KR20210151069A - Protective sheet for semiconductor processing and manufacturing method of semiconductor device - Google Patents

Abstract

A protective sheet for semiconductor processing having a substrate, an intermediate layer and an adhesive layer on the substrate in this order, wherein the product of the tensile storage elastic modulus of the substrate and the thickness of the substrate is 8.0 × 10 ⁵ N/m or less, and the intermediate layer after holding at 65° C. for 300 seconds It is a protective sheet for semiconductor processing whose residual stress is 10000 Pa or less.

Description

Protective sheet for semiconductor processing and manufacturing method of semiconductor device

The present invention relates to a protective sheet for semiconductor processing and a method for manufacturing a semiconductor device. In particular, in order to suppress the curvature of a semiconductor wafer, the protective sheet for a semiconductor process used suitably, and the manufacturing method of the semiconductor device using the said protective sheet for a semiconductor process are related.

BACKGROUND ART A large number of semiconductor devices in which a semiconductor chip obtained by dividing a semiconductor wafer having a circuit into pieces is mounted on various electronic devices are mounted thereon. Circuit protective layers, such as a passivation film for protecting a circuit from an external environment, and a passivation film for bump formation, may be formed in the semiconductor wafer in which the circuit was formed. The circuit formed on the semiconductor wafer is mechanically and chemically protected by such a circuit protective layer.

Moreover, miniaturization and multifunctionalization of an electronic device are progressing rapidly, and size reduction, reduction in size, and density increase are calculated|required also for a semiconductor chip. In order to miniaturize and reduce the size of a chip, it is common to form a circuit on the surface of a semiconductor wafer, then grind the back surface of the semiconductor wafer to adjust the thickness of the chip.

At the time of back grinding of a semiconductor wafer, in order to prevent contamination of the wafer surface at the time of grinding, and to hold a semiconductor wafer, the protective sheet called a back grind tape is affixed on the wafer surface. By sticking such a protective sheet, although grinding quality improves, it originates in sticking of a protective sheet, and residual stress generate|occur|produces in a protective sheet.

Since the semiconductor wafer before back surface grinding has high rigidity, the residual stress in a protective sheet is lose|eliminated. However, since the rigidity of a semiconductor wafer will fall when a semiconductor wafer becomes thin by back surface grinding, the residual stress in a protective sheet will become present, and the semiconductor wafer whose rigidity fell with a protective sheet will warp.

In addition, since residual stress is generated in the semiconductor wafer when the circuit protective layer is formed in the semiconductor wafer with the circuit protective layer, after the back surface grinding, the semiconductor wafer is warped by the residual stress in the protective sheet and the residual stress in the semiconductor wafer. tends to increase. When a semiconductor wafer is warped, a problem arises, such as a semiconductor wafer becoming easily damaged and conveyance to a next process becoming difficult.

Regarding such a problem, for example, in patent document 1, in order to suppress the curvature of a semiconductor wafer, the surface protection sheet which provided the high stress relaxation characteristic to the base material is disclosed.

International Publication No. 2016/063827

In patent document 1, the curvature of a semiconductor wafer is suppressed by providing a stress relaxation characteristic to a base material and eliminating the residual stress which generate|occur|produces in a base material. However, in the protective sheet of patent document 1, the residual stress which is generate|occur|produced in semiconductor wafer itself like a semiconductor wafer with a circuit protective layer cannot be eliminated. As a result, when residual stress was generated in the semiconductor wafer itself, there was a problem that the warpage of the semiconductor wafer could not be suppressed.

The present invention is made in view of such a real situation, and a protective sheet for semiconductor processing capable of suppressing warpage of a semiconductor wafer when affixed to a semiconductor wafer in which residual stress is generated, and a semiconductor device using the protective sheet for semiconductor processing It aims to provide a manufacturing method.

An aspect of the present invention is

[1] A protective sheet for semiconductor processing having a substrate, an intermediate layer and an adhesive layer on the substrate in this order,

The product of the tensile storage modulus of the substrate and the thickness of the substrate is 8.0 × 10 ⁵ N/m or less,

It is a protective sheet for semiconductor processing whose residual stress of the intermediate|middle layer after holding|maintenance for 300 second at 65 degreeC is 10000 Pa or less.

[2] The protective sheet for semiconductor processing according to [1], wherein the loss tangent of the intermediate layer at 65°C is 0.6 or more.

[3] A step of affixing the protective sheet for semiconductor processing according to [1] or [2] to a semiconductor wafer having residual stress;

It is a manufacturing method of the semiconductor device which has the process of reducing the rigidity of the semiconductor wafer to which the protective sheet for a semiconductor process was affixed.

ADVANTAGE OF THE INVENTION According to this invention, when sticking to the semiconductor wafer which residual stress generate|occur|produces, the protective sheet for semiconductor processing which can suppress the curvature of a semiconductor wafer rather than the conventional protective sheet, and the manufacturing method of a semiconductor device using the said protective sheet for a semiconductor process can provide

BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional schematic diagram which shows an example of the protective sheet for semiconductor processing which concerns on this embodiment.
It is a cross-sectional schematic diagram which shows the mode that the protective sheet for semiconductor processing which concerns on this embodiment was affixed on the circuit surface of a semiconductor wafer.
It is a cross-sectional schematic diagram which shows the semiconductor wafer after back surface grinding to which the protective sheet for a semiconductor process is not affixed.
It is a cross-sectional schematic diagram which shows the semiconductor wafer after back surface grinding to which the conventional protective sheet for a semiconductor process was affixed.
3C is a schematic cross-sectional view showing a semiconductor wafer after backside grinding to which the protective sheet for semiconductor processing according to the present embodiment is affixed.
3D is a schematic cross-sectional view showing a semiconductor wafer after backside grinding to which the protective sheet for semiconductor processing according to the present embodiment is affixed.
4 : is a cross-sectional schematic diagram for demonstrating that the residual stress of an intermediate|middle layer is low in the protective sheet for a semiconductor process which concerns on this embodiment.

EMBODIMENT OF THE INVENTION Hereinafter, based on specific embodiment, this invention is demonstrated in detail in the following order.

(1. Protective sheet for semiconductor processing)

The protective sheet 1 for semiconductor processing which concerns on this embodiment has the structure in which the intermediate|middle layer 20 and the adhesive layer 30 were laminated|stacked in this order on the base material 10, as shown in FIG. The protective sheet for a semiconductor process is not limited to the structure of FIG. 1, As long as the effect of this invention is acquired, you may have another layer. For example, in order to protect the adhesive layer 30 until the adhesive layer 30 is affixed to a to-be-adhered body, the peeling sheet may be formed in the main surface 30a of the adhesive layer 30.

