KR20050118302A - Base film for semiconductor wafer processing - Google Patents

Abstract

A base film for semiconductor wafer processing is disclosed which mainly contains polyethylene-2,6-naphthalene dicarboxylate, exhibits excellent dimensional stability, smoothness, mechanical strength under high temperature, high humidity conditions, and has an excellent processing aptitude. This base film for semiconductor wafer processing is a biaxially oriented film mainly containing polyethylene-2,6-naphthalene dicarboxylate. The thermal shrinkage rate of this base film when heat- treated at 200°C for 10 minutes is not more than 1.00% in both the film-forming direction and the width direction.

Description

Base film for semiconductor wafer processing {BASE FILM FOR SEMICONDUCTOR WAFER PROCESSING}

This invention relates to the base film for semiconductor wafer processing using the biaxially-oriented film which consists of polyethylene-2, 6- naphthalenedicarboxylate as a main component. More specifically, in semiconductor wafer processing, in particular in the backgrinding process or dicing process, when used as the substrate of the backgrinding tape or the substrate of the dicing tape, for backgrinding tape having excellent dimensional stability, smoothness, and mechanical strength, or It relates to a base film for dicing tape.

In the polishing process (backgrinding process) of the back surface of a wafer in semiconductor manufacturing, and the process (dicing process) of cutting an IC chip from a completed wafer, the adhesive tape which laminated | stacked various adhesive is used for fixing a wafer. In the backgrinding process, the wafer having a circuit formed on the surface is polished on the back side in a state of being fixed to the adhesive tape, and after the adhesive force of the adhesive is reduced by UV irradiation, heating or the like, the wafer is moved to the next dicing step. In the dicing step, the wafer fixed to the adhesive tape is cut into individual IC chip units, and in the same manner as in the backgrinding step, the adhesive force of the adhesive is reduced by UV irradiation, heating, or the like, and then taken out one by one. The extracted IC chip is transferred to the next bonding process and molding process.

Conventionally, plastic films such as polyolefins and copolymers thereof, polyvinyl chloride and copolymers thereof, polyesters, polycarbonates, polyamides, polyimides and the like have been used as base films of adhesive films and release films of dicing tapes. In view of mechanical strength, dimensional stability, heat resistance, price and the like, polyester films are used, for example, as disclosed in Japanese Patent Application Laid-open No. Hei 5-175332 and Japanese Patent Application Laid-open No. Hei 1-5838. On the other hand, a method of applying a germanium compound to a polymerization catalyst (Japanese Laid-Open Patent Publication No. H10-214801) for the purpose of preventing a decrease in yield of a silicon wafer due to impurities contained in a polyester film and a silicone resin release layer is Is disclosed. Moreover, the technique regarding the release film for adhesion layer protections in the storage of a backgrinding tape or a dicing tape is disclosed by Unexamined-Japanese-Patent No. 11-20105 from the same low-pollution viewpoint.

By the way, with the recent high integration of semiconductors, while thinning of semiconductor wafers is rapidly progressing, new semiconductor wafer processing techniques suitable for thinning of wafer thickness have been devised. In particular, since the wafer thickness has become very thin, the conventional polishing methods include problems such as breakage of the wafer and more time-consuming polishing than conventional methods, and methods such as etching with plasma have been devised as processing techniques.

However, in the processing method newly devised, since the processing temperature becomes high compared with the conventional processing method, the thermal dimensional stability and mechanical strength are the problems in the film for semiconductor wafer processing based on the conventional polyester film. In the dicing step, in general, when the tape is peeled off, the adhesive force of the adhesive is weakened by heating or UV irradiation, and then the chip is expanded from the tape side or the method of expanding the tape in order to pick up the cut chips. Although gaps are formed between the chips by using the picking-up method, a problem is that if the dimensional shrinkage of the tape during heating is large, pick-up failure of the chips occurs and the production efficiency of the semiconductor wafer is deteriorated.

On the other hand, when polyimide is used as a base film, since water absorption is high, higher dimensional stability is desired.

Moreover, in order to improve the productivity of a semiconductor wafer, in-process cleanliness and improvement of workability are always pursued.

(Patent Document 1) JP 5-175332 A

(Patent Document 2) Japanese Unexamined Patent Publication No. Hei 1-5838

(Patent Document 3) JP 10-214801 A

(Patent Document 4) Japanese Patent Application Laid-Open No. 11-20105

Disclosure of the Invention

The object of the present invention is to solve these problems of the prior art and to provide excellent dimensional stability under high temperature and high humidity, smoothness, mechanical strength, and when used as a substrate for semiconductor wafer processing, in particular, as a substrate of a backgrinding tape or a dicing tape, and It aims at obtaining the base film for semiconductor processing which has the outstanding processing titration.

Still other objects and advantages of the present invention will become apparent from the following description.

According to the present invention, the above objects and advantages of the present invention are first,

A biaxially oriented film composed mainly of polyethylene-2,6-naphthalenedicarboxylate, wherein the thermal contraction rate of the film when heat-treated at 200 ° C. for 10 minutes is 1.00% or less in both the film forming direction and the width direction of the film. It is achieved by a base film for wafer processing.

In addition, according to the present invention, the above objects and advantages of the present invention are second,

The base film for semiconductor wafer processing is also achieved by the base film for semiconductor wafer processing of the said 1st this invention which is for backgrinding tape or a dicing tape.

Moreover, according to this invention, the said objective and advantage of this invention are 3rd,

The extraction oligomer amount of the film is 0.8% by weight or less, and the refractive index in the thickness direction of the film is also achieved by the base film for processing a semiconductor wafer according to the first aspect of the present invention, which is 1.501 or more and 1.515 or less.

According to the present invention, the above object and advantages of the present invention are fourth,

Dicing which has an adhesive layer on the single side | surface of the base film for dicing tapes of the backgrinding tape which has an adhesive layer in the single side | surface of the base film for backgrinding tape of the said 1st or 2nd this invention, and said 1st or 2nd this invention Is achieved by at least one of the tapes.

Further, according to the present invention, the above objects and advantages of the present invention are fifth,

Of the backgrinding tape composite having a release film further on the pressure-sensitive adhesive layer of the backgrinding tape of the fourth invention, and the dicing tape composite having the release film further on the pressure-sensitive adhesive layer of the dicing tape of the fourth invention Achieved by at least one.

Effects of the Invention

The base film for semiconductor wafer processing of the present invention is excellent in excellent dimensional stability, smoothness and mechanical strength under high temperature and high humidity. It is especially preferable as a dicing tape or backgrinding tape used for semiconductor wafer processing.

Best Mode for Carrying Out the Invention

<Polyethylene-2,6-naphthalenedicarboxylate film>

In the present invention, the base film for semiconductor wafer processing may be a copolymer or a mixture having polyethylene-2,6-naphthalenedicarboxylate (hereinafter sometimes referred to as PEN) as a main component. In this polyethylene-2,6-naphthalenedicarboxylate, the main dicarboxylic acid component is naphthalenedicarboxylic acid, and the main glycol component is ethylene glycol. Here, as naphthalenedicarboxylic acid, 2, 6- naphthalenedicarboxylic acid, 2, 7-naphthalenedicarboxylic acid, 1, 5- naphthalenedicarboxylic acid, etc. are mentioned, for example, 2, 6-naphthalenedicarboxylic acid is preferred. In addition, main means that at least 80 mol% of all the repeating units are ethylene-2,6-naphthalenedicarboxylate in the structural component of the polymer which is a component of the film of this invention, More preferably, it is 90 mol% or more Especially preferably, it is 95 mol% or more. In other words, the polyethylene-2,6-naphthalenedicarboxylate film original properties of the present invention do not have to lose extremely the original characteristics, it is only necessary to ensure the dimensional stability and mechanical strength under high temperature use.

In the case of a copolymer, the compound which has two ester-forming functional groups in a molecule | numerator can be used as a copolymerization component which comprises copolymers other than ethylene-2,6-naphthalenedicarboxylate which is a main component. As such a compound, for example, oxalic acid, adipic acid, phthalic acid, sebacic acid, dodecanedicarboxylic acid, isophthalic acid, terephthalic acid, 1,4-cyclohexanedicarboxylic acid, 4,4'-diphenyldicarboxyl Dicarboxylic acids such as acid, phenylindandicarboxylic acid, 2,7-naphthalenedicarboxylic acid, tetralindicarboxylic acid, decalindicarboxylic acid, diphenyletherdicarboxylic acid and the like can be preferably used. have. Moreover, oxycarboxylic acid, such as p-oxybenzoic acid and p-oxyethoxy benzoic acid, can also be used preferably. Moreover, propylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, cyclohexane methylene glycol, neopentyl glycol, the ethylene oxide addition product of bisphenol sulfone, the ethylene oxide addition product of bisphenol A, diethylene glycol, polyethylene oxide glycol Dihydric alcohols, such as these, can also be used preferably.

These compounds can use not only 1 type but 2 types or more simultaneously. Among these compounds, isophthalic acid, terephthalic acid, 4,4'-diphenyldicarboxylic acid, 2,7-naphthalenedicarboxylic acid, p-oxybenzoic acid as the acid component, and trimethylene glycol, Preference is given to ethylene oxide adducts of hexamethylene glycol neopentyl glycol and bisphenol sulfone.

In addition, the polyethylene-2,6-naphthalenedicarboxylate used by this invention uses a monofunctional compound, such as benzoic acid and a methoxy polyalkylene glycol, for example, to partially or all of the terminal hydroxyl group and / or carboxyl group. It may be blocked. In addition, the polyethylene-2,6-naphthalenedicarboxylate used in the present invention is copolymerized within a range in which a substantially linear polymer is obtained with an extremely small amount of trifunctional or higher ester-forming compounds such as glycerin and pentaerythritol. It may be done.

