KR20240166486A - Protective tape, manufacturing method of semiconductor chips - Google Patents

Abstract

A protective tape having a substrate and an adhesive layer and used for bonding to a semiconductor wafer is provided, which is easy to stretch and has excellent unevenness following properties. A protective tape (1) having a substrate (2) and an adhesive layer (3) and used for bonding to a semiconductor wafer, wherein the substrate (2) has a first resin layer (21) formed on a surface on the side of the adhesive layer (3) and a second resin layer (22) formed on a surface of the first resin layer (21) opposite to the adhesive layer (3), and the first resin layer (21) has a storage elastic modulus of 1.000 KPa or more and 200 KPa or less at any temperature in a range of 50°C or more and 90°C or less, and the second resin layer (22) has a melting point measured by the DSC method of 80°C or more and 230°C or less, and a Young's modulus of 1000 MPa or less for the entire tape.

Description

Protective tape, manufacturing method of semiconductor chips

The present invention relates to a protective tape and a method for manufacturing a semiconductor chip using the same.

In a typical semiconductor chip manufacturing method, a plurality of semiconductor chips are formed on a semiconductor wafer by photolithography and etching techniques, and then the semiconductor wafer is cut along a cutting line formed between each semiconductor chip to cut the semiconductor wafer into a plurality of semiconductor chips.

This cutting process is performed by inserting a semiconductor wafer into a ring frame (a frame that is placed on the outside of the semiconductor wafer and supports the semiconductor wafer) and attaching a protective tape to the element formation surface of the semiconductor wafer and the ring frame. In addition, after the cutting process, a process (pickup process) is performed by pressing the semiconductor wafer from the side opposite to the protective tape to extract a plurality of semiconductor chips.

As a protective tape for this purpose, there is, for example, an adhesive film described in Patent Document 1. This adhesive film has a substrate layer, an intermediate layer, and an adhesive resin layer in this order, the thickness of the substrate layer X ₁ is smaller than the thickness of the intermediate layer X ₂ , the storage elastic modulus E' of the substrate layer at 85°C is 50 MPa or more and 10 GPa or less, and the storage elastic modulus E' of the intermediate layer at 85°C is 1 MPa or more and less than 50 MPa. Specifically, it is described that the substrate layer is particularly preferably polyethylene naphthalate, and the intermediate layer is particularly preferably an ethylene-vinyl acetate copolymer.

WO2020/203287

However, in the adhesive film described in Patent Document 1, since the substrate (substrate layer + intermediate layer) is hard and has poor deformability, it cannot be stretched well when bonded to the element formation surface of the semiconductor wafer via a ring frame, and thus bonding is not possible. Furthermore, even if it can be bonded, it shrinks and peels off over time. Furthermore, even if the film is stretched in the pick-up process to create a distance between the semiconductor chips, it does not work well because the substrate is difficult to stretch, and by applying a force to stretch the film, the film is peeled off from the ring frame.

In addition, when a bump is formed on an element of a semiconductor wafer, the surface of the semiconductor wafer on the element formation side is a surface having unevenness with a maximum height difference of 10 µm or more and 300 µm or less, but the adhesive film described in Patent Document 1 also has room for improvement in terms of unevenness followability when bonding to such an uneven surface.

The object of the present invention is to provide a protective tape having a substrate and an adhesive layer, which is used by adhering to a semiconductor wafer, and which is easy to stretch and has excellent unevenness following properties.

In order to solve the above problem, one aspect of the present invention provides a protective tape having a substrate and an adhesive layer, and used by adhering to a semiconductor wafer, wherein the substrate has a first resin layer formed on a surface on the adhesive layer side, and a second resin layer formed on a surface of the first resin layer opposite to the adhesive layer, wherein the first resin layer has a storage elastic modulus of 1.000 KPa or more and 200 KPa or less at any temperature in a range of 50°C or more and 90°C or less, and the second resin layer has a melting point measured by the DSC method of 80°C or more and 230°C or less, and a Young's modulus of 1000 MPa or less for the entire tape when in use (in a state where a separator is provided, the separator is peeled off).