The protective sheet for a semiconductor process which concerns on this embodiment is used suitably for the semiconductor wafer in which residual stress has generate|occur|produced before sticking of the protective sheet for a semiconductor process. As such a semiconductor wafer, the semiconductor wafer in which the circuit protection layer like various passivation films was formed is illustrated, for example.

As shown in FIG. 2, the protective sheet 1 for semiconductor processing which concerns on this embodiment is an adhesive layer on the main surface 51a of the circuit protective layer 51 currently formed in the circuit surface 50a of the semiconductor wafer 50. The main surface 30a of (30) is affixed and used.

In a semiconductor wafer having a circuit protective layer, residual stress is generated in the semiconductor wafer during thermal curing of the applied composition for a circuit protective layer. However, since the rigidity of the semiconductor wafer before back surface grinding is high, this residual stress is eliminated by the rigidity of the semiconductor wafer itself.

However, after grinding a semiconductor wafer, since the thickness of a semiconductor wafer becomes thin, the rigidity of a semiconductor wafer falls. Therefore, when it grinds without affixing the protective sheet for a semiconductor process to a semiconductor wafer, as shown to FIG. 3A, the curvature Wa resulting only from the residual stress which generate|occur|produced in the semiconductor wafer generate|occur|produces.

In the backside grinding of a semiconductor wafer, in order to ensure the uniformity of grinding, to prevent contamination of the circuit surface by grinding debris, etc., as described above, a protective sheet for semiconductor processing is affixed to the circuit surface, Temporarily protects the circuit surface. Therefore, at the time of back grinding of a semiconductor wafer, the advantage of affixing the protective sheet for a semiconductor process to a circuit surface is large.

When the protective sheet 1 for a semiconductor process is affixed on the semiconductor wafer 50, it sticks, applying tension to the protective sheet 1 for a semiconductor process (extending the protective sheet 1 for a semiconductor process). As a result, residual stress RS generate|occur|produces in the affixed protective sheet 1 for a semiconductor process. The base material usually has higher rigidity than components other than the base material and resists tension, so that residual stress is mainly generated in the base material.

That is, in addition to the residual stress which arose in the semiconductor wafer, the residual stress is generate|occur|produced also in the base material of the protective sheet for a semiconductor process in the semiconductor wafer after affixing of the protective sheet for a semiconductor process. The residual stress generated in the substrate is eliminated by the rigidity of the semiconductor wafer, similarly to the residual stress generated in the semiconductor wafer.

However, after the conventional protective sheet 100 for semiconductor processing is pasted and the residual stress is generated after grinding the semiconductor wafer, as shown in FIG. 3B , both the residual stress generated in the substrate and the residual stress generated in the semiconductor wafer are present. Therefore, the warpage Wb generated in the semiconductor wafer 50 becomes larger than the warpage Wa shown in FIG. 3A .

When the curvature which generate|occur|produces in the semiconductor wafer 50 is large, the handling property of the semiconductor wafer at the time of conveyance will be affected. Therefore, since the warpage Wb shown in FIG. 3B is a composite warpage of the warpage resulting from the residual stress generated in the semiconductor wafer and the warpage resulting from the residual stress generated in the substrate, it is highly likely to affect the handling property of the semiconductor wafer. . That is, if the curvature which does not affect the handleability of a semiconductor wafer is made into W, Wb > W.

Since the protective sheet 1 for semiconductor processing according to this embodiment has the characteristics mentioned later, the semiconductor wafer 50 to which the said protective sheet 1 for semiconductor processing was stuck has the above-mentioned advantage by sticking the protective sheet for semiconductor processing. Even if the thickness is reduced by grinding while enjoying it, as shown in FIG. 3C , the composite warpage Wc can be reduced to a level that does not affect the handleability of the semiconductor wafer. That is, if the warpage that does not affect the handleability of the semiconductor wafer is W, Wc < W.

Preferably, the semiconductor wafer 50 to which the protective sheet for semiconductor processing 1 was affixed by relieving the residual stress generated in the base material and also relieving a part of the residual stress generated in the semiconductor wafer, by sticking the protective sheet for semiconductor processing As shown in FIG. 3D, enjoying the advantage mentioned above, the curvature of a semiconductor wafer is reduced rather than the curvature Wa in the case of not affixing the protective sheet for a semiconductor process. That is, Wd < Wa. Hereinafter, the component of the protective sheet 1 for a semiconductor process is demonstrated in detail.

(2. Description)

The substrate is not limited as long as it is composed of a material capable of supporting a semiconductor wafer. For example, various resin films used as a base material of a back grind tape are illustrated. The base material may be comprised by the single|monolayer film which consists of one resin film, and may be comprised by the multilayer film in which the some resin film was laminated|stacked.

(2.1 Physical properties of the substrate)

In this embodiment, it is preferable that the rigidity of a base material is below a predetermined value. When the rigidity of the substrate is too high, the residual stress generated in the substrate cannot be fully relieved in the later-described intermediate layer, and the residual stress of the intermediate layer tends to exceed the above-mentioned range. As a result, in addition to the warpage resulting from the residual stress generated in the semiconductor wafer itself, warping caused by the residual stress of the intermediate layer occurs. Therefore, it becomes easy to generate|occur|produce the damage|damage of a semiconductor wafer, and problems arise, such as the handling property at the time of conveyance of a semiconductor wafer worsening.

In this embodiment, the rigidity of a base material is evaluated by the product of the tensile storage elastic modulus of a base material, and the thickness of a base material. The product of the tensile storage modulus of the substrate and the thickness of the substrate is 8.0 × 10 ⁵ N/m or less. Moreover, it is more preferable that the product of the tensile storage elastic modulus of a base material and the thickness of a base material is 7.5x10 ⁵ N/m or less.

On the other hand, the product of the tensile storage modulus of the substrate and the thickness of the substrate ^{is preferably 5.0 × 10 3} N/m or more, and more preferably 1.2 × 10 ⁵ N/m or more. When the rigidity of the substrate is equal to or greater than a predetermined value, curvature resulting from the residual stress generated in the semiconductor wafer can be suppressed by the rigidity of the substrate while the residual stress of the substrate is eliminated by the intermediate layer.

That is, by controlling the stress relaxation ability of the intermediate layer and the stress counteracting ability exhibited by the rigidity of the substrate, even when residual stress is generated in the semiconductor wafer, the warpage of the semiconductor wafer after back surface grinding can be suppressed.

The thickness of the substrate has a different preferable range depending on the tensile storage modulus of the substrate, but in the present embodiment, it is preferably 15 µm or more and 200 µm or less, and more preferably 40 µm or more and 150 µm or less.

