylic acid copolymer constituting the ionomer is a copolymer in which at least ethylene and acrylic acid or methacrylic acid are copolymerized, and further a ternary or more in which a third copolymerization component is copolymerized. It may be a multi-component copolymer.

In addition to ethylene and the (meth) acrylic acid copolymerizable with ethylene, the third copolymerization component includes unsaturated carboxylic acid esters (for example, methyl acrylate, (Meth) acrylic acid alkyl esters such as ethyl acrylate, isobutyl acrylate, n-butyl acrylate, isooctyl acrylate, methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, dimethyl maleate, diethyl maleate), vinyl esters (Eg, vinyl acetate, vinyl propionate, etc.), unsaturated hydrocarbons (eg, propylene, butene, 1,3-butadiene, pentene, 1,3-pentadiene, 1-hexene, etc.), vinyl sulfuric acid, vinyl nitric acid, etc. Oxides, halogen compounds (eg, vinyl chloride, vinyl fluoride) Le), vinyl group-containing 1,2 amine compounds, carbon monoxide, may be sulfur dioxide and the like have been copolymerized.
Among these, as the third copolymer component, an unsaturated carboxylic acid ester is preferable, and a (meth) acrylic acid alkyl ester (preferably having 1 to 4 carbon atoms in the alkyl moiety) is more preferable.

The content ratio of the structural unit derived from the third copolymer component in the ethylene / (meth) acrylic acid copolymer is preferably less than 7% by mass.
The ionomer resin in the present invention may contain an unsaturated carboxylic acid ester, but the content ratio of the constituent unit derived from the (meth) acrylic acid alkyl ester in the copolymer is preferably less than 7% by mass. When the content ratio of the structural unit derived from the (meth) acrylic acid alkyl ester is less than 7% by mass, the stress of the dicing film is maintained, so that more excellent fragmentation can be obtained. The content ratio of the structural unit derived from the (meth) acrylic acid alkyl ester is preferably 5% by mass or less, and does not have the structural unit derived from the (meth) acrylic acid alkyl ester (content ratio: zero% [mass ratio ]) Is more preferable.

~ B. Multi-layer configuration
Next, a case where the base material has a multilayer structure will be described.
As shown in FIG. 2, the base material 11 has a multilayer structure in which a layer 11X, a layer 11Y (first layer Y), and a layer 11Z (second layer Z) in contact with the adhesive layer 12 are stacked at least in this order, And a multilayer structure composed of three or more layers selected from a multilayer structure in which the layer X, the layer 11Z (second layer Z), and the layer 11Y (first layer Y) in contact with the adhesive layer 12 are stacked at least in this order. It can be provided and configured.

As shown in FIG. 2, the base material 11 can constitute a stealth dicing film by bringing it into contact with an adhesive layer 12 for fixing the wafer on one side thereof. In the case of a stealth dicing film, the adhesive layer 12 is in close contact with the “layer 11X in contact with the adhesive layer” in the multilayer structure of the substrate 11, as shown in FIG. Therefore, the layer 11X in contact with the adhesive layer is provided so as to be positioned on the surface layer (outermost layer) of the multilayer structure.

When the substrate 11 has a multilayer structure in which the layer X in contact with the adhesive layer, the first layer Y, and the second layer Z are arranged in this order, the first layer Y forms a three-layer structure. Make an intermediate layer. In addition to the three layers of the layer X, the first layer Y, and the second layer Z that are in contact with the adhesive layer, the multilayer structure is formed between the layer X and the first layer Y that is in contact with the adhesive layer or the first layer Y. Another layer on the second layer Z, which is one end of the three-layer structure of the layer X / the first layer Y / the second layer Z between the layer Y and the second layer Z or in contact with the adhesive layer May be provided to form a multilayer structure of four or more layers.

Moreover, as for the base material 11, the 1st layer Y and the 2nd layer Z are reverse as another aspect of the multilayer structure which has the layer X which touches the adhesion layer, the 1st layer Y, and the 2nd layer Z. The layer X, the second layer Z, and the first layer Y, which are disposed in contact with the adhesive layer, may be configured in a multilayer structure in this order. In this case, the second layer Z forms an intermediate layer forming a three-layer structure. In the case of this multi-layer structure, as in the case of the above-described structure, the layer X between the layer X and the second layer Z in contact with the adhesive layer, the second layer Z and the first layer Y, or the layer X in contact with the adhesive layer. On the first layer Y that is one end of the three-layer structure of / second layer Z / first layer Y, another layer may be provided to form a multilayer structure of four or more layers.

[Layer X in contact with adhesive layer]
The layer X in contact with the adhesive layer is a layer that is in close contact with the adhesive layer 12 made of, for example, an adhesive for fixing the wafer as shown in FIG. 2, and at least a resin (“resin A” in the present specification). (Also called). As an adhesion method, a method of directly applying an adhesive to the layer X surface using a known method such as a gravure roll coater, reverse roll coater, kiss roll coater, dip roll coater, bar coater, knife coater, spray coater, etc. Alternatively, it is possible to use a method in which a pressure-sensitive adhesive is coated on the release sheet by the above-mentioned known method to provide a pressure-sensitive adhesive layer, which is then adhered to the layer X, and the pressure-sensitive adhesive layer is transferred. As the resin A of the layer X, a resin having polarity and compatibility with the pressure-sensitive adhesive of the pressure-sensitive adhesive layer 12 that is suitably configured for ultraviolet curing is preferably used. As described later, the adhesive layer 12 is preferably an ultraviolet curable layer. In such a case, the adhesive layer 12 can be preferably configured using a resin capable of maintaining an ultraviolet curable composition and good adhesion.

The layer X in contact with the adhesive layer contains the resin A. The flexural modulus of the resin A is preferably in the range of 100 MPa to 350 MPa. The bending rigidity of the resin A being within the above range indicates that it is suitable for processing by stealth dicing (partition processing, particularly maintenance of initial stress). Among them, the bending rigidity of the resin A is more preferably 150 MPa or more and 350 MPa or less, and further preferably 180 MPa or more and 350 MPa or less in terms of wafer dividing property.

The resin A contained in the layer X in contact with the adhesive layer is preferably a thermoplastic resin, more preferably an olefin polymer, for example, an ethylene / unsaturated carboxylic acid system containing ethylene and an unsaturated carboxylic acid as a copolymerization component. It is a copolymer. Among these, an ionomer of a binary copolymer (ethylene / unsaturated carboxylic acid binary copolymer) obtained by copolymerizing ethylene and an unsaturated carboxylic acid is preferably used. By using an ionomer of an ethylene / unsaturated carboxylic acid binary copolymer, it is excellent in transparency (haze and total light transmittance) and fragmentability.

In the ethylene / unsaturated carboxylic acid binary copolymer serving as the base polymer of the ionomer, the content of the structural unit derived from the unsaturated carboxylic acid is preferably in the range of 1% by mass to 35% by mass, and preferably 5% by mass. The range of 25% by mass or less is more preferable, and the range of 10% by mass or more and 20% by mass or less is particularly preferable. When the content ratio of the structural unit derived from the unsaturated carboxylic acid is 1% by mass or more, this means that the structural unit is positively contained, and transparency and adhesion are improved due to the inclusion of the unsaturated carboxylic acid. Become. Practical heat resistance is maintained by the content rate of the structural unit guide | induced from unsaturated carboxylic acid being 35 mass% or less.
Moreover, as a content rate of the structural unit guide | induced from ethylene, the range of 99 to 65 mass% is preferable, More preferably, it is the range of 90 to 80 mass%.

Examples of the unsaturated carboxylic acid constituting the ethylene / unsaturated carboxylic acid binary copolymer include acrylic acid, methacrylic acid, maleic acid, fumaric acid, maleic anhydride, maleic acid monoester, and the like. Acrylic acid or methacrylic acid is preferred.

Examples of metal ions that neutralize the carboxyl group in the binary copolymer that is the base polymer of the ionomer include alkali metal ions such as lithium ions, sodium ions, and potassium ions; magnesium ions, calcium ions, zinc ions, and aluminum. And ions of polyvalent metals such as ions.
Among these, magnesium ion or zinc ion is more preferable. These metal ions may be used alone or in combination of two or more. The ionomer is neutralized by the metal ions in the range of 100% or less of the carboxyl group in the binary copolymer, and the degree of neutralization is preferably 90% or less, more preferably in the range of 20% or more and 85% or less. is there.

As the magnesium ionomer, a magnesium ionomer in which at least a part of the ethylene / (meth) acrylic acid copolymer is neutralized with magnesium is preferable. The copolymer may be any of a block copolymer, a random copolymer, or a graft copolymer, but a binary random copolymer is preferable in consideration of transparency.

Among the ionomer resins, a preferable magnesium ionomer is based on a copolymer of ethylene and (meth) acrylic acid synthesized by a high-pressure radical polymerization method, and the copolymerization ratio of the (meth) acrylic acid is 10% by mass. In the range of more than 30% by mass and neutralized with magnesium ions. The degree of neutralization with magnesium ions is in the range of more than 0% to 60%, and in this range, extensibility and severability are excellent. The degree of neutralization is preferably in the range of 10% or more and 60% or less, and transparency is excellent in this range. Furthermore, the preferable neutralization degree is in the range of 10% or more and 40% or less.
Among them, the copolymerization ratio of (meth) acrylic acid in the magnesium ionomer exceeds 10% by mass in terms of excellent balance of expandability, molding processability, fragmentability, and transparency, and is easily available industrially. 20 mass% or less is more preferable.

As the zinc ionomer, a zinc ionomer in which at least a part of the ethylene / (meth) acrylic acid copolymer is neutralized with zinc is preferable. The copolymer may be any of a block copolymer, a random copolymer, or a graft copolymer as in the case of the magnesium ionomer, but a binary random copolymer is preferable in consideration of transparency.

A suitable zinc ionomer is based on a copolymer of ethylene and (meth) acrylic acid synthesized by a high-pressure radical polymerization method, and the copolymerization ratio of the (meth) acrylic acid exceeds 10% by mass and is 30% by mass. The following range was neutralized with zinc ions. The degree of neutralization with zinc ions is in the range of more than 0% to 90%, and in this range, extensibility and severability are excellent. The degree of neutralization is preferably in the range of 10% or more and 90% or less, and transparency is excellent in this range.
Among them, the copolymerization ratio of (meth) acrylic acid in the zinc ionomer exceeds 10% by mass in terms of excellent balance of expandability, molding processability, fragmentability, and transparency, and is easily available industrially. 20 mass% or less is more preferable.

As the ionomer forming the layer X in contact with the adhesive layer, an ethylene / acrylic acid copolymer magnesium (Mg) ionomer or zinc (Zn) ionomer, and an ethylene / methacrylic acid copolymer are available from the viewpoint of availability. Of these, magnesium (Mg) ionomer or zinc (Zn) ionomer is preferred.