Moreover, the film of this invention may be the mixture which mixed other organic polymer other than the polyethylene-2,6-naphthalenedicarboxylate which is a main component. Such organic polymers include polyethylene terephthalate, polyethylene isophthalate, polytrimethylene terephthalate, polyethylene-4,4'-tetramethylenediphenyldicarboxylate, polyethylene-2,7-naphthalenedicarboxylate, and polytrimethylene- 2,6-naphthalenedicarboxylate, poly neopentylene-2,6-naphthalenedicarboxylate, poly (bis (4-ethyleneoxyphenyl) sulfone) -2,6-naphthalenedicarboxylate, etc. are mentioned. Can be. Among these, polyethylene isophthalate, polytrimethylene terephthalate, polytrimethylene-2,6-naphthalenedicarboxylate, and poly (bis (4-ethyleneoxyphenyl) sulfone) -2,6-naphthalenedicarboxylate are desirable.

The organic polymer mixed with these PEN may use not only 1 type but 2 types or more together. The proportion of the organic polymer to be mixed with PEN is in the range of 20 mol%, preferably 10 mol% or less, particularly preferably 5 mol% or less in the repeating units of the polymer. The preparation of such a mixture can be carried out by a generally known method for producing a polyester composition.

The polyester used by this invention can be obtained by a conventionally well-known method. For example, in the reaction of dicarboxylic acid and glycol, after directly obtaining a low-polymerization polyester or transesterifying the lower alkyl ester of dicarboxylic acid and glycol using a conventionally known transesterification catalyst, What is necessary is just to perform a polymerization reaction in presence of a polymerization catalyst. As a transesterification catalyst, the compound containing sodium, potassium, magnesium, calcium, zinc, strontium, titanium, zirconium, manganese, cobalt is mentioned, for example, These may use together 1 type (s) or 2 or more types. Examples of the polymerization catalyst include antimony compounds such as antimony trioxide, antimony tetraoxide, antimony pentoxide, antimony trichloride, antimony tribromide, antimony glycolate, and antimony acetate, germanium compounds represented by germanium dioxide, tetraethyl titanate, and tetrapropyl titanate. And titanium compounds such as tetraphenyl titanate or a partial hydrolyzate thereof, titanyl ammonium oxalate, potassium titanyl oxalate and titanium trisacetylacetonate.

Among the above polymerization catalysts, germanium compounds are particularly preferably used. Using such a germanium compound as a polycondensation reaction catalyst, for example, from the completion of the esterification reaction or the transesterification reaction to immediately after the start of the polymerization reaction, the germanium compound is added to the obtained transesterification reaction, and heated under stirring at a reduced pressure to carry out the polycondensation reaction. It is preferable. In the present invention, as the germanium compound used for the polycondensation reaction catalyst, for example, a solution in which (A) amorphous germanium oxide (B) fine crystalline germanium oxide (C) germanium oxide is dissolved in water can be preferably used. Among these germanium oxides, germanium compounds such as crystalline germanium dioxide, amorphous germanium dioxide, germanium tetraethoxide, germanium tetra-n-butoxide and the like can be preferably used, and in particular, crystalline germanium dioxide and amorphous germanium dioxide can be used. It can be used preferably.

If the amount of the germanium compound used in the polycondensation reaction catalyst is too small, a sufficient effect of promoting the polymerization reaction is not obtained, and if the content is extremely high, the softening point of the polyester obtained may be lowered. As a metal element, Preferably it is 10-1000 weight ppm, More preferably, it is 10-500 weight ppm, More preferably, it is 10-200 weight ppm. In addition, the concentration of the metal element of germanium is set to a scanning electron microscope (SEM, trade name "S570" manufactured by Hitachi Measuring Instruments Service Co., Ltd.), and the energy dispersive X-ray microanalyzer (XMA) connected thereto. , Brand value "EMAX-7000" manufactured by Horiba Corporation.

When superposing | polymerizing via transesterification, it is preferable to contain a phosphorus compound for the purpose of inactivating a transesterification catalyst before a polymerization reaction. Examples of such phosphorus compounds include phosphoric acid, phosphorous acid, phosphonic acid, phosphonate compounds and derivatives thereof, and these may be used alone or in combination of two or more thereof. Among these, as a phosphorus compound, the phosphonate compound represented by following formula (I) is preferable.

R ¹ OC (O) -XP (O)-(OR ² ) _{2 ...} (I)

Here, the expression of, R ¹ and R ² are alkyl groups of 1 to 4 carbon atoms Suwon, X is -CH ₂ - or -CH (Y) - (. Y represents a phenyl group), and, R ¹ and R ² are each It may be same or different.

Particularly preferred phosphorus compounds are carbomethoxymethanephosphonic acid, carboethoxymethanephosphonic acid, carbopropoxymethanephosphonic acid, carbobutoxymethanephosphonic acid, carbomethoxy-phosphono-phenylacetic acid, carboethoxy- Dimethyl esters, diethyl esters, dipropyl esters and dibutyl esters of phosphono-phenylacetic acid, carbopropoxy-phosphono-phenylacetic acid and carbobutoxy-phosphono-phenylacetic acid.

In the present invention, the reason why these phosphonate compounds are preferable is that the reaction time with the metal compound proceeds relatively slowly compared to the phosphorus compound which is usually used as a stabilizer, so that the duration of the catalytic activity of the metal compound during the polycondensation reaction This is because the addition amount of the catalyst to the polyester can be reduced as a result, and even if a large amount of stabilizer is added to the catalyst, it is difficult to impair the thermal stability of the polyester.

The addition time of these phosphorus compounds may be any time after the transesterification reaction is substantially complete, for example, under atmospheric pressure before starting the polycondensation reaction, under reduced pressure after starting the polycondensation reaction, and at the end of the polycondensation reaction. Or you may add after the completion of a polycondensation reaction, ie, after obtaining a polymer.

It is preferable that content of a phosphorus compound is 20-100 ppm by weight in polyethylene-2,6-naphthalenedicarboxylate as a phosphorus element in a phosphorus compound from a thermal stability viewpoint of polyester.

Polyethylene-2,6-naphthalenedicarboxylate in the present invention uses 2,6-naphthalenedicarboxylic acid and ethylene glycol as raw materials, but is 2,6-naphthalenedicar represented by 2,6-dimethylnaphthalate. The ester forming derivative of an acid and ethylene glycol may be used as a raw material. In the manufacturing method via a transesterification reaction, the addition amount of a metal compound can be further reduced by performing transesterification reaction under pressurization of 0.05 Mpa or more and 0.20 Mpa or less.

In addition, the polyester used in the present invention may be chipped after melt polymerization, and may be subjected to solid phase polymerization under heating and reduced pressure or in an inert air stream such as nitrogen. In order to reduce the amount of extraction oligomer of a film, solid-state polymerization can also be performed suitably in this invention.

Moreover, it is preferable that the intrinsic viscosity of the polymer which consists of polyethylene-2, 6- naphthalenedicarboxylate as a main component is 0.40 dl / g or more and 0.90 dl / g or less. In addition, intrinsic viscosity is the value (unit: dl / g) measured at 25 degreeC using o-chlorophenol as a solvent.

<Additive>

In order to provide slipperiness | lubricacy to a film, it is preferable to contain inert particle in a small ratio to the base film for semiconductor wafer processing of this invention. Examples of such inert particles include spherical silica, porous silica, calcium carbonate, alumina, inorganic particles such as titanium dioxide, kaolin clay, barium sulfate and zeolite, or organic particles such as silicone resin particles and crosslinked polystyrene particles. The inorganic particles are more preferable than natural products for reasons such as uniform particle size. The crystal form, hardness, specific gravity, and color of the inorganic particles are not particularly limited and may be used depending on the purpose.

Specific inorganic particles include calcium carbonate, porous silica, spherical silica, kaolin, talc, magnesium carbonate, barium carbonate, calcium sulfate, barium sulfate, lithium phosphate, calcium phosphate, magnesium phosphate, aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, Lithium fluoride and the like.

Among these, calcium carbonate particles, spherical silica particles, porous silica particles, and plate aluminum silicate are particularly preferable.

Examples of the organic particles include organic salt particles and crosslinked polymer particles. Examples of such organic salt particles include calcium oxalate, terephthalate such as calcium, barium, zinc, manganese and magnesium. Moreover, as a crosslinked polymer particle, the homopolymer or copolymer of the vinylic monomer of divinylbenzene, styrene, acrylic acid, or methacrylic acid is mentioned, for example. Moreover, organic particles, such as a polytetrafluoroethylene, a silicone resin, a benzoguanamine resin, a thermosetting epoxy resin, an unsaturated polyester resin, a thermosetting urea resin, and a thermosetting phenol resin, are also mentioned preferably. Among the crosslinked polymer particles, silicone resin particles and crosslinked polystyrene particles are particularly preferable.

The particle diameter of the inert particles added in these films is preferably 0.05 µm or more and 5 µm or less, more preferably 0.08 µm or more and 3.5 µm or less, more preferably 0.10 µm or more and 3 µm or less, for each kind of particles. Particularly preferred. Moreover, it is preferable that the total addition amount of the inert particle contained in a film is 0.05 weight% or more and 3 weight% or less, More preferably, it is 0.08 weight% or more and 2.0 weight% or less, Especially it is 0.1 weight% or more and 1.0 weight% or less desirable.

The inert particles added to the film may be a single component selected from those exemplified above, or may be a multicomponent containing two components or three or more components. In addition, when it is a single component, you may contain two or more types of particle | grains from which an average particle diameter differs.

In addition, the average particle diameter of inert particle | grains is measured using the brand name "CP-50 type centrifugal particle size analyzer (Centrifugal Particle Size Annalyzer)" made by Shimadzu Corporation, and is calculated based on the centrifugal sedimentation curve obtained from the measurement. It is the value which read | required the particle size corresponded to 50 weight% from the particle | grain of each particle diameter and the accumulation amount of the abundance (refer to "particle size measurement technology" Nikkan Kogyo Shimbun, 242-247 pages 1975).

The film of the present invention is 0.05 wt% or more and 0.4 wt% or less for calcium carbonate particles having an average particle size of 0.3 μm or more and 0.8 μm or less, and / or 0.03 wt% or more and 0.5 wt% for the spherical silica particles having an average particle size of 0.1 μm or more and 0.6 μm or less. In particular, it is particularly preferable to contain silicon particles having an average particle diameter of 0.1 µm or more and 0.6 µm or less in a proportion of 0.03% by weight or more and 0.4% by weight or less. In addition, the same kind of inert particles may contain particles of different particle diameters at the same time, and in that case, the content of all of the same kind of inert particles may be in the above range.