The protective tape of the present invention is a protective tape having a substrate and an adhesive layer, and used by bonding to a semiconductor wafer, and since the physical properties of the first resin layer and the second resin layer constituting the substrate and the entire tape at the time of use are specified, it can be expected to be easy to stretch and have excellent unevenness following properties.

Fig. 1 is a cross-sectional view showing a protective tape corresponding to an embodiment of the present invention.

(Form for carrying out the invention)

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the embodiments shown below. In the embodiments shown below, technically preferable limitations are made for carrying out the present invention, but these limitations are not essential requirements of the present invention.

[Composition of protective tape]

As shown in Fig. 1, the protective tape (1) of this embodiment is composed of a substrate (2), an adhesive layer (3), and a separator (4).

The substrate (2) is composed of a first resin layer (21) formed on the surface of the adhesive layer (3) side, and a second resin layer (22) formed on the surface opposite to the adhesive layer (3) of the first resin layer (21). The first resin layer (21) and the second resin layer (22) are in contact.

The first resin layer (21) has a storage elastic modulus of 1,000 KPa or more and 200 KPa or less at a temperature in the range of 50°C or more and 90°C or less (for example, 50°C, 70°C, 80°C, 90°C). The storage elastic modulus is preferably in the range of 1,000 KPa or more and 200,000 KPa or less, more preferably in the range of 10,000 KPa or more and 180,000 kPa or less, and particularly preferably in the range of 40,000 KPa or more and 160,000 KPa or less.

The second resin layer (22) has a melting point of 80°C or more and 230°C or less, as measured by the DSC method at a heating rate of 1°C/min. The preferred range of the melting point of the second resin layer (22) is 80°C or more and 180°C or less, and a particularly preferred range is 80°C or more and 150°C or less.

The resin constituting the second resin layer (22) is preferably one of EVA (ethylene vinyl acetate copolymer), α-olefin resin, LDPE (low density polyethylene), HDPE (high density polyethylene), PP (polypropylene), PP/SEPS (polypropylene/styrene-hydrogenated isoprene-styrene block copolymer), and COC (cyclic olefin copolymer).

The Young's modulus of the protective tape (1) when the separator (4) is peeled off, i.e., the Young's modulus of the entire tape when used, is 1000 MPa or less. The preferable range of the Young's modulus of the entire tape is 30 MPa or more and 1000 MPa or less, a more preferable range is 30 MPa or more and 950 MPa or less, a still more preferable range is 30 MPa or more and 500 MPa or less, and a particularly preferable range is 30 MPa or more and 200 MPa or less.

The thickness of the first resin layer (21) is preferably 100 µm or more and 500 µm or less, more preferably 150 µm or more and 400 µm or less, and even more preferably 200 µm or more and 350 µm or less.

The thickness of the second resin layer (22) is preferably 30 µm or more and 150 µm or less, more preferably 40 µm or more and 120 µm or less, and even more preferably 50 µm or more and 100 µm or less.

The second resin layer (22) is preferably thinner than the first resin layer (21). The ratio of the thicknesses of the first resin layer (21) and the second resin layer (22) is preferably 2.0 or more and 5.0 or less (thickness of the first resin layer (21)/thickness of the second resin layer (22)), more preferably 2.5 or more and 4.0 or less, and even more preferably 2.5 or more and 3.5 or less.

[Method for manufacturing protective tape]

Protective tape (1) can be manufactured, for example, by the method shown below.

First, the thermoplastic resin, which is the material forming the first resin layer (21), and the thermoplastic resin, which is the material forming the second resin layer (22), are each placed in an extruder and co-extrusion processed. Accordingly, the base material (2) is obtained as a co-extruded film.