The thickness of the layer X in contact with the adhesive layer is preferably in the range of 10 μm to 100 μm. That this thickness is in the above range indicates that it is suitable for processing by stealth dicing (parting processing, particularly maintaining initial stress). The preferred thickness of the layer X in contact with the adhesive layer is 15 μm or more and 80 μm or less.

The ratio of the thickness of the layer X in contact with the adhesive layer in the stealth dicing film base material is preferably 10% or more of the total thickness of the film base material from the viewpoint of stable production as a film base material. The ratio of the thickness of the first layer Y is preferably 20% or more of the total thickness of the film substrate from the viewpoint of balancing the splitting property and expandability.

[First layer Y]
The layer 11Y (first layer Y) constituting the multilayer structure of the substrate 11 is an intermediate layer (FIG. 2) provided between the layer X in contact with the adhesive layer and a layer 11Z (second layer Z) described later. 11Y) or an inner layer (reference numeral 11Y in FIG. 2) provided via the layer 11Z (second layer Z) with respect to the layer X in contact with the adhesive layer.

The first layer Y includes a resin B. The flexural rigidity of the resin B is preferably in the range of 5 MPa to 350 MPa. The bending rigidity of the resin B being within the above range indicates that it is suitable for processing by stealth dicing (parting processing, particularly maintaining initial stress). Especially, the bending rigidity rate of resin B is more preferably 5 MPa or more and 330 MPa or less, and more preferably 10 MPa or more and 270 MPa or less in terms of expandability.

The resin B contained in the first layer Y is preferably a thermoplastic resin, such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and ethylene. Vinyl acetate copolymer, ethylene / unsaturated carboxylic acid binary copolymer and its ionomer, ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester ternary copolymer and its ionomer, ethylene / unsaturated carboxylic acid ester 2 An original copolymer or the like is preferably used.

Among the examples of the resin B, an ethylene / unsaturated carboxylic acid binary copolymer and its ionomer, and an ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester ternary copolymer and its ionomer are unsaturated carboxylic acid. The content ratio of the structural unit derived from is preferably in the range of 1% by mass to 35% by mass, more preferably in the range of 5% by mass to 25% by mass, and particularly preferably in the range of 10% by mass to 20% by mass. Range. When the content ratio of the structural unit derived from the unsaturated carboxylic acid is 1% by mass or more, this means that the structural unit is positively contained, and transparency and metal adhesion are good due to the inclusion of the unsaturated carboxylic acid. become. Practical heat resistance is maintained by the content rate of the structural unit guide | induced from unsaturated carboxylic acid being 35 mass% or less.
Moreover, as a content rate of the structural unit guide | induced from ethylene, the range of 99 to 65 mass% is preferable, More preferably, it is the range of 90 to 80 mass%.

Examples of the unsaturated carboxylic acid constituting the binary copolymer or the ternary copolymer include acrylic acid, methacrylic acid, maleic acid, fumaric acid, maleic anhydride, maleic acid monoester, and the like. In particular, acrylic acid or methacrylic acid is preferable.

Examples of the unsaturated carboxylic acid ester constituting the terpolymer include, for example, methyl acrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, isooctyl acrylate, methyl methacrylate, ethyl methacrylate, methacrylic acid Examples include (meth) acrylic acid alkyl esters such as isobutyl acid, dimethyl maleate, and diethyl maleate. Of these, (meth) acrylic acid alkyl ester (the alkyl moiety preferably has 1 to 4 carbon atoms) is more preferable.

As the metal ion for neutralizing the carboxyl group in the binary copolymer or ternary copolymer serving as the ionomer base polymer, magnesium, zinc, sodium, potassium and the like are preferable, and among these, magnesium and zinc are more preferable. The ionomer is neutralized by the metal ions in the range of 100% or less of the carboxyl group in the binary copolymer, and the neutralization degree is preferably 90% or less, more preferably 20% or more and 85% or less. is there.

The magnesium ionomer includes at least ethylene / (meth) acrylic acid copolymer, ethylene / (meth) acrylic acid alkyl ester copolymer, or ethylene / (meth) acrylic acid / (meth) acrylic acid alkyl ester copolymer. A magnesium ionomer partially neutralized with magnesium is preferred. The copolymer may be any of a block copolymer, a random copolymer, or a graft copolymer, but in consideration of transparency, a binary random copolymer, a ternary random copolymer, It is preferable to use a graft copolymer of an original random copolymer or a graft copolymer of a ternary random copolymer, more preferably a binary random copolymer or a ternary random copolymer.

A suitable zinc ionomer is based on a copolymer of ethylene and (meth) acrylic acid synthesized by a high-pressure radical polymerization method, and the copolymerization ratio of the (meth) acrylic acid exceeds 10% by mass and is 30% by mass. The following range was neutralized with zinc ions. The degree of neutralization with zinc ions is in the range of more than 0% to 90%, and in this range, extensibility and splitting are excellent. The degree of neutralization is preferably in the range of 10% or more and 90% or less, and transparency is excellent in this range.
Among them, the copolymerization ratio of (meth) acrylic acid in the zinc ionomer exceeds 10% by mass in terms of excellent balance of expandability, molding processability, fragmentability, and transparency, and is easily available industrially. 20 mass% or less is more preferable.

Among the examples of the resin B, the ethylene / unsaturated carboxylic acid ester copolymer is preferably an ethylene / (meth) acrylic acid alkyl ester copolymer.
Examples of the (meth) acrylic acid alkyl ester constituting the ethylene / (meth) acrylic acid alkyl ester copolymer include, for example, methyl acrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, isooctyl acrylate, methacrylic acid. Preferable examples include methyl acid, ethyl methacrylate, isobutyl methacrylate, dimethyl maleate, and diethyl maleate.

In the present invention, one of the preferred embodiments is an embodiment in which the first layer Y is provided as an intermediate layer disposed between the layer X in contact with the adhesive layer and the second layer Z. Another preferred embodiment is an embodiment in which the second layer Z is provided as an intermediate layer disposed between the layer X in contact with the adhesive layer and the first layer Y.
When the first layer Y is provided as an intermediate layer disposed between the layer X and the second layer Z in contact with the adhesive layer constituting the multilayer structure, the layer X and the second layer Z in contact with the adhesive layer The resin B contained in the first layer Y is, for example, a low layer from the viewpoint of reducing the stress (particularly the initial stress) as a film base material and providing an expansion function. Low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), ethylene vinyl acetate copolymer, ethylene / unsaturated carboxylic acid binary copolymer and its ionomer, and Ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid terpolymers and their ionomers are preferred.
Further, when the second layer Z is provided as an intermediate layer disposed between the layer X and the first layer Y in contact with the adhesive layer, the stress (particularly the initial stress) as the film substrate is relieved, The resin C contained in the second layer Z is, for example, a low-density polyethylene (low-density polyethylene) from the viewpoint of providing an expansion function and providing sliding properties with the expansion stage that contacts the layer Y during expansion and blocking resistance. density polyethylene (LDPE), linear low-density polyethylene (LLDPE), ethylene / unsaturated carboxylic acid binary copolymer and its ionomer, and ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester Ternary copolymers and their ionomers are preferred.

The thickness of the first layer Y is preferably in the range of 10 μm to 100 μm. That this thickness is in the above range indicates that it is suitable for processing by stealth dicing (parting processing, particularly maintaining initial stress). A preferable thickness of the first layer Y is 15 μm or more and 80 μm or less.

The ratio of the thickness of the first layer Y in the film substrate for stealth dicing is preferably 10% or more of the thickness of the entire film substrate from the viewpoint of stable production as a film substrate. The ratio of the thickness of the first layer Y is preferably 20% or more of the total thickness of the film substrate from the viewpoint of balancing the splitting property and expandability.

[Second layer Z]
The layer 11Z (second layer Z) constituting the multi-layer structure of the substrate 11 is an inner layer (reference numeral in FIG. 2) provided via the layer 11Y (first layer Y) with respect to the layer X in contact with the adhesive layer. 11Z) or as an intermediate layer (reference numeral 11Z in FIG. 2) provided between the layer X in contact with the adhesive layer and the layer 11Y (first layer Y).

The second layer Z includes a resin C. The bending rigidity of the resin C is preferably in the range of 50 MPa to 350 MPa. The bending rigidity of the resin C being within the above range indicates that it is suitable for processing by stealth dicing (parting processing, particularly maintaining initial stress). Among these, the flexural rigidity of the resin C is more preferably 50 MPa or more and 330 MPa or less, and further preferably 70 MPa or more and 330 MPa or less in terms of wafer parting properties.

The resin C contained in the second layer Z is preferably a thermoplastic resin, for example, an ethylene / unsaturated carboxylic acid binary copolymer and its ionomer, and an ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester ternary. A copolymer and its ionomer are preferably used.

Among the examples of the resin C, an ethylene / unsaturated carboxylic acid binary copolymer and its ionomer, and an ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester ternary copolymer and its ionomer are unsaturated carboxylic acid. The content ratio of the structural unit derived from is preferably in the range of 1% by mass to 35% by mass, and more preferably in the range of 5% by mass to 20% by mass. When the content ratio of the structural unit derived from the unsaturated carboxylic acid is 1% by mass or more, this means that the structural unit is positively contained, and transparency and metal adhesion are good due to the inclusion of the unsaturated carboxylic acid. become. Practical heat resistance is maintained by the content rate of the structural unit guide | induced from unsaturated carboxylic acid being 35 mass% or less.
Further, the content ratio of the structural unit derived from ethylene is preferably in the range of 99% by mass to 65% by mass, and more preferably in the range of 95% by mass to 80% by mass.

The details of the unsaturated carboxylic acid constituting the binary copolymer or the ternary copolymer and the unsaturated carboxylic acid ester constituting the ternary copolymer are as follows. It is synonymous with the unsaturated carboxylic acid and unsaturated carboxylic acid ester which comprise a binary copolymer or a ternary copolymer, and its preferable aspect is also the same.

Examples of metal ions that neutralize the carboxyl group in the binary copolymer that is the base polymer of the ionomer include alkali metal ions such as lithium ions, sodium ions, and potassium ions; magnesium ions, calcium ions, zinc ions, and aluminum. Examples include ions of polyvalent metals such as ions.
Among these, magnesium ion or zinc ion is more preferable. These metal ions may be used alone or in combination of two or more. The ionomer is neutralized by the metal ions in the range of 100% or less of the carboxyl group in the binary copolymer, and the degree of neutralization is preferably 90% or less, more preferably in the range of 20% or more and 85% or less. is there.