The film of this invention can mix | blend a crystal nucleating agent, antioxidant, a heat stabilizer, a lubricating agent, a flame retardant, an antistatic agent, a polysiloxane, etc. according to the use.

The addition time of inert particle | grains and other additives will not be restrict | limited especially if it is a step until film forming polyethylene-2,6-naphthalenedicarboxylate, For example, you may add in a superposition | polymerization step, and may add at the time of film forming. . From the standpoint of uniform dispersion, it is preferable to add inert particles or other additives in ethylene glycol, add them in high concentration at the time of polymerization to make a master chip, and dilute the obtained master chip with no additive chip.

<Base film>

The base film for semiconductor wafer processing of this invention is a biaxially-oriented film which consists of the above-mentioned polyethylene-2, 6- naphthalenedicarboxylate as a main component. The base film (which may be abbreviated as a film) in this invention may consist of a single layer or two or more layers, and what consists of two or more layers of the flatness of the contact surface with a semiconductor wafer, and a base film It is preferable at the point which compatible winding property. Co-extrusion method, extrusion lamination method, coating method, etc. can be used as a means which comprises two or more layers. Although it does not specifically limit, From the viewpoint of productivity, the polyethylene-2,6-naphthalenedicarboxylate mentioned above is used. It is preferable to comprise multiple layers by the coextrusion method which uses each and extrudes resin from several extruder.

Moreover, it is preferable that the base film for semiconductor wafer processing of this invention is for a backgrinding tape or a dicing tape.

<Heat shrinkage rate>

As for the film of this invention, the heat shrink rate at the time of heat processing at 200 degreeC for 10 minutes is 1.00% or less in the film forming direction and the width direction of a film. The heat shrinkage of the film of the present invention is more preferably -0.20% or more and 0.80% or less, and particularly preferably -0.10% or more and 0.60% or less. In this invention, unless otherwise indicated, a film forming direction refers to the advancing direction at the time of continuous film forming of a film, and may be called a longitudinal direction, a longitudinal direction, a continuous film forming direction, or MD direction of a film. In addition, in this invention, the width direction refers to the direction orthogonal to the film forming direction in the film surface inside direction, and may be called a horizontal direction or TD.

When the heat shrinkage ratio when the heat treatment is performed at a temperature of 200 ° C. for 10 minutes exceeds 1.00%, when the temperature in the semiconductor wafer processing step becomes a high temperature, the dimensional shrinkage of the base film increases, while the wafer thermally expands, During the process, the wafer may fall off from the adhesive of the tape or, in some cases, the wafer may be damaged because of the thin thickness of the wafer. When the thermal contraction rate is less than -0.20%, that is, when thermally expanding, the thermal expansion of the base film is larger than that of the wafer, and the adhesive of the tape may return to the surface of the wafer from the periphery of the wafer. In addition, when the shrinkage or expansion of the film is larger than the range of the present invention, it is not preferable in any case because the semiconductor wafer loaded on the tape is bent due to the difference with the expansion rate of the wafer. In addition, when the expansion ratio of the film is larger than that of the semiconductor wafer, the wafer is bent inward to cause the chips to compete with each other. Therefore, it is necessary to minimize the expansion of the film, that is, the direction in which the thermal shrinkage becomes negative. have.

Moreover, in order to obtain the film which has a desired thermal contraction rate, it is more preferable to carry out the heat relaxation process of a film, after carrying out biaxial stretching and heat setting in manufacture of a film.

<Extract oligomer amount>

It is preferable that the oligomer extraction amount of the film of this invention is 0.8 weight% or less on the conditions which extract for 24 hours using chloroform. More preferably, it is 0.6 weight% or less, Especially preferably, it is 0.5 weight% or less. When the amount of the oligomer extracted exceeds 0.8% by weight, when used as a base film for semiconductor wafer processing, the oligomer is precipitated on the surface of the base film under the processing temperature environment in the process or during the pressure-sensitive adhesive layer laying process, and the contamination in the processing process, the pressure-sensitive adhesive layer and the base It may cause problems, such as the adhesive strength between films falling. In order to suppress precipitation of the oligomer on the film surface, it is most effective to reduce the amount of oligomer contained in the film, and it is preferable to reduce the amount of oligomer extraction for this use.

In addition, in order to reduce the amount of oligomer extraction and make it a desired range, it is preferable to make the intrinsic viscosity of polyethylene-2,6-naphthalenedicarboxylate 0.44 dl / g or more and 0.90 dl / g or less, More preferably, it is 0.48- 0.85 dl / g, particularly preferably 0.50 to 0.80 dl / g. When the intrinsic viscosity of polyethylene-2,6-naphthalenedicarboxylate does not reach the lower limit, the amount of the extracted oligomer of the film becomes too large, whereas when the upper limit is exceeded, an excessive load may be required in the polymerization and film forming process. .

In addition, in order to make an oligomer extraction amount into the desired range, it is preferable that the intrinsic viscosity of a film is 0.40-0.90 dl / g. Moreover, intrinsic viscosity is the value (unit: d1 / g) measured at 25 degreeC using o-chlorophenol as a solvent.

<Refractive index in the thickness direction>

It is preferable that the refractive index nz of the thickness direction of the film of this invention is 1.501 or more and 1.515 or less. More preferably, they are 1.503 or more and 1.513 or less, Especially preferably, they are 1.504 or more and 1.512 or less. If the refractive index in the thickness direction is less than 1.501, the delamination resistance of the film deteriorates, so that burrs are generated in the cut end surface of the film, and in some cases, the cutting powder may contaminate the inside of the process. Moreover, when the refractive index of thickness direction exceeds 1.515, a film will become weak and film breakage may arise at the time of tape peeling when it is used as a base film of a backgrinding tape or a dicing tape.

Moreover, in order to obtain the film which has a desired refractive index in the thickness direction of a film, it is possible by raising the heat setting temperature at the time of base film manufacture, or decreasing the draw ratio of a vertical direction or a horizontal direction.

<Deviation of film thickness>

It is preferable that the deviation of the film thickness of this invention is 15% or less with respect to the average thickness of a film, It is more preferable that it is 10% or less, It is especially preferable that it is 8% or less. The smaller the film thickness variation, the more uniform the adhesive strength of the backgrinding tape, the semiconductor wafer, and the bonding surface of the dicing tape and the semiconductor wafer, and the more stable the taping, the more accurate the backgrinding and the dicing becomes possible. It is possible to supply chips suitable for high density.

<Young's modulus>

It is preferable that the Young's modulus of the film of this invention is 540 Mpa or more and 690 Opa or less in any direction of the film forming direction and the width direction of a film, More preferably, it is 5500 Mpa or more and 6800 Mpa or less, Especially preferably, it is 5600 Mpa or more and 6700 Mpa or less It is as follows. Moreover, it is preferable that the difference of the Young's modulus of both directions is 1000 Mpa or less.

When Young's modulus is less than 5400 Mpa, the rigidity of a film will run out and the thin film of the base film for semiconductor wafer processing which utilizes the high modulus of elasticity of a polyethylene-2,6-naphthalenedicarboxylate film may become difficult. Moreover, when Young's modulus exceeds 6900 Mpa, a lot of cutting powder will generate | occur | produce easily at the time of cutting of a film, and it may contaminate the process in a clean state. In addition, when picking up each cut chip, it is difficult to expand the tape and to lift the chip from the tape side, resulting in a decrease in production efficiency.

<Surface roughness (Ra)>

It is preferable that center line average surface roughness Ra in the at least single side | surface of the film of this invention is 3 nm or more and 80 nm or less, More preferably, they are 5 nm or more and 60 nm or less, Especially preferably, they are 7 nm or more and 50 nm or less. Moreover, when a film is a two or more layered constitution, it is preferable that the sum of Ra of both surfaces of a film is 10 nm or more, and it is more preferable that it is 14 nm or more. Here, center line average roughness (Ra) is a method prescribed | regulated to JIS B-0601, cut-off is 0.15 mm, and the measuring needle is a thing of radius of 3 micrometers, The surface roughness meter (brand made by Kosaka Research Institute) Surfcoder SE-30C "or Tokyo Precision Co., Ltd. product name" Surcomb SE-3 CK ").

When Ra is less than 3 nm, the film slips, and the scratches easily occur on the surface of the film during conveyance during film production and the winding of the film, or when air is wound between the film and the film when the film is wound in a roll state, It is hard to fall out and the flat air of a film may be impaired by the generated accumulated air. On the other hand, when Ra exceeds 80 nm, since a film is too slippery, winding shift may occur frequently in the winding of a film, or the winding after coating an adhesive layer on the film surface, and making it into a tape.

<Film density>

It is preferable that the density of the film of this invention is 1.356 g / cm <3> or more and 1.364 g / cm <3> or less. More preferably, it is 1.357 g / cm <3> or more and l.362g / cm <3> or less. When the density is less than 1.356 g / cm 3, the crystallinity of the film is low, and thus the dimensional stability in the semiconductor wafer processing process may be insufficient. In addition, when the density exceeds 1.364 g / cm 3, the crystallinity becomes too high and the toughness of the film is lost, and thus it is easy to break when the tape is peeled off when the backgrinding tape or the dicing tape is used as the base material. In addition, the density of a film is the value measured by the immersion method at 25 degreeC in the density gradient which used the calcium nitrate aqueous solution as a solvent.

<Average Thickness of Film>

It is preferable that the average thickness of the film of this invention is 9 micrometers or more and 150 micrometers or less, More preferably, they are 9 micrometers or more and 125 micrometers or less, Especially preferably, they are 12 micrometers or more and 100 micrometers or less. If the average thickness of a film is less than 9 micrometers, the mechanical strength as a support body in wafer processing, and the protective function of a wafer surface may be insufficient. On the other hand, if the average thickness of the film exceeds 150 µm, the stiffness of the film becomes very strong, and if the adhesive strength of the tape is slightly strong, the wafer is broken during peeling of the tape, or the force for expanding the film after dicing is increased. It may be too big.

