JP2008214499A - Tape, method for using same and process for producing semiconductor device using the tape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tape which can surely be cured and can be easily peeled, furthermore can protect a semiconductor wafer from the impact added to the wafer, without damaging the productivity of the semiconductor device, in the production of a thin semiconductor device, and can be easily peeled from the semiconductor wafer. <P>SOLUTION: The tape 10 comprises a resin sheet 2 having electromagnetic wave transmission and thermosetting properties and an electromagnetic wave curable pressure-sensitive adhesive layer 4 formed on the surface of the resin sheet. The tape 10 is applied to the surface of a semiconductor wafer having an already formed semiconductor structure and, the resin sheet 2 is cured by heating. The tape can protect the semiconductor wafer from the impact, when the wafer is polished to a thin one or is conveyed. By irradiating the pressure-sensitive adhesive layer 4 with an electromagnetic wave, the tape 10 can be easily peeled from the surface of the semiconductor wafer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a tape and a method for using the same. In particular, the present invention relates to a tape used in a semiconductor device manufacturing process and a method for using the tape.

  The production of thin semiconductor devices is increasing. In order to reduce the thickness of a semiconductor device, it is necessary to process the semiconductor wafer thinly. When a semiconductor device is thinly processed, problems such as warping and cracking may occur in the semiconductor wafer during the manufacturing process of the semiconductor device. In order to deal with problems such as warping and cracking, a plurality of semiconductor structures may be formed on the surface of a semiconductor wafer that is thicker than the final thickness required, and then the back surface of the semiconductor wafer may be polished. In order to protect the semiconductor wafer from the impact and stress applied to the semiconductor wafer when polishing the back surface of the semiconductor wafer, or to protect the semiconductor wafer from the impact applied to the semiconductor wafer when transporting a thinly polished semiconductor wafer, Techniques have been developed for attaching a protective tape to the surface of a semiconductor structure.

Patent Document 1 discloses a technique for forming an intermediate layer between a substrate film and an adhesive layer in a substrate film and a tape having an ultraviolet curable adhesive layer on the surface side of the substrate film. The intermediate layer is formed using a material that reversibly changes in curing and softening depending on temperature, softens when heated, and reversibly changes when cured.
By sticking the tape to the semiconductor wafer with the intermediate layer softened, the tape can follow the irregularities of the semiconductor wafer. When the intermediate layer is cured, mechanical strength is obtained, and when the back surface of the semiconductor wafer is polished, the semiconductor wafer is protected from impact or stress applied to the semiconductor wafer, or when the thinly polished semiconductor wafer is transported The semiconductor wafer can be protected from an impact applied to the semiconductor wafer. It is possible to prevent problems such as warping and cracking in the semiconductor wafer. When the intermediate layer is softened again, the tape can be easily peeled off from the thinly polished semiconductor wafer.

JP 2005-48039 A

  As disclosed in Patent Document 1, it is possible to prevent defects such as warpage and cracking in the semiconductor wafer by repeating the curing and softening of the intermediate layer. However, in order to control the hardening and softening of the intermediate layer by heating or cooling the tape, it takes time to maintain the tape at a predetermined temperature. Although Patent Document 1 describes that the reversible change of the curing and softening of the intermediate layer is performed immediately, at least time for changing the temperature of the ambient environment of the semiconductor wafer is required. Therefore, the productivity of the semiconductor device is deteriorated.

  Patent Document 1 discloses a technique in which the intermediate layer softens when the temperature is higher than 23 ° C., and the intermediate layer is cured when the temperature is 23 ° C. or lower. The tape is attached to the semiconductor wafer while being heated to a temperature higher than 23 ° C. Next, the semiconductor wafer is polished, and then the temperature of the tape is set to 23 ° C. or lower to transport the semiconductor wafer. Next, the tape is heated to peel the tape from the surface of the semiconductor wafer. Heat may be generated by polishing the semiconductor wafer, and it is difficult to maintain the temperature of the tape at a desired temperature. Also, the ambient temperature when the semiconductor wafer is polished or transported must be managed. That is, it is difficult to control changes in the curing or softening of the intermediate layer. Insufficient change in the curing or softening of the intermediate layer may cause problems such as warping and cracking in the semiconductor wafer. If the intermediate layer is not sufficiently cured, the semiconductor wafer is damaged by an impact when the semiconductor wafer is polished or transported. If the intermediate layer is insufficiently softened, the semiconductor wafer is damaged when the protective tape is peeled off from the semiconductor wafer.

