TWI512077B - Thermo-setting double-sided adhesive film excellent in adhesive property and heat resistance - Google Patents

Description

Thermosetting double-sided adhesive film excellent in adhesion and heat resistance Field of invention

The disclosure is generally directed to an adhesive film for a stacked CSP (wafer level package), and more particularly to a thermosetting double-sided adhesive film having excellent adhesion properties and heat resistance. A thermosetting double-sided adhesive film for obtaining space for electric wires, preventing electronic interference, and providing adhesion between crystal grains to be stacked, which has excellent adhesive properties and heat resistance, and is capable of preventing high temperature processing The problem of interfacial peeling or popcorn bursting of the package caused by the high water vapor pressure of the water content absorbed inside the package.

Background of the invention

Recently, a CSP (wafer level package) has been developed due to a new trend of high integration and miniaturization of semiconductor wafers. As can be seen from its name, in one such CSP, the wafer size is considered to be nearly identical to the package size.

As part of a current package trend, a stacked CSP is one of the more advanced packages. In other words, one or more of the wafers are mounted over a wafer, whereby a much higher capacity than conventional packages can be housed in a package of nearly the same size. The stacked CSP has the advantage of increased capacity and has the advantage of reducing the size of a memory to double the functionality of the electronic device by combining a thin film core substrate material and crystal back grinding technology to conventional BGA surface mount technology. Due to such technology, it is possible to effectively use the area of a motherboard and reduce its weight and size, thus ultimately achieving the goal of reducing costs at a system level. In addition, since the stacked CSP makes it possible to connect to many components in the memory system on the market, it provides a way to reduce the cost of the entire system.

As the wafer size becomes smaller, the gap between the wafer and the substrate becomes smaller, and it is also necessary to develop a binder system that conforms to the new package. As a result, various new technology systems are being developed. Although syrup is mainly used in the prior art, new techniques in the form of an adhesive film are being developed due to productivity and resin bleeding problems.

Currently, most packages are converted to a CSP type without regard to their substrates, and most assembly companies are actively focusing on the development of lead-free products that are part of environmentally friendly products. However, such products have the disadvantage of having a higher melting point (about 220 ° C) than a conventional lead solder. In order to overcome this shortcoming, since other products used for assembly should also overcome popcorn burst or other packaging problems caused by such high temperatures, the reliability standard of the demand becomes higher. For example, although a conventional solder is used, its melting point is relatively low at about 220 ° C, but since the melting point of a current lead-free solder is about 260 ° C higher, the water content absorbed inside the package may be due to this high temperature processing. The high temperature during the formation of a high water vapor pressure causes problems such as popping of a package of popcorn or interfacial peeling.

Therefore, there is an urgent need for the development of an adhesive film that overcomes the above mentioned problems.

Summary of invention

The present disclosure provides a thermosetting double-sided adhesive film having excellent adhesive properties and heat resistance, which has excellent adhesive properties and heat resistance, and which can prevent high water content absorbed by a package interior such as high temperature processing. The problem of interface peeling or popcorn bursting of the package caused by water vapor pressure.

Many objects and advantages of the present disclosure will become apparent from the Detailed Description.

The above object can be achieved by a thermosetting double-sided adhesive film having excellent adhesive properties and heat resistance, the thermosetting double-sided adhesive film being an adhesive film between crystal grains and having a coating on a polyimine. An adhesive layer on two sides of the film, wherein the adhesive layer contains one part of 5-200 parts by weight of epoxy resin, 50-200 parts by weight per 100 parts by weight of NBR containing 1-10% by weight of one carboxyl group. The phenol resin, and 2 to 40 parts by weight of one or more curing agents selected from the group consisting of amine-based or acid-based curing agents, and wherein the phenol resin has a softening point of 60 to 120 ° C as measured by a ring and ball method.

Here, after bonding one crystal grain (2 cm × 2 cm) to another crystal grain (2 cm × 2 cm) at 125 ° C / 1.5 kg / 1 second, and after a curing process (175 ° C / 1 hour), the The adhesive film has a grain shear stress of 5 kg or more at room temperature and 100 g or more at 260 °C.

The role of this disclosure

The present disclosure has the effects of providing excellent adhesion properties and heat resistance, and preventing the problem of interfacial peeling or popcorn bursting of one of the packages caused by high water vapor pressure such as water content absorbed inside the package during high temperature processing.