Among the above, magnesium ionomer includes ethylene / (meth) acrylic acid copolymer, ethylene / (meth) acrylic acid alkyl ester copolymer, or ethylene / (meth) acrylic acid / (meth) acrylic acid alkyl ester copolymer. A magnesium ionomer in which at least a part of the polymer is neutralized with magnesium is preferred.
The zinc ionomer includes at least ethylene / (meth) acrylic acid copolymer, ethylene / (meth) acrylic acid alkyl ester copolymer, or ethylene / (meth) acrylic acid / (meth) acrylic acid alkyl ester copolymer. Zinc ionomers partially neutralized with zinc are preferred.
The details of these magnesium ionomer and zinc ionomer are the same as the magnesium ionomer and zinc ionomer described in the section of the first layer Y described above, and the preferred embodiments are also the same.

The thickness of the second layer Z is preferably in the range of 10 μm to 100 μm. That this thickness is in the above range indicates that it is suitable for processing by stealth dicing (parting processing, particularly maintaining initial stress). A preferred thickness of the second layer Z is not less than 15 μm and not more than 80 μm.

The ratio of the thickness of the second layer Z in the stealth dicing film base material is preferably 10% or more of the thickness of the entire film base material from the viewpoint of stable production as a film base material. The ratio of the thickness of the second layer Z is preferably 20% or more of the total thickness of the film base material from the viewpoint of balancing the splitting property and the expandability.

In the present invention, the bending rigidity of the resin B included in the layer Y is subtracted from the bending rigidity of the resin A included in the layer X in contact with the adhesive layer or the bending rigidity of the resin C included in the layer Z. The larger value of the absolute value of the difference (| the bending rigidity of resin A−the bending rigidity of resin B | or | the bending rigidity of resin C−the bending rigidity of resin B |) is 50 MPa or more and 345 MPa or less. It is preferable to be within the range. The symbol “||” represents an absolute value.
When the value is 50 MPa or more, the wafer cutting property is excellent even when the strength of X is low, and the extensibility is excellent even when the strength of X is high. Further, when the value is 345 MPa or less, it is advantageous in that the strength (flexural rigidity) of the layer X in contact with the adhesive layer can be relaxed to a good degree of separation.
Among these, for the same reason as described above, it is more preferable that the value having the larger absolute value of the difference is in the range of 50 MPa to 330 MPa.

The film base material for stealth dicing of the present invention is superior in terms of the ability to divide the wafer by stealth dicing, and the thickness of the layer X in contact with the adhesive layer is 15 μm or more and 80 μm or less, and the thickness of the layer Y is 15 μm or more and 80 μm or less. And the thickness of the layer Z is preferably 15 μm or more and 80 μm or less.

The film substrate for stealth dicing according to the present invention includes a multilayer structure in which the layer X, the first layer Y, and the second layer Z in contact with the adhesive layer are sequentially stacked, or the layer X and the second layer in contact with the adhesive layer. Z and the first layer Y are sequentially laminated, the layer X in contact with the adhesive layer contains the resin A, the bending rigidity of the resin A is 180 MPa or more and 350 MPa or less, the first A mode in which the layer Y includes the resin B, the bending rigidity of the resin B is 10 MPa or more and 270 MPa or less, the second layer Z includes the resin C, and the bending rigidity of the resin C is 70 MPa or more and 330 MPa or less. Is preferred.
Furthermore, the film substrate for stealth dicing of the present invention includes a multilayer structure in which a layer X in contact with the adhesive layer, a first layer Y, and a second layer Z are sequentially stacked, and the layer X in contact with the adhesive layer The resin A included is an ethylene / acrylic acid copolymer Zn ionomer or Mg ionomer, an ethylene / methacrylic acid copolymer Zn ionomer or Mg ionomer, and the resin B included in the first layer Y is a low density polyethylene. (Low-density polyethylene (LDPE)), linear low-density polyethylene (LLDPE), ethylene vinyl acetate copolymer, ethylene / (meth) acrylic acid binary copolymer and its Zn ionomer, ethylene・ (Meth) acrylic acid ・ (Meth) acrylic acid (preferably having 1 to 4 carbon atoms) alkyl ester terpolymer and its Zn Resin C contained in the second layer Z, which is an ionomer, is an ethylene / (meth) acrylic acid binary copolymer, its Zn ionomer and Mg ionomer, and ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester 3 The embodiment which is an original copolymer and its ionomer is preferable.

Ratio of layer thickness (μm) of layer X, second layer Z (or layer Y) and first layer Y (or layer Z) in contact with the adhesive layer constituting the stealth dicing film substrate (X / Z) / Y (or X / Y / Z)), the ratio of layer X is 10% or more and 80% or less, the ratio of layer Y is 10% or more and 70% or less, and the ratio of layer Z is 10% or more. It is preferable that it is 80% or less. The ratio of each layer thickness is selected so that the total is 100%. The ratio [%] is obtained from “thickness of each layer / total thickness × 100”.

~ Physical properties ~
The haze of the film substrate for stealth dicing according to the present invention is preferably as small as possible so as not to impede the transmission of laser light in terms of enhancing the splitting property. Specifically, the haze is 10 or less. A haze of 10 or less indicates that the haze has transparency suitable for processing by stealth dicing using laser light. Among them, the haze is preferably 9.0 or less, and more preferably 8.0 or less.
The haze is a value measured according to JIS K 7136 using a haze meter.

In addition, the total light transmittance of the film substrate for stealth dicing of the present invention is 90% or more from the viewpoint of improving the irradiation position accuracy using the camera in the stealth dicing process. A total light transmittance of 90% or more indicates that the light transmittance suitable for processing by stealth dicing using laser light is provided. The total light transmittance is a value measured according to JIS K 7361 using HM-150 type (manufactured by Murakami Color Research Co., Ltd.) in an atmosphere of 23 ° C. and 50% relative humidity.

The initial stress of the film substrate for stealth dicing of the present invention is in the range of 9 MPa to 19 MPa, and the preferred lower limit is in the range exceeding 10 MPa. Furthermore, the initial stress is more preferably 10 MPa or more and less than 17 MPa. If the initial stress is less than 9 MPa, the external stress when the wafer is divided cannot be maintained, and the wafer cannot be divided satisfactorily. On the other hand, when the initial stress exceeds 19 MPa, the expansion rate is deteriorated, and it is inferior in severability such as being unable to sever uniformly.
The initial stress in the present invention is based on JIS K 7127, and the test speed: 500 mm / s, test piece: width 10 mm × length 200 mm, and chuck interval: 100 mm for the MD direction and the TD direction of the film substrate for stealth dicing. Under the conditions, it is obtained as the stress measured when the specimen is stretched by 6%, and is evaluated by the average of the measured values of MD and TD.

The expansion rate of the film substrate for stealth dicing according to the present invention is 102% or more and 120% or less, preferably 104% or more and 120% or less, and more preferably 104% or more and 110% or less. If the expansion rate is less than the lower limit (102%) of the above range, the external stress at the time of dividing the wafer cannot be maintained, and the wafer cannot be divided well. A film substrate for stealth dicing whose expansion rate exceeds the upper limit (120%) of the above range cannot actually exist in the range of the initial stress of 9 MPa to 19 MPa.
The expansion rate is a value measured by the following method.
That is, a rectangular sample piece having a longitudinal (MD) direction of 300 mm or more and a transverse (TD) direction of 300 mm or more is cut out from the produced stealth dicing film substrate. A measuring object 1 in which a 141 mm square is drawn on this sample piece with a writing instrument such as an oil-based pen is created. It is set in a wafer expansion device for inch wafers (a wafer expansion device TEX-218G GR-8 manufactured by Technovision). Next, the stage is pulled up by 15 mm, the film for stealth dicing is expanded, and then left still for 60 seconds, and the length (side length) of each side of the square of the measuring object 1 is measured. The elongation percentage (%; = side length after extension / side length before extension × 100) is calculated for each of the four obtained side lengths, and the average value is obtained.

The thickness of the substrate 11 is in the range of 50 μm to 200 μm. The total thickness of the base material being within the above range indicates that the base material is suitable for stealth dicing. Further, the thickness of the substrate is preferably 150 μm or less from the viewpoints of expandability and transparency, and is preferably 80 μm or more from the viewpoint of fragmentability.

Moreover, it is preferable that the base material 11 is what does not scatter the laser beam L, and it is preferable that the surface and the back surface are smooth. The surface 11 and the back surface of the substrate 11 preferably have a surface roughness Ra (calculated average roughness) of 1.0 μm or less.
The surface roughness (Ra) is a value measured according to JIS B 0601-2001 using an optical interference type non-contact type surface shape roughness measuring instrument.

The surface resistivity of the stealth dicing film substrate of the present invention is preferably 1.0 × 10 ⁹ Ω / sq or more and 1.0 × 10 ¹² Ω / sq or less from the viewpoint of antistatic performance. For adjusting the surface resistivity, for example, as disclosed in Japanese Patent No. 4,606,029, a method of adding an antistatic agent containing a polyetherester component or an ion conductive compound is added in advance to a film substrate for stealth dicing. It can carry out using well-known methods, such as the method of doing.
The surface resistivity is a value measured with an applied voltage of 500 V using a Hiresta-UP (manufactured by Mitsubishi Chemical Corporation) at a test temperature of 23 ° C. and a relative humidity of 50%.

The film substrate for stealth dicing of the present invention preferably contains an antistatic agent containing a polyether ester component. The melting point of the antistatic agent is preferably 155 ° C. or higher and 185 ° C. or lower, more preferably 160 ° C. or higher and 185 ° C. or lower, and particularly preferably 160 ° C. or higher and 180 ° C. or lower. By including such an antistatic agent, the antistatic property can be enhanced without impairing the transparency of the film substrate. When the melting point of the antistatic agent is within the above range, the transparency of the ionomer resin (particularly, zinc ionomer or magnesium ionomer) when containing the antistatic agent can be maintained high.

The melting point is obtained from the peak waveform that appears by measuring the difference in the calorific value between the measurement sample and the reference material by differential scanning calorimetry (DSC).

Examples of the antistatic agent include a low molecular weight antistatic agent and a high molecular weight antistatic agent, and a high molecular weight antistatic agent is preferable, and the high molecular weight antistatic agent includes a sulfonate in the molecule. Examples thereof include vinyl copolymers, alkyl sulfonates, alkyl benzene sulfonates, and betaines. Further, mention may be made of inorganic protonic acid salts of polyether, polyamide elastomer, polyester elastomer, polyether amide or polyether ester amide. Examples of the salt of the inorganic proton acid include alkali metal salts, alkaline earth metals, zinc salts, and ammonium salts.