  An object of the present invention is to provide a tape that can be reliably cured and easily peeled off. Another object of the present invention is to provide a protective tape that protects a semiconductor wafer from an impact when the semiconductor wafer is polished or transported without damaging the productivity of the semiconductor device and can be easily peeled off from the semiconductor wafer. To do.

In this invention, the layer which increases the intensity | strength of a tape by hardening and the layer which makes it easy to peel a tape by hardening are provided separately.
The tape of the present invention includes a resin sheet having electromagnetic wave permeability and thermosetting property, and is formed on the surface of the resin sheet, and includes an electromagnetic wave curable pressure-sensitive adhesive layer.

According to the above tape, the resin sheet is cured when heated, and the pressure-sensitive adhesive layer is cured when irradiated with a predetermined electromagnetic wave (including ultraviolet rays). Since the resin sheet has thermosetting properties, it does not soften once cured. Even if the ambient temperature at which the tape is used changes, the resin sheet can be prevented from being softened when not intended. Since the resin sheet has electromagnetic wave permeability, the pressure-sensitive adhesive layer can be cured without directly irradiating the pressure-sensitive adhesive layer with electromagnetic waves.
For example, when the tape is attached to the surface of the semiconductor wafer, the resin sheet is cured, so that the semiconductor wafer can be protected from an impact applied to the semiconductor wafer. Moreover, the tape can be easily peeled off from the surface of the semiconductor wafer by curing the pressure-sensitive adhesive layer. Since it is not necessary to soften the resin sheet by heating after the resin sheet is cured, the productivity of the semiconductor device can be improved.
As used herein, “curing of the pressure-sensitive adhesive layer” means that the pressure-sensitive adhesive strength of the pressure-sensitive adhesive layer is reduced. Generally, an adhesive is firmly bonded to an object to which the adhesive is applied by being cured. On the other hand, the pressure-sensitive adhesive has a property that the adhesive force is reduced by being cured.

In the tape of the present invention, the resin sheet preferably has an electromagnetic wave transmittance of 10 to 500 nm of 10% or more.
According to said tape, an adhesive layer can be hardened reliably from the back surface (surface in which the adhesive layer is not formed) of a resin sheet. That is, the tape can be reliably peeled off from the member to which the tape is attached. In addition, although the wavelength of ultraviolet rays is said to be 10 to 400 nm, a pressure-sensitive adhesive that cures at a wavelength near 500 nm is also generally referred to as an ultraviolet curable type. In the present specification, a pressure-sensitive adhesive that cures at a wavelength of 10 to 500 nm is referred to as an ultraviolet curing type.

In the tape of this invention, it is preferable that the thermosetting temperature of a resin sheet is 40 degreeC or more and 200 degrees C or less.
By setting the thermosetting temperature of the resin sheet to the above range, the tape can be used more efficiently. When the thermosetting temperature is lower than 40 ° C., the resin sheet may be cured at an ambient temperature where the tape is used or an ambient temperature where the tape is stored. On the other hand, when the thermosetting temperature is higher than 200 ° C., gas may be generated from the pressure-sensitive adhesive layer or the like. When the tape is used in a vacuum, the degree of vacuum may not be maintained due to the generated gas.

The present invention also provides a method for using the tape described above. The method includes a step of attaching a surface on which a pressure-sensitive adhesive layer of a tape is formed on a semiconductor wafer, a step of heating the resin sheet, and a step of irradiating electromagnetic waves from the back surface of the resin sheet.
According to the above method, the resin sheet is cured by heating the tape. When a tape is applied to the surface of a semiconductor wafer, when the back surface of the semiconductor wafer is polished or a thinly polished semiconductor wafer is transported, stress is applied to the semiconductor wafer, causing problems such as warping or cracking of the semiconductor wafer. Can be prevented. Moreover, in said method, a tape can be easily peeled off from the surface of a semiconductor wafer only by irradiating electromagnetic waves from the back surface of a resin sheet. Note that “heating the tape” here is not limited to heating only the tape, but also includes heating the ambient temperature of the tape to a temperature at which the resin sheet is cured. That is, it means that at least the resin sheet is heated. Moreover, a tape can be affixed on the back surface of a semiconductor wafer, and a tape may be affixed on both front and back surfaces if necessary.

  The present invention also provides a method for manufacturing a semiconductor device. The method includes a step of forming a semiconductor structure on a surface of a semiconductor wafer, a step of attaching a surface on which the adhesive layer of the tape is formed on the surface of the semiconductor body structure, and a step of heating a resin sheet. And a step of polishing the back surface of the semiconductor wafer and a step of irradiating electromagnetic waves from the back surface of the resin sheet.