Simple illustration

1 is a cross-sectional view of a stacked wafer level package; and FIG. 2 is a cross-sectional view of an adhesive film between the dies in accordance with an embodiment of the present disclosure.

1. . . wire

2. . . Molding compound

3. . . Adhesive film

4. . . Solder mask

5. . . style

6. . . Substrate

7. . . Sub-grain

8. . . Mother grain

10. . . Polyimine film

20. . . Adhesive layer

30. . . Release film

Detailed description

Hereinafter, several preferred embodiments of the present disclosure will be described in detail with reference to the appended drawings. The detailed description of the preferred embodiments of the present disclosure is to be understood as the description of the invention, and the various changes and modifications within the spirit and scope of the disclosure will be apparent to those skilled in the art.

In accordance with an embodiment of the present disclosure, FIG. 1 is a cross-sectional view of a stacked wafer level package, and FIG. 2 is a cross-sectional view of an adhesive film between the dies.

As can be seen from Fig. 2, a thermosetting double-sided adhesive film having excellent adhesive properties and heat resistance according to the present disclosure has an adhesive property coated on both sides of a polyimide film (10). Layer (20). Here, each adhesive layer (20) comprises a NBR containing a carboxyl group, an epoxy resin, a phenol resin, a curing agent, etc., and the top surface of the adhesive layer (20) is laminated with a release film. (30).

The thickness of the polyimide film (10) used for the thermosetting double-sided adhesive film having excellent adhesive properties and heat resistance according to the present disclosure can be freely selected in accordance with the required height of a package.

The adhesive layer (20) of the thermosetting double-sided adhesive film having excellent adhesive properties and heat resistance according to the present disclosure contains 5 to 200 parts by weight of a polyfunctional epoxy resin per 100 parts by weight of the NBR. And 5 to 200 parts by weight of the polyfunctional phenol resin, and may additionally comprise a curing agent, a rubber crosslinking agent and other additives.

The carboxyl group-containing NBR has a weight average molecular weight of from 3,000 to 200,000, and contains 20 to 50% by weight of acrylonitrile and 1 to 10% by weight of a carboxyl group. In this case, if the weight average molecular weight is less than 3,000, the adhesive strength at a high temperature becomes insufficient, and if it is more than 200,000, the solubility in a solvent is decreased, and workability is prepared in the solution. The time decreases due to increased viscosity, and the bond strength at room temperature also decreases. If the NBR contains less than 20% by weight of acrylonitrile, the solubility in a solvent is reduced, and if the NBR contains more than 50% by weight of acrylonitrile, the electrical insulation becomes worse. Further, if the NBR contains 1-10% by weight of a carboxyl group, the bonding between the NBR and other resins and the adhesive substrate becomes easier, and thus the bonding strength thereof is also increased. An NBR that does not have a carboxyl group will have poor adhesion strength.

Further, the NBR system preferably contains 5 to 200 parts by weight of the epoxy resin per 100 parts by weight of the NBR, and the epoxy resin may comprise a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, and a phenolic aldehyde. Epoxy resin. The equivalent weight (g/eq) of the epoxy resin may be from 100 to 1,000.

Further, the NBR system preferably contains 50 to 200 parts by weight of the phenol resin per 100 parts by weight, and if the phenol resin is more than 200 parts by weight, the adhesive layer becomes very brittle and it is almost impossible to make the The adhesive layer is made in the form of a film. Further, the phenol resin preferably has a molecular weight of from 200 to 900, and it preferably uses a phenol resin having a softening point of 60 to 120 ° C as measured by a ring and ball method. If a phenol resin having a softening point lower than 60 ° C is used, resin bleed may occur as in the case of a paste, and conversely, if the softening point is too high, it is necessary to apply a very high temperature to link The adhesive film is on a die, thereby reducing the bond strength. Thus, a resin having a suitable softening point (60-120 ° C) is required.

As the curing agent, it is preferred to use an amine curing agent and an acid anhydride curing agent separately or in combination, and to have 2 to 40 parts by weight of a curing agent per 100 parts by weight of NBR. Further, the organic or inorganic peroxide may be used in an amount of from 1 to 5 parts by weight per 100 parts by weight of the NBR as the rubber crosslinking agent.