Examples of the polyether ester amide include a block copolymer composed of a polyamide block and a polyoxyalkylene glycol block, and these blocks are ester-bonded.
Polyamide blocks in the polyether ester amide include, for example, dicarboxylic acid (eg, succinic acid, succinic acid, adipic acid, sebacic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, 1,4-cyclohexanedicarboxylic acid, etc.) and diamine ( Examples: ethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, decamethylenediamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 1,3-bis (aminomethyl) ) Cyclohexane, 1,4-bis (aminomethyl) cyclohexane, methylenebis (4-aminocyclohexane), m-xylylenediamine, p-xylylenediamine, etc.), ε-caprolactam, ω-dodecalactam, etc. Lactam It can be obtained by ring-opening polymerization, polycondensation of aminocarboxylic acids such as 6-aminocaproic acid, 9-aminononanoic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, or copolymerization of the lactam, dicarboxylic acid and diamine. Is. Such polyamide segments are nylon 4, nylon 6, nylon 46, nylon 66, nylon 610, nylon 612, nylon 6T, nylon 11, nylon 12, nylon 6/66, nylon 6/12, nylon 6/610, nylon 66/12, nylon 6/66/610, and nylon 11 and nylon 12 are particularly preferable. The molecular weight of the polyamide block is, for example, about 400 to 5000.
Examples of the polyether block include polyoxyethylene glycol, polyoxypropylene glycol, polyoxytetramethylene glycol, polyoxyalkylene glycols such as polyoxyethylene / polyoxypropylene glycol, and mixtures thereof. These molecular weights are preferably about 400 to 6000, and more preferably about 600 to 5000.

Commercially available products may be used as the antistatic agent. Specific examples include irgastat P-16, P-18, P-20, and P-22 manufactured by BASF Japan, Sanyo. Examples include Pelestat 230, Pelestat HC250, Pelestat 300, Pelestat 2450, Peletron PVH, and ENTILA MK400, MK440, SD100 manufactured by Mitsui DuPont Polychemical Co., Ltd.

The antistatic agent can be melt-mixed in a predetermined amount in the thermoplastic resin, or dry blended with an antistatic agent, and melt-mixed.

The antistatic agent may be contained in any of the layer X, the layer Y, and the layer Z constituting the film base material, or may be contained in all the layers of the layer X, the layer Y, and the layer Z. When the ultraviolet absorber is contained, it can be carried out by the above-described method such as a method of kneading the ultraviolet absorber.
When the antistatic agent is contained, the content of the antistatic agent in the film base material is preferably more than 10% by mass, more preferably 30% by mass, and more than 10% by mass to 20% by mass with respect to the ionomer resin. % Is more preferable. When the content of the antistatic agent exceeds 10% by mass, the antistatic effect of the film substrate is excellent. The transparency of a film base material is maintained because content of an antistatic agent is 30 mass% or less. By adjusting the content of the antistatic agent in the above range, the surface resistivity of the film substrate is suitably adjusted to a range of 1.0 × 10 ⁹ Ω / sq to 1.0 × 10 ¹² Ω / sq. Can do.

The stealth dicing film substrate of the present invention may further contain various other additives in addition to the above components. Examples of such additives include antioxidants, heat stabilizers, light stabilizers, UV absorbers, lubricants, antiblocking agents, rust inhibitors, antibacterial agents, flame retardants, flame retardant aids, crosslinking materials, and crosslinking agents. An auxiliary agent etc. can be mentioned. Moreover, you may perform electron beam irradiation to the film base material for stealth dicing as needed.

As a method for producing a stealth dicing film base material, a conventionally known method such as a T-die cast molding method, a T-die nip molding method, an inflation molding method, an extrusion laminating method, or a calendar molding method can be used.

(Adhesive layer)
The adhesive layer 12 is not particularly limited, but is preferably an ultraviolet curable layer, and can be formed using, for example, an ultraviolet curable acrylic adhesive.

Specific examples of UV curable acrylic pressure-sensitive adhesives include (meth) acrylic monomers (meth) acrylic monomers such as (meth) acrylic acid and (meth) acrylic acid esters, the (meth) acrylic Copolymers of functional monomers and functional monomers (for example, polyacrylic esters such as polybutyl acrylate and 2-ethylhexyl polyacrylate), urethane acrylate oligomers, and mixtures of these polymers; An ultraviolet curable pressure-sensitive adhesive containing at least a photopolymerization initiator can be mentioned.
The average molecular weight of the polymer is preferably a high molecular weight of about 500,000 to 1,000,000. The average molecular weight refers to the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

Examples of the (meth) acrylic acid ester include trimethylolpropane tri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, and dipentaerythritol mono. Hydroxypenta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,4-butylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, polyethylene glycol di (meth) acrylate, oligoester (Meth) acrylate etc. are mentioned.

The urethane acrylate oligomer is an ultraviolet polymerizable compound having at least two carbon-carbon unsaturated double bonds. For example, a polyol compound such as a polyester type or a polyether type and a polyvalent isocyanate compound (for example, 2, 4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, diphenylmethane 4,4-diisocyanate, etc.) The terminal isocyanate urethane prepolymer to be used is an acrylate or methacrylate having a hydroxyl group (for example, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate). DOO, polyethylene glycol acrylate, those obtained by reacting a polyethylene glycol methacrylate).

Examples of the photopolymerization initiator include isopropyl benzoin ether, isobutyl benzine ether, benzophenone, Michler's ketone, chlorothioxanthone, dodecyl thioxanthone, dimethyl thioxanthone, diethyl thioxanthone, benzyl dimethyl ketal, α-hydroxycyclohexyl phenyl ketone, 2-hydroxymethyl phenyl Examples include propane. A photoinitiator can be used individually or in combination of 2 or more types. By adding a photopolymerization initiator to the adhesive layer, the curing reaction can be efficiently advanced while suppressing the curing reaction time or radiation dose.

Moreover, it is preferable that the adhesive layer also has high transparency like the base material described above.
As the light transmittance of visible light in the adhesive layer, the light transmittance in the adhesive layer is preferably 90% or more in the entire wavelength region of visible light from 400 nm to 800 nm.
Furthermore, when visible light having a wavelength at which the light transmittance of the substrate is 90% or more is used, the light transmittance of the whole stealth dicing film is preferably 90% or more, and more preferably 400 nm to 800 nm. When light in the entire wavelength region is used, the light transmittance of the entire stealth dicing film is preferably 90% or more.
The light transmittance is a value measured using a spectrophotometer.

The thickness of the adhesive layer 12 is preferably 5 μm or more, and more preferably 10 μm or more.

The haze of the stealth dicing film of the present invention is preferably as small as possible so as not to impede the transmission of laser light in terms of increasing the fractionation rate. Specifically, the haze is preferably 10.0 or less, more preferably 9.0 or less, and still more preferably 8.0 or less. The method for measuring haze is as described above.
Further, it is desirable that no whitening phenomenon is observed in the whole or a part of the film after the film expansion.

The initial stress of the stealth dicing film of the present invention is preferably more than 9 MPa, more preferably 10 MPa or more and 19 MPa or less, and still more preferably 10 MPa or more and less than 17 MPa. When the initial stress is in the range exceeding 9 MPa, the external stress at the time of dividing the wafer is maintained, and the wafer can be divided satisfactorily. Moreover, it is advantageous in terms of expandability when the initial stress is 19 MPa or less. The method for measuring the initial stress is as described above (based on JIS K 7127).

The expansion rate of the stealth dicing film of the present invention is preferably 102% to 120%, more preferably 104% to 120%. When the expansion rate is equal to or greater than the lower limit of the above range, the external stress at the time of dividing the wafer is maintained, and the wafer can be divided well. When the expansion rate is less than or equal to the upper limit of the above range, the film is uniformly stretched, and expansion unevenness and film distortion can be suppressed. The method for measuring the expansion rate is as described above.

[Method of manufacturing electronic parts]
The manufacturing method of the electronic component using the film for stealth dicing of this invention is explained in full detail.
The method for manufacturing an electronic component of the present invention includes a step of attaching the above-described stealth dicing film of the present invention to the back surface of the wafer (film pasting step) A step (dicing step) of irradiating a laser beam from the dicing film side and stealth dicing the wafer with the laser beam through the stealth dicing film is provided. The method for manufacturing an electronic component of the present invention may be configured by further providing other steps as necessary.

As shown in FIG. 3A, the adhesive layer 12 of the stealth dicing film 1 is fixed to the back surface (surface opposite to the element forming surface) of the wafer W, and the stealth dicing film 1 is attached to the end of the adhesive layer 12. Is placed in contact with the dicing table 6 and fixed to the dicing table with the adhesive layer 12 (film sticking step).
Next, laser light is irradiated from the substrate 11 side of the dicing tape 1 and the laser light L is guided to the inside of the wafer W through the stealth dicing film 1, thereby along the dicing line inside the wafer W. Then, as shown in FIG. 3B, a reforming portion (modified region) W1 is formed. Thereafter, as shown in FIG. 4, the film is expanded by pulling the end of the stealth dicing film 1 in the direction of the arrow (dicing step). As a result, the wafer W is divided into a plurality of parts along the reforming portion W1 starting from the reforming portion W1.
Next, when the adhesive layer 12 of the stealth dicing film 1 is irradiated with ultraviolet rays, the adhesive layer 12 is solidified and the adhesive strength of the layer is reduced. Thereby, a plurality of wafers, that is, individual chips (electronic components) can be removed from the stealth dicing film 1, and a desired electronic component can be obtained.

As the laser, for example, a known laser such as an Nd: YAG laser, an Nd: YVO laser, an Nd: YLF laser, a titanium sapphire laser, a CO ₂ laser, or an argon ion laser that generates pulsed laser light is selected depending on the case. can do.

The method for manufacturing an electronic component according to the present invention is intended for a silicon wafer. For example, a compound semiconductor wafer such as a glass wafer, a silicon carbide wafer, a sapphire wafer, a gallium phosphide wafer, or a gallium arsenide wafer may be used. .

Hereinafter, the present invention will be described by way of examples, but the present invention is not limited to these examples. The ethylene unit content is the content ratio of structural units derived from ethylene, the methacrylic acid unit content is the content ratio of structural units derived from methacrylic acid, and the isobutyl acrylate unit content is the content of structural units derived from isobutyl acrylate. The ratio is shown respectively.

[A] Examples 1-27 and Comparative Examples 1-4
The composition and physical properties of raw materials used in Examples 1 to 27 and Comparative Examples 1 to 4 shown below, and methods for measuring the physical properties of the obtained films and sheets are as follows.