  According to the above method, the semiconductor structure can be formed on the surface of the semiconductor wafer that is thicker than the thickness when the semiconductor device is completed. The resin sheet is cured by heating the resin sheet. When the back surface of the semiconductor wafer is polished or a thinly polished semiconductor wafer is transported, it is possible to prevent the semiconductor wafer from being warped or cracked due to stress applied to the semiconductor wafer. It is possible to prevent defects such as warpage and cracking from occurring in the semiconductor wafer due to an impact when forming the semiconductor structure. By subsequently irradiating electromagnetic waves from the back surface of the resin sheet, the tape can be peeled off from the surface of the semiconductor wafer without damaging the semiconductor structure.

  According to the present invention, it is possible to obtain a tape that is cured when heated and can be easily peeled off when irradiated with electromagnetic waves. By using the tape, it is possible to manufacture a thin semiconductor device while preventing problems such as warping and cracking in the semiconductor wafer.

The features of the present invention are listed.
(First Form) An epoxy film or a melamine film is used as the resin sheet 2.
(2nd form) After grind | polishing the back surface of the semiconductor wafer 6, electromagnetic waves are irradiated from the back surface of the resin sheet 2, and the tape 10 is peeled from the surface of the semiconductor wafer 6. FIG. After removing the tape 10 from the surface of the semiconductor wafer 6, the semiconductor wafer 6 is diced (manufacturing method 1).
(3rd form) After grind | polishing the back surface of the semiconductor wafer 6, the semiconductor wafer 6 is diced before irradiating electromagnetic waves from the back surface of the resin sheet 2. FIG. After the semiconductor wafer 6 is diced, the electromagnetic wave is irradiated from the back surface of the resin sheet 2 and the tape 10 is peeled off from the diced surface of the semiconductor wafer 6 (Manufacturing methods 2 and 3).

Embodiments will be described in detail below with reference to the drawings.
(Example 1)
In FIG. 1, sectional drawing of the tape 10 of a present Example is typically shown. Note that the configuration of each part does not accurately represent the actual size scale. In order to clarify the drawing, the scale of the drawing is appropriately changed.
The tape 10 is formed on the surface of the epoxy film (resin sheet) 2 having a thickness of 100 μm and the resin sheet 2 and has an adhesive layer 4 having a thickness of 20 μm. The resin sheet 2 has electromagnetic wave transparency, and has an electromagnetic wave transmittance of 10 to 500 nm of 10% or more. Moreover, the thermosetting temperature of the resin sheet 2 is about 90 degreeC. The pressure-sensitive adhesive layer 4 is an ultraviolet curable acrylic pressure-sensitive adhesive, and is cured by irradiating an electromagnetic wave having a wavelength of 10 to 500 nm. That is, the adhesive strength of the pressure-sensitive adhesive layer 4 is reduced by being irradiated with electromagnetic waves (ultraviolet rays). A separator (not shown) is formed on the surface of the adhesive layer 4. By forming the separator, the adhesive material layer 4 can be prevented from coming into contact with the outside.

In this embodiment, a resin sheet 2 having a curing temperature of approximately 90 ° C. is used. However, the resin sheet 2 only needs to have electromagnetic wave permeability and thermosetting properties, and various materials can be selected. For example, a melamine film having a curing temperature of 100 ° C. can be used. If the resin sheet 2 has electromagnetic wave permeability, a resin having a curing temperature of 0 ° C. or higher and 500 ° C. or lower can be used. However, considering the usage environment and storage environment of the tape 10, the curing temperature is preferably 40 ° C or higher. Moreover, it is preferable that a curing temperature is 200 degrees C or less from a viewpoint of suppressing the gas emitted from the adhesive layer 4. FIG. That is, the curing temperature of the resin sheet 2 is particularly preferably 40 ° C. or higher and 200 ° C. or lower.
In this embodiment, only the cross section of the tape 10 is shown. The shape of the tape 10 may be a single sheet in which the resin sheet 2 and the adhesive layer 4 are laminated, or may be a roll of a sheet in which the resin sheet 2 and the adhesive layer 4 are laminated.

(Example 2: Manufacturing method 1 of a semiconductor device)
A method of using the tape 10 and a method of manufacturing a semiconductor device using the tape 10 will be described with reference to FIGS. In this embodiment, an example in which a thin semiconductor device is manufactured by attaching the tape 10 to the surface of the semiconductor device will be described. Here too, the scale of the drawing is changed as appropriate for the sake of clarity of the drawing. The drawings do not accurately indicate the number of semiconductor devices that can be manufactured from one semiconductor wafer.
First, as shown in FIG. 2, a semiconductor wafer 6 is prepared, and a semiconductor structure and an electrode structure 8 are formed on the surface of the semiconductor wafer 6. The thickness of the semiconductor wafer 6 is 700 μm, which is thicker than the thickness (100 μm) of the semiconductor region 6a of the semiconductor device 18 described later. Since the semiconductor wafer 6 is sufficiently thick, even if the semiconductor structure and the electrode structure 8 are formed on the surface of the semiconductor wafer 6, the semiconductor wafer 6 may be warped or cracked due to an impact when the semiconductor structure and the electrode structure 8 are formed. There is no problem.