Dynamic Friction Coefficient

As for the film of this invention, it is preferable that the dynamic friction coefficient (micro d) of films is 0.5 or less. If the dynamic friction coefficient (μd) exceeds 0.5, the handling property during the film forming process and the pressure-sensitive adhesive layer coating process becomes poor, and for example, defects such as wrinkles and scratches during running on the roll in the process or winding up in a roll shape Generates.

<Difference in Heat Shrinkage Rate>

The thermal contraction rate of the film when the film of the present invention was heat-treated at 200 ° C. for 10 minutes is the absolute value (| SMD-STD |) of the difference between the thermal contraction rate (SMD) in the film forming direction and the thermal contraction rate (STD) in the width direction. It is preferable that it is 0.60% or less. This value is more preferably 0.50% or less, particularly preferably 0.40% or less. When the absolute value of the difference in thermal contraction rate exceeds 0.60%, when used as a base film of a backgrinding tape or a dicing tape, the anisotropy of the dimensional change amount of a film is large, and a semiconductor wafer may be bent.

<Backgrinding tape>

The backgrinding tape in this invention has an adhesive layer on the single side | surface of the base film for backgrinding tape mentioned above. In the backgrinding step, which is the polishing step of the backside of the semiconductor wafer, the backgrinding tape having an adhesive layer laminated on one side of the base film for backgrinding tape is used for fixing the silicon wafer, so that the silicon wafer can be fixed in a stable state. do.

<Dicing tape>

The dicing tape in this invention has an adhesive layer in the single side | surface of the base film for dicing tape mentioned above. In a dicing step, which is a step of cutting an IC chip from a semiconductor wafer, the silicon wafer is fixed in a stable state by using a dicing tape having an adhesive layer laminated on one side of a base film for dicing tape for fixing the silicon wafer. You can do it.

<Application layer>

In the base film for backgrinding tape or dicing tape of this invention, an application layer can be formed in the at least single side | surface on the purpose of improving the adhesiveness with an adhesive. It is preferable that an application layer consists of at least 1 sort (s) of water-soluble or water-dispersible polymer resin chosen from polyester resin, urethane resin, acrylic resin, and vinyl resin, and it is especially preferable to contain both a polyester resin and an acrylic resin. . As for the polyester resin of the coating layer used by this invention, a glass transition point (Tg) is 0-100 degreeC, More preferably, it is 10-90 degreeC. The polyester resin is preferably a soluble or dispersible polyester in water, but may contain some organic solvent.

Such polyester resin consists of the following polybasic acid or its ester formation derivative (s), and a polyol or its ester formation derivative (s). That is, as the polybasic and acid component, terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid, trimellitic acid, Pyromellitic acid, dimer acid, 5-sodium sulfoisophthalic acid, and the like. Two or more of these acid components are used to synthesize a copolyester resin. It is also possible to use hydroxycarboxylic acids such as maleic acid, itaconic acid and the like, and p-hydroxybenzoic acid, which are small amounts of unsaturated polybasic acid components. As the polyol component, ethylene glycol, 1,4-butanediol, diethylene glycol, dipropylene glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, xylene glycol, dimethylol propane, poly (ethylene jade Seed) glycol, poly (tetramethylene oxide) glycol, bisphenol A, ethylene oxide or propylene oxide adduct of bisphenol A, etc. are mentioned, It is not limited to these.

As for the acrylic resin of the coating layer used by this invention, a glass transition point (Tg) is -50-50 degreeC, More preferably, it is -50-25 degreeC. The acrylic resin is preferably soluble or dispersible acrylic in water, but may contain some organic solvent.

As such an acrylic resin, it can copolymerize from the following acrylic monomers. As this acryl monomer, alkyl acrylate and alkyl methacrylate (as an alkyl group, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclo Hexyl group etc.); Hydroxy-containing monomers such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, and 2-hydroxypropyl methacrylate; Epoxy group-containing monomers such as glycidyl acrylate, glycidyl methacrylate and allyl glycidyl ether; Monomers containing carboxyl groups or salts thereof such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrenesulfonic acid and salts thereof (sodium salt, potassium salt, ammonium salt, tertiary amine salt and the like); Acrylamide, methacrylamide, N-alkylacrylamide, N-alkyl methacrylamide, N, N-dialkylacrylamide, N, N-dialkyl methacrylate (as alkyl group, methyl group, ethyl group, n-propyl group, Isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group, etc.), N-alkoxy acrylamide, N-alkoxy methacrylamide, N, N- dialkoxy acryl Amide, N, N- dialkoxy methacrylamide (as the alkoxy group, methoxy group, ethoxy group, butoxy group, isobutoxy group, etc.), acryloyl morpholine, N-methylol acrylamide, N-methylol methacrylamide Monomers containing amide groups such as N-phenylacrylamide and N-phenylmethacrylamide; Monomers of acid anhydrides such as maleic anhydride and itaconic anhydride; Vinyl isocyanate, allyl isocyanate, styrene, α-methyl styrene, vinyl methyl ether, vinyl ethyl ether, vinyl trialkoxysilane, alkyl maleic acid monoester, alkyl fumaric acid monoester, alkyl itaconic acid monoester, acrylonitrile, methacrylo Monomers such as nitrile, vinylidene chloride, ethylene, propylene, vinyl chloride, vinyl acetate, butadiene, and the like. Acrylic resin used as an application layer is not limited to these.

The composition used in the present invention is preferably used in the form of an aqueous coating solution such as an aqueous solution, an aqueous dispersion or an emulsion in order to form a coating film. In order to form a coating film, if necessary, other resins other than the composition, for example, polymers having an oxazoline group, melamine, epoxy, aziridine and other crosslinking agents, antistatic agents, colorants, surfactants, ultraviolet absorbers, lubricants (fillers) , Wax) and the like can be added. Such a lubricant may be added, if necessary, for the purpose of improving slipperiness or blocking resistance of the film.

It is preferable that it is 20 weight% or less normally, and, as for solid content concentration of an aqueous coating liquid, it is more preferable that it is 1-10 weight%. If this ratio is less than 1 weight%, the wettability to a polyester film will run short, and if it exceeds 20 weight%, stability of a coating agent and application appearance may deteriorate.

An application layer can be firmly formed on a film by apply | coating an aqueous coating liquid to the unstretched film or the film | membrane which uniaxial stretching was complete | finished, and extending | stretching and heat setting in 2 directions or 1 direction. As a coating method, the roll coating method, the gravure coating method, the roll brush method, the spray method, the air knife coating method, the impregnation method, the curtain coating method, etc. can be used individually or in combination.

<Adhesive>

Although the conventionally well-known thing can be widely used as an adhesive which comprises the backgrinding tape or dicing tape of this invention, an acrylic adhesive is preferable. Specifically as an acrylic adhesive, the copolymer with the acrylic polymer other functional monomers chosen from the homopolymer and copolymer which make an acrylate ester the main structural unit, and a mixture of these polymers are used. For example, acrylic acid ester of C1-C10 alkyl alcohol, methacrylic acid ester of C1-C10 alkyl alcohol, vinyl acetate, acrylonitrile, vinyl alkyl ether, etc. can be used preferably. In addition, the said acrylic copolymer can be used individually by 1 type or in combination of 2 or more types.

Moreover, acrylic acid, methacrylic acid, maleic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, etc. are used as a functional monomer. The copolymer pressure sensitive adhesive having a functional monomer can set the adhesive strength and the cohesion force to arbitrary values by using a crosslinking agent. Such crosslinking agents include polyhydric isocyanate compounds, polyvalent epoxy compounds, polyvalent aziridine compounds, chelate compounds and the like. Specific examples of the polyisocyanate compound include toluylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate and those of adduct type. Specifically as a polyvalent epoxy compound, ethylene glycol diglycidyl ether, terephthalic acid diglycidyl ester acrylate, etc. are used. Specific examples of the polyvalent aziridine compound include tris-2,4,6- (1-aziridinyl) -1,3,5-triazine and tris [1- (2-methyl) -aziridinyl] phosphine oxide. , Hexa [1- (2-methyl) -aziridinyl] triphosphatazine, and the like are used. As the chelate compound, ethylacetoacetate aluminum diisopropylate, aluminum tris (ethylacetoacetate) and the like are used.

The molecular weight of the acryl-type copolymer obtained by superposing | polymerizing these monomers is 1.0 * 10 <^5> -10.O * 10 <^5> , Preferably it is 4.O * 10 <^5> -8.O * 10 <^5> . Moreover, as an adhesive layer, what can harden | cure by irradiating a radiation and can reduce the adhesive force at the time of pickup can be used. It is preferable to use the adhesive which specifically made the said acryl-type copolymer the subject and contained the radiation polymeric compound in this. As such a radiation polymerizable compound, for example, as disclosed in JP-A-60-196,956 and JP-A-60-223,139, light in a molecule capable of shaping a three-dimensional network by light irradiation is disclosed. Low molecular weight compounds having at least two or more synthetic carbon-carbon double bonds are widely used, specifically trimethylolpropanetriacrylate, tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylic acid Latex, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate or 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, commercially available Oligoester acrylate etc. are used.

In addition to the above acrylate compound, a urethane acrylate oligomer may be used as the radiation polymerizable compound. The urethane acrylate oligomer is a polyol compound such as polyester type or polyether type, a polyhydric isocyanate compound such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, Acrylate or methacrylate which has a hydroxyl group in the terminal isocyanate urethane prepolymer obtained by making 1, 4- xylylene diisocyanate, diphenylmethane 4, 4- diisocyanate etc. react, for example 2-hydroxyethyl acrylate Or 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, polyethylene glycol acrylate, polyethylene glycol methacrylate, or the like. The urethane acrylate oligomer is a radiation polymerizable compound having at least one carbon-carbon double bond.