(2.2 Material of base material)

The material of the substrate is preferably a material in which the product of the tensile storage elastic modulus of the substrate and the thickness of the substrate is within the above range when the thickness of the substrate is within the above range. In the present embodiment, for example, polyester such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, and wholly aromatic polyester, polyamide, polycarbonate, polyacetal, modified polyphenylene oxide, polyphenylene sulfide Phide, polysulfone, polyether ketone, biaxially stretched polypropylene, etc. are mentioned. Among these, polyester is preferable and polyethylene terephthalate is more preferable.

(3. Middle floor)

An intermediate|middle layer is a layer arrange|positioned between a base material and an adhesive layer. In this embodiment, an intermediate|middle layer is a layer with high stress relaxation property which accepts the residual stress of a base material, and can relieve|moderate the residual stress in an intermediate|middle layer. As shown in FIG. 4, although the base material 10 after affixing the protective sheet 1 for semiconductor processing is contracted by residual stress, in an intermediate|middle layer, since most of the residual stress is relieve|moderated, the curvature of the semiconductor wafer 50 is suppressed. . An intermediate|middle layer may be comprised from one layer (single layer), and may be comprised from multiple layers of two or more layers.

The thickness of the intermediate|middle layer 20 is set arbitrarily within the range from which the effect of this invention is acquired. In this embodiment, it is preferable that the thickness of the intermediate|middle layer 20 is 50 micrometers or more and 500 micrometers or less. In addition, the thickness of an intermediate|middle layer means the thickness of the whole intermediate|middle layer. For example, the thickness of the intermediate|middle layer comprised from multiple layers means the thickness of the sum total of all the layers which comprise an intermediate|middle layer.

In the present embodiment, the intermediate layer has the following physical properties.

(3.1 Residual stress after holding at 65°C for 300 seconds)

In this embodiment, the residual stress of the intermediate|middle layer after holding|maintenance for 300 second at 65 degreeC is 10000 Pa or less. The residual stress received from the base material is rapidly relieved in the intermediate layer, and is substantially stabilized after 300 seconds. Moreover, the protective sheet for a semiconductor process is affixed to a semiconductor wafer at the temperature of around 65 degreeC normally.

Therefore, when the stress remaining in the intermediate layer after holding at 65°C for 300 seconds falls within the above range, the residual stress received from the affixed base material is sufficiently relaxed in the intermediate layer. In addition, "residual stress of the intermediate layer after holding at 65 degreeC for 300 seconds" means the residual stress of the intermediate layer measured after the temperature of the intermediate layer is maintained at 65 degreeC for 300 seconds.

It is preferable that it is 6000 Pa or less, and, as for the residual stress of the intermediate|middle layer after holding|maintenance at 65 degreeC for 300 second, it is more preferable that it is 5000 Pa or less. Moreover, it is preferable that the residual stress of the intermediate|middle layer after holding|maintenance for 300 second at 65 degreeC is 1 Pa or more.

In this embodiment, the residual stress of the intermediate|middle layer after holding|maintenance for 300 second at 65 degreeC can be measured as follows. The material constituting the intermediate layer is a sample having a predetermined size, and the sample having a temperature of 65°C is twisted using a dynamic viscoelasticity measuring device to apply shear strain to the sample. The shear stress 300 seconds after application of a strain is measured, and let the measured shear stress be the residual stress of the intermediate|middle layer after holding|maintenance at 65 degreeC for 300 second.

(3.2 Loss tangent at 65°C)

In the present embodiment, the loss tangent (tanδ) of the intermediate layer at 65°C is preferably 0.6 or more. The loss tangent is defined as "loss elastic modulus/storage elastic modulus" and is a value measured by the response to the stress applied to the object by the dynamic viscoelasticity measuring apparatus. When the loss tangent of the intermediate|middle layer in 65 degreeC is in said range, since the residual stress received from a base material is consumed as heat|fever, the curvature of a semiconductor wafer can be suppressed.

As for the loss tangent of the intermediate|middle layer in 65 degreeC, it is more preferable that it is 0.8 or more, and it is still more preferable that it is 1.0 or more. Moreover, it is preferable that the loss tangent of the intermediate|middle layer in 65 degreeC is 3.0 or less.

What is necessary is just to measure the loss tangent of the intermediate|middle layer in 65 degreeC by a well-known method. For example, the intermediate layer is a sample of a predetermined size, and the sample is subjected to deformation at a predetermined frequency in a predetermined temperature range by a dynamic viscoelasticity measuring device, the elastic modulus is measured, and the loss is obtained from the measured elastic modulus. The tangent can be calculated.

(3.3 Composition for Interlayer)

The composition of the intermediate layer is not particularly limited as long as the intermediate layer has the above physical properties. In the present embodiment, the intermediate layer is preferably composed of a resin-containing composition (composition for an intermediate layer). It is preferable that the composition for intermediate|middle layer contains the component shown below.

(3.3.1 Urethane (meth)acrylate)

Urethane (meth)acrylate is a compound which has at least a (meth)acryloyl group and a urethane bond, and has the property of superposing|polymerizing by energy-beam irradiation. In this embodiment, urethane (meth)acrylate is a component used in order to provide softness|flexibility to an intermediate|middle layer, and to provide the characteristic which reduces residual stress. In addition, in this specification, "(meth)acrylate" is used as a word which shows both "acrylate" and "methacrylate", and it is the same about other similar terms.

A monofunctional type may be sufficient as urethane (meth)acrylate, and a polyfunctional type may be sufficient as it. In this embodiment, polyfunctional urethane (meth)acrylate is preferable, and bifunctional urethane (meth)acrylate is preferable from a viewpoint of making the residual stress of an intermediate|middle layer in said range.

The urethane (meth)acrylate may be an oligomer, a polymer, or a mixture thereof. In this embodiment, a urethane (meth)acrylate oligomer is preferable.

Urethane (meth)acrylate can be obtained by making (meth)acrylate which has a hydroxyl group react with the terminal isocyanate urethane prepolymer obtained by making a polyol compound and a polyhydric isocyanate compound react, for example. In addition, urethane (meth)acrylate may be used 1 type or in combination of 2 or more type.

It is preferable that it is 20 mass % or more, and, as for the content rate of the urethane (meth)acrylate in the composition for intermediate|middle layer, it is more preferable that it is 25 mass % or more, It is still more preferable that it is 30 mass % or more. Moreover, it is preferable that it is 70 mass % or less, and, as for the content rate of the urethane (meth)acrylate in the composition for intermediate|middle layer, it is more preferable that it is 65 mass % or less, It is still more preferable that it is 50 mass % or less.

