TWI514527B - Heat-resistant adhesive tape for semiconductor package manufacturing process - Google Patents

Description

Heat-resistant adhesive tape for semiconductor packaging process

The present invention relates to a heat resistant adhesive tape for use in a semiconductor packaging process.

In recent years, CSP (Chip Size/Scale Package) technology has attracted attention in the mounting technology of LSI (Large Scale Integration). In this technology, a package in which a lead terminal is housed inside a package, which is represented by a QFN (Quad Flat Non-leaded Package), is a package form that is attracting attention in terms of miniaturization and high integration. one. In the manufacturing method of such a QFN, the following manufacturing method has been attracting attention in recent years, in which a plurality of QFN wafers are neatly arranged on a wafer pad of a package pattern region of a lead frame, and in a cavity of the mold, After batch sealing with a sealing resin, the individual QFN structures are cut by cutting, whereby the productivity of the lead frame per unit area is drastically improved.

In the method of manufacturing a QFN in which a plurality of semiconductor wafers are sealed in a batch, the region where the molding die is sealed by the resin is only the outer side of the resin sealing region which is expanded outward from the package pattern region. Therefore, in the package pattern region, particularly the central portion thereof, the external lead surface cannot be pressed against the molding die with sufficient pressure, and it is extremely difficult to suppress leakage of the sealing resin to the external lead side, and it is easy to generate a QFN terminal or the like which is coated with a resin. Overwrite the problem.

Therefore, with respect to the manufacturing method of the QFN as described above, the following manufacturing method is considered to be particularly effective: the adhesion is attached to the outer lead side of the lead frame. The tape prevents leakage of the resin to the external lead side at the time of resin sealing by utilizing the sealing effect of the adhesive tape itself (shielding).

In such a manufacturing method, after the semiconductor wafer is mounted on the lead frame, or after the wire bonding is performed, it is substantially difficult to perform the bonding of the heat-resistant adhesive tape. Therefore, it is expected that the heat-resistant adhesive is brought to the initial stage. The film is bonded to the outer pad surface of the lead frame, and then subjected to a step of mounting the semiconductor wafer or a wire bonding step, and is bonded until the sealing step by the sealing resin. As such a method, a heat-resistant adhesive tape having an adhesive layer having a thickness of 10 μm or less is used, and a series of steps such as wire bonding can be prevented while preventing resin leakage (see Patent Document 1).

Patent Document 1: Japanese Patent Laid-Open Publication No. 2002-184801

In the method of manufacturing a semiconductor device, when a tape is attached to the lead frame, when a tape failure occurs, the tape may be temporarily peeled off and then reattached (reworked). At this time, if the adhesive force of the tape is too high, there is a possibility that the lead frame is deformed at the time of peeling. On the other hand, in the forming and sealing step, if the adhesive force of the tape is too low, the resin shielding property cannot be exhibited, and resin leakage occurs. Therefore, it is desirable that the tape exerts a low adhesive force when attached at a normal temperature and exhibits a high adhesive force in a molding step at a high temperature.

Accordingly, it is an object of the present invention to provide a heat-resistant adhesive tape for a semiconductor package process which is used in a semiconductor packaging process and which is excellent in workability at the time of attachment at a normal temperature and a resin sealing step in a high temperature environment. Prevents resin leakage.

In order to achieve the above object, the inventors of the present invention have made an effort to study the material and structure of the heat-resistant adhesive tape. As a result, it was found that the above object can be achieved by using the following adhesive tape.

A heat-resistant adhesive tape for a semiconductor package process, which is attached to a lead frame when a resin-sealed semiconductor wafer is used by a user, and the heat-resistant adhesive tape has a substrate layer and an adhesive layer, and is Cu at a normal temperature. The board has a micro-adhesion of 0.01 to 0.30 N/20 mm, and the adhesion is increased to 0.50 N/20 mm or more in a high temperature environment.

2. The heat-resistant adhesive tape for a semiconductor package process according to 1, wherein a polyoxyxene adhesive having a polyoxyxene rubber component ratio of 80% by weight or more is used in the adhesive layer.