In particular, when the urethane acrylate oligomer has a molecular weight of 3000 to 30000, preferably 3000 to 10000, more preferably 4000 to 8000, even when the surface of the semiconductor wafer is rough, the surface of the chip at the time of pickup of the wafer chip is Since an adhesive does not adhere to it, it is preferable. In the case of using a urethane acrylate oligomer as a radiation polymerizable compound, a low molecular weight compound having at least two or more photopolymerizable carbon-carbon double bonds in a molecule disclosed in JP-A-60-196,956 is used. Compared with the adhesive sheet, what is very excellent is obtained. In other words, the adhesive force before irradiation of the pressure sensitive adhesive sheet is sufficiently large, and the adhesive force is sufficiently lowered after radiation irradiation, so that the adhesive does not remain on the chip surface during the pickup of the wafer chip.

If necessary, in addition to the pressure-sensitive adhesive and the radiation-polymerizable compound described above, the pressure-sensitive adhesive layer may contain a compound colored by radiation. By irradiating the pressure-sensitive adhesive sheet with radiation by containing such a colored compound in the pressure-sensitive adhesive layer by such radiation irradiation, the sheet is colored, and thus the detection accuracy increases when the wafer chip is detected by an optical sensor, resulting in a wafer chip. No malfunction occurs during pickup. In addition, the effect that the adhesive sheet is irradiated with the naked eye is immediately determined by the naked eye.

As a preferable specific example of the compound colored by irradiation, leuco dye is mentioned. As the leuco dye, conventional triphenylmethane-based, fluorane-based, phenothiazine-based, auramine-based and spiropyran-based ones are preferably used. As a developer used suitably with these leuco dyes, electron acceptors, such as the initial polymer of the phenol formalin resin, aromatic carboxylic acid derivative, activated clay, etc. which are used conventionally, are mentioned, and when changing a hue, various well-known A coloring agent can also be used in combination. The compound colored by such radiation irradiation may be contained in the pressure-sensitive adhesive layer once dissolved in an organic solvent or the like, or may be contained in the pressure-sensitive adhesive layer as a fine powder. This compound is preferably used in an amount of 0.01 to 10% by weight, preferably 0.5 to 5% by weight in the pressure-sensitive adhesive layer.

<Backgrinding Tape Composite>

In the present invention, the backgrinding tape is usually stored in the state of the backgrinding tape composite protected by the release film on the surface of the pressure-sensitive adhesive layer and used by peeling off the release film in the backgrinding step. That is, the backgrinding tape composite of the present invention further has a release film on the adhesive layer of the backgrinding tape.

Such a release film consists of laminating | stacking a silicone mold release layer on the single side | surface of the base film which consists of polyester, and bonds a silicone mold release layer surface and the adhesion layer surface of a backgrinding tape, and makes it a backgrinding tape composite. The release film may further have a primer layer between the silicone release layer and the base film which consists of polyester.

<Dicing Tape Composite>

In the present invention, the dicing tape is usually stored in the state of the dicing tape composite in which the surface of the pressure-sensitive adhesive layer is protected by the release film, and is used by peeling off the release film in the dicing step. That is, the dicing tape composite of the present invention further has a release film on the adhesive layer of the dicing tape.

Such a release film consists of laminating | stacking a silicone mold release layer on the single side | surface of the base film which consists of polyester, and joins a silicone mold release layer surface and the adhesion layer surface of a dicing tape, and is set as a dicing tape composite. The release film may further have a primer layer between the silicone release layer and the base film which consists of polyester.

<Polyester base film constituting a release film>

The polyester base film which comprises the release film of this invention may be comprised from the same polyester as the base film for semiconductor wafer processing of this invention, and may be comprised from different polyester. As such polyester, polyester which has polyethylene terephthalate and polyethylene-2,6-naphthalenedicarboxylate as a main component is illustrated preferably. The main means here that at least 80 mol% of all the repeating units in a component of a polymer is ethylene terephthalate or ethylene-2,6-naphthalenedicarboxylate, More preferably, it is 90 mol% or more, Especially preferable Preferably it is 95 mol% or more.

Moreover, it is preferable that the light transmittance of the base film is 85% or more in order that the polyester base film which comprises a mold release film may irradiate ultraviolet-ray, harden an adhesive, and reduce adhesive force after a backgrinding process and a dicing process.

<Silicone release layer>

The silicone mold release layer which comprises the mold release film of this invention can be formed by apply | coating the coating liquid containing curable silicone resin to the single side | surface of a polyester base film, and drying and hardening, for example. As curable silicone resin, the thing of all reaction systems, such as a condensation reaction system, an addition reaction system, an ultraviolet-ray, or an electron beam hardening system, is illustrated, It can use 1 or more types of these curable silicone resins.

<Production conditions>

The manufacturing method of the base film of this invention is described in detail. The polyethylene-2,6-naphthalenedicarboxylate film of the present invention is obtained by melt extrusion of a resin, for example, at a normal extrusion temperature, that is, at a melting point (hereinafter referred to as Tm) or more (Tm + 70 ° C) or lower. The film melt is quenched at the surface of the rotary cooling drum to obtain an unstretched film having an intrinsic viscosity of 0.40 to 0.90 dl / g. In this process, for the purpose of improving the adhesion between the film melt and the rotary cooling drum, an electrostatic adhesion method is known in which an electrostatic charge is applied to the film melt. In general, polyethylene-2,6-naphthalenedicarboxylate has a high electrical resistance of the melt, so that electrostatic adhesion with the cooling drum may be insufficient. As a countermeasure, it is preferable to contain the sulfonic acid quaternary phosphonium which has 0.1-10 mmol% ester formation functional group with respect to the total bifunctional carboxylic acid component of polyethylene-2, 6- naphthalenedicarboxylate.

The unstretched film thus obtained is stretched at a draw ratio of 2.8 to 3.5 times in the longitudinal direction at a temperature of 120 to 170 ° C, more preferably 130 to 160 ° C, and then 2.8 at a temperature of 120 to 150 ° C in the horizontal direction. It extends | stretches at the draw ratio of -3.6 times, and becomes a biaxially-oriented film. Moreover, it is preferable to make the lateral stretch magnification into about 0.90-1.15 times the magnification of a longitudinal stretch magnification in making the dispersion | variation of film thickness into a desired range. In addition, these extending | stretching may be multistage extending | stretching performed by dividing into several steps.

The biaxially oriented film thus obtained is preferably heat-set for 0.3 to 20 seconds at a temperature of 235 to 255 ° C, more preferably 240 ° C to 250 ° C. Thereafter, for the purpose of lowering the heat shrinkage rate, it is more preferable to perform a heat relaxation treatment in the longitudinal direction and / or in the transverse direction in the range of 0.5 to 15% of the relaxation rate. Moreover, on the mechanism of the stretching machine, it is generally easy to relax in the horizontal direction, and the heat shrinkage in the horizontal direction tends to be close to 0%. On the other hand, since it is difficult to reduce the thermal contraction rate in the longitudinal direction, in particular, the thermal contraction rate in the vicinity of 200 ° C, the stretching ratio and the stretching temperature in the longitudinal direction and the transverse direction as described above are effective.

Moreover, it is more preferable that the polyester film of this invention is heat-processed after winding in addition to the above-mentioned heat processing. Although the heat treatment method after winding is not specified, the relaxation heat treatment method of suspension type is especially preferable. Suspension type relaxation heat treatment method hangs down the film to be processed by self weight downward through the roller which installed upward, and heats in the middle, and changes direction to substantially horizontal direction, cooling with a lower roller, Winding in the state which interrupted winding tension is mentioned preferably. The distance to hang is good about 2-10m, and when it is less than 2m, self-weight is too small, flatness is easy to be damaged, and since a heating range is short, it is very difficult to obtain a relaxation effect. On the other hand, when the stretching distance exceeds 10 m, the workability is poor and the self weight becomes heavy, so the desired heat shrinkage rate may not be obtained depending on the position of the heating region.

Heat treatment after this film forming process may be performed in the film forming process of a film (relaxation after heat fixation), if the thermal contraction rate in 200 degreeC of the biaxially-oriented polyester film obtained becomes a desired range, and after film-forming and winding up a film once It may be performed by a relaxation heat treatment, and the treatment method is not particularly limited. The preferred heating method is infrared heating in that the film can be heated immediately. In addition, a preferable relaxation heat processing temperature is processing so that film temperature may be 200-240 degreeC. If the film temperature is less than 200 ° C, it is difficult to reduce the heat shrinkage at 200 ° C. On the other hand, if the film temperature exceeds 240 ° C, the flatness tends to deteriorate. In severe cases, the oligomer may precipitate and the film may become white. This whitening depends on the pressure history, for example, when conveying a hawk-like belt over the film part of a film roll, the part which contacted the belt may whiten even if it is 200 degrees C or less. In addition, a film temperature can be measured using a non-contact infrared thermometer (for example, a Barnes radiation thermometer). Among these heat treatment methods, the suspension type relaxation heat treatment method is preferable to the heat treatment in the film forming step because it is easier to suppress the heat shrinkage in a wide range of films more uniformly.

On the other hand, the polyester film which comprises a mold release film is known conventionally or can be obtained by the method accumulating in the art. That is, the unstretched film of the melted and extruded polyester is stretched in the uniaxial direction, then stretched in the direction perpendicular to the stretching direction, and further subjected to heat setting treatment. In this invention, a mold release layer can be coat | covered by apply | coating the coating liquid containing the component of a mold release layer to a polyester base film, and heat-drying, for example. As a coating method of a coating liquid, a well-known coating method can be applied, For example, the roll coater method and the blade coater method can be used. Each composite is obtained by bonding the release film obtained by the above method to a backgrinding tape or a dicing tape.

Hereinafter, the present invention will be described in more detail with reference to Examples. In addition, each characteristic value in an Example is measured or evaluated by the following method. In addition, the part and ratio in an Example represent a weight part and weight ratio unless there is particular notice.

(1) heat shrinkage

The film is held for 10 minutes in an untensioned state in an oven set at a temperature of 200 ° C, and the dimensional change before and after the heat treatment is calculated by the following formula (1) as the heat shrinkage ratio S (%).

S = [(L ₀ -L) / L ₀ ] × 100 (1)

However, L ₀ : distance between the gages before heat treatment and L: the distance between gages after heat treatment, respectively. Moreover, it is 20 mm in sample width, 200 mm in length, and the distance between the gages before heat processing is 150 mm. It measured in both directions of the film forming direction (MD) of the film, and the width direction (TD), and calculated | required thermal contraction rate.

