JPH10125825A - Seal structure of chip device and method of sealing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a seal structure having hollow parts, using a seal resin, without increasing the production cost by forming the resin into a film. SOLUTION: A chip device 2 is flip-chip-mounted on a dielectric substrate 4 and encapsulated with a filmy encapsulating resin 1. On the surface of the device 2 such as elastic surface wave device e.g. electrodes are formed with pads 10 formed at corresponding positions on the substrate 4. The pads 10 and electrodes are interconnected through bumps 3. The slip-chip-mounted device 2 is covered with the resin film 1 from above and adhesive parts 6 at the periphery of the film 1 are pressed and adhered to the substrate 4 to seal them. The film 1 uses one insulative and hydrophobic and showing a flexible property at room temp. and made of a polymer such as epoxy resin or silicone resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing structure for a chip type device and a method therefor, and more particularly to a sealing structure for a chip type device having a hollow portion after sealing and a sealing method therefor.

[0002]

2. Description of the Related Art As a general method of sealing a chip type device, there are roughly two methods: a hermetic sealing method and a resin sealing method. The former example is a ceramic package, and the latter is a plastic package. The ceramic package is hermetically sealed by using a lid made of glass or metal, and has high reliability, but at the same time, high cost. The plastic package has a chip type device embedded in a sealing resin and is sealed, and is low in cost, but has lower reliability than a ceramic package.

[0003] In a general semiconductor device, these two types of sealing methods are selectively used depending on the reliability required for each application. Because you need space,
Irrespective of the required reliability, a hermetically sealed package has to be used, which is a factor of cost increase. Further, even in a semiconductor integrated circuit chip requiring high-speed operation, a hermetically sealed package is used in order to eliminate a characteristic deterioration factor such as a signal delay due to a dielectric constant of a sealing resin.

[0004] For this reason, as a sealing method for this type of chip type device, a method for obtaining an airtight sealing type structure using an inexpensive resin material has been proposed.

For example, in JP-A-3-16412,
A method for obtaining a space on the surface of a chip-type device in a resin material by a combination of a thermosetting resin material and an inert gas is shown. Specifically, a substance that has been cooled and compressed to solidify by compressing the gas is placed on the surface of the chip-type device, and then the sealing resin is applied. Is to provide a space on the surface of the. Further, the publication also proposes a method in which an inert gas is injected in a state where the sealing resin is semi-cured after being applied, and a space is provided on the surface of the chip-type device.

On the other hand, in Japanese Patent Application Laid-Open No. Hei 5-218222, a chip type device is first wrapped with an epoxy resin, and a mold resin is coated thereon. Then, when the mold resin is heated and cured, the epoxy resin is converted into the mold resin. It mentions a method of absorbing and creating a space in the mold resin.

[0007]

The first problem is that the first method disclosed in Japanese Patent Application Laid-Open No. HEI 3-16412 has a problem that the manufacturing cost is increased. The reason is that since the sealing gas is required to have a low moisture content, the solidified gas used in this method needs to be dried after vaporization. Since the solidified sealing gas has a low temperature, moisture contained in the outside air that touches the surface adheres. The attached water is included in the gas after vaporization. To prevent this, it is necessary to always dry the working and storage atmosphere at low temperature, and it is costly to maintain this working environment. Having.

The second problem is that the second method disclosed in Japanese Patent Application Laid-Open No. Hei 3-16412 and the method disclosed in Japanese Patent Application Laid-Open No. Hei 5-21822
In Japanese Patent Publication No. 2 (1993), there is a problem that a defect that the sealing resin remains on the chip surface cannot be eliminated. The reason is that in either case, there is a process in which a sealing resin (the latter is an epoxy resin) is first applied to the chip surface and then removed, but the sealing resin is required to have a strong adhesive force. In order to remove the sealing resin from the chip surface by gas encapsulation, which is the former method, encapsulation at an extremely high pressure is required, and encapsulation of the gas volume sealed in a minute space By itself, the sealing resin on the chip surface cannot be sufficiently removed. In the latter method, absorption of epoxy resin into mold resin during heating,
The acting force for removing the epoxy resin is only the osmotic pressure of the epoxy resin into the mold resin, and since the epoxy resin is not volatile, the epoxy resin cannot be sufficiently removed from the chip surface. Therefore, there is a problem that in actual production, it is impossible to avoid occurrence of defective products in which the sealing resin remains on the chip surface at least with a certain probability.

An object of the present invention is to provide a sealing structure having a hollow portion by using a sealing resin material without removing the above-mentioned drawbacks and increasing the production cost, and a method thereof.