(3.3.2 Polymerizable Monomer)

A polymerizable monomer is a polymeric compound other than said urethane (meth)acrylate, It is preferable that it is a compound which can superpose|polymerize with another component by irradiation of an energy ray. Specifically, the polymerizable monomer is preferably a compound having at least one (meth)acryloyl group.

As a polymerizable monomer, For example, (meth)acrylate which has a C1-C30 alkyl group; (meth)acrylate which has functional groups, such as a hydroxyl group, an amide group, an amino group, and an epoxy group; (meth)acrylate having an alicyclic structure; (meth)acrylate having an aromatic structure; (meth)acrylate having a heterocyclic structure; and vinyl compounds such as styrene, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, N-vinylformamide, N-vinylpyrrolidone, and N-vinylcaprolactam.

As (meth)acrylate which has a C1-C30 alkyl group, For example, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acryl rate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) Acrylate, tetradecyl (meth)acrylate, hexadecyl (meth)acrylate, octadecyl (meth)acrylate, and eicosyl (meth)acrylate are mentioned.

As (meth)acrylate which has a functional group, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2- hydroxyl group-containing (meth)acrylates such as hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-butyl (meth)acrylamide, N-methylol (meth)acrylamide, N-methylolpropane (meth)acrylamide, N-methyl Amide group-containing compounds, such as oxymethyl (meth)acrylamide and N-butoxymethyl (meth)acrylamide; amino group-containing (meth)acrylates such as primary amino group-containing (meth)acrylate, secondary amino group-containing (meth)acrylate, and tertiary amino group-containing (meth)acrylate; Epoxy group-containing (meth)acrylates, such as glycidyl (meth)acrylate, methyl glycidyl (meth)acrylate, and allyl glycidyl ether, are mentioned.

As (meth)acrylate which has an alicyclic structure, for example, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyloxy (meth)acrylate, cyclohexyl (meth)acrylate, trimethylcyclohexyl (meth)acrylate, and adamantane (meth)acrylate are mentioned.

Examples of the (meth)acrylate having an aromatic structure include phenylhydroxypropyl (meth)acrylate, benzyl (meth)acrylate, and 2-hydroxy-3-phenoxypropyl (meth)acrylate. can

As (meth)acrylate which has a heterocyclic structure, tetrahydrofurfuryl (meth)acrylate and morpholine (meth)acrylate are mentioned, for example.

In this embodiment, it is preferable that the (meth)acrylate which has a C1-C30 alkyl group, and (meth)acrylate which has an alicyclic structure are contained in a polymerizable monomer. From a viewpoint of making the residual stress of an intermediate|middle layer within the said range, (meth)acrylate which has a C4-C14 alkyl group is preferable, As (meth)acrylate which has an alicyclic structure, isobornyl (meth)acryl The rate and trimethylcyclohexyl (meth)acrylate are preferable.

In addition, when a crosslinking agent is included in the composition for an intermediate layer, (meth)acrylate having a functional group capable of reacting with the crosslinking agent is not preferable. This is because the crosslinked structure formed by the crosslinking reaction may increase the residual stress of the intermediate layer. For example, the composition for an intermediate|middle layer containing a polyisocyanate type crosslinking agent and the (meth)acrylate which has a hydroxyl group is not preferable.

It is preferable that it is 20 mass % or more, and, as for the content rate of the polymerizable monomer in the composition for intermediate|middle layer, it is more preferable that it is 30 mass % or more. Moreover, it is preferable that it is 80 mass % or less, and, as for the content rate of the polymerizable monomer in the composition for intermediate|middle layers, it is more preferable that it is 70 mass % or less.

In addition, the mass ratio (urethane (meth)acrylate/polymerizable monomer) of the urethane (meth)acrylate and the polymerizable monomer in 100 parts by mass in total of the urethane (meth)acrylate and the polymerizable monomer is 20/80 to It is preferable that it is 80/20, and it is more preferable that it is 30/70 - 70/30.

(3.3.3 Photoinitiator)

When the composition for an intermediate layer contains the urethane (meth)acrylate and a polymerizable monomer, the composition for an intermediate layer preferably contains a photopolymerization initiator. By including a photoinitiator, superposition|polymerization advances reliably and the intermediate|middle layer which has the above-mentioned characteristic can be obtained easily.

As a photoinitiator, For example, Photoinitiators, such as a benzoin compound, an acetophenone compound, an acylphosphine oxide compound, a titanocene compound, a thioxanthone compound, a peroxide compound, Photosensitizers, such as an amine and a quinone and the like. Specifically, for example, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin Phosphorus isopropyl ether and 2,2-dimethoxy-1,2-diphenylethan-1-one are mentioned. You may use these photoinitiators 1 type or in combination of 2 or more type.

The compounding amount of the photoinitiator is preferably 0.05 parts by mass or more and 15 parts by mass or less, and more preferably 0.5 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass in total of the urethane (meth)acrylate and the polymerizable monomer. desirable.

(3.3.4 chain transfer agent)

It is preferable that the composition for intermediate|middle layer contains a chain transfer agent. A chain transfer agent can raise|generate a chain transfer reaction and can adjust advancing of the hardening reaction of the composition for intermediate|middle layer. By containing a chain transfer agent, even after hardening, since it becomes possible for a component with a short molecular chain to remain|survive comparatively, the polymer after hardening has a structure which has comparatively softness|flexibility. As a result, the residual stress applied to the intermediate layer can be sufficiently relieved, and it becomes easy to make the residual stress of the intermediate layer within the above range.

As a chain transfer agent, a thiol group containing compound is mentioned, for example. Examples of the thiol group-containing compound include nonylmercaptan, 1-dodecanthiol, 1,2-ethanedithiol, 1,3-propanedithiol, triazinethiol, triazinedithiol, triazinetrithiol, 1,2, 3-propanetrithiol, tetraethylene glycol-bis(3-mercaptopropionate), trimethylolpropanetris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptopropionate), Pentaerythritol tetrakisthioglycolate, dipentaerythritol hexakis (3-mercaptopropionate), tris[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, 1,4-bis (3-mercaptobutyryloxy)butane, pentaerythritol tetrakis(3-mercaptobutylate), 1,3,5-tris(3-mercaptobutyloxyethyl)-1,3,5-triazine -2,4,6-(1H,3H,5H)-trione. A chain transfer agent may be used 1 type or in combination of 2 or more type.

The blending amount of the chain transfer agent is preferably 0.1 parts by mass or more and 10 parts by mass or less, and more preferably 0.3 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass in total of the urethane (meth)acrylate and the polymerizable monomer. do.