-1. raw materials-
(1) Ionomer (IO-1)
Base polymer: ethylene / methacrylic acid copolymer (ethylene unit content: 85% by mass, methacrylic acid unit content: 15% by mass)
Metal cation source: Magnesium Neutralization degree: 35%
MFR (190 ° C., 2160 g load): 5.9 g / 10 minutes (2) Ionomer (IO-2)
Base polymer: ethylene / methacrylic acid copolymer (ethylene unit content: 85% by mass, methacrylic acid unit content: 15% by mass)
Metal cation source: Magnesium Neutralization degree: 54%
MFR (190 ° C., 2160 g load): 0.7 g / 10 min (3) Ionomer (IO-3)
Base polymer: ethylene / methacrylic acid / isobutyl acrylate copolymer (ethylene unit content: 80 mass%, methacrylic acid unit content: 10 mass%, isobutyl acrylate unit content: 10 mass%)
Metal cation source: Zinc Neutralization degree: 70%
MFR (190 ° C., 2160 g load): 1.0 g / 10 min (4) Ionomer (IO-4)
Base polymer: ethylene / methacrylic acid copolymer (ethylene unit content: 89% by mass, methacrylic acid unit content: 11% by mass)
Metal cation source: Zinc Neutralization degree: 65%
MFR (190 ° C., 2160 g load): 5.0 g / 10 min (5) Ionomer (IO-5)
Base polymer: ethylene / methacrylic acid / isobutyl acrylate copolymer (ethylene unit content: 81% by weight, methacrylic acid unit content: 11.5% by weight, isobutyl acrylate unit content: 7.5% by weight)
Metal cation source: Magnesium Neutralization degree: 14%
MFR (190 ° C., 2160 g load): 5.9 g / 10 minutes (6) Ionomer (IO-6)
Base polymer: ethylene / methacrylic acid / isobutyl acrylate copolymer (ethylene unit content: 82 mass%, methacrylic acid unit content: 13 mass%, isobutyl acrylate unit content: 5 mass%)
Metal cation source: Magnesium Neutralization degree: 27%
MFR (190 ° C., 2160 g load): 5.9 g / 10 min (7) Ionomer (IO-7)
Base polymer: ethylene / methacrylic acid copolymer (ethylene unit content: 85% by mass, methacrylic acid unit content: 15% by mass)
Metal cation source: Zinc Neutralization degree: 59%
MFR (190 ° C., 2160 g load): 0.9 g / 10 min

(8) Ethylene / (meth) acrylic acid copolymer (EMAA)
Ethylene / methacrylic acid copolymer (ethylene unit content: 91% by mass, methacrylic acid unit content: 9% by mass)
MFR (190 ° C., 2160 g load): 3.0 g / 10 min

(9) Polyetherester component (B-1)
Product name: Irgastat P-16 (melting point (DSC measurement): 158 ° C., manufactured by BASF Japan Ltd., polyether ester amide block copolymer)
(10) Polyetherester component (B-2)
Product name: Irgastat P-18 (melting point (DSC measurement): 173 ° C., manufactured by BASF Japan Ltd., polyether ester amide block copolymer)
(11) Polyetherester component (B-3)
Product name: Irgastat P-20 (melting point (DSC measurement): 195 ° C., manufactured by BASF Japan Ltd., polyether ester amide block copolymer)

-2. Physical property measurement method
About the physical property of the film base material for stealth dicing, it measured using the ionomer film base material etc. which were manufactured by the Example and comparative example which are mentioned later. The measurement results are shown in Tables 1 and 2 below.

(1) Initial stress The longitudinal (MD) direction and transverse (TD) direction of each produced stealth dicing film substrate was measured in accordance with JIS K 7127, and the stress when stretched by 6% under the following conditions was measured. did. The values shown in Tables 1 and 2 below are average values of MD and TD.
<Condition>
・ Test speed: 500 mm / second ・ Test specimen: width 10 mm × length 200 mm
-Between chucks: 100mm

(2) Haze For each produced stealth dicing film base material, HM-150 type manufactured by Murakami Color Research Co., Ltd. was used, and the temperature was 23 ° C. and the relative humidity was 50%, in accordance with JIS K 7136. Measured.

(3) Expandability (expansion rate)
From each produced stealth dicing film substrate, a rectangular film substrate piece of 300 mm or more in the vertical direction (MD direction of the film) x 300 mm or more in the horizontal direction (TD direction of the film) was cut, and this cut film substrate piece was A 141 mm square was drawn using a writing instrument such as an oil pen (hereinafter, measurement target 1). Measurement object 1 was set on a wafer expansion device for 8-inch wafers (a wafer expansion device TEX-218G GR-8 manufactured by Technovision). At this time, the stage center of the wafer expansion apparatus was set so that the center of the square drawn on the measuring object 1 was aligned. Next, after raising the stage by 15 mm and expanding the film for stealth dicing, the stage was left still for 60 seconds, and the length (side length) of each side of the square of the measuring object 1 was measured. The elongation percentage (%; = side length after expansion / side length before expansion × 100) was calculated for each of the obtained four side lengths, and the average value was defined as the expansion ratio [%].

(4) Splitting property The cutting performance of each stealth dicing film base material produced was evaluated according to the following evaluation criteria. The division rate [%] is a value obtained by “(number of actually divided) / (total number of divisions) × 100”.
<Evaluation criteria>
A: The dividing rate was 80% or more and 100% or less.
B: The division rate was 60% or more and less than 80%.
C: The division rate was less than 60%.
D: The division could not be easily performed.

(5) Surface resistivity Measured using a Hiresta-UP manufactured by Mitsubishi Chemical Corporation at an applied voltage of 500 V in an atmosphere of 23 ° C. and 50% relative humidity.

(6) Total light transmittance About each produced stealth dicing film base material, using HM-150 type made by Murakami Color Research Co., Ltd., compliant with JIS K 7361 under an atmosphere of 23 ° C. and 50% relative humidity. And measured.

First, as an example in which no antistatic agent is contained, Examples 1 to 4 are shown in comparison with Comparative Examples.
[Example 1]
Using a 50 mmφ single-screw extruder inflation molding machine, the ionomer (IO-1) is introduced into the resin inlet of this molding machine, and the die temperature is set to 190 ° C. and the 80 μm-thick ionomer film substrate (stealth dicing film) Substrate). About this produced film base material, the initial stress, haze, expansion rate, and total light transmittance were measured. The results are shown in Table 1 below.

[Example 2]
In Example 1, an ionomer film substrate (stealth dicing film) was prepared in the same manner as in Example 1 except that the ionomer (IO-1) was changed to the ionomer (IO-6) and the die temperature was changed to 200 ° C. Substrate). About this produced film base material, the initial stress, haze, expansion rate, and total light transmittance were measured. The results are shown in Table 1 below.

[Example 3]
In Example 1, an ionomer film substrate (stealth dicing film) was prepared in the same manner as in Example 1 except that the ionomer (IO-1) was replaced with the ionomer (IO-2) and the die temperature was changed to 230 ° C. Substrate). About this produced film base material, the initial stress, haze, expansion rate, and total light transmittance were measured. The results are shown in Table 1 below.

[Example 4]
In Example 1, except that the ionomer (IO-1) was replaced with the ionomer (IO-4) and the die temperature was changed to 180 ° C., the ionomer film substrate (the film for stealth dicing) was the same as in Example 1. Substrate). About this produced film base material, the initial stress, haze, expansion rate, and total light transmittance were measured. The results are shown in Table 1 below.

[Comparative Example 1]
In Example 1, an ionomer film substrate (stealth dicing film) was prepared in the same manner as in Example 1 except that the ionomer (IO-1) was replaced with the ionomer (IO-3) and the die temperature was changed to 210 ° C. Substrate). About this produced film base material, the initial stress, haze, expansion rate, and total light transmittance were measured. The results are shown in Table 1 below.

[Comparative Example 2]
In Example 1, an ionomer film substrate (stealth dicing film) was prepared in the same manner as in Example 1 except that the ionomer (IO-1) was replaced with the ionomer (IO-5) and the die temperature was changed to 180 ° C. Substrate). About this produced film base material, the initial stress, haze, expansion rate, and total light transmittance were measured. The results are shown in Table 1 below.

[Comparative Example 3]
In Example 1, except that the ionomer (IO-1) was replaced with the ionomer (IO-7), the die temperature was changed to 210 ° C., and the thickness was changed to 220 μm. (Film substrate for stealth dicing) was produced. About this produced film base material, the initial stress, haze, expansion rate, and total light transmittance were measured. The results are shown in Table 1 below.

[Comparative Example 4]
In Example 1, a film substrate (a film substrate for stealth dicing) was produced in the same manner as in Example 1 except that ionomer (IO-1) was replaced with EMAA and the die temperature was changed to 180 ° C. . About this produced film base material, the initial stress, haze, expansion rate, and total light transmittance were measured. The results are shown in Table 1 below.

Next, examples in the case of containing an antistatic agent are shown in Examples 5 to 9.
[Example 5]
In Example 1, the ionomer (IO-1) used was 85 parts by mass of ionomer (IO-1), 7.5 parts by mass of irgastat P-16 (polyetherester component (B-1)), and irgastat. Instead of 7.5 parts by mass of P-18 (polyether ester component (B-2)), these components were dry blended. The dry blended raw material was charged into a resin charging port of a single screw extruder equipped with a full flight type screw (40 mmφ), and then melt kneaded and pelletized. Using the obtained pellets, an ionomer film substrate (film substrate for stealth dicing) was produced in the same manner as in Example 1. About this produced film base material, the initial stress, haze, expansion rate, surface resistivity, and total light transmittance were measured. The results are shown in Table 2 below.

[Example 6]
In Example 1, the ionomer (IO-1) used was replaced with 85 parts by weight of ionomer (IO-1) and 15 parts by weight of Irgastat P-18 (polyetherester component (B-2)). Dry blended. The dry blended raw material was charged into a resin charging port of a single screw extruder equipped with a full flight type screw (40 mmφ), and then melt kneaded and pelletized. Using the obtained pellets, an ionomer film substrate (film substrate for stealth dicing) was produced in the same manner as in Example 1. About this produced film base material, the initial stress, haze, expansion rate, surface resistivity, and total light transmittance were measured. The results are shown in Table 2 below.

[Example 7]
An ionomer film substrate (a film substrate for stealth dicing) was produced in the same manner as in Example 5 except that ionomer (IO-1) was replaced with ionomer (IO-2) in Example 5. About this produced film base material, the initial stress, haze, expansion rate, surface resistivity, and total light transmittance were measured. The results are shown in Table 2 below.

[Example 8]
An ionomer film substrate (a film substrate for stealth dicing) was produced in the same manner as in Example 6 except that the ionomer (IO-1) was replaced with the ionomer (IO-2) in Example 6. About this produced film base material, the initial stress, haze, expansion rate, surface resistivity, and total light transmittance were measured. The results are shown in Table 2 below.

[Example 9]
In Example 6, the ionomer (IO-1) was replaced with the ionomer (IO-2), and Irgastat P-18 (15 parts by mass) was replaced with Irgastat P-16 (polyetherester component (B-1)) 15 An ionomer film substrate (a film substrate for stealth dicing) was produced in the same manner as in Example 6 except that the mass parts were replaced. About this produced film base material, the initial stress, haze, expansion rate, surface resistivity, and total light transmittance were measured. The results are shown in Table 2 below.

