JPS622557A - Method for preventing static breakdown of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent a semiconductor device from having a static breakdown by a method wherein a film is formed to cover the surface of the sealing plastic member of the semiconductor device for reducing surface resistance for the reduction of static charges without degrading the performance characteristics of the sealing material. CONSTITUTION:The surface of a sealing plastic member is washed with a solvent or is roughed by other means, whereafter metal heated by plasma or the like is sprayed onto the surface. A metal coating may be formed on the sealing plastic member, instead. Such other means may be employed as the oxidation of the surface in the presence of ozone or active oxygenor the baking of the surface by laser beams or hydrogen flame, which all result in the formation of an oxide film on the sealing plastic member surface. Any such means contributes to the reduction in the resistance to be presented by the sealing plastic member surface.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for preventing electrostatic damage in plastic-sealed semiconductor devices, and in particular, to highly integrated plastic-sealed LSIs (large vAix integrated circuits). 3
calCIntegratedQlrcuiLs)
and VLSI (FB large scale integrated circuit: Very lar
ge 5cale integrated C1
This invention relates to a method for preventing electrostatic damage in semiconductor devices such as electronic devices such as electronic devices.

[Prior Art] As is well known, semiconductor devices are protected from the environment by being encapsulated in plastic using epoxy resin or the like. However, with conventional plastic encapsulation materials, This is not sufficient because moisture dissolves impurities in the sealing material and enters, corroding the aluminum wiring.

Incidentally, in recent years, ultrafine processing technology for semiconductor devices has progressed, and today it has become possible to process devices down to the order of microns or submicrons. Semiconductor devices developed using such processing techniques are highly integrated and require even greater protection from the environment. Therefore, it is used for such semiconductor devices.

The plastic sealing material used is highly purified and highly insulated.

[Problems to be Solved by the Invention] As described above, although highly purified and highly insulated sealing materials are highly effective in preventing corrosion of aluminum wiring, they also have the disadvantage of being easily charged with static electricity. has. This type of static electricity is generated when the encapsulant rubs against the outside air or when it rubs against other insulators during the marking process, but a particular problem is when the encapsulant and the encapsulant rub against each other during product transportation. This is static electricity generated by friction between the product and the product storage tube. Such electrostatic charging is caused by the surface resistance (
When 11(ρ, ) exceeds 10'' to 10sΩ, it tends to increase rapidly, and is particularly likely to occur in winter.

In this way, the charged static electricity acts on the device as a surge voltage and destroys the extremely weak insulating layer, such as the gate oxide film, in the device.

Regarding the degree of integration, for example, Dynamic R
More highly integrated lζ semiconductor devices, including AM, are more likely to be destroyed.

By the way, if electrostatic damage occurs during the above-mentioned product transportation, the product must be re-inspected one by one, as the product may have been good at the time of shipment but becomes defective by the time it is used.
It is extremely complicated.

Conventionally, in order to prevent such charging during transportation without sacrificing the ability to effectively protect semiconductor devices from the environment, low insulation resistance values have been applied to the inner surface of the product storage tube and the surface of the sealing plastic. It has been practiced to apply a paint containing

However, in the winter when the atmosphere is dry, there is a risk that the resistance value will increase and the coating film will peel off, causing many problems in terms of reliability and workability.

Although there is a method of making the product storage tube made of metal such as aluminum, there is a problem that it is inconvenient to check the product because the product inside cannot be seen from the outside.

Therefore, an object of the present invention is to provide a plastic-encapsulated LSI without sacrificing the properties of the encapsulant.

The purpose of the present invention is to provide a method to prevent semiconductor devices from being damaged by electrostatic discharge by reducing the electrostatic charge that occurs when semiconductor devices such as VLSI are transported or stored before being mounted on a board. .

[Means for Solving the Problems] In the present invention, a film is formed on the surface of a plastic member for sealing a semiconductor device to lower its surface resistance.

[Function] Since the surface of the sealing plastic member of the semiconductor device of the present invention has a low surface resistance value, static electricity charging is reduced.

[Example] Next, an example of the present invention will be described in detail. In the embodiment described here, the surface of the sealing plastic member is subjected to a surface treatment such as roughening or cleaning with a solvent such as alcohol, acetone, or trichloride, and the surface is subjected to, for example, (1) heating or plasma heating. (2) by chemical vapor deposition (CvD) or physical vapor deposition (PVD) such as vacuum evaporation or sputtering, or (3) by plating treatment such as electroless plating. Forming a metal coating on the surface of the encapsulating plastic, or alternatively.

(4) The plastic surface is oxidized by ultraviolet rays emitted by a low-pressure mercury lamp, or by ozone or active oxygen generated by plasma or corona discharge, or (5) The plastic surface is sintered by a laser beam or hydrogen flame. , by forming an oxide film on the surface of the sealing plastic,
This reduces the surface resistance of the sealing plastic surface. Here, the above-mentioned embodiments are merely illustrative;
This invention is not limited to the methods (1) to (5) above.

Note that when performing each of the above-mentioned processes, it is necessary to shield the area around the leads with a mask or the like to prevent short circuits between the leads of the semiconductor device. This is not the case.

Regarding (1) and (2) above, it is preferable to use gold, platinum, metal, aluminum, copper, etc., which have high electrical conductivity and are oxidation-resistant, and if necessary,
Paint may be applied to the surface to prevent metal oxidation.

Below, the experimental examples of the present invention and comparative examples will be explained in detail, and the results obtained from the experiments will be described.