(4. Adhesive layer)

An adhesive layer is affixed on the circuit surface of a semiconductor wafer, and protects a circuit surface until it peels from a circuit surface, and supports a semiconductor wafer. An adhesive layer may be comprised by one layer (single layer), and may be comprised by multiple layers of two or more layers. When an adhesive layer has multiple layers, these multiple layers may mutually be same or different, and the combination in particular of the layer which comprises these multiple layers is not restrict|limited.

Although the thickness in particular of an adhesive layer is not restrict|limited, Preferably they are 1 micrometer or more and 50 micrometers or less, More preferably, they are 2 micrometers or more and 30 micrometers or less. In addition, the thickness of an adhesive layer means the thickness of the whole adhesive layer. For example, the thickness of the adhesive layer comprised from multiple layers means the thickness of the sum total of all the layers which comprise an adhesive layer.

The composition of the adhesive layer will not be limited, if it has the adhesiveness of the grade which can protect the circuit surface of a semiconductor wafer. In this embodiment, it is preferable that an adhesive layer is comprised from an acrylic adhesive, a urethane adhesive, a rubber adhesive, a silicone adhesive, etc., for example.

Moreover, it is preferable that an adhesive layer is formed from an energy-beam curable adhesive. When the adhesive layer of the protective sheet for semiconductor processing is formed of an energy ray-curable adhesive, when affixed to a semiconductor wafer, it is affixed to a semiconductor wafer with high adhesive force, and when peeling from a semiconductor wafer, adhesive force can be reduced by irradiating an energy ray. Therefore, when peeling the protective sheet for a semiconductor process, protecting the circuit etc. of a semiconductor wafer suitably, it is prevented that the circuit on the surface of a semiconductor wafer is destroyed or an adhesive is electrodeposited on a semiconductor wafer.

In this embodiment, it is preferable that an energy-beam curable adhesive is comprised from the adhesive composition containing an acrylic adhesive. It is preferable to use an acrylic polymer as an acrylic adhesive.

As an acrylic polymer, although a well-known acrylic polymer may be sufficient, in this embodiment, a functional group containing acrylic polymer is preferable. The functional group-containing acrylic polymer may be a homopolymer formed of one type of acrylic monomer, a copolymer formed of multiple types of acrylic monomer, or a copolymer formed of one or more types of acrylic monomer and a monomer other than the acrylic monomer. .

In this embodiment, it is preferable that the functional group containing acrylic polymer is the acrylic copolymer which copolymerized the alkyl (meth)acrylate and the functional group containing monomer.

Examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, iso Butyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylic a rate, n-octyl (meth)acrylate, etc. are mentioned.

The functional group-containing monomer is a monomer containing a reactive functional group. A reactive functional group is a functional group which can react with other compounds, such as a crosslinking agent mentioned later. As a functional group in a functional group containing monomer, a hydroxyl group, a carboxy group, and an epoxy group are mentioned, for example, A hydroxyl group is preferable.

As a hydroxyl-containing monomer, (meth)acrylic acid hydroxymethyl, (meth)acrylic acid 2-hydroxyethyl, (meth)acrylic acid 2-hydroxypropyl, (meth)acrylic acid 3-hydroxypropyl, (meth)acrylate is, for example, ) (meth)acrylic acid hydroxyalkyl, such as 2-hydroxybutyl acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; Non-(meth)acrylic-type unsaturated alcohols (unsaturated alcohol which does not have (meth)acryloyl skeleton), such as vinyl alcohol and allyl alcohol, are mentioned.

It is preferable that an adhesive composition contains the energy-beam curable compound which has an energy-beam curable group further. As an energy-beam-curable compound which has an energy-beam curable group, the compound which has 1 type(s) or 2 or more types chosen from an isocyanate group, an epoxy group, and a carboxy group is preferable, and the compound which has an isocyanate group is more preferable.

Examples of the compound having an isocyanate group include 2-methacryloyloxyethyl isocyanate, meta-isopropenyl-α,α-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, 1,1-(bis acryloyloxymethyl)ethyl isocyanate; Acryloyl monoisocyanate compound obtained by reaction of a diisocyanate compound or a polyisocyanate compound, and hydroxyethyl (meth)acrylate; The acryloyl monoisocyanate compound etc. which are obtained by reaction of a diisocyanate compound or a polyisocyanate compound, a polyol compound, and hydroxyethyl (meth)acrylate are mentioned. The isocyanate group is addition-reacted with the hydroxyl group of the functional group-containing acrylic polymer.

It is preferable that an adhesive composition contains a crosslinking agent further. A crosslinking agent reacts with a functional group, and bridge|crosslinks resin contained in the functional group containing acrylic polymer, for example.

As a crosslinking agent, For example, isocyanate type crosslinking agents (crosslinking agent which has an isocyanate group), such as tolylene diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, and the adduct body of these diisocyanate; Epoxy type crosslinking agents (crosslinking agent which has a glycidyl group), such as ethylene glycol glycidyl ether; aziridine-based crosslinking agents (crosslinking agents having an aziridinyl group) such as hexa[1-(2-methyl)-aziridinyl]triphosphatriazine; Metal chelate type crosslinking agents (crosslinking agent which has a metal chelate structure), such as an aluminum chelate; isocyanurate-based crosslinking agent (crosslinking agent having isocyanuric acid skeleton); and the like.

It is preferable that the crosslinking agent is an isocyanate type crosslinking agent from points, such as the point which improves the cohesive force of an adhesive, and improves the adhesive force of an adhesive layer, and an acquisition is easy.

The pressure-sensitive adhesive composition may further contain a photoinitiator. When an adhesive composition contains a photoinitiator, even if it irradiates comparatively low energy energy rays, such as an ultraviolet-ray, hardening reaction fully advances.

Examples of the photopolymerization initiator include photoinitiators such as benzoin compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, thioxanthone compounds and peroxide compounds, and photosensitizers such as amines and quinones. . Specifically, α-hydroxycyclohexylphenyl ketone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl diphenyl sulfide, benzyl dimethyl ketal, tetramethylthiuram monosulfide, and azobisisobutyronitrile, dibenzyl, diacetyl, β-chloranthraquinone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide and the like.

(5. Manufacturing method of protective sheet for semiconductor processing)

The method for producing the protective sheet for semiconductor processing according to the present embodiment is not particularly limited as long as it can be formed by laminating an intermediate layer and an adhesive layer on one surface of the substrate, and a known method may be used.

