JPS58166745A - Sealing method for chip carrier - Google Patents

Abstract

PURPOSE:To prevent the generation of a pin hole in a sealing section (an adhesive solidifying layer), and to improve the reliability of sealing and yield on manufacture by coating the whole circumferential end surface of the carrier and the sealing bonding section of the carrier and a cap with a two-pack type shaping agent, which does not adhere on the solder pad of the carrier. CONSTITUTION:The shaping agent (such as a two-pack type silicon rubber) is compounded and defoamed, and the layer 12 of the shaping agent is applied and formed onto a metal (such as stainless) plate 11 on which a release agent is applied as shown in the figure. Each thickness of the carrier 2, the cap 4 and the layer 12 of the shaping agent on which adhesives 10 do not adhere is made thicker than that of the carrier 2 and thinner than the stacked thickness of the carrier 2 and the cap 4. Second curing treatment is a process in which adhesives 10 under a semirigid state are cured completely, the metal plate 11, on the cap 4 thereon a weight 13 is placed as shown in the figure, is placed into a high- temperature tank, and adhesives 10 are cured completely through heating for time such as approximately one hr. at a temperature under approximately 200 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a method for sealing a chip carrier, and more particularly to a method for sealing a chip carrier in which a space for sealing a cap is narrowly limited.

(b) Technology Background LSI chips are housed in various package structures, and chip elements are mounted using Gui bonding technology and wire bonding technology, and electrodes formed on the elements are connected to electrodes inside the package. This chip carrier allows for electrical characteristics to be checked after assembly, requires less surface area for mounting on a circuit board, and can be used to form pandas! It has the advantage of not requiring special technology. but,
When comparing the nine-chip carrier developed as part of hybrid technology with the film carrier developed for the same purpose, the chip carrier, which has a cap for sealing the mounted element on the chip carrier 41, is slightly larger. There was a strong desire to reduce the cap bonding space as much as possible.

(c) Prior art and problems Figure 1 is a side sectional view of a chip 2 designed to be miniaturized to mount two high-density chip elements 1, and the elements mounted by die bonding. 1 electrode (not shown) and an electrode formed on the top surface of the carrier (not shown)
After connecting them with a thin metal wire 3 (wire bonding), a cap 4 covering the element 1t is bonded to the upper surface of the carrier 2 using an epoxy adhesive. As shown in an enlarged view in FIG. 2, the peripheral end surface 5 of the carrier 2 is covered with a solder pad 6 in the recessed part of the semicircular #R surface. Thin +13
is connected to element 1 via.

In such a carrier 2, the outer end surface of the cap 4 is required to be air-tightly attached to the peripheral edge of the upper surface of the carrier 2, and the adhesion is performed by pressing the cap 4 against the carrier 2 with a predetermined pressing force by heating it from the front side. Therefore, it is necessary to set the adhesive width A to approximately 0.8 mm or more and to strictly control the adhesive thickness so that the adhesive does not soften and flow into the carrier recess and cover the solder pad 6. there were.

Therefore, the work of adhering the cap 4 to the carrier 2 has become difficult, and the efficiency and manufacturing yield have been impaired.

(d) OBJECTS OF THE INVENTION The object of the present invention is to eliminate the above-mentioned drawbacks and to provide a method for sealing (cn capping) a nine-chip carrier.

(e) Structure of the Invention The above objects include a step of loading a cap coated with a peripheral edge wK thermosetting adhesive onto a chip carrier, a step of semi-curing the adhesive, and a step of loading a cap coated with a thermosetting adhesive onto a chip carrier. A process of coating the entire circumferential end surface of the carrier as well as the seal bonding area between the carrier and the inner cap with a two-component type JLD agent that does not adhere to the solder pads, and applying an appropriate pressing force to bond the cough carrier and the cap. 01f) Embodiment of the invention achieved by a method for sealing a chip carrier characterized by the steps of adding and completely curing the adhesive and peeling off the coating agent. Below, FIG. 3 shows the main steps related to an embodiment applied to adhesion between a chip carrier and a cap shown in the method of the present invention, and FIGS. 4 to 9 are explanatory diagrams of the main steps.
The present IjlI will be explained using figures.

Figure 3 is a schematic diagram of the process for sealing and adhering the chip carrier (1a) and the chip element (4) as shown in Figure 1.
1) The carrier 2 that has been mounted by T-die bonding and connected with the thin metal wire (3) is coated with a female molding agent with dimensions equal to the external dimensions of the carrier 2, as shown in Fig. 4, and the jig 9 is inserted. 0 inserted into the hole 8, and an appropriate amount of a thermosetting adhesive (for example, an embossed adhesive for sealing) 10 is evenly applied to the end surface of the scrap track of the cap 40 as shown in FIG.