Alternatively, a first resin layer (21) is prepared, and a thermoplastic resin, which is a material for forming a second resin layer (22), is extruded in layers on one surface of the first resin layer (21), and then cooled. Accordingly, the substrate (2) is obtained as an extruded laminate film.

Next, an adhesive layer (3) is formed by coating an adhesive on one surface of a separator (4), thereby obtaining a separator with an adhesive layer attached.

Next, the adhesive layer attachment separator is bonded to the first resin layer (21) of the substrate (2) toward the adhesive layer (3), thereby transferring the adhesive layer (3) to the first resin layer (21).

[The function and effect of protective tape]

The protective tape (1) of this embodiment is composed of a first resin layer (21) having a storage elastic modulus of 1,000 KPa or more and 200 KPa or less at a temperature in the range of 50°C or more and 90°C or less, and a second resin layer (22) having a melting point of 80°C or more and 230°C or less as measured by the DSC method, and the Young's modulus of the entire tape at the time of use is 1,000 MPa or less. Accordingly, the protective tape (1) of this embodiment exhibits the following functions and effects.

The protective tape (1) has excellent deformability since the Young's modulus of the entire tape at the time of use is 1000 MPa or less, and thus can adhere well when bonded to the element formation surface of a semiconductor wafer and the ring frame. In addition, since the protective tape (1) is easy to elongate, the protective tape (1) can be elongated in the pick-up process to create a distance between semiconductor chips. In addition, if the Young's modulus is less than 30 MPa, the protective tape is easy to deform excessively, and there is a possibility that elongation will be completed when heat is applied, and therefore the Young's modulus is preferably 30 MPa or more and 1000 MPa or less.

In addition, since the storage elastic modulus of the first resin layer (21) is 200 KPa or less, and the substrate (2) has excellent unevenness following properties, even when a bump is formed on an element of a semiconductor wafer and the surface on the element formation side of the semiconductor wafer has an unevenness of a maximum height difference of 10 µm or more and 300 µm or less, the protective tape (1) can be neatly adhered. In this case, the thickness of the first resin layer (21) is preferably a dimension in a range equal to or greater than the maximum value and less than or equal to 10 times the value. In addition, if the storage elastic modulus of the first resin layer is less than 1.000 KPa, there is a possibility that the state of the protective tape becomes unstable (for example, when transporting the protective tapes in a laminated state, the first resin layer may bulge out and the protective tapes adjacent to each other in the laminated direction may become bonded).

In addition, since the melting point of the second resin layer (22) is 80℃ or more and 230℃ or less, the Young's modulus of the entire tape during use can be 30㎫ or more and 1000㎫ or less.

If the melting point of the second resin layer exceeds 230°C, the Young's modulus of the entire tape during use greatly exceeds 1000 MPa, making it difficult to deform, and thus making it difficult to adhere the protective tape well to the element formation surface of the semiconductor wafer and the ring frame.

In addition, if the melting point of the second resin layer is lower than 80°C, there is a high possibility that the melting point of the second resin layer is lower than the temperature within the device being used, and therefore there is a risk that it will melt during use and adhere within the device.

That is, the protective tape (1) of this embodiment is suitably used in a method for manufacturing a semiconductor chip, which comprises a step of adhering a protective tape to a semiconductor wafer and a ring frame (a frame that is arranged on the outside of the semiconductor wafer and supports the semiconductor wafer), a step of cutting the semiconductor wafer into a plurality of semiconductor chips by making a cut along a cutting line from the protective tape side, and a step of pressing the semiconductor wafer from the side opposite to the protective tape and taking out the plurality of semiconductor chips (pickup step).

Example

〔Preparation of adhesive composition〕

<Adhesive composition A>

By adding 1.0 part by mass of Coronate L (trade name, manufactured by Nippon Polyurethane Kogyo Co., Ltd.) to 100 parts by mass of a copolymer obtained by setting the mass ratio of monomers to 2-ethylhexyl acrylate:2-hydroxyacrylate:methacrylic acid = 80:15:5 and mixing the mixture, an adhesive composition A was obtained.