First, as a composition for forming an intermediate|middle layer, the composition for the intermediate|middle layer containing the above-mentioned component, or the composition which diluted the said composition for intermediate|middle layer with a solvent etc. is prepared, for example. Similarly, as a pressure-sensitive adhesive composition for forming a pressure-sensitive adhesive layer, for example, a pressure-sensitive adhesive composition containing the above-mentioned components or a composition obtained by diluting the pressure-sensitive adhesive composition with a solvent or the like is prepared.

Examples of the solvent include organic solvents such as methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexane, n-hexane, toluene, xylene, n-propanol, and isopropanol.

Then, the composition for an intermediate layer is applied onto the substrate by a known method such as a spin coat method, a spray coat method, a bar coat method, a knife coat method, a roll coat method, a blade coat method, a die coat method, and a gravure coat method. The coating is applied to form a coating film, and the coating film is cured to form an intermediate layer on the substrate. In this embodiment, it is preferable to perform hardening of a coating film by irradiation of an energy-beam. As an energy beam, an ultraviolet-ray and an electron beam are mentioned, for example, An ultraviolet-ray is preferable.

Moreover, in this embodiment, it is preferable to irradiate an energy ray in multiple times and to harden a coating film. By doing in this way, the hardening degree of an intermediate|middle layer can be controlled, and it becomes easy to make the residual stress of an intermediate|middle layer into said range.

Specifically, it is preferable to irradiate the energy ray a plurality of times in a state in which the coating film is shielded from oxygen.

Moreover, when an energy ray is an ultraviolet-ray, as for the irradiation conditions of the ultraviolet-ray implemented for the 1st time, the illumination intensity of an ultraviolet-ray becomes like this. Preferably it is 30-500 mW/cm<2>, More preferably, it is 50-340 mW/cm<2>, The irradiation amount of an ultraviolet-ray Preferably it is 100-2500 mJ/cm<2>, More preferably, it is 150-2000 mJ/cm<2>.

As for the irradiation conditions of the ultraviolet-ray implemented for the 2nd time, it is preferable that illuminance and irradiation amount are larger than the illuminance and irradiation amount in 1st irradiation.

On the intermediate layer thus cured and formed, a pressure-sensitive adhesive composition or the like is applied by a known method, heated and dried to prepare a protective sheet for semiconductor processing in which the intermediate layer and the pressure-sensitive adhesive layer are formed on the substrate in this order.

Moreover, you may manufacture the protective sheet for semiconductor processing as follows. That is, the coating film formed by apply|coating the composition for intermediate|middle layer etc. to the peeling process surface of one peeling sheet is hardened as mentioned above, and an intermediate|middle layer is formed on the peeling sheet.

An adhesive composition etc. are apply|coated to the peeling process surface of the other peeling sheet, it is heated and dried, and an adhesive layer is formed on the peeling sheet. Then, the intermediate|middle layer and base material on one peeling sheet are bonded together, and the peeling sheet is removed. Then, you may manufacture the protective sheet for a semiconductor process in which the intermediate|middle layer and the adhesive layer on the other peeling sheet are bonded together, and the intermediate|middle layer, the adhesive layer, and the peeling sheet were formed in this order on the base material. What is necessary is just to peel and remove a peeling sheet suitably before use of the protective sheet for a semiconductor process.

(6. Manufacturing method of semiconductor device)

As a manufacturing method of a semiconductor device using the protective sheet for semiconductor processing according to this embodiment, the process of attaching the protective sheet for semiconductor processing according to this embodiment to a semiconductor wafer in which residual stress has occurred, and the protective sheet for semiconductor processing is pasted It will not restrict|limit especially if it has a process which reduces the rigidity of a semiconductor wafer.

As a process of affixing the protective sheet for semiconductor processing which concerns on this embodiment to a semiconductor wafer, for example, in a semiconductor wafer, the process of affixing the protective sheet for semiconductor processing which concerns on the surface in which the circuit was formed is preferable.

Moreover, as a process of reducing the rigidity of a semiconductor wafer, the process of grinding a semiconductor wafer and making the thickness of a semiconductor wafer thin is illustrated, for example.

Hereinafter, as an example of the manufacturing method of the semiconductor device using the protective sheet for semiconductor processing which concerns on this embodiment, the method of manufacturing a semiconductor device from the semiconductor wafer which residual stress generate|occur|produced is demonstrated using FIGS.

First, a semiconductor wafer is prepared. As a semiconductor wafer, what is necessary is just a well-known wafer. Moreover, the thickness before grinding of a semiconductor wafer is about 500-1000 micrometers normally. Moreover, it is preferable that the thickness after grinding of a semiconductor wafer is 100-300 micrometers.

In the present embodiment, the semiconductor wafer in which the residual stress is generated is a semiconductor wafer in which the above-described circuit protective layer is formed. A circuit protective layer is normally formed by apply|coating and thermosetting the composition which comprises a circuit protective layer. At the time of thermal curing, since the composition shrinks, a force to bend the semiconductor wafer, that is, residual stress, acts on the circuit surface side. Therefore, as shown in FIG. 2, residual stress RS1 is generate|occur|produced in the circuit protective layer 51 in the semiconductor wafer after circuit protective layer formation. In addition, convex electrodes, such as a bump and a filler electrode, may be formed in the circuit surface to which the protective sheet for semiconductor processing which concerns on this embodiment is pasted.

Then, before the backside grinding of the semiconductor wafer, as shown in FIG. 2 , on the circuit side surface of the semiconductor wafer 50 on which the circuit protection layer 51 was formed, that is, on the surface 51a of the circuit protection layer 51 . , The protective sheet 1 for semiconductor processing is affixed, and a circuit surface is protected from the bad influence resulting from grinding. At this time, it is affixed to a circuit surface, tensioning the protective sheet 1 for a semiconductor process. Therefore, the residual stress RS2 which acts on the protective sheet|seat 1 for semiconductor processing after affixing, especially the high rigidity base material in the direction in which the said base material shrink|contracts, generate|occur|produces.

As shown in Fig. 4, the substrate 10 is contracted by this residual stress RS2, and the residual stress generated in the substrate 10 is eliminated, but due to the deformation of the substrate 10, the substrate 10 is formed on the substrate. A residual stress RS2 is generated in the intermediate layer 20 . However, in this embodiment, since the intermediate|middle layer has the above-mentioned characteristic, in an intermediate|middle layer, most of the residual stress is relieve|moderated, and it becomes below the value mentioned above. Moreover, when the convex electrode is formed on the circuit surface, the convex electrode can be protected by sufficiently following the level difference of the circuit surface while the intermediate layer relieves the residual stress.