The adhesive layer (20) provided with the above composition has a viscosity of 200-1,500 CPS and is applied to both sides of a polyimide film (10) so that the adhesive layer is dried. The thickness can be 10-30 μm. Thereafter, the polyimide film (10) coated with the adhesive layer (20) is cured at 50-180 ° C for 2-10 minutes, followed by coating a release film (30). ) to produce an adhesive film. The thickness of the adhesive layer can be appropriately varied in accordance with the height required for a package.

Although the thickness of the release film (30) for the thermosetting double-sided adhesive film having excellent adhesive properties and heat resistance according to the present disclosure is not particularly limited, it is generally preferably 38 μm. Examples of such release film to be used may include polyethylene, polyethylene terephthalate, polypropylene film, and the aforementioned film with peeling properties if necessary by a silicone resin.

The adhesive film for a thermosetting double-sided adhesive film having excellent adhesive properties and heat resistance according to the present disclosure is preferably bonded to a crystal grain (2 cm × 2 cm) at 125 ° C / 1.5 kg / 1 second. With another crystal grain (2 cm × 2 cm), and after a curing process (175 ° C / 1 hour), there is a grain shear stress of 5 kg or more at room temperature and 100 g or more at 260 ° C .

Hereinafter, the present disclosure will be described in detail through preferred embodiments and comparative examples.

[Specific Example 1]

First, 50 parts by weight of one phenolic novolac epoxy resin (epoxy equivalent 199), 150 parts by weight of a phenol resin represented by the following structural formula 1, and 10 parts by weight of hexamethoxymethyl group as a curing agent Melamine and 10 parts by weight of phthalic anhydride were added to 120 parts by weight of NBR (containing 27% by weight of acrylonitrile and 5% by weight of carboxyl groups). Next, 2 parts by weight of dicumyl peroxide as a rubber crosslinking agent was added, and the amount of acetone was adjusted by using an acetone solvent, so that the viscosity became 400 CPS. After all the components prepared as described above were dissolved in the solution at room temperature, the adhesive solution was applied to both sides of a polyimide film having a thickness of 25 μm, so that the thickness was 12 μm after drying. After a dry process (150 ° C for three minutes), a polyethylene terephthalate film having a thickness of 38 μm was laminated thereon to produce an adhesive film.

(Structure 1, softening point: 110 ° C)

[Specific embodiment 2]

An adhesive solution prepared by the same composition as that of the specific example 1 was used in the same manner as in the specific example 1, except that the phenol resin used above was replaced by a phenol resin represented by the following structural formula 2. Produce an adhesive film.

(Structure 2, softening point: 85 ° C)

[Detailed Example 3]

An adhesive solution prepared by the same composition as that of Example 1 was used in the same manner as in Concrete Example 1, except that the epoxy resin used above was replaced by an epoxy resin represented by the following Structural Formula 3. , to produce an adhesive film.

(Structure 3)

[Comparative Example 1]

An adhesive solution prepared from the same composition as in Example 1 was used in the same manner as in Example 1 except that the NBR used above was replaced by a NBR having no carboxyl group to produce a bond. Film.

[Comparative Example 2]

An adhesive solution prepared from the same composition as that of Specific Example 1 was used in the same manner as in Example 1 except that the amount of the phenol resin was increased to 250 parts by weight to produce an adhesive film.

[Comparative Example 3]

An adhesive solution prepared from the same composition as that of Specific Example 1 was used in the same manner as in Example 1 except that the amount of the phenol resin was reduced to 50 parts by weight to produce an adhesive film.

[Comparative Example 4]

An adhesive solution prepared by the same composition as that of Specific Example 1 was used in the same manner as in Concrete Example 1, except that the phenol resin was replaced by a phenol resin having the same structure but a softening point of 125 °C. To produce an adhesive film.

The properties of the adhesive film of the specific examples and comparative examples produced in accordance with the present disclosure were evaluated based on the following test examples, and the results are shown in Table 1.

[Test Example 1: Measurement of preservation in film form]

This is a test for checking whether the form of the adhesive film is retained after a physical impact is applied to the adhesive film produced according to the specific examples and the comparative examples, and it is designed to test whether the adhesiveness is adhered. The film is destroyed by the cutting impact applied to the adhesive film at the time of manufacture of the semiconductor package using the adhesive film.