(2) oligomer extraction amount

5 g of the film sample was extracted for 24 hours using a Soxhlet extractor in chloroform. By measuring the weight of the film sample after drying, before extraction was determined by the weight W ₀ (g) and then extracted to the oligomer extraction amount K (% by weight) from the weight W ₁ (g) (2).

K = [(W ₀ -W ₁ ) / W ₀ ] × 100 (2)

(3) Oligomer precipitation rate after heating

After fixing a film to a wooden frame, it hold | maintains in 160 degreeC hot air circulation (air) type | mold dryer for 10 minutes, and aluminum is deposited on a film surface, and the photograph of a film surface is taken with a differential interference optical microscope. The heating oligomer precipitation rate is evaluated as a percentage of the total photographic area of the sum of the areas occupied by the oligomer (taken as white spots) on this photograph.

○: less than 2.5% oligomer precipitation rate

△: oligomer precipitation rate 2.5-4.5%

X: oligomer precipitation rate 4.5% or more

(4) refractive index in the thickness direction of the film (nz)

Using an Abbe refractometer (manufactured by Atago Co., Ltd.), the refractive index in the thickness direction z of the film was determined using a Na-D line at 25 ° C.

(5) Young's modulus

The sample was cut into a width of 10 mm and a length of 150 mm, set to a length of 100 mm between the chucks, and pulled out by an instron type universal tensile test apparatus at a tensile speed of 10 mm / minute and a chart speed of 500 mm / minute. It measures in both directions of the film forming direction MD and the width direction TD of a film, and a Young's modulus is computed from the tangent of the rise part of the obtained load-extension curve.

(6) Center line average roughness (Ra)

By the method prescribed | regulated to JIS B-0601, cut-off is 0.25 mm and the measuring needle is measured with a surface roughness meter (trade name "Surcom SE-3CK" made by Tokyo Precision Co., Ltd.) using the thing of a radius of 3 micrometers.

(7) film thickness

Using a micrometer (trade name "K-402B type" manufactured by Anritsu Co., Ltd.), each film was measured at 10 cm intervals in the film-forming direction (MD) and the width direction (TD) of the film, and the film thickness was all 300 places. Measure Calculating the average of the film thickness of 300 points obtained to give the film an average thickness of t ₀ (㎛).

In addition, using an electron micrometer (trade name "K-312A type" manufactured by Anritsu Co., Ltd.), the length of the film forming direction (MD) and the width direction (TD) of the film, respectively, was set to 30 g of needle pressure and a traveling speed of 25 mm / sec. Measure over to get a continuous thickness chart. From this chart, the maximum thickness t ₁ (µm) and the minimum thickness t ₂ (µm) are read.

From the film average thickness t ₀ (micrometer), the maximum thickness t ₁ (micrometer), and the minimum thickness t ₂ (micrometer) obtained in this way, the deviation D (%) of thickness is calculated | required by following formula (3).

D = [(t ₁ -t ₂ ) / t ₀ ] × 100 (3)

(8) dynamic friction coefficient (μd)

A cut film (sample) of 75 mm (width) x 100 mm (length) was loaded on two sheets of a weight of 200 g as a load W (g), and the upper film was slid at a speed of 150 mm / min, The dynamic friction coefficient (mu d) is calculated from the force F _d (g) when sliding. In addition, the film is measured after humidity control at 23 degreeC and 65% RH for 24 hours. Dynamic Friction Coefficient = F _d / W

(9) difference in thermal contraction rate

The film was held for 10 minutes in an unstrained state in an oven set at 200 ° C, and (1) heat from the dimensional change before and after each heat treatment in each of the film forming direction (MD) and the width direction (TD) of the film. Similarly to the shrinkage rate, the heat shrinkage rate S (%) is calculated by the following equation (1), and the absolute value of the difference between the heat shrinkage rates in both directions is calculated.

S = [(L ₀ -L) / L ₀ ] × 100 (1)

However, L ₀ : distance between the gages before heat treatment and L: the distance between gages after heat treatment, respectively.

(10) density

The density of the biaxially oriented polyethylene-2,6-naphthalenedicarboxylate film was measured according to JIS C2151.

(11) water absorption

According to JIS K7209, the water absorption of the film was measured after immersion in water of 23 degreeC for 24 hours using the square base film of 50 mm in one side.

(12) dimensional stability

After leaving 100 degreeC in the atmosphere of 65 degreeC and 85% RH using a 25x25cm base film, the curl state of 4 corners was measured and the average value of the amount of curvature (mm) was measured. ○ passes.

○; Deflection less than 10mm

×; 10mm or more warpage

(13) Processability of Semiconductor Wafers (Backgrinding and Dicing)

An acrylic adhesive (copolymer of n-butyl acrylate and acrylic acid) was applied to the biaxially oriented polyethylene-2,6-naphthalenedicarboxylate film of each example and the comparative example so that it might become thickness of 14 micrometers, and the adhesive sheet was produced. The 8-inch silicon wafer was affixed on the adhesive layer of the obtained adhesive sheet, and the backgrinding of the wafer and the dicing test were performed, respectively. After dicing, the chips were picked up by a non-expandable die bonder. The conditions for dicing and pick-up at this time are dicing cutting depth: 20 micrometers from the tape surface, 4 lifting pins, 28 mm diameter of an adsorption holder, a collet: a pyramidal collet, a lifting distance: 2 mm, die | dye Singh size: 8 mm x 8 mm.

(14) Processability of Semiconductor Wafer (Backgrinding and Tape Peeling)

An acrylic adhesive (copolymer of n-butyl acrylate and acrylic acid) was applied to the biaxially oriented polyethylene-2,6-naphthalenedicarboxylate film of each example and the comparative example so that it might become thickness of 14 micrometers, and the adhesive sheet was produced. The 8-inch silicon wafer was affixed on the adhesive layer of the obtained adhesive sheet, and the backgrinding of the wafer and the test | inspection of tape peeling were performed, respectively. In addition, test conditions are backgrinding temperature: 180 degreeC and heat processing temperature before tape peeling: 150 degreeC.

Example 1

0.03 parts of manganese acetate tetrahydrate was added to a mixture of 100 parts of 2,6-naphthalenedicarboxylic acid dimethyl and 60 parts of ethylene glycol, and a transesterification reaction was carried out while gradually raising the temperature from 150 ° C to 240 ° C. On the other hand, 0.024 part of antimony trioxide was added at the time when reaction temperature reached 170 degreeC, and 0.2 weight% of the spherical silica particles of the average particle diameter of 0.4 micrometer and the particle size ratio 1.1 were further added. And 0.042 part (corresponding to 2 mmol%) of 3, 5- dicarboxy benzene sulfonate tetrabutyl phosphonium salt was added when reaction temperature reached 220 degreeC. Then, transesterification reaction was performed and 0.023 part of trimethyl phosphate was added after completion | finish of transesterification reaction. Subsequently, the reaction product was transferred to a polymerization reactor, the temperature was raised to 290 ° C, a polycondensation reaction was carried out under a high vacuum of 0.2 mmHg or less, and a polyethylene having an intrinsic viscosity of 0.62 dl / g measured with a 25 ° C o-chlorophenol solution. A -2,6-naphthalenedicarboxylate polymer (called "polymer C") was obtained. After drying this polymer C for 6 hours at 170 degreeC, it supplied to an extruder, melted at 305 degreeC of melting temperature, and rotated through the slit-shaped die of 1 mm of opening degree at surface finish 0.3S, and the rotating drum at surface temperature of 50 degreeC. Extruded onto to give an unstretched film.

The unstretched film thus obtained was stretched 3.3 times in the longitudinal direction (film forming direction) at 145 ° C, then stretched 3.4 times in the horizontal direction (width direction) at 140 ° C, and further heat-setting treatment at 243 ° C for 5 seconds and It contracted 5% in the width direction (toe-in), and wound the biaxially-oriented PEN film of thickness 16micrometer and intrinsic viscosity 0.52 dl / g in 1500 mm width at 3000 m roll shape. Thereafter, the obtained biaxially oriented PEN film is stretched downward by its own weight through the nip roller provided above, while being heated by an infrared heating device so that the film temperature becomes 225 ° C in the middle, and then 4 m downward from the roller installed above. While cooling with the nip roller at, the direction was changed substantially in the horizontal direction, the winding tension was interrupted with the nip roller, and then wound up, followed by a relaxation heat treatment. Relaxation was performed by giving a difference to the speed of the nip roller which blocks an upper nip roller, and winding tension.

Thus, the biaxially-oriented PEN film after relaxation heat processing obtained was made into Example 1.

Table 1 shows the results of characteristic evaluation of the film of Example 1 obtained. EXAMPLES The wafer workability of the film did not occur due to the malfunction of the die bonder device due to the change in the thermal dimension of the film, the thickness variation of the film, the flatness of the film, or the like, and a good pick-up operation was possible. Moreover, without damaging the inside of the adhesion layer laying process and the inside of a semiconductor wafer processing process, and there was no film damage at the time of tape peeling, the workability in manufacture of a semiconductor wafer was favorable.

Example 2

The same procedure as in Example 1 was repeated except that the stretching ratio in the longitudinal direction was set to 2.9 times, the stretching ratio in the horizontal direction was changed to 3.1 times, and the suspension-type relaxation heat treatment was not performed. The biaxially oriented PEN film having a thickness of 75 µm was repeated. Got.

Table 1 shows the characteristics evaluation results of the obtained film of Example 2. EXAMPLES The wafer workability of the film did not occur due to the malfunction of the die bonder device due to the change in the thermal dimension of the film, the thickness variation of the film, the flatness of the film, or the like, and a good pick-up operation was possible. Moreover, without damaging the inside of the adhesion layer laying process and the inside of a semiconductor wafer processing process, and there was no film damage at the time of tape peeling, the workability in manufacture of a semiconductor wafer was favorable.

