JPS606558B2 - Resin packaging method for electronic components - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resin packaging method for hybrid integrated circuits (hereinafter abbreviated as HIC), and more specifically, to a method for packaging hybrid integrated circuits (HIC) on a ceramic substrate.
An IC is bonded to a metal plate, and the edge of the ceramic substrate has a glass transition temperature (hereinafter abbreviated as Tg).

) A new packaging method is provided in which resin packaging is performed after sealing with a thermosetting resin of 60 pm or less. HIC is a circuit component in which various semiconductor chips and capacitor chips are attached with solder or the like to a ceramic substrate, mainly alumina porcelain, on which conductors and resistors are printed or bonded.

This HIC is packaged to improve reliability under various environmental conditions.

In general, the current situation in the industry is that there is a shift to resin packages that can reduce costs. Such resin packaging methods include processing techniques such as transfer molding, casting, dipping, potting, dropping, tableting, and fluidized dip coating, and the resins used include epoxy resins, silicone resins, and the like.

If the resin-packaged HIC has large heat generation characteristics,
After bonding the HIC ceramic substrate to a metal plate serving as a heat sink, resin packaging is performed. Generally, a rubber-like adhesive is used to bond a metal plate and a ceramic substrate because if a hard adhesive is used, the ceramic substrate will be destroyed due to the difference in coefficient of thermal expansion between the metal plate and the ceramic substrate. Further, resin-packaged HICs are required to have properties such as heat cycle resistance, moisture resistance and water resistance, and mechanical strength. Therefore, the packaging resin has a Tg of 80o.
o or more, preferably 100 qo or more.

In order to alleviate thermal stress on the HIC circuit components, a soft resin with a low Tg is often applied and the components are packaged in the resin as a buffer agent. Conventional H with above metal plate
IC resin package parts often show cracks and poor moisture resistance during heat cycle tests and moisture and water resistance tests.

As a result of intensive research into the cause of this, we found that since the metal plate and ceramic substrate are bonded with a rubber-like adhesive, each expands and contracts independently, and the Tg8 packaged on top of the metal plate and ceramic substrate expand and contract independently.
It was found that the resin with a temperature of 0.0 or more peeled off from the ceramic edge and peeled off from the metal plate. Therefore, in the present invention, the end portion of the ceramic plate bonded to the metal plate has a Tg6
The conventional drawbacks were solved by sealing with a thermosetting resin having a temperature of 0.000°C or less, preferably 20°C or less.

It has also been found that the sealing effect is such that voids in the rubber adhesive between the ceramic metal plates do not come in and out due to temperature changes, and that voids and pinholes do not occur due to heating and cooling during resin packaging. In particular, it was confirmed that resin packages using potting, dropping, doublet, or fluidized dip coating are good processing methods that do not allow air to enter or exit during the heating process, and are free of voids and pinholes. Incidentally, it is also possible to prevent cracks from occurring from the edges of the ceramic substrate. An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of a conventional resin packaged product in which an alumina porcelain plate 2 is bonded onto an aluminum plate 1 with a silicone adhesive 5, and a circuit component 4 is packaged with a thermosetting resin 3.

FIG. 2 shows a resin package product according to the present invention, in which the ends of an alumina porcelain plate 2 bonded onto an aluminum plate 1 are sealed with a thermosetting resin 7 having a Tg of 6000 or less.

The present invention can prevent moisture from entering through the lead portion 6, relieve stress at the edge of the alumina porcelain, and further prevent peeling from the edge of the alumina porcelain.
Thermosetting resins with a Tg of 60° or less used in the present invention include ordinary epoxy resins, polyester resins, polyurethane resins, and the like.

If necessary, the thermosetting resin according to the invention may contain an inorganic filler. To explain the operation of the present invention in more detail, the coefficient of linear expansion of the aluminum plate 1 is 24xl.
o-6, alumina porcelain plate is 7 x 10-6, and resin for packaging is generally 30 to 70 x 10-6.

The packaging resin has a low coefficient of linear expansion because it contains an inorganic filler, so it has a high modulus of elasticity. Generally, the thermal stress that occurs between two types of joined materials is 8
△T・E (generalized residual stress, △1-air T is the temperature difference between Tg and the required temperature, △Q is the difference in linear expansion coefficient, E is the elastic modulus of the resin, and y is the Poisson's ratio of the resin. .

), and in general, the smaller 6 is, the more advantageous it is against cracking and cracking, as long as it does not increase and deform below Tg.
Since the thermosetting resin according to the present invention has a low Tg, it has the following properties: ■ Residual stress in the lead part is small, ■ Relaxes the movement of the aluminum plate and alumina porcelain plate, ■ Relaxes the concentration of residual stress at the edge part of the alumina porcelain plate, etc. There is an effect.

Because it performs these three major functions, it is possible to create a highly reliable mC. Examples will be described in further detail below. Aluminum 30x30x1.5 on the heat sink side 25x
An alumina porcelain plate with 25 x 0.8 willow circuit components attached was glued using a commercially available silicone adhesive, and a polyurethane resin with a T-thickness of 0 or less, polysin was attached to a 14-pin single pin type HIC placed horizontally. /Borite (commercially available product name) was applied to the four corners of the alumina porcelain plate using a needle-shaped object as shown in FIG. 2, and the mixture was left at room temperature for 2 hours to harden. This H
Scotchcast No. on the IC. 28/B (commercial product name) was dropped to form a resin layer of about 1% on the entire surface of one side, and the resin layer was heated and cured for 125,005 hours. As a comparative product, a HIC was prepared which was subjected to the same treatment as above without applying the polyurethane resin according to the present invention. These H
A heat cycle test of 16,000 to 1,500 degrees and a steam pressure test were conducted on 10 ICs each. The results are shown in the table. According to the present invention explained above, a highly reliable HIC can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional resin packaging method, and FIG. 2 is a block diagram showing an embodiment of the present invention. In the figure, 1 is a metal plate, 2 is a ceramic foil substrate, 3 is a packaging resin, 4 is a circuit component, and 7 is a thermosetting resin. Note that the same reference numerals in the figures indicate the same or equivalent parts. Figure 1 Figure 2

Claims (1)

[Claims] 1. In a hybrid integrated circuit in which a plurality of electronic components are mounted on a ceramic substrate, the ceramic substrate is bonded onto a metal plate for heat dissipation, and then the edges of the ceramic substrate are bonded to a thermosetting material with a glass transition temperature of 60°C or less. A resin packaging method for electronic parts, characterized in that after sealing with resin, only the ceramic substrate on the metal plate and the electronic parts are packaged with resin.