[Comparative Example 5]
In Example 6, the ionomer (IO-1) was replaced with the ionomer (IO-2), and Irgastat P-18 (15 parts by mass) was replaced with Irgastat P-20 (polyetherester component (B-3)) 15 An ionomer film substrate (a film substrate for stealth dicing) was produced in the same manner as in Example 6 except that the mass parts were replaced. About this produced film base material, the initial stress, haze, expansion rate, surface resistivity, and total light transmittance were measured. The results are shown in Table 2 below.

[Examples 10 to 18]
As the base material, the ionomer film base materials prepared in Examples 1 to 9 were prepared, and as the adhesive material for forming the adhesive layer, an ultraviolet curable acrylic adhesive (Beamset 575 (urethane acrylate type manufactured by Arakawa Chemical Industries, Ltd.) was used. Oligomer)) was prepared.
An ionomer film base material 11 as shown in FIG. 1 is applied on the base material by bar coating using the above base material and pressure-sensitive adhesive, which is obtained by dissolving an ultraviolet curable acrylic pressure-sensitive adhesive material in ethyl acetate. / Nine types of stealth dicing films having a multilayer structure of the adhesive layer 12 having a dry thickness of 20 μm were prepared.

[Examples 19 to 27]
As shown in FIG. 3A, the adhesive layer 12 of each stealth dicing film 1 was fixed to the back surface of the wafer W using the stealth dicing films prepared in Examples 10 to 18, and the stealth dicing film 1 was The end of the adhesive layer 12 is brought into contact with the dicing table 6 and fixed to the dicing table. Next, the laser beam is irradiated from the base material 11 side of the dicing tape 1 and guided through the stealth dicing film 1, thereby modifying along the dicing line inside the wafer W as shown in FIG. 3B. A portion W1 is formed. Thereafter, as shown in FIG. 4, the end portion of the stealth dicing film 1 is pulled in the direction of the arrow to expand the film, and is divided into a plurality of portions starting from the modified portion W1. Thereafter, the adhesive layer 12 is irradiated with ultraviolet rays, and a plurality of chips are taken out to obtain a desired electronic component.

[B] Examples 28 to 89 and Comparative Examples 6 to 10
The composition and physical properties of the raw materials used in Examples 28 to 49 and Comparative Examples 6 to 10 shown below, and methods for measuring the physical properties of the obtained films and sheets are as follows.

-1. raw materials-
(1) Ionomer (IO-11)
Base polymer: ethylene / methacrylic acid copolymer (ethylene unit content: 85% by mass, methacrylic acid unit content: 15% by mass)
Metal cation source: Magnesium Neutralization degree: 35%
MFR (190 ° C., 2160 g load): 5.9 g / 10 minutes Flexural rigidity (according to JIS K 7106): 330 MPa
(2) Ionomer (IO-12)
Base polymer: ethylene / methacrylic acid copolymer (ethylene unit content: 85% by mass, methacrylic acid unit content: 15% by mass)
Metal cation source: Magnesium Neutralization degree: 54%
MFR (190 ° C., 2160 g load): 0.7 g / 10 min Flexural rigidity (according to JIS K 7106): 320 MPa
(3) Ionomer (IO-13)
Base polymer: ethylene / methacrylic acid / isobutyl acrylate copolymer (ethylene unit content: 80 mass%, methacrylic acid unit content: 10 mass%, isobutyl acrylate unit content: 10 mass%)
Metal cation source: Zinc Neutralization degree: 70%
MFR (190 ° C., 2160 g load): 1.0 g / 10 min Flexural rigidity (according to JIS K 7106): 90 MPa
(4) Ionomer (IO-14)
Base polymer: ethylene / methacrylic acid copolymer (ethylene unit content: 89% by mass, methacrylic acid unit content: 11% by mass)
Metal cation source: Zinc Neutralization degree: 65%
MFR (190 ° C., 2160 g load): 5.0 g / 10 min Flexural rigidity (according to JIS K 7106): 260 MPa
(5) Ionomer (IO-15)
Base polymer: ethylene / methacrylic acid copolymer (ethylene unit content: 85% by mass, methacrylic acid unit content: 15% by mass)
Metal cation source: Zinc Neutralization degree: 23%
MFR (190 ° C., 2160 g load): 5.0 g / 10 min Flexural rigidity (according to JIS K 7106): 200 MPa
(6) Ionomer (IO-16)
Base polymer: ethylene / methacrylic acid copolymer (ethylene unit content: 85% by mass, methacrylic acid unit content: 15% by mass)
Metal cation source: Zinc Neutralization degree: 59%
MFR (190 ° C., 2160 g load): 0.9 g / 10 min Flexural rigidity (according to JIS K 7106): 310 MPa

(7) Ethylene / (meth) acrylic acid copolymer (EMAA)
Ethylene / methacrylic acid copolymer (ethylene unit content: 91% by mass, methacrylic acid unit content: 9% by mass)
MFR (190 ° C., 2160 g load): 3.0 g / 10 min Flexural rigidity (according to JIS K 7106): 140 MPa
(8) Ethylene / vinyl acetate copolymer (EVA)
Ethylene / vinyl acetate copolymer (ethylene unit content: 81% by mass, vinyl acetate unit content: 19% by mass)
MFR (190 ° C., 2160 g load): 2.5 g / 10 min Flexural rigidity (according to JIS K 7106): 40 MPa

(9) Polyolefin (C1)
Linear low density polyethylene (LLDPE: Prime Polymer, Evolue SP2320, density: 919 kg / m ³ , MFR: 1.9 g / 10 min)
Flexural rigidity (according to JIS K 7106): 240 MPa
(10) Polyolefin (C2)
Low density polyethylene (LDPE: density: 920 kg / m ³ , MFR: 1.6 g / 10 min)
Flexural rigidity (conforming to JIS K 7106): 140 MPa
(11) Polyolefin (C3)
Random polypropylene (r-PP: Prime Polymer, Prime Polypro F219DA, density: 910 kg / m ³ , MFR: 8.0 g / 10 min)
Flexural rigidity (according to JIS K 7106): 960 MPa
(12) Polyolefin (C4)
Homopolypropylene (Homo-PP: Prime Polymer Co., Ltd., Prime Polypro F113DA, density: 910 kg / m ³ , MFR: 3.0 g / 10 min)
Flexural rigidity (according to JIS K 7106): 1290 MPa

(13) Polyetherester component (B-1)
Product name: Irgastat P-16, manufactured by BASF Japan Ltd. (14) Polyether ester component (B-2)
Product name: Irgastat P-18, manufactured by BASF Japan Ltd. (15) Polyether ester component (B-4)
Product name: Pelestat 230, manufactured by Sanyo Chemical Industries, Ltd. (melting point (DSC measurement): 163 ° C.)

-2. Physical property measurement method
About the physical property of the film base material for stealth dicing, it measured using the ionomer film base material etc. which were manufactured by the Example and comparative example which are mentioned later. The results of measurement and evaluation are shown in Tables 3 to 5 below.

(1) Initial stress About the machine direction (MD) direction of each produced film base material for stealth dicing, based on JISK7127, the stress when extending 6% on the following conditions was measured.
<Condition>
・ Test speed: 500mm / sec
・ Test specimen: width 10 mm x length 200 mm
-Between chucks: 100mm

(2) Haze / Severability About each produced stealth dicing film base material, it measured and evaluated by the method similar to the case in said [A].

(3) Total light transmittance About each produced stealth dicing film base material, using HM-150 type made by Murakami Color Research Co., Ltd., compliant with JIS K 7361 under an atmosphere of 23 ° C. and 50% relative humidity. And measured.

(4) Expandability (expansion rate)
From each of the produced film substrates for stealth dicing, a rectangular film substrate piece of 300 mm or more in the vertical direction (MD direction of the film) × 300 mm or more in the horizontal direction (TD direction of the film) was cut, and 141 mm was added to the cut film substrate piece. A square of the corner was drawn using a writing instrument such as an oil pen (hereinafter, measurement object 2). The length (side length) of each side of the square drawn on the measuring object 2 is measured by the same method as in [A] above, and the elongation percentage (%; = after expansion) is obtained for each of the obtained four side lengths. Side length / side length before expansion × 100) was calculated, and the average value was obtained as the expansion rate [%]. Further, it was visually confirmed that the whitening phenomenon occurred (exists) or did not occur (none) in the expanded film.

(5) Flexural rigidity (Olsen type)
The raw material was press-molded with a press molding machine set at 190 ° C., and a 250 mm × 250 mm, 2 mm thick press sheet was prepared. About the created 2 mm thickness sheet | seat, the bending rigidity was measured based on JISK7106.

[Example 28]
Using a three-type three-layer inflation molding machine with a screw diameter of 45 mmφ, IO-12 (Mg) as layer X forming resin in contact with the adhesive layer, IO-13 (Zn) as layer Y forming resin, and layer Z Using IO-12 (Mg) as a forming resin, a three-layer film having a multilayer structure of layer X / layer Y / layer Z in contact with the adhesive layer at a die temperature of 220 ° C. (total thickness 80 μm; stealth dicing Film base material). The layer thicknesses of the layer X, the layer Y, and the layer Z that are in contact with the adhesive layer of the three-layer film are 25 μm, 30 μm, and 25 μm, respectively. Subsequently, the initial stress, haze, total light transmittance, and expansion rate were measured for the produced three-layer film. The results are shown in Table 3 below.

[Example 29]
Ionomer (IO-11 (Mg)) 85 parts by mass, Irgastat P-16 (polyetherester component (B-1)) 7.5 parts by mass, and Irgastat P-18 (polyetherester component (B-2) )) 7.5 parts by mass were melt-kneaded with a single screw extruder having a screw diameter of 40 mmφ to prepare an ionomer composition for forming layer X and layer Z in contact with the adhesive layer. Next, in Example 1, this ionomer composition is used as the layer X forming resin in contact with the adhesive layer, IO-14 (Zn) is used as the layer Y forming resin, and the die temperature is changed from 220 ° C. to 210 ° C. A three-layer film was produced in the same manner as in Example 1 except that. About this produced 3 layer film, the initial stress, the haze, the total light transmittance, and the expansion rate were measured. These results are also shown in Table 3 below. In addition, when the surface resistivity was measured, the surface resistivity was 1.7 × 10 ¹⁴ Ω / sq.

[Example 30]
In Example 28, the layer X forming resin in contact with the adhesive layer was changed to IO-15 (Zn), the layer Z forming resin was changed to IO-15 (Zn), and the die temperature was changed from 220 ° C. to 200 ° C. A three-layer film was produced in the same manner as in Example 28 except for the above. About this produced 3 layer film, the initial stress, the haze, the total light transmittance, and the expansion rate were measured. These results are also shown in Table 3 below.