〔Preparation of the resin constituting the first resin layer〕

<Measurement of storage elastic modulus>

A film having a thickness of 300 ㎛ composed of the following resins A to E was punched into a disk shape having a diameter of 8 mm to produce a test sample, and each test sample was sandwiched between parallel plates, and a viscoelasticity measuring device (product name: ARES, manufactured by Rheometrics Scientific F.E., Ltd.) was operated under the conditions of a measurement frequency of 0.1 to 10 Hz and a set temperature of 23°C. From the data representing the obtained viscoelasticity, the dynamic shear storage modulus G' at 70°C was specified, and this value was taken as the measured value of the storage modulus.

<Suzy A>

As resin A, an ethylene-butylacrylate copolymer (EBA) having a butylacrylate content of 30% and a weight average molecular weight of 100000 was prepared. The storage elastic modulus of resin A at 70°C measured by the above method was 9.0×10 ⁴ ㎩ (90 KPa), the MFR was 30 g/10 min, and the molecular weight distribution was 5.8.

<Suzy B>

As resin B, an ethylene-vinyl acetate copolymer (EVA) having a vinyl acetate content of 40% and a weight average molecular weight of 40000 was prepared. The storage elastic modulus of resin B at 70°C measured by the above method was 4.0×10 ⁴ ㎩ (40 KPa), the MFR was 70 g/10 min, and the molecular weight distribution was 6.5.

<Suzy C>

As resin C, an α-olefin resin having a density of 0.89 and a weight average molecular weight of 40,000 was prepared. The storage elastic modulus of resin C at 70°C measured by the above method was 1.6×10 ⁵ ㎩ (160 KPa), the MFR was 40 g/10 min, and the molecular weight distribution was 2.4.

<Suzy D>

As Resin D, an ethylene-vinyl acetate copolymer (EVA) having a vinyl acetate content of 42% and a weight average molecular weight of 40,000 was prepared. The storage elastic modulus of Resin D at 70°C measured by the above method was 900㎩ (0.900KPa), the MFR was 70 g/10 min, and the molecular weight distribution was 6.5.

<Suzy E>

As Resin E, an α-olefin resin having a density of 0.90 and a weight average molecular weight of 40000 was prepared. The storage elastic modulus of Resin E at 70°C measured by the above method was 2.2×10 ⁵ ㎩ (220 KPa), the MFR was 40 g/10 min, and the molecular weight distribution was 2.0.

〔Preparation of the resin constituting the second resin layer〕

<HDPE>

As a high-density polyethylene (HDPE), “Nippon Hard 2500” manufactured by Tosoh Co., Ltd. was prepared.

<α-olefin resin>

As an α-olefin resin (poly α-olefin), "Kernel (trademark) KS260" manufactured by Nippon Polyethylene Co., Ltd. was prepared. This resin is a metallocene olefin resin, has a DSC melting point of 92°C, a Shore A hardness of 90, and a density of 0.902 g/cm3.

<PP/SEPS mixed resin (elastomer)>

As a homopolypropylene (PP) resin, "J-105G" manufactured by Ube Kosan Co., Ltd. was prepared, and as a styrene-hydrogenated isoprene-styrene block copolymer (SEPS), "Hybra (registered trademark) 7125" manufactured by Kuraray Co., Ltd. was prepared. By mixing these resins at a mass ratio of 50:50, a PP/SEPS mixed resin was obtained.

<LDPE>

As a low-density polyethylene (LDPE), “Petrosene (registered trademark) 231F” manufactured by Tosoh Co., Ltd. was prepared.

<EVA>

As an ethylene vinyl acetate copolymer (EVA), “Ultracen (registered trademark) 640” manufactured by Tosoh Co., Ltd. was prepared.

<COC>

As a fantasy olefin copolymer (COC), “TOPASS (registered trademark) 8007F-600” manufactured by Polyplastics Co., Ltd. was prepared.