Then, the back surface of the semiconductor wafer to which the protective sheet 1 for a semiconductor process was affixed is performed. When a semiconductor wafer becomes thin and the rigidity of a semiconductor wafer falls, the curvature resulting from the residual stress of a semiconductor wafer will generate|occur|produce. When the rigidity of the base material is low, as shown in FIG. 3C , the curvature can be reduced to the extent that the handleability of the semiconductor wafer is not affected. When the rigidity of the base material is high, as shown in FIG. 3D , a part of the curvature resulting from the residual stress generated in the semiconductor wafer can also be suppressed. Therefore, conveyance to the next process becomes easy, and damage|damage of a semiconductor wafer is prevented.

The semiconductor wafer after back surface grinding is divided into pieces by a well-known method, and becomes a some semiconductor chip. The obtained semiconductor chip is mounted on a board|substrate by a predetermined method, and a semiconductor device is obtained.

As mentioned above, although embodiment of this invention was described, this invention is not limited at all to said embodiment, You may change in various aspects within the scope of this invention.

Example

Hereinafter, the present invention will be described in more detail using Examples, but the present invention is not limited to these Examples.

The measuring method and evaluation method in a present Example are as follows.

(residual stress in the intermediate layer)

The composition for an intermediate layer, which will be described later, was coated on a PET-based release film (SP-PET382150, 38 µm thick) by a knife method to a thickness of 400 µm to form a composition layer for the intermediate layer. Next, the formed composition layer for an intermediate layer was laminated with a PET-based release film (manufactured by Lintec, SP-PET381130, thickness 38 µm) to shield the composition layer for the intermediate layer from oxygen. Then, using a high-pressure mercury lamp, after irradiating ultraviolet rays under the conditions of an illuminance of 80 mW/cm 2 and an irradiation amount of 200 mJ/cm 2 , using a metal halide lamp, the conditions of an illuminance of 330 mW/cm 2 and an irradiation amount of 1260 mJ/cm 2 The composition layer for an intermediate|middle layer was hardened by performing ultraviolet irradiation with this, and the intermediate|middle layer with a thickness of 400 micrometers was obtained. This intermediate layer was laminated to prepare a measurement sample having a thickness of about 0.8 mm. The residual stress measurement was performed using the rheometer MCR302 by Anton Paar. The measurement conditions are as follows. The sample was sandwiched from the top and bottom with a parallel plate, and a shear stress was applied to the sample under the conditions of a measurement temperature of 65°C, a gap of 1 mm, and a strain of 100%, and held for a predetermined time. The shear stress value of the intermediate|middle layer in 300 second after relaxation time was made into the residual stress value.

(Loss tangent in the middle layer)

It carried out similarly to the sample for residual stress measurement, and the sample for loss tangent measurement was manufactured. Loss tangent (tanδ) was performed using a rheometer MCR302 manufactured by Anton Paar. The measurement conditions are as follows. A sample is sandwiched from the top and bottom with a parallel plate, and a shear stress is applied to the sample under the conditions of a measurement temperature of 0 to 100° C., a gap of 1 mm, a strain of 0.05 to 0.5%, and an angular frequency of 1 Hz, and the measurement is performed at 65° C. from these values. The loss tangent (tanδ) was calculated.

(wafer warpage evaluation)

Two sheets of LC2850 (25 µm in thickness) manufactured by Lintec Co., Ltd. (25 µm in thickness) were affixed on a 12-inch silicon wafer as a pseudo circuit protective layer and heated at 180°C for 3 hours, followed by annealing to room temperature. This silicon wafer was used as a silicon wafer with a pseudo circuit protective layer formed thereon. A general-purpose back grind tape was affixed to the protective layer side on this silicon wafer with a circuit protective layer formed thereon, and it was ground until the thickness was set to 250 µm. When the tape was peeled off after grinding, it was confirmed that the tape was warped by about 9.0 mm.

The protective sheet for semiconductor processing produced in Examples and Comparative Examples is affixed to the surface of the pseudo circuit protective layer of the silicon wafer with the pseudo circuit protective layer formed thereon at 65 ° C., and the protective sheet for semiconductor processing is applied until the thickness becomes 250 µm. The surface on the opposite side to the affixed surface was ground. That is, the thickness of the silicon wafer after grinding was 200 micrometers.

The protective sheet pasting surface for semiconductor processing (pseudo circuit protective layer surface) was placed on a flat plate, the maximum distance between the back surface of the silicon wafer and the flat plate was measured, and the warpage of the silicon wafer was evaluated. In this example, the difference with the amount of deflection (9.0 mm) after peeling of the back grind tape was calculated, and the sample with the difference in deflection of 5.0 mm or less was judged as good, and the sample with the difference of deflection of more than 5.0 mm was judged as bad.

(Example 1)

With respect to a total of 100 parts by mass of 65 parts by mass of urethane acrylate oligomer (CN9021 NS, manufactured by Alkema Corporation), 25 parts by mass of isobornyl acrylate, and 10 parts by mass of dodecyl acrylate, a photopolymerization initiator (Irgacure) 1173, manufactured by BASF) 3.4 parts by mass and 1.0 parts by mass of a chain transfer agent (Karenz MT PE1, manufactured by Showa Denko Co., Ltd.) were blended to obtain a composition for an intermediate layer.

The obtained composition for an intermediate layer was coated by a knife method on a PET film (manufactured by Toray Co., Ltd., thickness 75 µm) as a base material to a thickness of 400 µm to form a composition layer for an intermediate layer. Next, the composition layer for the intermediate layer formed of a PET-based release film (manufactured by Lintec, SP-PET752150, thickness 75 µm) was laminated to shield the composition layer for the intermediate layer from oxygen. Then, using a high-pressure mercury lamp, after irradiating ultraviolet rays under the conditions of an illuminance of 80 mW/cm 2 and an irradiation amount of 200 mJ/cm 2 , using a metal halide lamp, the conditions of an illuminance of 330 mW/cm 2 and an irradiation amount of 1260 mJ/cm 2 The composition layer for an intermediate|middle layer was hardened by performing ultraviolet irradiation with this, and the intermediate|middle layer with a thickness of 400 micrometers was formed on the PET film which is a base material.

In addition, the tensile storage modulus of the PET film serving as the substrate was 4.0 × 10 ⁹ N/m 2 . Therefore, the product of the tensile storage modulus of the substrate and the thickness (75 μm) of the substrate was 3.0×10 ⁵ (N/m).