3. The heat-resistant adhesive tape for a semiconductor package process according to 1 or 2, wherein a polyphenylene oxide adhesive in which a part of a methyl group of a dimethyl siloxane main chain is substituted with a phenyl group is used in the above adhesive layer.

The heat-resistant adhesive tape of the present invention is used by being bonded to a lead frame when sealing a semiconductor wafer mounted on a lead frame made of metal, and has a microadhesive property at room temperature, for example, after heating at 200 ° C. Designed in a high-temperature environment at 175 ° C.

Therefore, the adhesion to the lead frame and the workability can be simultaneously achieved at normal temperature, and the resin shielding property which does not cause resin leakage can be exhibited in the high-temperature molding step.

The heat-resistant adhesive tape for a semiconductor package process of the present invention is attached to a lead frame when a resin-sealed semiconductor wafer is attached to a lead frame, and is provided with an adhesive layer on the base material layer, and has a micro-adhesive property at a normal temperature. Adhesion increases in high temperature environments.

Thus, the reworkability at the time of manufacturing the semiconductor package and the prevention of resin leakage at the time of the resin sealing step can be simultaneously achieved by changing the properties of the adhesive layer between the normal temperature and the high temperature, that is, regarding the adhesive property.

The heat-resistant adhesive tape for a semiconductor package process of the present invention is required to exhibit the desired properties in the heating at the time of the resin sealing step.

Therefore, the base material layer of the heat-resistant adhesive tape for a semiconductor package process of the present invention must have a heat resistance of a melting point of 180 ° C, preferably 260 ° C or higher, and examples thereof include polyethylene terephthalate (PET). , polyethylene terephthalate) film, polyethylene naphthalate film (PEN, polyethylene naphthalate) film, polyether oxime (PES, Polyether sulfone) film, polyether phthalimide (PEI) film, polyfluorene (PSF, Polysulfone) membrane, polyphenylene sulfide (PPS) membrane, polyether ether ketone (PEEK) membrane, polyarylate (PAR, Polyarylate) membrane, aromatic polyamide membrane, polyimine membrane Liquid crystal polymer (LCP) film.

The thickness of the base material layer is 5 to 250 μm, preferably 20 to 100 μm, in consideration of workability such as workability and rework.

As the adhesive layer in the present invention, it is necessary to have the same as the above-mentioned substrate layer The heat resistance is, for example, an adhesive layer containing a polyoxygen-based adhesive.

The adhesive layer has the properties of being slightly adhesive at normal temperature and having an improved adhesive force at a high temperature, and the adhesive force at normal temperature is 0.01 to 0.30 N/20 mm, preferably 0.02 to 0.20 for the Cu plate. N/20 mm, adhesion at high temperature (in the present invention, the adhesion at 175 ° C after heating at 200 ° C for 1 hour) is 0.50 N / 20 mm or more, preferably 0.60 N / 20 mm or more.

As the adhesive agent in the present invention, a polyfluorene oxide adhesive having a polyoxon rubber component ratio of 80% by weight or more, or a part of a methyl group of a dimethyl siloxane main chain may be used. A poly-oxygen adhesive substituted with a base.

In particular, the polyoxynoxy adhesive having a polyoxyxene rubber component ratio of 80% by weight or more is preferably an adhesive comprising a polyoxynoxy adhesive as a resin component and a two-liquid addition reaction type polyoxymethylene rubber. . In particular, an adhesive obtained by crosslinking a polyoxyxylene adhesive as a resin component and a polyoxyethylene rubber component containing a vinyl group by using the polyfluorene crosslinking agent is preferred.

As the two-liquid addition reaction type polyoxyxene rubber, those comprising a vinyl group-containing polyoxyethylene rubber component and a SiH group (hydroalkylene group) polyfluorene crosslinking agent can be used.

Here, the polyoxygen-based adhesive which is a resin component is a network-structured organopolyoxane obtained by a dehydration condensation reaction after hydrolysis reaction of organochloromethane. Further, the polyoxyethylene rubber component contains a diorganopolyoxyalkylene having a linear structure. As the organic group, a methyl group or a phenyl group is contained in both the resin component and the rubber component, and may be substituted with an ethyl group, a propyl group, a butyl group or the like.