〔Making protective tape〕

[Example 1]

A protective tape (1) of the configuration of Fig. 1 was manufactured as follows.

First, the HDPE and the resin A were each placed in different extruders and co-extrusion was performed to produce a substrate (2) in which a first resin layer (21) made of the resin A and having a thickness of 300 ㎛ was formed on top of a second resin layer (22) made of the HDPE and having a thickness of 120 ㎛.

Next, corona treatment was performed on the upper surface of the first resin layer (21) (the surface opposite to the second resin layer (22)).

Next, adhesive composition A was applied onto a separator (4) made of polyethylene terephthalate (PET) having a thickness of 40 ㎛ so that the film thickness after drying was 10 ㎛, and the film was dried to form an adhesive layer (3). Accordingly, a separator (4) with an adhesive layer (3) attached was obtained.

Next, the adhesive layer (3) attachment separator (4) was attached to the first resin layer (21) of the substrate (2) toward the adhesive layer (3), thereby transferring the adhesive layer (3) to the first resin layer (21).

In this way, the protective tape (1) of Example 1 was obtained.

From the protective tape (1) of Example 1, a separator (4) was removed, and a test piece was produced in accordance with the “Test method for tensile properties of plastic films and sheets having a thickness of 1 mm or less” specified in JIS K7127. The Young’s modulus was measured by performing a tensile test using this test piece. This test was performed using five test pieces, and the average value thereof was taken as the “Young’s modulus of the entire tape” of the protective tape (1) of Example 1.

[Example 2]

A protective tape (1) of the configuration of Fig. 1 was manufactured as follows.

First, the above-mentioned α-olefin resin and the above-mentioned resin B were each placed in different extruders and co-extrusion was performed to produce a substrate (2) in which a first resin layer (21) made of the above-mentioned resin B and having a thickness of 300 ㎛ was formed on a second resin layer (22) made of the above-mentioned α-olefin resin and having a thickness of 100 ㎛.

Next, the adhesive layer (3) attached separator (4) obtained in the same manner as Example 1 was bonded to the first resin layer (21) of the substrate (2) toward the adhesive layer (3), and the adhesive layer (3) was transferred to the first resin layer (21) by performing the same manner as Example 1.

In this way, the protective tape (1) of Example 2 was obtained. In addition, the “Young’s modulus of the entire tape” of the protective tape (1) of Example 2 was measured in the same manner as in Example 1.

[Example 3]

A protective tape (1) of the configuration of Fig. 1 was manufactured as follows.

First, the PP/SEPS and the resin C were each placed in different extruders and co-extrusion was performed to produce a substrate (2) in which a first resin layer (21) made of the resin C and having a thickness of 300 ㎛ was formed on a second resin layer (22) made of the PP/SEPS and having a thickness of 100 ㎛.

Next, the adhesive layer (3) attached separator (4) obtained in the same manner as Example 1 was bonded to the first resin layer (21) of the substrate (2) toward the adhesive layer (3), and the adhesive layer (3) was transferred to the first resin layer (21) by performing the same manner as Example 1.

In this way, the protective tape (1) of Example 3 was obtained. In addition, the “Young’s modulus of the entire tape” of the protective tape (1) of Example 3 was measured in the same manner as in Example 1.

[Example 4]

A protective tape (1) of the configuration of Fig. 1 was manufactured as follows.

First, the LDPE and the resin C were each placed in different extruders and co-extrusion was performed to produce a substrate (2) in which a first resin layer (21) made of the resin C and having a thickness of 300 ㎛ was formed on top of a second resin layer (22) made of the LDPE and having a thickness of 100 ㎛.

Next, the adhesive layer (3) attached separator (4) obtained in the same manner as Example 1 was bonded to the first resin layer (21) of the substrate (2) toward the adhesive layer (3), and the adhesive layer (3) was transferred to the first resin layer (21) by performing the same manner as Example 1.