[Example 31]
In Example 28, the layer X forming resin in contact with the adhesive layer was changed to IO-14 (Zn), the layer Z forming resin was changed to IO-14 (Zn), and the die temperature was changed from 220 ° C. to 200 ° C. A three-layer film was produced in the same manner as in Example 28 except for the above. About this produced 3 layer film, the initial stress, the haze, the total light transmittance, and the expansion rate were measured. These results are also shown in Table 3 below.

[Example 32]
In Example 28, the layer X forming resin in contact with the adhesive layer was replaced with IO-16 (Zn), the layer Y forming resin was replaced with C1, and the layer Z forming resin was replaced with IO-16 (Zn), and the die temperature was changed. The same as Example 28, except that the temperature was changed from 220 ° C. to 210 ° C., and the thicknesses of the layers X (A), Y, and Z of the three-layer film were 28 μm, 21 μm, and 30 μm, respectively. Thus, a three-layer film was produced. About this produced 3 layer film, the initial stress, the haze, the total light transmittance, and the expansion rate were measured. These results are also shown in Table 3 below.

[Example 33]
In Example 28, the layer X-forming resin in contact with the adhesive layer is replaced with IO-16 (Zn), the layer Y-forming resin is replaced with C1, and the layer Z-forming resin is replaced with IO-16 (Zn). A three-layer film was produced in the same manner as in Example 28 except that the temperature was changed from 220 ° C to 210 ° C. About this produced 3 layer film, the initial stress, the haze, the total light transmittance, and the expansion rate were measured. These results are also shown in Table 3 below.

[Example 34]
In Example 28, the layer X forming resin in contact with the adhesive layer was replaced with IO-16 (Zn), the layer Y forming resin was replaced with C1, and the layer Z forming resin was replaced with IO-16 (Zn), and the die temperature was changed. The same as Example 28, except that the layer thicknesses of layer X, layer Y, and layer Z in contact with the adhesive layer of the three-layer film were changed from 220 ° C. to 210 ° C. to 20 μm, 40 μm, and 20 μm, respectively. Thus, a three-layer film was produced. About this produced 3 layer film, the initial stress, the haze, the total light transmittance, and the expansion rate were measured. These results are also shown in Table 3 below.

[Example 35]
In Example 28, the layer X-forming resin in contact with the adhesive layer is replaced with IO-16 (Zn), the layer Y-forming resin is replaced with EMAA, and the layer Z-forming resin is replaced with IO-16 (Zn). A three-layer film was produced in the same manner as in Example 28 except that the temperature was changed from 220 ° C to 200 ° C. About this produced 3 layer film, the initial stress, the haze, the total light transmittance, and the expansion rate were measured. These results are also shown in Table 3 below.

[Example 36]
In Example 28, the layer X forming resin in contact with the adhesive layer was replaced with IO-16 (Zn), the layer Z forming resin was replaced with IO-16 (Zn), and the die temperature was changed from 220 ° C. to 210 ° C. A three-layer film was produced in the same manner as in Example 28 except for the above. About this produced 3 layer film, the initial stress, the haze, the total light transmittance, and the expansion rate were measured. These results are also shown in Table 3 below.

[Example 37]
In Example 28, the layer X-forming resin in contact with the adhesive layer is replaced with IO-16 (Zn), the layer Y-forming resin is replaced with EVA, and the layer Z-forming resin is replaced with IO-16 (Zn). A three-layer film was produced in the same manner as in Example 28 except that the temperature was changed from 220 ° C to 210 ° C. About this produced 3 layer film, the initial stress, the haze, the total light transmittance, and the expansion rate were measured. These results are also shown in Table 3 below.

[Example 38]
In Example 28, the layer X forming resin in contact with the adhesive layer was replaced with IO-16 (Zn), the layer Y forming resin was replaced with C2, and the layer Z forming resin was replaced with IO-16 (Zn), and the die temperature was changed. Other than changing from 220 ° C. to 210 ° C. and changing the layer thicknesses of layer X, layer Y, and layer Z of the three-layer film to 28 μm, 22 μm, and 30 μm, respectively (total thickness of the three-layer film: 80 μm) Produced a three-layer film in the same manner as in Example 28. About this produced 3 layer film, the initial stress, the haze, the total light transmittance, and the expansion rate were measured. These results are also shown in Table 3 below.

[Example 39]
Using a three-type three-layer cast film molding machine with a screw diameter of 40 mmφ, IO-16 (Zn) is used as the layer X forming resin in contact with the adhesive layer, EMAA is used as the layer Y forming resin, and layer Z forming resin is used. A three-layer film having a multilayer structure of layer X / layer Y / layer Z in contact with the adhesive layer using IO-16 (Zn) at a die temperature of 210 ° C. (total thickness 77 μm; film substrate for stealth dicing) ) Was produced. The layer thicknesses of the layer X, the layer Y, and the layer Z that are in contact with the adhesive layer of the produced three-layer film are 29 μm, 20 μm, and 28 μm, respectively. Subsequently, the initial stress, haze, total light transmittance, and expansion rate were measured for the prepared three-layer film. These results are also shown in Table 3 below.

[Example 40]
In Example 39, a three-layer film was produced in the same manner as in Example 39 except that the layer Y forming resin was changed to C1. About this produced 3 layer film, the initial stress, the haze, the total light transmittance, and the expansion rate were measured. These results are also shown in Table 3 below.

[Example 41]
85 parts by mass of ionomer (IO-16 (Zn)) and 15 parts by mass of perestat 230 (B-4) were melt-kneaded by a twin screw extruder having a screw diameter of 30 mmφ, and layer X and layer Z in contact with the adhesive layer were obtained. An ionomer composition was prepared for forming. Next, in Example 28, the ionomer composition is used as the layer X-forming resin in contact with the adhesive layer, the layer Y-forming resin C2, the layer Z-forming resin is used as the ionomer resin composition, and the die temperature is set. A three-layer film was produced in the same manner as in Example 28 except that the temperature was changed from 220 ° C to 210 ° C. About this produced 3 layer film, the initial stress, the haze, the total light transmittance, and the expansion rate were measured. These results are also shown in Table 3 below. In addition, the surface resistivity was measured. The surface resistivity was 1.3 × 10 ¹⁰ Ω / sq.

[Example 42]
In Example 28, the layer X-forming resin in contact with the adhesive layer is replaced with IO-16 (Zn), the layer Y-forming resin is replaced with C1, and the layer Z-forming resin is replaced with IO-16 (Zn). A three-layer film having a multilayer structure of layer X / layer Z / layer Y was produced under the same conditions as in Example 28 except that was changed from 220 ° C. to 210 ° C. About this produced 3 layer film, the initial stress, the haze, the total light transmittance, and the expansion rate were measured. These results are also shown in Table 4 below.

[Example 43]
In Example 28, the layer X forming resin in contact with the adhesive layer was replaced with IO-16 (Zn), the layer Y forming resin was replaced with C2, and the layer Z forming resin was replaced with IO-16 (Zn), and the die temperature was changed. Other than changing from 220 ° C. to 210 ° C. and changing the layer thicknesses of layer X, layer Y, and layer Z of the three-layer film to 30 μm, 20 μm, and 30 μm, respectively (total thickness of the three-layer film: 80 μm) Produced a three-layer film having a multilayer structure of layer X / layer Z / layer Y in the same manner as in Example 28. About this produced 3 layer film, the initial stress, the haze, the total light transmittance, and the expansion rate were measured. These results are also shown in Table 4 below.

[Example 44]
In Example 28, the layer X forming resin in contact with the adhesive layer was replaced with IO-16 (Zn), the layer Y forming resin was replaced with C2, and the layer Z forming resin was replaced with IO-16 (Zn), and the die temperature was changed. Other than changing from 220 ° C. to 210 ° C. and changing the layer thicknesses of the three-layer film layers X, Y, and Z to 20 μm, 30 μm, and 30 μm, respectively (total thickness of the three-layer film: 80 μm) Produced a three-layer film having a multilayer structure of layer X / layer Z / layer Y in the same manner as in Example 28. About this produced 3 layer film, the initial stress, the haze, the total light transmittance, and the expansion rate were measured. These results are also shown in Table 4 below.

[Example 45]
In Example 28, the layer X forming resin in contact with the adhesive layer was replaced with IO-16 (Zn), the layer Y forming resin was replaced with C2, and the layer Z forming resin was replaced with IO-16 (Zn), and the die temperature was changed. Other than changing from 220 ° C. to 210 ° C. and changing the layer thicknesses of the three-layer film layers X, Y, and Z to 20 μm, 40 μm, and 20 μm, respectively (total thickness of the three-layer film: 80 μm) Produced a three-layer film having a multilayer structure of layer X / layer Z / layer Y in the same manner as in Example 28. About this produced 3 layer film, the initial stress, the haze, the total light transmittance, and the expansion rate were measured. These results are also shown in Table 4 below.

[Example 46]
In Example 28, the layer X forming resin in contact with the adhesive layer was replaced with IO-16 (Zn), the layer Y forming resin was replaced with C2, and the layer Z forming resin was replaced with IO-16 (Zn), and the die temperature was changed. Other than changing from 220 ° C. to 210 ° C. and changing the layer thicknesses of the three-layer film layers X, Y, and Z to 15 μm, 50 μm, and 15 μm (total thickness of the three-layer film: 80 μm), respectively. Produced a three-layer film having a multilayer structure of layer X / layer Z / layer Y in the same manner as in Example 28. About this produced 3 layer film, the initial stress, the haze, the total light transmittance, and the expansion rate were measured. These results are also shown in Table 4 below.

[Example 47]
To melt and knead 85 parts by mass of ionomer (IO-16 (Zn)) and 15 parts by mass of perestat 230 (B-4) with a twin screw extruder having a screw diameter of 30 mmφ to form layer X in contact with the adhesive layer An ionomer composition was prepared. Further, an ionomer for forming layer Z by melt-kneading 85 parts by mass of ionomer (IO-13 (Zn)) and 15 parts by mass of perestat 230 (B-4) with a twin screw extruder having a screw diameter of 30 mmφ. Composition Z was prepared.
Next, in Example 28, using this ionomer composition as the layer X forming resin in contact with the adhesive layer, using C2 as the layer Y forming resin, and using this ionomer resin composition Z as the layer Z forming resin, the die temperature Was changed from 220 ° C. to 210 ° C., and the layer thicknesses of layer X, layer Y, and layer Z of the three-layer film were changed to 45 μm, 15 μm, and 30 μm, respectively (total thickness of the three-layer film: 90 μm). A three-layer film having a multilayer structure of layer X / layer Z / layer Y was prepared in the same manner as in Example 28 except for the above. About this produced 3 layer film, the initial stress, the haze, the total light transmittance, and the expansion rate were measured. These results are also shown in Table 4 below. In addition, the surface resistivity was measured. The surface resistivity was 1.5 × 10 ¹¹ Ω / sq.