It is another object of the present invention to provide a sealing structure and a method thereof that do not cause a defect in which a sealing resin remains on the surface of a chip type device.

[0011]

In order to solve the above-mentioned problems, a chip type device sealing structure of the present invention comprises a chip type device mounted on a dielectric substrate by flip-chip bonding, an epoxy resin, a silicone type It has a configuration in which a sealing film made of a resin, a bisphenol-based resin, or another polymer material is covered, and the outer periphery of the sealing film is bonded to the dielectric substrate using an adhesive.

In the above configuration, since the chip-type device is flip-chip mounted and sealed by covering with a flexible sealing film, the sealing resin material does not adhere to the surface of the chip-type device. Can be sealed. Also, there is a gap between the surface of the chip-type device and the mounted dielectric substrate due to the height of the bumps and the like, which becomes a hollow portion after sealing.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of the present invention.

Referring to FIG. 1, electrodes (not shown) are formed on the surface of a chip type device 1 such as a surface acoustic wave device. On the dielectric substrate 4 on which the chip type device 2 is mounted, pads 10 are formed at positions opposite to the electrodes, and the pads 10 and the electrodes are interconnected by bumps 3. For sealing, the chip-type device 2 mounted on the flip-chip is covered with the sealing film 1 from above (the back side of the chip-type device), and the bonding portion 6 provided on the outer periphery of the sealing film 1 is attached to the chip-type device 2. Is pressed against the dielectric substrate 4 in a range outside the above, and the sealing film 1 and the dielectric substrate 4 are adhered at that location.

The sealing film 1 is an insulating and hydrophobic film which exhibits flexibility at room temperature. Materials include epoxy resin, silicone resin,
There is application of a polymer material such as a bisphenol-based resin or a urethane-based resin alone or in combination.

The adhesion between the sealing film 1 and the dielectric substrate 4 can be achieved by a method of leaving the adhesive property of the sealing film 1 before curing as a polymer material, or by a method of allowing the sealing film 1 to remain plastic after curing. And bonding to the dielectric substrate 4 using an adhesive by using a material having the following.

As a flip chip mounting method for the chip type device 2, a method which does not cause a problem in the heat history in the above sealing step which is a later step is selected. For example, in the sealing process, 120
When the heating is performed at a temperature of from 1 to 160 ° C., flip-chip mounting is performed at a temperature of from 190 to 230 ° C. by a method using solder balls as the bumps 3.

Next, the operation of the embodiment of the present invention will be described in detail with reference to FIG.

FIGS. 2A to 2C are cross-sectional views for explaining respective steps of the sealing step of the embodiment of the present invention shown in FIG. In FIG. 2A, a sealing film 1 formed of a plastic material and an outer peripheral portion of the sealing film 1 are formed on a chip type device 2 which is flip-chip mounted on a dielectric substrate 4. The pressing die 12 for holding is arranged. In FIG. 2B, the bonding part 6 of the sealing film 1 is pressed against the dielectric substrate 4 by the pressing die 12. Since the sealing film 1 has plasticity, it is deformed so as to cover the side surface of the chip type device 2 and seals the whole. FIG. 2C shows a state after completion of removal of the pressing die 12.

The bonding between the sealing film 1 and the dielectric substrate 4 is carried out by heating the entirety of the pressing film 12 or locally by heating the pressing die 12 while pressing with the pressing die 12 shown in FIG. 2B. In addition, it is also possible to heat the whole after removing the pressing mold 12 of FIG.

Next, an embodiment of the present invention will be described in detail with reference to FIG.

Referring to FIG. 1, an embodiment of the present invention comprises a dielectric substrate 4 having a glass epoxy substrate having a thickness of 1 mm, a chip type device 2 having a surface acoustic wave device having a thickness of 0.4 mm,
0.8 μm thick gold conductor for electrode, 50 μm diameter for bump 3
m solder balls, 0.3 mm thick on sealing film 1
It is formed of an epoxy resin having plasticity and adhesiveness before curing, and a pad 10 and a wiring conductor which are formed by applying a copper plating of 20 μm thickness and a gold plating of 0.3 μm thickness on a copper foil base. You.

Next, the manufacturing process of the embodiment of the present invention will be described in detail with reference to FIG.