In this way, the protective tape (1) of Example 4 was obtained. In addition, the “Young’s modulus of the entire tape” of the protective tape (1) of Example 4 was measured in the same manner as in Example 1.

[Comparative Example 1]

First, the HDPE and the resin D were each placed in different extruders and co-extrusion was performed to produce a substrate (2) in which a first resin layer (21) made of the resin D and having a thickness of 300 ㎛ was formed on top of a second resin layer (22) made of the HDPE and having a thickness of 100 ㎛.

Next, corona treatment was performed on the upper surface of the first resin layer (21) (the surface opposite to the second resin layer (22)).

Next, the adhesive layer (3) attached separator (4) obtained in the same manner as Example 1 was bonded to the first resin layer (21) of the substrate (2) toward the adhesive layer (3), and the adhesive layer (3) was transferred to the first resin layer (21) by performing the same manner as Example 1.

In this way, the protective tape of Comparative Example 1 was obtained. In addition, the “Young’s modulus of the entire tape” of the protective tape of Comparative Example 1 was measured in the same manner as Example 1.

[Comparative Example 2]

First, the HDPE and the resin E were each placed in different extruders and co-extrusion was performed to produce a substrate (2) in which a first resin layer (21) made of the resin E and having a thickness of 300 ㎛ was formed on top of a second resin layer (22) made of the HDPE and having a thickness of 100 ㎛.

Next, corona treatment was performed on the upper surface of the first resin layer (21) (the surface opposite to the second resin layer (22)).

Next, the adhesive layer (3) attached separator (4) obtained in the same manner as Example 1 was bonded to the first resin layer (21) of the substrate (2) toward the adhesive layer (3), and the adhesive layer (3) was transferred to the first resin layer (21) by performing the same manner as Example 1.

In this way, the protective tape of Comparative Example 2 was obtained. In addition, the “Young’s modulus of the entire tape” of the protective tape of Comparative Example 2 was measured in the same manner as Example 1.

[Comparative Example 3]

First, the EVA and the resin C were each placed in different extruders and co-extrusion was performed to produce a substrate (2) in which a first resin layer (21) made of the resin C and having a thickness of 300 ㎛ was formed on top of a second resin layer (22) made of the EVA and having a thickness of 100 ㎛.

Next, corona treatment was performed on the upper surface of the first resin layer (21) (the surface opposite to the second resin layer (22)).

Next, the adhesive layer (3) attached separator (4) obtained in the same manner as Example 1 was bonded to the first resin layer (21) of the substrate (2) toward the adhesive layer (3), and the adhesive layer (3) was transferred to the first resin layer (21) by performing the same manner as Example 1.

In this way, the protective tape of Comparative Example 3 was obtained. In addition, the “Young’s modulus of the entire tape” of the protective tape of Comparative Example 3 was measured in the same manner as in Example 1.

[Comparative Example 4]

First, the COC and the resin C were each placed in different extruders and co-extrusion was performed to produce a substrate (2) in which a first resin layer (21) made of the resin C and having a thickness of 300 ㎛ was formed on top of a second resin layer (22) made of the COC and having a thickness of 100 ㎛.

Next, corona treatment was performed on the upper surface of the first resin layer (21) (the surface opposite to the second resin layer (22)).

Next, the adhesive layer (3) attached separator (4) obtained in the same manner as Example 1 was bonded to the first resin layer (21) of the substrate (2) toward the adhesive layer (3), and the adhesive layer (3) was transferred to the first resin layer (21) by performing the same manner as Example 1.

In this way, the protective tape of Comparative Example 4 was obtained. In addition, the “Young’s modulus of the entire tape” of the protective tape of Comparative Example 4 was measured in the same manner as in Example 1.

[Comparative Example 5]

First, extrusion lamination of the resin C to a thickness of 300 μm was performed on a polyethylene terephthalate (PET) film having a thickness of 50 μm. Accordingly, a substrate (2) was produced in which a first resin layer (21) made of the resin C and having a thickness of 300 μm was formed on a second resin layer (22) made of PET.