Example 3

As Example 3, the film of the two-layered constitution was produced as follows. First, 0.03 part of manganese acetate tetrahydrate was added to the mixture of 100 parts of 2, 6-naphthalenedicarboxylic acid dimethyls, and 60 parts of ethylene glycol, and the ester exchange reaction was performed, heating up gradually from 150 degreeC to 240 degreeC. At the time when reaction temperature reached 170 degreeC, 0.024 part of antimony trioxide was added, and 0.15 weight% of calcium carbonate particles of 0.5 micrometer of average particle diameters were further added. And 0.042 part (corresponding to 2 mmol%) of 3, 5- dicarboxy benzene sulfonate tetrabutyl phosphonium salt was added when reaction temperature reached 220 degreeC. Then, transesterification reaction was performed and 0.023 part of trimethyl phosphate was added after completion | finish of transesterification reaction. Next, the reaction product was transferred to a polymerization reactor, heated to 290 ° C, subjected to a polycondensation reaction under a high vacuum of 0.2 mmHg or less, and a polyethylene having an intrinsic viscosity of 0.63 dl / g measured with a 25 ° C o-chlorophenol solution. A -2,6-naphthalenedicarboxylate polymer (called "polymer A") was obtained.

The polymer was subjected to a transesterification reaction in the same manner as in Polymer A, to which 0.02 parts of amorphous germanium dioxide was added as a polymerization catalyst, and 0.05% by weight of spherical silica particles having an average particle diameter of 0.1 µm and a particle size ratio of 1.1 were added. It superposed | polymerized similarly to A and obtained the polyethylene-2, 6- naphthalenedicarboxylate polymer (it calls "polymer B") whose intrinsic viscosity measured by the 25 degreeC o-chlorophenol solution is 0.63 dl / g.

Each of these polymers was dried at 170 ° C. for 6 hours, then fed to two respective extruders, each melted at a melting temperature of 300 ° C., and then surfaced through a slit-like die having an opening of 1 mm by coextrusion. It extruded on the rotating drum of finishing 0.3S and surface temperature of 50 degreeC, and obtained the unstretched film of the two-layered constitution. The unstretched film was biaxially stretched sequentially in the same manner as in Example 1, and subjected to heat setting to give a film thickness of 16 µm (polymer A layer side 10 µm / polymer B layer side 6 µm), 2 having an intrinsic viscosity of 0.54 dl / g. The axially oriented PEN film was wound into a roll shape of 3000 m at a width of 1500 mm. Thereafter, the biaxially oriented PEN film obtained in the same manner as in Example 1 was subjected to relaxation heat treatment using the same suspension heat treatment apparatus. The biaxially oriented PEN film after the relaxation heat treatment thus obtained was defined as Example 3.

Table 1 shows the results of characteristic evaluation of the film of the obtained example. In particular, regarding the wafer processability of these examples films, defects due to the malfunction of the die bonder device due to the change in the thermal dimension of the film, the variation in the thickness of the film, the flatness of the film, and the like did not occur, and good pick-up operation was possible. Moreover, without damaging the inside of the adhesion layer laying process and the inside of a semiconductor wafer processing process, and there was no film damage at the time of tape peeling, the workability in manufacture of a semiconductor wafer was favorable.

Comparative Example 1

Manufactured by Torre Dupont "Kapton; 50 micrometers film of type H "was used.

Table 1 shows the results of the evaluation of the characteristics of the film. Although the thermal dimension change of the film was very excellent, the water absorption was high, so that the dimensional stability was inferior under high humidity.

Comparative Example 2

0.03 parts of manganese acetate and tetrahydrate were added to a mixture of 100 parts of dimethyl terephthalate and 60 parts of ethylene glycol, and a transesterification reaction was carried out while gradually raising the temperature from 150 ° C to 240 ° C. On the other hand, 0.024 part of antimony trioxide was added at the time when reaction temperature reached 17 degreeC, and 0.2 weight% of the spherical silica particles of the average particle diameter of 0.4 micrometer and the particle size ratio 1.1 were further added. And 0.042 part (corresponding to 2 mmol%) of 3, 5- dicarboxy benzene sulfonate tetrabutyl phosphonium salt was added when reaction temperature reached 220 degreeC. Then, transesterification reaction was performed and 0.023 part of trimethyl phosphate was added after completion | finish of transesterification reaction. Subsequently, the reaction product was transferred to a polymerization reactor, the temperature was raised to 290 ° C, a polycondensation reaction was carried out under a high vacuum of 0.2 mmHg or less, and a polyethylene having an intrinsic viscosity of 0.62 dl / g measured with a 25 ° C o-chlorophenol solution. A terephthalate polymer was obtained. After drying this polymer at 170 degreeC for 3 hours, it supplied to an extruder and melted at the melting temperature of 290 degreeC, and through the slit-shaped die of 1 mm of opening degree, it finished surface rotation 0.3S and the rotating drum on surface temperature 25 degreeC. Extrusion was carried out to obtain an unstretched film.

The unstretched film thus obtained was stretched 3.2 times in the longitudinal direction (film forming direction) at 90 ° C, then 3.8 times in the transverse direction (width direction) at 120 ° C, and further heat-fixed at 210 ° C for 5 seconds and It shrink | contracted 5% in the width direction (toe-in), and wound the biaxially-oriented polyethylene terephthalate film which is thickness of 16 micrometers, and intrinsic viscosity of 0.55 dl / g in roll shape of 3000 m by 1500 mm width. Thereafter, the resulting biaxially orientated polyethylene terephthalate film is stretched downward by its own weight through the nip roller provided above, while being heated by an infrared heating device so that the film temperature becomes 180 ° C in the meantime, and then from the roller installed above. While cooling with the nip roller below 4m, the direction was changed to almost horizontal direction, the winding tension was interrupted | blocked by the nip roller, and it wound up and relaxed and heat-treated. Relaxation was performed by giving a difference to the speed of the nip roller which blocks an upper nip roller, and winding tension.

Thus obtained biaxially orientated polyethylene terephthalate film after the relaxation heat treatment was used as Comparative Example 2.

Table 1 shows the characteristics evaluation results of the obtained film of Comparative Example 2. Since the dimensional stability of a film was bad about the wafer workability, the position shift of a chip | tip etc. generate | occur | produced, and the defect by the malfunction of the die bonder apparatus generate | occur | produced. In addition, it was an amount of oligomer precipitation which contaminated in the adhesion layer laying process and the semiconductor wafer processing process. Moreover, the oligomer precipitation rate to the film surface after heating was also high.

Comparative Example 3

As Comparative Example 3, the same operation as in Example 2 was repeated except that the draw ratio in the vertical direction was changed to 3.6 times and the draw ratio in the horizontal direction was changed to 3.7 times to obtain a biaxially oriented PEN film having a thickness of 50 μm.

Table 1 shows the results of characteristic evaluation of the film of Comparative Example 3 obtained. The change in the thermal dimension of the film exceeded 1.00% in both the film longitudinal direction and the transverse direction, and chip dislocation and the like occurred in the wafer processability, and defects due to malfunction of the die bonder device occurred.

Comparative Example 4

In Comparative Example 4, the same operation as in Example 1 was repeated except that the draw ratio in the longitudinal direction was 3.6 times, and the draw ratio in the horizontal direction was changed to 3.9 times. An oriented PEN film was obtained.

Table 1 shows the results of characteristic evaluation of the film of Comparative Example 4 obtained. The change in the thermal dimension of the film exceeded 1.00% in the film longitudinal direction, the chip position shift and the like occurred with respect to the wafer workability, and a defect due to the malfunction of the die bonder device occurred.

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Layered fault fault Second floor fault fault fault fault Polymer Polymer C Polymer C Polymer A Polymer B - - Polymer C Polymer C Added particles Kinds Spherical silica Spherical silica Calcium carbonate Spherical silica - Spherical silica Spherical silica Spherical silica Particle diameter Μm 0.4 0.4 0.5 0.1 - 0.4 0.4 0.4 Amount weight% 0.20 0.20 0.15 0.05 - 0.20 0.20 0.20 Portrait Magnification ship 3.3 2.9 3.3 - 3.2 3.6 3.6 Temperature ℃ 145 145 145 - 90 145 145 Horizontal stretching Magnification ship 3.4 3.1 3.1 - 3.8 3.7 3.9 Temperature ℃ 140 140 140 - 120 140 140 Heat setting temperature ℃ 243 243 243 - 210 243 243 Suspension Relaxation Heat Treatment Temperature ℃ 225 No treatment 225 - 180 No treatment 225 Film intrinsic temperature dl / g 0.52 0.52 0.54 - 0.55 0.52 0.52 Film thickness Μm 16 75 16 50 16 50 20 Thickness deviation % 8 11 8 - 8 6 4 Heat shrinkage Portrait (MD) % 0.50 0.80 0.50 0.20 0.60 1.40 1.10 Horizontal (TD) % 0.05 0.30 0.05 0.10 0.10 1.20 0.30 Young's modulus Portrait (MD) MPa 6100 5600 6100 3700 5300 6500 6400 Horizontal (TD) MPa 6200 5800 6200 3700 5250 6600 7000 Surface roughness Nm 15 16 19 4 - 18 16 15 density g / cm 3 1.360 1.362 1.360 - - 1.357 1.358 Oligomer Extract weight% 0.4 0.5 0.5 - 1.3 - - Heating oligomer precipitation rate % ○ ○ ○ - × - - Water absorption % 0.3 0.3 0.3 1.3 0.4 - - Dimensional stability - ○ ○ ○ × × - - Processability of Semiconductor Wafers (Backgrinding and Dicing) Good Good Good Good Bad Bad Bad Processability of Semiconductor Wafers (Backgrinding and Tape Peeling) Good Good Good Good Bad Bad Bad

Example 4

0.03 parts of manganese acetate tetrahydrate was added to a mixture of 100 parts of 2,6-naphthalenedicarboxylic acid dimethyl and 60 parts of ethylene glycol, and a transesterification reaction was carried out while gradually raising the temperature from 150 ° C to 240 ° C. In the meantime, 0.024 part of antimony trioxide was added at the time when reaction temperature reached 170 degreeC, and 0.1 weight% of the spherical silica particles of the average particle diameter of 0.6 micrometer and the particle size ratio 1.1 were further added. And 0.042 part (corresponding to 2 mmol%) of 3, 5- dicarboxy benzene sulfonate tetrabutyl phosphonium salt was added when reaction temperature reached 220 degreeC. Then, transesterification reaction was performed and 0.023 part of trimethyl phosphate was added after completion | finish of transesterification reaction. Subsequently, the reaction product was transferred to a polymerization reactor, the temperature was raised to 290 ° C, a polycondensation reaction was carried out under a high vacuum of 0.2 mmHg or less, and a polyethylene having an intrinsic viscosity of 0.43 dl / g measured with a 25 ° C o-chlorophenol solution. A -2,6-naphthalenedicarboxylate polymer (polymer D) and a polyethylene-2,6-naphthalenedicarboxylate polymer (polymer E) having an intrinsic viscosity of 0.69 dl / g were obtained. Moreover, polymer E was solid-phase polymerized and the intrinsic viscosity was 0.78 dl / g (polymer F).