Next, with respect to 100 parts by mass of the acrylic copolymer (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., composition: 2EHA/EA/MMA//HEA-MOI% = 60/15/5/20//60%, Mw = 800,000), 1.1 parts by mass of trimethylolpropane adduct tolylene diisocyanate (manufactured by Tosoh Corporation, Colonate L) as a crosslinking agent, and 2.2 parts by mass of 2,2-dimethoxy-2-phenylacetophenone (manufactured by BASF, Irgacure651) as a photoinitiator It added, further added toluene, adjusted so that solid content concentration might be set to 30 %, it stirred for 30 minutes, and prepared the adhesive composition.

Next, the solution of the prepared pressure-sensitive adhesive composition was applied to a PET release film (manufactured by Lintec, SP-PET382150, thickness 38 µm), dried to form a pressure-sensitive adhesive layer having a thickness of 10 µm, and an adhesive sheet was prepared.

The release film on the base material which has an intermediate|middle layer obtained above was removed, the intermediate|middle layer and the adhesive layer of an adhesive sheet were bonded together, and the protective sheet for semiconductor processing was manufactured.

(Example 2)

As a composition for an intermediate layer, 65 parts by mass of a urethane acrylate oligomer (CN9021 NS, manufactured by Alkema Corporation) and a total of 100 parts by mass of 35 parts by mass of isobornyl acrylate, a photopolymerization initiator (Irgacure 1173, BASF Corporation) Manufacture) A protective sheet for semiconductor processing was prepared in the same manner as in Example 1 except for using a composition in which 3.4 parts by mass and 1.0 parts by mass of a chain transfer agent (Karenz MT PE1, manufactured by Showa Denko Co., Ltd.) were used.

(Example 3)

As a composition for an intermediate layer, 65 parts by mass of a urethane acrylate oligomer (CN9021 NS, manufactured by Alkema Corporation) and a total of 100 parts by mass of 35 parts by mass of isobornyl acrylate, a photopolymerization initiator (Irgacure 1173, BASF Corporation) Production) A protective sheet for semiconductor processing was prepared in the same manner as in Example 1 except that a composition containing 3.4 parts by mass and 0.9 parts by mass of a chain transfer agent (Karenz MT PE1, manufactured by Showa Denko Co., Ltd.) was used.

(Example 4)

As a composition for an intermediate layer, 65 parts by mass of a urethane acrylate oligomer (CN9021 NS, manufactured by Alkema Co., Ltd.), 25 parts by mass of isobornyl acrylate, and 10 parts by mass of dodecyl acrylate in total, 100 parts by mass, photopolymerized A protective sheet for semiconductor processing was prepared in the same manner as in Example 1 except that a composition containing 3.4 parts by mass of an initiator (Irgacure 1173, manufactured by BASF) was used.

(Examples 5 and 6)

A protective sheet for semiconductor processing was manufactured in the same manner as in Example 4, except that the thickness of the substrate was set to the thickness shown in Table 1.

(Example 7)

The composition for an intermediate layer obtained in the same manner as in Example 1 was coated on a PET-based release film (SP-PET382150, 38 µm, 38 µm, manufactured by Lintec) to a thickness of 400 µm by a knife method to form a composition layer for an intermediate layer did Next, the formed composition layer for an intermediate layer was laminated with a PET-based release film (manufactured by Lintec, SP-PET381130, thickness 38 µm) to shield the composition layer for the intermediate layer from oxygen. Then, using a high-pressure mercury lamp, after irradiating ultraviolet rays under the conditions of an illuminance of 80 mW/cm 2 and an irradiation amount of 200 mJ/cm 2 , using a metal halide lamp, the conditions of an illuminance of 330 mW/cm 2 and an irradiation amount of 1260 mJ/cm 2 The composition layer for an intermediate|middle layer was hardened by performing ultraviolet irradiation with this. Further, a PET-based release film (manufactured by Lintec Co., Ltd., SP-PET381130, thickness 38 µm) is peeled from the intermediate layer, and the surface of the intermediate layer and a PET film (manufactured by Toray Corporation, thickness 2 µm) serving as the substrate are bonded together to form a thickness on the PET film. A structure in which an intermediate layer having a thickness of 400 μm was laminated was obtained. Subsequent operation was the same as in Example 1, and the protective sheet for semiconductor processing was manufactured.

(Example 8)

A protective sheet for semiconductor processing was produced in the same manner as in Example 7 except that the composition for intermediate layers obtained in the same manner as in Example 4 was used.

(Comparative Example 1)

As a composition for an intermediate layer, 65 parts by mass of a urethane acrylate oligomer (CN9021 NS, manufactured by Alkema Co., Ltd.), 25 parts by mass of isobornyl acrylate, and 10 parts by mass of dodecyl acrylate in total, 100 parts by mass, photopolymerized A protective sheet for semiconductor processing was prepared in the same manner as in Example 1 except that a composition containing 3.4 parts by mass of an initiator (Irgacure 1173, manufactured by BASF) was used.

(Comparative Examples 2 and 3)

A protective sheet for semiconductor processing was manufactured in the same manner as in Comparative Example 1, except that the thickness of the substrate was set to the thickness shown in Table 1.

(Comparative Example 4)

A protective sheet for semiconductor processing was manufactured in the same manner as in Example 1, except that the thickness of the substrate was set to the thickness shown in Table 1.

Said measurement and evaluation were performed about the obtained sample (Examples 1-8 and Comparative Examples 1-4). A result is shown in Table 1.

From Table 1, when the product of the tensile storage elastic modulus of the substrate and the thickness of the substrate is within the above-mentioned range, and the residual stress of the intermediate layer after holding at 65 ° C. for 300 seconds is within the above-mentioned range, the warpage of the wafer where the residual stress has occurred It was confirmed that it could be suppressed.

1 Protective sheet for semiconductor processing
10 entries
20 mezzanine
30 adhesive layer
50 semiconductor wafers
51 circuit surface protection layer

Claims (3)

A protective sheet for semiconductor processing having a substrate, an intermediate layer and an adhesive layer on the substrate in this order,
The product of the tensile storage modulus of the substrate and the thickness of the substrate is 8.0 × 10 ⁵ N/m or less,
The protective sheet for semiconductor processing whose residual stress of the said intermediate|middle layer after holding|maintenance for 300 second at 65 degreeC is 10000 Pa or less. The method of claim 1,
The protective sheet for a semiconductor process whose loss tangent of the said intermediate|middle layer in 65 degreeC is 0.6 or more. The process of affixing the protective sheet for semiconductor processing of Claim 1 or 2 to the semiconductor wafer which residual stress generate|occur|produced;
The manufacturing method of the semiconductor device which has the process of reducing the rigidity of the semiconductor wafer to which the said protective sheet for a semiconductor process was affixed.

Images