[Example 48]
Example 47 In Example 47, except that the layer thicknesses of the layer X, layer Y, and layer Z of the three-layer film were changed to 35 μm, 15 μm, and 40 μm (total thickness of the three-layer film: 90 μm), respectively. In the same manner as above, a three-layer film having a multilayer structure of layer X / layer Z / layer Y configuration was produced. About this produced 3 layer film, the initial stress, the haze, the total light transmittance, and the expansion rate were measured. These results are also shown in Table 4 below. In addition, the surface resistivity was measured. The surface resistivity was 2.1 × 10 ¹¹ Ω / sq.

[Example 49]
Example 47 In Example 47, except that the layer thicknesses of the layer X, layer Y, and layer Z of the three-layer film were changed to 40 μm, 15 μm, and 25 μm (total thickness of the three-layer film: 80 μm), respectively. In the same manner as above, a three-layer film having a multilayer structure of layer X / layer Z / layer Y configuration was produced. About this produced 3 layer film, the initial stress, the haze, the total light transmittance, and the expansion rate were measured. These results are also shown in Table 4 below. In addition, when the surface resistivity was measured, the surface resistivity was 1.7 × 10 ¹¹ Ω / sq.

[Comparative Example 6]
In Example 28, the layer X forming resin in contact with the adhesive layer was replaced with IO-13 (Zn), the layer Z forming resin was replaced with IO-13 (Zn), and the die temperature was changed from 220 ° C. to 210 ° C. A film was produced in the same manner as in Example 28 except for the above. Here, each layer is formed using IO-13 (Zn), and the substantially produced film is composed of a single layer. Moreover, with respect to the produced film, the initial stress, haze, total light transmittance, and expansion rate were measured. These results are also shown in Table 5 below.

[Comparative Example 7]
In Example 39, the layer X forming resin in contact with the adhesive layer is changed to C4, the layer Y forming resin is changed to C4, the layer Z forming resin is changed to C4, the die temperature is changed from 210 ° C. to 240 ° C., and A film was produced in the same manner as in Example 39 except that the total thickness was 80 μm. Here, each layer is formed using C4, and the substantially produced film consists of a single layer. Moreover, the initial stress and the expansion rate were measured with respect to the produced film. These results are also shown in Table 5 below.

[Comparative Example 8]
In Example 28, the layer X forming resin in contact with the adhesive layer was replaced with IO-16 (Zn), the layer Y forming resin was replaced with C1, and the layer Z forming resin was replaced with IO-16 (Zn), and the die temperature was changed. Other than changing from 220 ° C. to 210 ° C. and changing the layer thicknesses of the three-layer film layers X, Y, and Z to 70 μm, 90 μm, and 70 μm (total thickness of the three-layer film: 230 μm), respectively. Produced a three-layer film in the same manner as in Example 28. About this produced three-layer film, the initial stress, the haze, and the total light transmittance were measured. These results are also shown in Table 5 below. Further, although the expansion rate was measured, the wafer expansion apparatus stage did not rise and measurement was impossible (NG).

[Comparative Example 9]
In Example 28, the layer X forming resin in contact with the adhesive layer was changed to C2, the layer Y forming resin was changed to EVA, the layer Z forming resin was changed to C2, and the die temperature was changed from 220 ° C. to 200 ° C. A three-layer film was produced in the same manner as in Example 28 except for the above. About this produced three-layer film, the initial stress, the haze, and the total light transmittance were measured. These results are also shown in Table 5 below.

[Comparative Example 10]
In Example 28, the layer X forming resin in contact with the adhesive layer was replaced with IO-16 (Zn), the layer Y forming resin was replaced with C3, and the layer Z forming resin was replaced with IO-16 (Zn), and the die temperature was changed. A three-layer film was produced in the same manner as in Example 28 except that the temperature was changed from 220 ° C to 210 ° C. About this produced 3 layer film, the initial stress, the haze, the total light transmittance, and the expansion rate were measured. These results are also shown in Table 5 below.

[Examples 50 to 69]
As the base material, the ionomer film base materials prepared in Examples 28 to 49 were prepared, and as the adhesive material for forming the adhesive layer, an ultraviolet curable acrylic adhesive (Beamset 575 (urethane acrylate type manufactured by Arakawa Chemical Industries, Ltd.) was used. Oligomer)) was prepared.
Using the above-mentioned base material and pressure-sensitive adhesive, an ionomer film base material 11 as shown in FIG. 2 is applied on the base material by bar coating a solution obtained by dissolving an ultraviolet curable acrylic pressure-sensitive adhesive material in ethyl acetate. / A film for stealth dicing consisting of a multilayer structure of the adhesive layer 12 having a dry thickness of 20 μm was prepared.

[Examples 70 to 89]
Using the stealth dicing films prepared in Examples 50 to 69, as shown in FIG. 3A, the adhesive layer 12 of each stealth dicing film 1 was fixed to the back surface of the wafer W, and the stealth dicing film 1 was The end of the adhesive layer 12 is brought into contact with the dicing table 6 and fixed to the dicing table. Next, the laser beam is irradiated from the base material 11 side of the dicing tape 1 and guided through the stealth dicing film 1, thereby modifying along the dicing line inside the wafer W as shown in FIG. 3B. A portion W1 is formed. Thereafter, as shown in FIG. 4, the end portion of the stealth dicing film 1 is pulled in the direction of the arrow to expand the film, and is divided into a plurality of portions starting from the modified portion W1. Thereafter, the adhesive layer 12 is irradiated with ultraviolet rays, and a plurality of chips are taken out to obtain a desired electronic component.

As shown in Tables 3 to 5, in Examples, films suitable for stealth dicing have high transparency so that good results are obtained with respect to haze and total light transmittance, and good initial stress. A substrate and a film for dicing were obtained.
On the other hand, in Comparative Examples 6 and 9, although a certain degree of haze value and light transmittance were obtained, the initial stress was too small, resulting in poor stealth dicing. On the contrary, in Comparative Example 7, the initial stress becomes too high, and a good expansion rate cannot be obtained during expansion by stealth dicing. In Comparative Example 10, although expansion was possible, whitening occurred after expansion. Oops. And in the comparative example 8, since total thickness was too thick, expandability was not maintained and it was inferior to parting property.

The disclosures of Japanese applications 2011-284379, 2012-053389, and 2012-122540 are incorporated herein by reference in their entirety.
All documents, patent applications, and technical standards described in this specification are specifically and individually incorporated by reference as if individual documents, patent applications, and technical standards were incorporated by reference. To the extent incorporated herein by reference.

Claims

Used as the base material of the stealth dicing film provided with the adhesive layer and the base material, the thickness is in the range of 50 μm to 200 μm, the initial stress is in the range of 9 MPa to 19 MPa, and the expansion rate is 102% or more A film substrate for stealth dicing having a range of 120% or less, a haze value of 10 or less, and a total light transmittance of 90% or more.
It is selected from magnesium ionomer of ethylene / (meth) acrylic acid copolymer and zinc ionomer of ethylene / (meth) acrylic acid copolymer, and a structural unit derived from (meth) acrylic acid alkyl ester in the copolymer. The film base material for stealth dicing according to claim 1, comprising an ionomer resin having a copolymerization ratio of less than 7% by mass.
The copolymerization ratio in the copolymer of the structural unit derived from the (meth) acrylic acid of at least one of the magnesium ionomer and the zinc ionomer is more than 10% by mass and 30% by mass or less. Film substrate for stealth dicing.
The film substrate for stealth dicing according to claim 2 or 3, wherein at least one of the magnesium ionomer and the zinc ionomer has a degree of neutralization of more than 0% and 60% or less.
The film substrate for stealth dicing according to claim 2 or 3, wherein at least one of the magnesium ionomer and the zinc ionomer has a degree of neutralization of 10% to 40%.
A multilayer structure in which the layer X in contact with the adhesive layer, the first layer Y, and the second layer Z are sequentially stacked, or the layer X in contact with the adhesive layer, the second layer Z, and the first layer Y The film base material for stealth dicing according to claim 1, wherein the film base material has a multilayer structure in which layers are sequentially stacked, and the thickness of the layer X, the layer Y, and the layer Z is in the range of 10 µm to 100 µm.
The layer X in contact with the adhesive layer includes the resin A, the bending rigidity of the resin A is in the range of 100 MPa to 350 MPa, the first layer Y includes the resin B, and the bending rigidity of the resin B is 5 MPa or more and 350 MPa or less, the second layer Z contains the resin C, and the bending rigidity of the resin C is 50 MPa or more and 350 MPa or less.
The stealth according to claim 6, wherein a value of a larger absolute value of a difference obtained by subtracting a bending rigidity of the resin B from each of the bending rigidity of the resin A or the resin C is in a range of 50 MPa to 345 MPa. Film substrate for dicing.
The film substrate for stealth dicing according to claim 6 or 7, wherein the layer X in contact with the adhesive layer contains a resin A, and the resin A is an ionomer of an ethylene / unsaturated carboxylic acid binary copolymer.
The film substrate for stealth dicing according to claim 8, wherein the content of the structural unit derived from the unsaturated carboxylic acid in the binary copolymer is 1% by mass or more and 35% by mass or less.
The first layer Y includes a resin B, and the resin B is a low density polyethylene, a linear low density polyethylene, an ethylene vinyl acetate copolymer, an ethylene / unsaturated carboxylic acid binary copolymer, and an ionomer thereof. The ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid terpolymer and its ionomer, and at least one selected from ethylene-unsaturated carboxylic acid ester terpolymers. The film base material for stealth dicing according to any one of the above.
The second layer Z contains a resin C, and the resin C is an ethylene / unsaturated carboxylic acid binary copolymer and its ionomer, and an ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester ternary copolymer. The stealth dicing film substrate according to any one of claims 6 to 10, which is at least one selected from the group consisting of an ionomer and an ionomer thereof.
The film substrate for stealth dicing according to any one of claims 1 to 11, comprising an antistatic agent having a melting point of 155 ° C or higher and 185 ° C or lower.
The film substrate for stealth dicing according to any one of claims 1 to 12, which has a surface resistivity of 1.0 x 10 9 Ω / sq to 1.0 x 10 12 Ω / sq.
A stealth dicing film comprising an adhesive layer and the stealth dicing film substrate according to any one of claims 1 to 13.
Attaching the film for stealth dicing according to claim 14 to the back surface of the wafer;
Irradiating the wafer with the stealth dicing film a laser beam from the stealth dicing film side, and dicing the wafer with the laser beam through the stealth dicing film. Production method.