  Next, as shown in FIG. 3, the surface of the tape 10 on which the adhesive material layer 4 is formed is attached to the surface of the semiconductor wafer 6 (the surface on which the semiconductor structure and the electrode structure 8 are formed). Thereafter, the semiconductor wafer 6 is placed on a heating table (not shown) with a built-in heater so that the back surface of the semiconductor wafer 6 (the surface on which the tape 10 is not attached) is in contact, and heated at 90 ° C. for 5 minutes. To do. At this stage, the thermosetting resin sheet 2 is cured.

  Next, as shown in FIG. 4, the semiconductor wafer 6 is polished from the back surface until the semiconductor wafer 6 reaches 100 μm, and the back electrode 12 is formed on the polished back surface. Since the resin sheet 2 is cured, when the semiconductor wafer 6 is polished or the back electrode 12 is formed, it is possible to prevent the semiconductor wafer 6 from being troubled such as warping or cracking.

Next, 10 to 500 nm electromagnetic waves (ultraviolet rays) are irradiated from the back surface of the resin sheet 2. The electromagnetic wave is irradiated from a position 200 mm away from the pressure-sensitive adhesive layer 4 until the integrated light quantity (electromagnetic wave intensity × irradiation time) reaches 300 mJ / cm ² . At this stage, the adhesive strength of the pressure-sensitive adhesive layer 4 is reduced from 100 N / mm ² to 0.1 N / mm ² . The tape 10 can be easily peeled off from the surface of the semiconductor wafer 6. In addition, the arrow in a figure has shown the range irradiated with electromagnetic waves.

  Next, as shown in FIG. 5, the tape 10 is peeled off from the surface of the semiconductor wafer 6, and the back surface of the back electrode 12 is attached to the dicing tape 14. Next, as shown in FIG. 16, the semiconductor wafer 6 and the back electrode 12 are diced along the dicing line 16. As shown in FIG. 6, a plurality of semiconductor devices 18 having a semiconductor structure and an electrode structure 8 formed on the surface of the semiconductor region 6a and a back electrode 12 formed on the back surface of the semiconductor region 6a are completed.

In this embodiment, an example is shown in which the resin sheet 2 is heated from the back surface of the semiconductor wafer 6 in order to cure it. The resin sheet 2 can be cured by raising the temperature around the resin sheet 2 (that is, the temperature around the semiconductor wafer 6 and the tape 10) to a temperature at which the resin sheet 2 is cured. Moreover, the resin sheet 2 can also be hardened by heating the resin sheet 2 directly.
Moreover, when making the resin sheet 2 into a melamine film, in order to harden a melamine film, it heats at 100 degreeC for 5 minute (s).

Example 3 Semiconductor Device Manufacturing Method 2
Another method for manufacturing a semiconductor device using the tape 10 will be described. The present embodiment is a modification of the second embodiment, and the description of the same steps as those of the second embodiment will be omitted. Moreover, about the same structure as Example 2, description is abbreviate | omitted by attaching | subjecting the same reference number.
2 and 3 are the same as those in the second embodiment. That is, it is the same as Example 2 until the resin sheet 2 is hardened. Next, as shown in FIG. 7, after the back surface of the semiconductor wafer 6 is polished and the back electrode 12 is formed on the polished back surface, the back surface of the resin sheet 2 is pasted on the dicing tape 14.
Next, as shown in FIG. 8, after dicing from the surface of the back electrode 12 to the resin sheet 2, electromagnetic waves are irradiated from the back surface of the dicing tape 14. In addition, the conditions for irradiating electromagnetic waves are the same as in manufacturing method 1, and the dicing tape 14 is selected to have electromagnetic wave permeability. The adhesive strength of the pressure-sensitive adhesive layer 4 is reduced, and the tape 10 can be easily peeled off from the surfaces of the plurality of semiconductor devices 18.
In this method, after the back surface of the semiconductor wafer 6 is polished, the tape 10 is also diced together with the semiconductor wafer 6 before the electromagnetic wave is irradiated from the back surface of the resin sheet 2. When the tape 10 is peeled off from the semiconductor wafer 6, it is possible to effectively prevent the semiconductor wafer 6 from being broken.