FIGS. 2A to 2C are cross-sectional views for explaining the respective steps of the sealing step of the embodiment of the present invention shown in FIG. In FIG. 2A, a plastic and adhesive sealing film 1 made of an epoxy resin material is formed on a surface acoustic wave device flip-chip mounted on a glass epoxy substrate. And a pressing die 12 for holding the bonding portion 6 provided on the outer periphery of the film 1 for use. Since the sealing film 1 also has an adhesive property to the pressing die 12 and is difficult to separate after pressing, wax is applied as a release material to a contacting portion. Since the atmosphere in which the sealing operation is performed is taken into the hollow portion 5 after the sealing, a dry nitrogen atmosphere 25 is used to prevent corrosion of the surface acoustic wave device after the sealing. In FIG. 2B, the bonding portion 6 of the sealing film 1 is pressed against the glass epoxy substrate by the pressing die 12. Since the sealing film 1 has plasticity, it is deformed so as to cover the side surface of the surface acoustic wave device, and the whole is sealed. By hardening the epoxy resin in a state where the bonding portion 6 is pressed by the press mold 12, the entirety is heated in the step of FIG. 2B for the purpose of improving the adhesion to the glass epoxy substrate. The epoxy resin is cured. The curing temperature is set to 150 ° C. 230 for flip chip mounting
There is no problem in heat history because the test is performed at ° C. FIG. 2 (c)
Indicates the state after the completion of the sealing with the mold removed.

Another example of the first embodiment of the present invention will be described with reference to FIG.

The sealing film 1 may be replaced with a configuration in which a silicone-based resin having plasticity even after curing is used, and an adhesive is applied to and bonded to the bonding portion 6. In that case,
Since it is not necessary to heat the whole when the adhesive is cured, the sealing method may be replaced with a sealing method in which, for example, the pressing die 12 is heated and heated to be cured in the step of FIG. The thickness may be changed as long as the properties of the sealing film 1 such as plasticity and moisture resistance are not impaired. The sealing film 1 is formed by using a glass fiber or the like made into a net or cloth as a base material.
It may be formed by attaching a sealing resin thereto.

The bumps 3 may be replaced by gold balls instead of solder balls. In this case, the connection between the bump 3 and the pad 10 on the dielectric substrate 4 is performed by a thermocompression method in which the bump 3 is heated to 300 ° C. to 400 ° C. and a pressure is applied, or a method using a conductive adhesive (Nikkei Microdevices) , March 1996, pp. 148 to 149).

The thickness of the glass epoxy substrate of the dielectric substrate 4 may be replaced with a value other than 1.0 mm. Further, the glass epoxy substrate may be a ceramic substrate, and in this case, the thickness may be a value other than 1.0 mm.

The chip type device 2 may use a surface acoustic wave device as a semiconductor integrated circuit chip.

A second embodiment of the present invention will be described in detail with reference to FIG.

FIG. 3 is a sectional view showing a second embodiment of the present invention. In FIG. 3, a chip carrier 7 is used in place of the dielectric substrate so that the assembly can be handled as a packaged component. The chip carrier 7 is formed by forming a metallized portion 8 for obtaining electrical connection between the pad 10 and the outside on a ceramic substrate.

The replacement of each component in the second embodiment can be the same as that performed for the example of the first embodiment.

[0034]

As described above, in the chip type device sealing structure of the present invention, the chip type device can be sealed at room temperature and no special cost is required to maintain the working environment. It is possible to realize a sealing structure having a hollow portion by using a sealing resin material without increasing the cost required for the device, which requires a space on the surface of the chip due to the principle of operation such as a surface acoustic wave device A chip-type device can be manufactured at low cost by using a sealing resin.

In addition, since the sealing film is put on the back surface of the chip type device and sealed so that the sealing resin does not come into contact with the surface of the chip, the surface of the chip type device is sealed with the sealing resin. No residual defect occurs, thereby eliminating the same mode defect during manufacturing.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view illustrating a sealing step of the embodiment of FIG. 1;

FIG. 3 is a sectional view showing a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sealing film 2 Chip-type device 3 Bump 4 Dielectric substrate 5 Hollow part 6 Adhesion part 7 Chip carrier 10 Pad 12 Press type 25 Dry nitrogen atmosphere

Claims (3)

[Claims] 1. A sealing structure of a chip-type device including a chip-type device flip-chip mounted on a dielectric substrate using bumps and a sealing resin, wherein the sealing resin is in a film shape. A sealing structure for a chip-type device. 2. A method for sealing a chip-type device including a chip-type device flip-chip mounted on a dielectric substrate using bumps and a sealing resin, wherein the sealing resin is formed into a plastic film. And sealing the chip-type device by covering the chip-type device and pressing the device against the dielectric substrate around the chip-type device. 3. In a chip device sealing structure including a chip device flip-chip mounted on a dielectric substrate using bumps and a sealing resin, a hollow portion is formed on a surface of the chip device after sealing. Characterized by having
Sealing structure for chip type devices.