The polymer E was dried at 170 ° C. for 6 hours, then fed to an extruder, melted at a melting temperature of 305 ° C., and through a slit-shaped die having an opening of 1 mm, on a rotating drum at a surface finish of 0.3 S and a surface temperature of 50 ° C. Extrusion was carried out to obtain an unoriented film.

The unstretched film thus obtained was stretched 3.0 times in the longitudinal direction (film forming direction) at 145 ° C, then stretched 3.0 times in the horizontal direction (width direction) at 140 ° C, and heat-setting treatment at 246 ° C for 5 seconds and It contracted 4% in the width direction (toe-in), and wound up the biaxially-oriented PEN film which is 30 micrometers in thickness, and intrinsic viscosity 0.59 dl / g in roll shape of 3000 m by 1500 mm width. Thereafter, the obtained biaxially oriented PEN film is stretched downward by its own weight through the nip roller provided above, while being heated by an infrared heating device so that the film temperature becomes 225 ° C in the middle, and then 4 m downward from the roller installed above. While cooling with the nip roller at, the direction was changed in almost the horizontal direction, and the winding tension was cut off with the nip roller, followed by winding up, followed by relaxation heat treatment. Relaxation was performed by giving a difference to the speed of the nip roller which blocks an upper nip roller, and winding tension.

The biaxially oriented PEN film after the relaxation heat treatment thus obtained was defined as Example 4.

Table 2 shows the results of the evaluation of the properties of the film of Example 4 obtained. Example With respect to the wafer processability of the film, a defect due to malfunction of the die bonder device due to the change in the thermal dimension of the film, the thickness variation of the film, the flatness of the film, or the like did not occur, and good pick-up operation was possible. In addition, the film was not contaminated in the adhesion layer laying step and the semiconductor wafer processing step, and there was no film breakage at the time of peeling the tape, and the processability in the manufacture of the semiconductor wafer was good.

Example 5

Except having used the polymer F in Example 4, operation similar to Example 4 was repeated and the biaxially-oriented PEN film of thickness 50micrometer was obtained. Thus, the obtained biaxially-oriented PEN film was made into Example 5.

Table 2 shows the results of characteristic evaluation of the film of Example 5 obtained. EXAMPLES The wafer workability of the film did not occur due to the malfunction of the die bonder device due to the change in the thermal dimension of the film, the thickness variation of the film, the flatness of the film, or the like, and a good pick-up operation was possible. In addition, the film was not contaminated in the pressure-sensitive adhesive layer laying step and the semiconductor wafer processing step, and there was no film breakage at the time of peeling the tape, and the workability in manufacturing the semiconductor wafer was good.

Example 6

In Example 4, the same operation as in Example 4 was repeated except that the film was stretched 3.3 times in the longitudinal direction at 145 ° C and 3.3 times in the horizontal direction at 140 ° C, thereby obtaining a biaxially oriented PEN film having a thickness of 30 µm. The biaxially oriented PEN film thus obtained was referred to as Example 6.

Table 2 shows the characteristics evaluation results of the films of the obtained examples. EXAMPLES The wafer workability of the film did not occur due to the malfunction of the die bonder device due to the change in the thermal dimension of the film, the thickness variation of the film, the flatness of the film, or the like, and a good pick-up operation was possible. In addition, the film was not contaminated in the pressure-sensitive adhesive layer laying step and the semiconductor wafer processing step, and there was no film breakage at the time of peeling the tape, and the workability in manufacturing the semiconductor wafer was good.

Example 7

Except having used the polymer D in Example 4, operation similar to Example 4 was repeated and the biaxially-oriented PEN film of thickness 50micrometer was obtained. The biaxially oriented PEN film thus obtained was referred to as Example 7.

Table 2 shows the results of the evaluation of the properties of the film of Example 7 obtained. Regarding the wafer workability, failure due to malfunction of the die bonder due to the change in the thermal dimension of the film, the thickness variation of the film, the planarity of the film, or the like did not occur, and good pick-up operation was possible. On the other hand, in-process contamination occurred due to oligomer precipitation on the film surface.

Example 8

In Example 6, the same operation as in Example 6 was repeated except that the amount of the inert particles contained in the film was 0.01% by weight, and the heat setting temperature was 233 ° C. Got. The biaxially oriented PEN film thus obtained was referred to as Example 8.

Table 2 shows the results of the evaluation of the characteristics of the obtained film of Example 8. Although the change in the thermal dimension of a film is small about wafer workability, since the difference of the thermal contraction rate of a longitudinal direction and a horizontal direction exceeds a desired range, there existed a problem slightly in stability in manufacture of a semiconductor wafer.

Example 9

In Example 4, the same operation as in Example 4 was repeated except that the film was stretched 2.7 times in the longitudinal direction at 145 ° C and then 2.7 times in the horizontal direction at 140 ° C to obtain a biaxially oriented PEN film having a thickness of 30 µm. The biaxially oriented PEN film thus obtained was referred to as Example 9.

Table 2 shows the results of the evaluation of the properties of the obtained example films. Although the change of the thermal dimension of a film was small about wafer processability, the refractive index of the film thickness direction was high, and in-process contamination by the cutting part of a film, etc., and film breakage at the time of tape peeling generate | occur | produced.

Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Polymer E F E D E E Intrinsic Viscosity of Polymer dl / g 0.69 0.78 0.69 0.43 0.69 0.69 Added particles Kinds Spherical silica Spherical silica Spherical silica Spherical silica Spherical silica Spherical silica Particle diameter Μm 0.6 0.6 0.6 0.6 0.6 0.6 Amount weight% 0.1 0.1 0.1 0.1 0.01 0.1 Vertical stretching Magnification ship 3.0 3.0 3.3 3.0 3.3 2.7 Temperature ℃ 145 145 145 145 145 145 Horizontal stretching Magnification ship 3.0 3.0 3.3 3.0 3.3 2.7 Temperature ℃ 140 140 140 140 140 140 Heat setting temperature ℃ 246 246 246 246 233 246 Suspension Relaxation Heat Treatment Temperature ℃ 225 225 225 225 225 225 Film intrinsic viscosity dl / g 0.59 0.64 0.59 0.39 0.59 0.59 Film thickness Μm 30 50 30 50 30 30 Thickness deviation % 10 9 7 12 6 17 Oligomer Extract weight% 0.5 0.3 0.4 1.0 0.4 0.5 Refractive index in the thickness direction (nz) 1.508 1.510 1.503 1.505 1.499 1.518 Heat shrinkage SMD % 0.35 0.37 0.40 0.30 0.85 0.20 SMD % 0.03 0.02 0.03 0.01 0.10 0.00 car % 0.32 0.35 0.37 0.29 0.75 0.20 Friction coefficient μd 0.4 0.3 0.3 0.4 0.6 0.4 density g / cm 3 1.360 1.362 1.362 1.357 1.358 - Processability of Semiconductor Wafers (Backgrinding and Dicing) Good Good Good Good usually usually Processability of Semiconductor Wafers (Backgrinding and Tape Peeling) Good Good Good Bad Bad Bad

Claims (15)

A biaxially oriented film comprising polyethylene-2,6-naphthalenedicarboxylate as a main component, wherein the thermal contraction rate of the film when heat-treated at 200 ° C. for 10 minutes is 1.00% or less in both the film forming direction and the width direction of the film. A base film for semiconductor wafer processing. The base film for semiconductor wafer processing according to claim 1, wherein the base film for semiconductor wafer processing is for backgrinding tape or for dicing tape. The base film for semiconductor wafer processing of Claim 1 whose amount of extraction oligomers of a film is 0.8 weight% or less, and the refractive index of the thickness direction of a film is 1.501 or more and 1.515 or less. The base film for semiconductor wafer processing in any one of Claims 1-3 whose thickness variation of a film is 15% or less. The base film for semiconductor wafer processing in any one of Claims 1-3 whose Young's modulus of a film is 5400 Mpa or more and 6900 Mpa or less. The base film for semiconductor wafer processing in any one of Claims 1-3 whose centerline average surface roughness in the at least single side | surface of a film is 3 nm or more and 80 nm or less. The base film for semiconductor wafer processing in any one of Claims 1-3 whose density of a film is 1.356 g / cm <3> or more and 1.364 g / cm <3> or less. The base film for semiconductor wafer processing in any one of Claims 1-3 whose average thickness of a film is 9 micrometers or more and 150 micrometers or less. The base film for semiconductor wafer processing in any one of Claims 1-3 whose dynamic coefficient of friction of a film is 0.5 or less. The semiconductor according to any one of claims 1 to 3, wherein the thermal contraction rate of the film when heat-treated at 200 ° C. for 10 minutes is 0.60% or less in the absolute value of the difference between the thermal contraction rate in the film forming direction of the film and the thermal contraction rate in the width direction. Base film for wafer processing. The base film for semiconductor wafer processing as described in any one of Claims 1-3 in which a film consists of two or more layers. The backgrinding tape of Claim 2 which has an adhesive layer in the single side | surface of the base film for backgrinding tape. The backgrinding tape composite which has a release film further on the adhesive layer of the backgrinding tape of Claim 12. The dicing tape of Claim 2 which has an adhesive layer on the single side | surface of the base film for dicing tapes. The dicing tape composite which has a release film further on the adhesive layer of the dicing tape of Claim 14.