JPS61113240A - Method for sealing electronic parts - Google Patents

Abstract

PURPOSE:To maintain sufficient airtightness on the sealed electronic parts, to obtain high adhesive strength, to cut down the period of formation and to reduce the generation of burrs by a method wherein epoxy bonding agent is coated on the material to be sealed in the thickness of 0.0001-0.01mm, and polyphenylene sulphide polymer (PPS) is used as a sealing material. CONSTITUTION:An IC, a transistor and other electronic parts are mounted on a substrate, and an epoxy bonding agent is coated on the outer surface of the material to be sealed. A spray coating, a potting and the like can be used as the coating method, but the most simple and derirable method is that the material to be sealed is dipped in the epoxy bonding agent diluted by an organic solvent. The desirable thickness of the film formed on the material to be sealed is 0.0001-0.01mm, and 0.002-0.005mm is considered better. Then, said material to be sealed is airtightly sealed using PPS. The well known molding method such as transfer molding or an injection molding can be adopted for the above-mentioned airtight sealing.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for sealing electronic components.

[Prior Art] Various electronic components such as ICs, ) transistors, diodes, resistors, capacitors, coils, and connectors must be electrically insulated between terminals, maintain mechanical strength, and protect from external environments such as humidity and floating impurities. Internal protection is essential to maintain its performance.

For this reason, so-called encapsulation, in which electronic components mounted on a board are sealed with synthetic resin, is generally used.

There are two methods for sealing: one using thermosetting resin as the sealing material, and the other using thermoplastic TM sheet as the sealing material. Generally, polyphenylene salt 7T hydride remer is used.

Further, as the sealing means, a molding method using transformer 77 molding or injection molding is adopted from the viewpoint of productivity and dimensional stability.

[Problems to be solved by the invention] In conventional sealing methods, when epoxy resin is used, it has advantages such as strong mechanical strength and excellent airtightness, but on the other hand, molding time is slow. It takes a long time (1-5 minutes)
As the viscosity of the resin decreases in the mold due to heat, a lot of flakes occur, making it difficult to remove the flakes after molding, and runners that are not needed for molded products cannot be recycled, resulting in a high material floss F. There are drawbacks.

On the other hand, sealing methods using polyphenylene sulfide polymers have advantages such as excellent heat resistance, less generation of flakes, short molding time, and the ability to recycle some parts such as runners. Since there is essentially no thermal crosslinking reaction, it has the disadvantage of weak adhesion to the upper material (and insufficient airtightness).

As described above, each conventional method has its advantages and disadvantages, and there is still no known sealing method that satisfies all the requirements.

Therefore, the present invention provides an extremely excellent sealing method that combines the advantages of a sealing method using an epoxy resin and the advantages of a sealing method using a polyphenylene sulfide polymer, and does not have any drawbacks. With the goal.

[Means for Solving the Problems] The electronic component sealing method of the present invention includes attaching the electronic component to a substrate and applying an epoxy adhesive to the sealed object.
t to o, oi is applied to the film thickness of the wing, and then polyphenylene sulfide polymer (hereinafter referred to as PPS) is applied as a sealing material.
), and electronic components are encapsulated using a molding method that is superior to transfer molding or injection molding.

[Example 1] In applying the sealing method of the present invention, first, ICs, transistors, and other electronic components are attached to a substrate such as a metal frame by a method such as wire bonding or wire bonding.

Once the object to be sealed is obtained in this way, an epoxy adhesive is applied to the outer surface of the object.

Application methods for epoxy adhesive include spray application,
Although botting or the like can be used, it is preferable to dilute the epoxy adhesive with an organic solvent and immerse it in the solution because it is very simple.

The coating film formed on the object to be sealed by the above method has a thickness of 0.0OO1
If it is less than zz, the sealing performance will be impaired, and 0,0111
If it is 11 or more, problems such as deformation of the adhesive coating will occur during sealing, so it is preferably o,ooot to 0.01 mm, and more preferably 0.002 to 0,005 zg.

Once the epoxy J1% adhesive is applied to the object to be sealed as described above, the object to be sealed is then coated with PPS'? Seal. For this purpose, a known molding method such as transfer molding or injection molding is employed. That is, in both transfer molding and injection molding, PPS as a sealing material is placed in a plasticizing chamber provided above the mold, heated to a softening temperature to plasticize it, and then used as the sealing material. The product is press-fitted into the mold into which it is inserted, allowed to harden, and subjected to V-ply molding.

As mentioned above, when applying the epoxy adhesive using the dipping method, the adhesive is applied to the entire surface of the object to be sealed, so in order to facilitate soldering in the subsequent process, It is necessary to remove the paint film other than the sealing area. The removal operation is preferably carried out after the sealing operation by a method such as a shot blasting method, a liquid honing method, or a brushing method.

[Effect of the invention 1 Evokin wood applied to the sealed object by the method of the present invention
Since the 1FF adhesive itself has excellent airtightness, electronic components sealed with it can be kept sufficiently airtight and have strong adhesive strength.

Moreover, since PPS is used as the sealing material, PP
The advantage of the sealing method using S is that the molding time is short (usually 20 to 40 seconds), there is less generation of flakes, and finishing work after sealing is easier, and part of the runner can be reused. You can take advantage of certain points.

Therefore, according to the sealing method of the present invention, electronic components can be sealed with sufficient performance at low cost.

Claims (1)

[Claims] (1) A method of sealing electronic components with synthetic resin, in which an epoxy adhesive is applied to a film thickness of 0.0001 to 0.01 mm on an object to be sealed, which is an electronic component mounted on a substrate,
A method for sealing an electronic component, characterized in that the electronic component is then sealed by a molding method using transfer molding or injection molding using polyphenylene sulfide polymer as a sealing material.