In the case of a two-liquid addition reaction type polyoxynoxy adhesive, the vinyl The addition reaction with hydroquinone is used for crosslinking of the adhesive. Usually, the vinyl moiety is introduced by substituting the organic group of the polyoxyethylene rubber component. Further, the hydroquinone group is not introduced into the adhesive main component side containing the polyoxyxylene resin component and the polyoxyxylene rubber component, and is used as a polyfluorene oxygen crosslinking agent having a hydroquinone alkyl group. Further, a catalyst such as a platinum catalyst for promoting the reaction is blended in the addition reaction type polyoxyxene adhesive as needed.

Further, the crosslinking agent and/or the catalyst may be of a type that is formulated into the adhesive main agent during coating. When the catalyst is used, the crosslinking agent may be of a type that has been formulated into the adhesive main agent.

a polyphenylene oxide adhesive in which a part of a methyl group of a dimethyl siloxane main chain is substituted with a phenyl group in the same structure as the above polyoxyxasiloxane rubber component, and corresponds to a methyl group of a part of a dimethyl siloxane main chain An adhesive formed by substituting a phenyl group. Further, in the repeating unit of dimethyloxane of the polyoxyxylene adhesive, the repeating unit substituted with a phenyl group is 0.5 to 30 mol%, preferably 1.0 to 25 mol%, of all the repeating units.

The adhesive layer in the present invention may further contain an antioxidant. Examples of the antioxidant include hindered phenol-based antioxidants, phosphorus-based antioxidants, and lactone-based antioxidants, and these may be used singly or in combination.

In order to form an adhesive layer by applying an adhesive to a base material layer, as an organic solvent contained in the adhesive before coating, an aromatic hydrocarbon solvent such as toluene or xylene may be used, and hexane or heptane may be used. An aliphatic hydrocarbon solvent such as an alkane, octane, isooctane, decane, cyclohexane, methylcyclohexane or isoalkane, or a hydrocarbon system such as industrial gasoline, petroleum benzine or naphtha solvent. Further, various solvents such as a ketone system, an ester system, and an ether system can be used as the solvent. Agent.

As a means for applying the polyoxygen adhesive to the substrate layer, it can be applied by a known coating method, and can be used as a comma coater or a lip coater. Roll coater, extrusion coater, blade coater, blade coater, bar coater, staple coater, gravure coater, screen coating Any method is employed among the dip coating, the casting coating, and the like.

In the heat-resistant adhesive tape for a semiconductor package process of the present invention, a protective film may be used to protect the adhesive layer before use. Examples of the protective film include a polyvinyl chloride, a vinyl chloride copolymer, and a polycondensation treatment using a polyfluorene-based, long-chain alkyl-based, fluorine-based, fatty amide-based or cerium oxide-based release agent. Ethylene terephthalate, polybutylene terephthalate, polyurethane, ethylene-vinyl acetate copolymer, ionic polymer resin, ethylene-(meth)acrylic acid copolymer, ethylene-( A plastic film of a methyl acrylate copolymer, polystyrene, polycarbonate, or the like. Further, a film of a polyolefin resin such as polyethylene, polypropylene, polybutene, polybutadiene or polymethylpentene has mold release property without using a release agent, and therefore it can be separately used. Used as a protective film. The thickness of the protective film is preferably about 10 to 100 μm.

Example

Hereinafter, embodiments and the like which specifically disclose the configuration and effects of the present invention will be described.

Example 1

In a polyoxygenated adhesive (a rubber component ratio of 70% by weight), added to The dimethyloxane main chain contains a two-liquid addition hardening type polyoxyethylene rubber of a vinyl group and a hydroquinone group (the rubber component ratio is 100% by weight), and an adhesive having a rubber component ratio of about 85% by weight is prepared. This was applied onto a polyimide film substrate layer having a thickness of 25 μm and dried to prepare a heat-resistant adhesive tape having an adhesive layer having a thickness of about 6 μm.