The test method is as follows: the adhesive film produced as described above is cut to a size of 5 cm × 5 cm to be placed on a glass plate having a thickness of 1 cm, and then dropped from a height of 20 cm to have a size of 1 cm × 1 cm. One of the weights (weight: 100 g) was dimensioned to the adhesive film; thereafter, the adhesive film was visually observed to check whether the adhesive film was damaged or not. If no cracks are found, the lines are marked "good" and if they are found to be cracked, they are marked "damaged".

[Test Example 2: Measurement of grain shear stress at room temperature]

The grain shear stress of the adhesive film is bonded to a crystal grain (2 cm × 2 cm) and another crystal grain (2 cm × 2 cm) at 125 ° C / 1.5 kg / 1 second, and is continued at 175 ° C / 1 After an hour of curing, it was measured at room temperature using a half automatic die bonding equipment. Generally, a grain shear stress of 5 kg or more is required to prevent deformation of the bonded crystal grains during epoxy molding or other semiconductor assembly processes.

[Test Example 3: Measurement of grain shear stress at high temperature]

The grain shear stress of the adhesive film was measured at 260 ° C after bonding and curing in the same manner as the grain shear stress measurement at room temperature.

A shear stress of 100 g or more is required to prevent deformation of the crystal grain bonded to the adhesive film due to deterioration of the adhesive strength at a high temperature of 260 ° C applied at the time of the curing process.

[Test Example 4: Measurement of PCT (pressure cooker test)]

After bonding a grain and another grain in the grain shear stress measurement at room temperature, the appearance of bubbles or peeling between the film and the grain is examined by X-ray, followed by 85 ° C. PCT was performed at /85% RH/84 hours. If it is found to be free of air bubbles or peeling, it is marked "passed" and if it is found to have bubbles or peeling, it is marked "failed".

For reference, the adhesive film between commercially available dies should not have any "failure" in all four of the above tests.

As can be seen from Table 1, the adhesion of the adhesive film used between the crystal grains in the form of a film according to the specific embodiment of the present disclosure, the grain shear stress at room temperature, the grain shear stress at a high temperature, and Excellent results were obtained in the PCT measurement test, which are the basic properties required for an adhesive film.

The present disclosure has been described in detail with reference to the embodiments of the present invention and the specific embodiments of the present invention, but it is understood that many changes and modifications may be made without departing from the spirit and scope of the disclosure. It can be implemented by those skilled in the art.

1. . . wire

2. . . Molding compound

3. . . Adhesive film

4. . . Solder mask

5. . . style

6. . . Substrate

7. . . Sub-grain

8. . . Mother grain

10. . . Polyimine film

20. . . Adhesive layer

30. . . Release film

Figure 1 is a cross-sectional view of a stacked wafer level package;

Figure 2 is a cross-sectional view of an adhesive film between the dies in accordance with one of the preferred embodiments of the present disclosure.

10. . . Polyimine film

20. . . Adhesive layer

30. . . Release film

Claims (2)

A use of a thermosetting double-sided adhesive film for bonding between stacked crystal grains, the thermosetting double-sided adhesive film having excellent adhesive properties and heat resistance, and having a coating on a polyimide film An adhesive layer on the side, wherein the adhesive layer contains 5 to 200 parts by weight of one epoxy resin, 50 to 200 parts by weight of one phenol resin per 100 parts by weight of NBR containing 1-10% by weight of a carboxyl group, And 2-40 parts by weight of one or more curing agents selected from the group consisting of amine or acid anhydrides, and wherein the phenol resin has a softening point of 60-120 ° C measured according to a ring and ball method, and the NBR has a 3,000 a weight average molecular weight of -200,000, and 20-50% by weight of acrylonitrile. The use of a thermosetting double-sided adhesive film for bonding between stacked crystal grains, as in claim 1, wherein a die is bonded at a temperature of 125 ° C / 1.5 kg / 1 second (2 cm × 2 cm) After bonding with another crystal grain (2 cm × 2 cm) and subsequent curing (175 ° C / 1 hour), the adhesive film has a capacity of 5 kg or more at room temperature and 100 g or more at 260 ° C High grain shear stress.