Example 1 First, dynamic R was applied to 256 sealed with epoxy resin.
A sealed plastic package of A.M. was boiled and cleaned with Tric-1-Non, and then metallic aluminum was plasma sprayed on the front and back surfaces to form a metal coating.

This was packed into a tube for plastic products and rotated at a cycle of about 4 seconds to generate ll*, and an experiment was conducted for one week to charge static electricity on the surface of the sealed plastic. We checked the characteristics of The results are shown in Table 1.

Example 2 In the same manner as in Example 1, the front and back surfaces of the dynamic RAM were sputtered using metal aluminum to form a metal film on 256, which had been previously boiled and cleaned with trichlene. After subjecting this to a charging experiment using the method described above, the characteristics of each bottle of the semiconductor device were checked.

The results are shown in Table 1.

Example 3 Electroless plating treatment was performed using aluminum on the front and back surfaces of the same sealed package used in Example 1 and Example 2, and each bottle of the semiconductor device was subjected to a similar charging experiment. I checked the characteristics. The result is the first
Shown in the table.

Example 4 The front and back surfaces of the same sealed packages used in Examples 1 to 3 were subjected to firing treatment using a hydrogen flame, and the characteristics of each bottle of semiconductor devices subjected to similar charging experiments were checked. . The results are shown in Table 1. Note that in this example, boiling cleaning with trichlene was not performed. Comparative Example 1 and Comparative Example 2 To Example 1 - The same sealed package used in Example 4 was subjected to the same charging experiment without any surface treatment. A paint having a low resistance value (ρ, ) of 10'20 or less at 50% humidity is applied to the inner surface of the product storage tube,
Comparative Example 2 is one in which the paint was not applied. The results are shown in Table 1.

As is clear from the results in Table 1, Examples 1 to 1 of the present invention
Sample No. 4 has a negligible number of defects and is extremely effective in preventing electrostatic damage to semiconductor devices due to charging of the sealing plastic member. In addition, the above-mentioned surface oxidation treatment method (4) and (
5) is particularly preferred since it is not necessary to perform surface treatment on the sealed package in advance.

['R, Ming's vJ result] As described above, according to the present invention, the surface resistance formed on the surface of the sealing plastic member of the semiconductor device chair lowers the surface resistance, so that static electricity charging is reduced. Semiconductor devices no longer suffer from electrostatic damage.

Agent Masuo Oiwa Procedural amendment (voluntary) 2. Title of the invention: Method for preventing electrostatic damage in semiconductor devices 3. Name of person making the amendment (601) Mitsubishi Electric Corporation 5. Specification subject to amendment Claims column and Detailed Description of the Invention column 6, Contents of amendment (1) Specification - Claims are as attached.

(2) [High purity and high insulation] on page 3, lines 13 to 14 of the specification is corrected to "high purity, ie, low electrical conductivity."

(3) "High purity and high insulation" on page 3, line 16 of the specification is corrected to "high purity, that is, low electrical conductivity."

(4) Specification - “iI” on page 6, lines 19 and 20
Correct "processing" to "processing".

(5) In the third line of page 7 of the specification, "rimmed film" is corrected to "thin treated film."

(6) "Sputtering treatment" on page 3, line 13 to line 17 of the specification was changed to [Sputtering treatment (PVD) J
Correct.

(7) "Surface oxidation lI!1y11 method" in page 10, line 14 to yA15 of the specification is corrected to "processing method."

Above 2, Claim (1) A method for preventing electrostatic damage due to charging in a semiconductor device sealed with a sealing plastic member, comprising forming a film on the surface of the sealing plastic member. A method for preventing electrostatic damage of a semiconductor device, characterized in that electrostatic damage is prevented by lowering surface resistance.

(2) The method for preventing electrostatic damage of a semiconductor device according to claim 1, wherein the film is a metal coating formed by metal spraying.

(3) The method for preventing electrostatic damage in a semiconductor device according to claim 1, wherein the film is a metal film formed by a chemical deposition method or a physical vapor deposition method.

(4) The semiconductor device according to claim 1, wherein the film is a metal film formed by plating. Destruction prevention method.

(5) The method for preventing electrostatic damage of a semiconductor device according to item 1, wherein the film is formed by ozone or active oxygen.

(6) The method for preventing electrostatic damage of a semiconductor device according to claim 1, wherein the film is a thin film layer formed by firing with a laser beam or a hydrogen flame.

Claims (6)

[Claims] (1) A method for preventing electrostatic damage caused by charging in a semiconductor device sealed with a sealing plastic member, which prevents static electricity by forming a film on the surface of the sealing plastic member to lower the surface resistance. A method for preventing electrostatic damage in semiconductor devices, characterized in that electrostatic damage is prevented. (2) The method for preventing electrostatic damage of a semiconductor device according to claim 1, wherein the film is a metal coating formed by metal spraying. (3) The method for preventing electrostatic damage in a semiconductor device according to claim 1, wherein the film is a metal film formed by a chemical deposition method or a physical vapor deposition method. (4) The method for preventing electrostatic damage in a semiconductor device according to claim 1, wherein the film is a metal coating formed by plating. (5) The method for preventing electrostatic damage in a semiconductor device according to claim 1, wherein the film is an oxide film oxidized by ozone or active oxygen. (6) The method for preventing electrostatic damage of a semiconductor device according to claim 1, wherein the film is an oxide film formed by firing with a laser beam or a hydrogen flame.