Using a hand-pressing roller, at room temperature, a nickel-palladium-plated and a thin-plated gold is applied to one side of the 16-pin type QFN. The external pad side of the copper lead frame formed by four × 4 arrays is attached to the heat-resistant side. Sexual adhesive tape.

Next, in order to reproduce the heat treatment in the semiconductor wafer mounting step, the lead frame was aged at about 200 ° C for about 1 hour.

Further, an epoxy-based sealing resin (manufactured by Nitto Denko Corporation: HC-300B6) was used, and a molding machine (Model-Y-seriese manufactured by TOWA) was used, and preheating was set at 175 ° C for 3 seconds, and the injection time was 12 seconds. After forming under the conditions of 90 seconds, the heat-resistant adhesive tape was peeled off to form a QFN package.

Example 2

In the polyoxynoxy adhesive of Example 1, a two-liquid addition-hardening type polyoxyxene rubber was added to prepare an adhesive having a rubber component ratio of about 90% by weight. Thereafter, a QFN package was produced in the same manner as in Example 1.

Comparative example 1

A QFN package was produced in the same manner as in Example 1 except that the two-liquid addition-hardening type polyoxymethylene rubber was not added to the adhesive.

Comparative example 2

In the same manner as in Comparative Example 1, except that another polyoxynitride-based adhesive (a rubber component ratio of 40% by weight) was used as the adhesive. QFN package.

Comparative example 3

A QFN package was produced in the same manner as in Comparative Example 1, except that a polyoxygen-based adhesive having a low adhesion level (a rubber component ratio of 70% by weight) was used for the adhesive.

Example 3

A polyoxynoxy adhesive in which a part of a methyl group of a dimethyl siloxane main chain is substituted with a phenyl group (a rubber component ratio of 80% by weight, wherein a phenyl group is substituted by 1.2%), and a two-liquid type hardening type polypene is not added. Adhesive is prepared by oxy rubber. Thereafter, a QFN package was produced in the same manner as in Example 1.

Comparative example 4

A QFN package was produced in the same manner as in Example 3 except that another methyl oxy-oxygen adhesive (the rubber component ratio of 80% by weight) in which the methyl group of the dimethyl siloxane main chain was not substituted with a phenyl group was used. .

Comparative Example 5

A QFN package was produced in the same manner as in Example 3 except that another polyoxymethylene-based adhesive in which the methyl group of the dimethyl siloxane main chain was not substituted with a phenyl group (rubber component ratio: 30% by weight) was used. .

result

After bonding the respective tapes to the lead frame, it was confirmed whether or not the L/F lead pad portion was deformed when the tape was manually peeled off, and the evaluation of the workability was performed (for a representative example of the L/F deformation, see FIG. 1). Further, for each tape, the adhesion to the Cu plate of the same material as the above L/F was measured. The measurement is carried out at room temperature after envisagement of the attaching step, and the heating step at 200 ° C for 1 hour after the assumption of the forming step is performed at 175 ° C. It is carried out in two cases in the environment (hereinafter referred to as high-temperature adhesion). The measurement conditions are as follows.

[Measurement of normal temperature adhesion]

Attachment conditions: after pressing back and forth 1 time with a 2 kg roller, leave it at room temperature for 30 min.

Measurement environment: After attachment, measure at room temperature

Peeling angle: 180°

Peeling speed: 300 mm/min

[High Temperature Adhesion Measurement]

Attachment conditions: after pressing back and forth 1 time with a 2 kg roller, leave it at room temperature for 30 min.

Measurement environment: After attachment, heat at 200 ° C for 1 hour and measure at 175 ° C

Peeling angle: 180°

Peeling speed: 300 mm/min

Further, in the QFN package produced as described above, it was observed whether or not resin leakage occurred, and the resin leakage property was evaluated (for a representative example, see FIG. 2).

Fig. 1 is a view for confirming the effect of the heat-resistant adhesive tape for semiconductor package process of the present invention which is a target of a lead frame. Although no deformation was observed in the lead pad portion in the case where L/F deformation did not occur, in the case where L/F deformation occurred, deformation such as a change in direction of the lead pad was found in a portion surrounded by a broken line.