Next, the step of loading the cap 4 onto the chip carrier 2 is to place the cap 4 face down on the carrier 2 inserted into the jig 9, as shown in FIG. The cap 4, which has been machined to the desired dimensions, is fitted into the jig insertion hole 8 (KL) so that the carrier 2 and the cap 4 are aligned vertically.

Next, the first curing step is a step in which the adhesive 10 is semi-hardened, and the cap 4 placed on the carrier 2 inserted into the jig 9 is heated at about 150° C., for example, together with the jig 9.
Heat it for about 1 hour and harden it by about 70℃.As a result, the carrier 2 and the middle coat 4 will be in a temporary condition.On the other hand, prepare a mold removal agent (for example, two-component silicone rubber) and remove it. As shown in Figure 7, a layer of mold throat agent 12 is placed on the metal (e.g. stainless steel) @11 coated with the female mold agent.
However, the thickness of the lint remover layer 12 to which the carrier 2, cap 4, and adhesive 10 do not adhere is as follows:
Carrier 2 and cap 4t- thicker than carrier 2
Make it thinner than the layered thickness.

Next, as shown in FIG. 8, the cap 4 is temporarily attached on the lint remover layer 120, and the multi-sided inner ring 2 that has been hemmed from the jig 9 is placed on it, and after that, a weight 13 is placed on each cap number. As shown in FIG. 9, each carrier 12 and the cap 4 are sandwiched between the metal [11] and the weight 113, and the end surface of the entire circumference of the carrier 2 (5 in FIG. 1) and the solder pad (5 in FIG. 6) in FIG. 2, and the periphery of the bonding surface # of the carrier 2 and the cap 4 which are in contact through the adhesive 10t is buried and covered by the m-removal agent layer 12. Then, #E2
The next curing process is a process in which 10 tons of adhesive in a semi-hardened state is completely cured, and as shown in FIG.
The adhesive is completely cured by heating at 00 DEG C. for about 1 hour. When the adhesive 10 is softened and then hardened as the temperature rises, pinholes are formed in the hardened adhesive 10 due to gas generated from the adhesive 10.
The molding agent layer 12, which is hardened during the heating process, suppresses and prevents the hermetic seal of the cap 4 from being compromised.

Next, the molding p agent layer 12 and the chip carrier 2 are separated by peeling the molding pagent layer 12 from the metal plate 11.
Each carrier 2 is separated from the metal plate 11 by the adhesive layer 12. Therefore, the flexible plate-shaped sludge remover layer 12f
: 111 or solidify l1IIZ, adhesive layer (12
) The cap-sealed chip carrier 2 is obtained by cutting.

The molding agent to be used preferably has a viscosity that allows the molding agent layer 12 to adhere to the solder pad etc., for example, 11f, which allows the carrier 2 to sink naturally when placed on top of the molding agent NJ12. In addition, the weight 13 is mainly used to ensure airtightness of the solidified adhesive 10, and for example, the bonding area between the carrier 2 and the cap 4 is 1.5Kdl with a bonding area of 1AiK. According to the method of the present invention, the bonding width required for airtightly adhering (sealing) the cap (4) to the chip carrier C2 having the configuration shown in FIG. 1 is approximately 0.13 m compared to the conventional method. 0.6■ is all that is needed, so the carrier 2 can be made smaller by the difference, and the solder pad (6)
K-seal adhesive (10) does not flow, improving the reliability of the solder pad and manufacturing yield. Also, the reliability of the seal is improved because pinholes are less likely to form in the seal area (adhesive solidified layer) between the carrier and the cap. This improves performance and manufacturing yield, resulting in the 9th grade effect.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing a schematic structure in which a cap is bonded to a chip carrier on which a chip element is mounted, FIG. 2 is an enlarged perspective view of a part of the chip carrier, and FIG. 3 is an embodiment of the method of the present invention. Figures 4 to 9 are explanatory drawings of the main construction plan. In the figure, 1 is a chip element, 2 is a chip carrier, 4 is a cap, 5 is a side end surface of the chip carrier, 6 is a solder pad, 9 is a temporary adhesive, 10 is a thermosetting adhesive, and 11 is a metal. The plate, 12 is a molding agent layer, and 13 is a weight. v1 flash further 20 3rd flash Q Figure 6 Figure V

Claims (1)

[Claims] A chip-like element is mounted on a chip carrier with a large number of solder pads formed on the peripheral end face, and the element is sealed in a new cap f: This is a method of attaching the chip carrier KI11, and a thermosetting adhesive is applied to the peripheral end face. A step of loading the cap onto the carrier, a step of semi-curing the mosquito repellent and attaching the carrier to the middle cap, and a step of adhering the mosquito repellent to the carrier and the solder pad of the carrier. A process of coating the entire circumference of the carrier with a liquid O11 remover and sealing the carrier and the inner cap, and applying an appropriate pressing force of 111K for adhesion between the carrier and the cap, and #adhesive. The process of completely curing the
Covered circle! 1. Peeling off the removal agent! Chip carrier O-sealing method characterized by 1.