Example 4 Semiconductor Device Manufacturing Method 3
Another method for manufacturing a semiconductor device using the tape 10 will be described. The present embodiment is a modification of the third embodiment, and the description of the same steps as those of the third embodiment is omitted. Moreover, about the same structure as Example 3, description is abbreviate | omitted by attaching | subjecting the same reference number.
The steps up to FIG. 7 are the same as those in the third embodiment. That is, the process from polishing the back surface of the semiconductor wafer 6 and forming the back surface electrode 12 to sticking the back surface of the resin sheet 2 on the dicing tape 14 is the same as that in the third embodiment.
Next, as shown in FIG. 9, dicing is performed from the surface of the back electrode 12 to the vicinity of the middle of the resin sheet 2. Subsequent steps are the same as those in manufacturing methods 1 and 2. That is, electromagnetic waves are irradiated from the back surface of the dicing tape 14 to reduce the adhesive strength of the pressure-sensitive adhesive layer 4.
In this method, the resin sheet 2 of the tape 10 is not separated when the tape 10 is peeled off from the surfaces of the plurality of semiconductor devices 18. Since a large adhesion area between the tape 10 and the dicing tape 14 can be secured, the diced semiconductor device 18 can be easily picked up from the tape 10.

Specific examples of the present invention have been described above in detail, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
For example, in the said Example, it showed about the example whose thickness of a resin sheet is 100 micrometers and the thickness of an adhesive layer is 20 micrometers. The thickness of the resin sheet and / or the thickness of the pressure-sensitive adhesive layer is not limited to the examples. It can be appropriately changed depending on the magnitude of the impact applied to the semiconductor wafer and the state of the semiconductor structure formed on the surface of the semiconductor wafer.
The electromagnetic wave irradiation position and the integrated light amount described in the examples are examples for curing the pressure-sensitive adhesive layer, and can be appropriately changed according to the type of the pressure-sensitive adhesive layer.
In this embodiment, a resin sheet having electromagnetic wave transparency with a wavelength of 10 to 500 nm is used. However, the resin sheet should just have the electromagnetic wave transmittance of the wavelength which an adhesive layer hardens | cures. Many UV-curable pressure-sensitive adhesives are cured by electromagnetic waves having a wavelength of 200 to 500 nm, and the resin sheet can also transmit electromagnetic waves having a wavelength of 200 to 500 nm in accordance with the wavelength at which the pressure-sensitive adhesive layer is cured.
In addition, the technical elements described in the present specification or drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in the present specification or the drawings can achieve a plurality of objects at the same time, and has technical utility by achieving one of the objects.

The tape of Example 1 is shown. The manufacturing process of the semiconductor device in the manufacturing method 1 is shown. The manufacturing process of the semiconductor device in the manufacturing method 1 is shown. The manufacturing process of the semiconductor device in the manufacturing method 1 is shown. The manufacturing process of the semiconductor device in the manufacturing method 1 is shown. The manufacturing process of the semiconductor device in the manufacturing method 1 is shown. The manufacturing process of the semiconductor device in the manufacturing method 2 is shown. The manufacturing process of the semiconductor device in the manufacturing method 2 is shown. The manufacturing process of the semiconductor device in the manufacturing method 3 is shown.

Explanation of symbols

2: Resin sheet
4: Adhesive material 6: Semiconductor wafer 8: Semiconductor structure 10: Tape

Claims (5)

A resin sheet having electromagnetic wave permeability and thermosetting property;
Formed on the surface of the resin sheet, and an electromagnetic wave curing pressure-sensitive adhesive layer;
A tape characterized by comprising.   The tape according to claim 1, wherein the resin sheet has an electromagnetic wave transmittance of 10 to 500 nm or more.   The tape according to claim 1 or 2, wherein the resin sheet has a thermosetting temperature of 40C or higher and 200C or lower. It is a usage method of the tape in any one of Claim 1 to 3,
A step of affixing the surface on which the adhesive layer of the tape is formed on the semiconductor wafer;
Heating the resin sheet;
Irradiating electromagnetic waves from the back surface of the resin sheet;
The usage method characterized by providing. A method for manufacturing a semiconductor device,
Forming a semiconductor structure on the surface of the semiconductor wafer;
Attaching the surface of the semiconductor structure on which the adhesive layer of the tape of any one of claims 1 to 3 is formed;
Heating the resin sheet;
Polishing the back surface of the semiconductor wafer;
Irradiating electromagnetic waves from the back surface of the resin sheet;
A manufacturing method comprising:

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