Next, corona treatment was performed on the upper surface of the first resin layer (21) (the surface opposite to the second resin layer (22)).

Next, the adhesive layer (3) attached separator (4) obtained in the same manner as Example 1 was bonded to the first resin layer (21) of the substrate (2) toward the adhesive layer (3), and the adhesive layer (3) was transferred to the first resin layer (21) by performing the same manner as Example 1.

In this way, the protective tape of Comparative Example 5 was obtained. In addition, the “Young’s modulus of the entire tape” of the protective tape of Comparative Example 5 was measured in the same manner as in Example 1.

〔Performance Evaluation〕

The performance of the protective tapes of Examples 1 to 4 and Comparative Examples 1 to 5 obtained was investigated as follows.

<Vacuum Mount Performance>

A semiconductor wafer having a diameter of 200 mm (8 inches) and having bumps on its surface with a height of 200 μm and a pitch of 400 μm, a scribe width of 100 μm, and a semiconductor chip of 5 mm square was prepared.

This semiconductor wafer was placed on a table heated to 70℃ of a vacuum laminator (manufactured by Omiya Kogyo Co., Ltd., product name OVM-1200MSH), and then each protective tape attached to a ring frame was set on top of it to examine whether or not it could be bonded under vacuum to the element formation surface of the semiconductor wafer using the vacuum laminator. If bonding was possible, the vacuum mount performance was evaluated as good (○), and if it was not possible, the vacuum mount performance was evaluated as poor (×).

<Followability>

Regarding the adhesion of the protective tape to the semiconductor wafer that was able to be bonded under vacuum by the above test, after 22 hours, the adhesion of the protective tape to the semiconductor wafer was visually observed.

Products in which floating was confirmed in the bump portion from the bonding surface of the semiconductor wafer were evaluated as defective products with an "×"; products in which floating was confirmed only in the scribe portion were evaluated as acceptable products with an "○"; and products in which no floating was confirmed were evaluated as good products with an "◎".

<Expandability>

First, a bare wafer having a diameter of 150 mm (6 inches) and a thickness of 350 μm and a ring frame having a size corresponding to the bare wafer were prepared. Next, the bare wafer was adhered to the ring frame using each protective tape, thereby obtaining each ring frame attachment tape. Each obtained ring frame attachment tape was set on a die picker (manufactured by Canon Machinery Co., Ltd., product name CAP-3000Ⅱ).

By fixing the outer portion of the set ring frame attachment tape and pushing up the table in the central portion (wafer portion), the expansion amount was expanded to 2 mm. When the tape did not peel off during expansion, the expandability was evaluated as good (○), and if the protective tape peeled off from the ring frame, the expandability was evaluated as poor (×).

<Stability>

When transported in a laminated state, if there is a concern that the protective tapes adjacent to each other in the laminated direction may adhere to each other, or that the protective tape may melt and adhere to the device when the temperature inside the device is high, it was evaluated as “×”, and if there is no such concern, it was evaluated as “○”.

<Comprehensive Evaluation>

When all performances are “○” or “◎”, the overall evaluation is considered good and is evaluated as “○”. When any performance is ×, the overall evaluation is considered poor and is evaluated as “×”.

These results are shown in Table 1 below along with the composition of each protective tape.

In addition, with regard to stability, Comparative Examples 1 and 3 were evaluated as poor, and the reasons are as follows.

In the protective tape of Comparative Example 1, since the storage elastic modulus of the first resin layer is less than 1.0 KPa, there is a risk that the first resin layer may bulge out when transported in a laminated state, and the protective tapes adjacent to each other in the laminated direction may become bonded. In the protective tape of Comparative Example 3, since the melting point of the second resin layer is 75°C, there is a risk that the protective tape melts during use and adheres to the inside of the device when the temperature inside the device in which it is used becomes 75°C or higher.