Moreover, FIG. 2 is a figure for confirming the presence or absence of the resin leakage after shaping|molding by a sealing resin. In the case where no resin leakage occurred, since the resin did not leak, the resin did not flow out of the sealing portion. However, in the case where resin leakage occurred, the resin leaked out of the sealing portion due to resin leakage.

In the first embodiment, by adding the two-component type hardening type polyoxyxene rubber, the rubber component ratio of the adhesive is as high as 85% by weight, and has a slight adhesiveness at normal temperature, so that the L/F when the tape is peeled off once is not The deformation, good workability, and high adhesion at high temperatures prevent leakage of the resin after forming.

In Example 2, as in Example 1, by adding a two-liquid type hardening The type of polyoxyxene rubber has a rubber component ratio of 90% by weight, has a microadhesive property at normal temperature, and has high adhesion at a high temperature, so that workability and resin leakage can be simultaneously achieved.

In Comparative Examples 1 and 2, although the leakage of the resin was prevented, the ratio of the polyoxyxene rubber was 70% by weight, and the adhesion at normal temperature was high. Therefore, the lead frame was deformed when the tape was peeled off, and the workability was poor.

In Comparative Example 3, the normal temperature adhesion was as low as 0.20 N/20 mm. Therefore, even if the rubber component ratio was 70%, the workability was excellent, but the high temperature adhesion was as low as 0.13 N/20 mm, so that resin leakage occurred.

In Example 3, the methyl group of the dimethyl methoxy siloxane main chain of the adhesive was substituted with a phenyl group, and had the same adhesion of 0.05 N/20 mm as those of Examples 1 and 2 at room temperature, and had microadhesiveness. Therefore, when the tape is peeled off once, the L/F is not deformed, the workability is good, and the adhesive force at a high temperature is 1.98 N/20 mm, which has high adhesiveness, thereby preventing leakage of the resin after molding. In the case of containing a phenyl group, it was confirmed that the adhesion at a high temperature was improved.

In Comparative Example 4, the methyl group of the dimethyl oxirane main chain of the adhesive was not substituted with a phenyl group, and the adhesion at room temperature was 0.08 N/20 mm, which was slightly adhesive, so that the tape was peeled off once. /F is not deformed and has good workability, but the adhesion at low temperatures is also 0.22 N/20 mm, so resin leakage cannot be prevented.

In Comparative Example 5, the methyl group of the dimethyl methoxy siloxane main chain of the adhesive was not substituted with a phenyl group, and the adhesion at a high temperature was 0.85 N/20 mm, which was highly adhesive, thereby preventing resin leakage, but The adhesion at normal temperature is 3.57 N/20 mm, so the lead frame is deformed when the tape is peeled off, and the workability is better. difference.

According to the above results, the present invention can provide a heat-resistant adhesive tape for a semiconductor package process, which is used for a semiconductor package process, and is excellent in workability at the time of attachment at a normal temperature, and is sealed in a high-temperature environment. The resin is prevented from leaking in the step.

Fig. 1 shows the results of examples and comparative examples of L/F deformation.

Fig. 2 shows the results of examples and comparative examples of resin leakage.

Claims (2)

A heat-resistant adhesive tape for a semiconductor package process, which is attached to a lead frame when a resin-sealed semiconductor wafer is used by a user, and the heat-resistant adhesive tape has a base material layer and an adhesive layer, and the adhesive layer is polymerized The polyoxynoxy adhesive having a composition ratio of the silicone rubber is 80% by weight or more; the Cu plate has a micro-adhesion of 0.01 to 0.30 N/20 mm at a normal temperature, and the adhesion is increased to 0.50 N/20 mm or more in a high-temperature environment. A heat-resistant adhesive tape for a semiconductor package process according to claim 1, wherein a polyphenylene oxide adhesive in which a part of a methyl group of a dimethyl siloxane main chain is substituted with a phenyl group is used in the above adhesive layer.