From the results in Table 1, it can be seen that the protective tapes of Examples 1 to 4 have a storage elastic modulus of the first resin layer (21) at 70°C of 40 KPa or more and 160 KPa or less, a melting point of the second resin layer (22) measured by the DSC method of 83°C or more and 128°C or less, a Young's modulus of the entire tape during use of 35 MPa or more and 950 MPa or less, and a thickness of the first resin layer (21) that is 1.5 times (300 μm) the maximum value (200 μm) of the height difference of the unevenness of the semiconductor wafer surface, thereby being excellent in all of vacuum mount performance, followability, expandability, and stability.

In this regard, the protective tape of Comparative Example 1 had excellent vacuum mount performance, followability, and expandability, but because the storage elastic modulus of the first resin layer at 70°C was less than 1.000 KPa, the stability was poor as described above.

The protective tape of Comparative Example 2 had excellent vacuum mount performance, expandability, and stability, but had poor followability because the storage elastic modulus of the first resin layer at 70°C exceeded 200 KPa.

The protective tape of Comparative Example 3 had poor stability as described above because the melting point of the second resin layer measured by the DSC method was less than 80°C, and the Young's modulus of the entire tape during use was less than 30 MPa, so that when bonding was performed using a vacuum laminator, elongation was completed and bonding was impossible. In addition, the expandability was also poor.

The protective tape of Comparative Example 4 had excellent vacuum mount performance, followability, and stability, but had poor expandability because the Young's modulus of the entire tape during use exceeded 1000 MPa.

The protective tape of Comparative Example 5 had a melting point of over 230℃ as measured by the DSC method of the second resin layer, and thus the Young's modulus of the entire tape when used was 3650 MPa, which significantly exceeded 1000 MPa. Therefore, it could not be deformed and bonded when bonding was performed using a vacuum laminator. In addition, the expandability was also poor.

1: Protective tape
2 : Description
3: Adhesive layer
4: Separator
21: 1st resin layer
22: Second resin layer

Claims (7)

A protective tape having a base material and an adhesive layer and used for bonding to a semiconductor wafer.
The above-mentioned description comprises a first resin layer formed on a surface of the adhesive layer side, and a second resin layer formed on a surface of the first resin layer opposite to the adhesive layer.
The above first resin layer has a storage elastic modulus of 1.000 KPa or more and 200 KPa or less at any temperature in the range of 50°C or more and 90°C or less,
The above second resin layer has a melting point measured by the DSC method of 80°C or more and 230°C or less,
Protective tape having a Young's modulus of 1000 MPa or less throughout the entire tape when used. In the first paragraph,
Protective tape having a Young's modulus of 30 MPa or more and 1000 MPa or less throughout the entire tape when used. In the first paragraph,
A protective tape in which the first resin layer and the second resin layer are in contact. In the first paragraph,
A protective tape used by adhering to a surface having irregularities of a semiconductor wafer, the maximum difference in height of the irregularities being 10 ㎛ or more and 300 ㎛ or less. In paragraph 4,
A protective tape having a thickness of the first resin layer that is equal to or greater than the maximum value of the height difference of the unevenness and less than or equal to 10 times the maximum value. In the first paragraph,
A protective tape wherein the resin constituting the second resin layer is any one of EVA (ethylene vinyl acetate copolymer), α-olefin resin, LDPE (low density polyethylene), HDPE (high density polyethylene), PP (polypropylene), PP/SEPS (polypropylene/styrene-hydrogenated isoprene-styrene block copolymer), and COC (cyclic olefin copolymer). A process of bonding a protective tape as described in any one of claims 1 to 6 to a semiconductor wafer and a frame that is arranged on the outside of the semiconductor wafer and supports the semiconductor wafer,
A process of cutting the semiconductor wafer into a plurality of semiconductor chips by cutting the semiconductor wafer along a cutting line from the protective tape side,
A process of pressing the semiconductor wafer from the side opposite to the protective tape to extract the plurality of semiconductor chips.
A method for manufacturing a semiconductor chip having a .