JPH03283435A - Resin discharge device - Google Patents

Abstract

PURPOSE:To obtain a liquid resin discharge device, by which bubbles are never formed in a bonding agent layer, by a method wherein the sectional form of the arrangement of a plurality of nozzles to discharge a liquid resin, which is used for a resin bonding agent to bond a semiconductor device, is formed radially from the center of the sectional form toward the outside. CONSTITUTION:This device is one pertaining to a liquid resin discharge device to discharge a bonding agent resin for die bonding use in the manufacturing process of a semiconductor device and a plurality of nozzles which are used for this device are arranged in such a way that the sectional form of the arrangement of the nozzles is a radial form with the center of the sectional form as its center. In this constitution, wherein the nozzles are radially arranged, it is not always necessary that the nozzles are arranged linearly and a constitution such that the section form is helically distored is also included. The diameters of the nozzles can be different from one another.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a resin discharging device for discharging adhesive resin for dumb bonding of semiconductor devices.

(Prior Art) The assembly process of semiconductor devices such as ICs and LSIs consists of a large number of chips (semiconductor elements) formed on one semiconductor wafer.
dicing process).

Each chip is mounted on its own package and frame (die bonding process), and the electrode pads on the chip and the external leads or lead frame on the package are connected using thin gold (Au) or aluminum (Al1) wires. (wire bonding process) and finally sealing a part of the chip and its accompanying leads (sealing process).

Die bonding is a technique for attaching a chip to the die pad of a ceramic package frame prior to the wire bonding process, which facilitates the mechanical and electrical connection between the chip and the package as well as heat dissipation. It can be carried out. In general, die bonding requires that the joint be electrically conductive and have low thermal resistance, and that a physically and chemically stable bond be obtained, and die bonding must be performed with these conditions in mind. To date, three methods have been known: Au-5i eutectic alloy method, solder bonding method, and resin bonding method.

Au-Si eutectic alloy has a relatively low melting point of 370° C. and is widely used in die bonding. While heating to around 400° C. in an N2 or N2+H2 atmosphere to prevent oxidation, the back surface of the chip is pressed against the Au-plated die pad to perform an Au-8i eutectic reaction and bond. This method is commonly used because it provides good mechanical and electrical connection between the chip and the package. The solder bonding method uses a Pb-8n solder instead of the Au-5i eutectic alloy, and the working temperature is about 200 to 300°C, which is relatively low. This method allows the solder to be easily applied to the backside of the chip in advance for Ni-Au, Ti-Ni
- Form a metallized layer such as an Au film, sandwich a small piece of Pb-5n solder between the chip and the base metal on the die pad such as an Ag plating layer, and then apply N2 or N,
Bond by heating in +H2 atmosphere. The advantage of this method is that the solder layer absorbs the thermal strain caused by the difference in thermal expansion coefficients between the substrate and silicon (Si).
Chip breakage is less likely to occur even if the chip of I has a large area.

The third method is to use a resin adhesive. Epoxy resin containing Ag powder or Au powder is used as a standard adhesive, but adhesives must not emit gas that has a negative effect on the device during curing, and must have high thermal and electrical conductivity. This is the condition for A for the purpose of lowering the electrical contact resistance to the die pad for bonding.
It is common to apply G plating, Au plating, etc.

Since the curing temperature of the resin is about 150 to 200°C, which is lower than the previous two methods, the resin layer can absorb the thermal strain caused by the difference in coefficient of thermal expansion, and it is possible to attach large chips. However, since the curing time of the resin is long, productivity tends to be low.

When using this resin adhesive, Fig. 6(a).

As shown in (b), adhesive is applied to the lead frame 3, ceramic package, etc. by screen printing,
Alternatively, the adhesive 2 is discharged onto a lead frame or the like from a liquid resin discharge device (not shown) called a dispenser. Then, the chip 1 is pressed onto it using a die bonding tool, temporarily fixed, and then heated to harden the adhesive to complete die bonding.

In order to use this liquid resin discharging device, a device having a plurality of nozzles has been used. Rather than discharging the resin from a single nozzle, it is better to discharge the resin from multiple nozzles onto the lead frame 3 as a large number of points, so that when the chip 1 is pressed, the resin layer 2 will spread evenly, improving the bonding strength. Because it does. The cross-sectional shape of the nozzle is usually circular. It may be oval or polygonal, but there is no particular merit in using these shapes. So, when multiple nozzles are combined into one, the overall cross-sectional shape is
Since the shape of the chip 1 is square, it is usually square. That is, each nozzle is arranged in a lattice-like cross-sectional shape, and the circular resin discharged from this nozzle group is also arranged in a lattice-like shape, as shown in FIG. 5(a). In this figure, nine nozzles are used,
The number is not limited to this, and may be 16, 4, or 25. Also, 12, 15, 20
It may also be a rectangle in which each piece is arranged. moreover,
For example, it is also possible to form a houndstooth check pattern with 13 pieces arranged. A device including such a plurality of nozzles is called a multipoint liquid resin discharging device (hereinafter referred to as a multipoint device), considering the resin discharged from each nozzle as a point. The arrangement of the nozzles does not need to have an exact grid-like cross-sectional shape as a whole, and even if there is some deviation, no particular difference in operation and effect will be observed. Resin is discharged onto the lead frame 3 in a grid pattern of nine points (Fig. 5 (a), Fig. 6 (a)), and when the die bonding tool carries the chip 1 onto this and presses it, dots of resin are discharged. After passing through a state where they are stuck together (Fig. 5)
b)) A rectangular adhesive layer 2 (FIG. 5(C)) is formed, and the resin is finally cured to firmly bond the chip 1 and lead frame 3 (FIG. 6(b)).

(Problem to be Solved by the Invention) However, as described above, the liquid resin discharged onto a lead frame or the like from the multi-point device equipped with nozzles whose cross-sectional shape is arranged in a grid pattern is initially However, when a chip is placed on the chip and pressure is applied little by little, the resin sticks together and becomes a single piece (Fig. 5 (b)). . At that time, air bubbles are trapped between each point. Then, when the resin is finally integrated to form the resin layer, that is, the adhesive layer 2, the air bubbles are taken into this layer (Fig. 5 (C), 6
Figure (b)). Thereafter, during the heating process performed to cure the resin, these bubbles often grow into huge pores, leading to poor adhesion and poor product properties.

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a liquid resin discharging device in which bubbles are not formed in the adhesive layer by improving the nozzle arrangement.

[Structure of the invention]

(Means for Solving the Problems) The present invention relates to a liquid resin discharging device for discharging adhesive resin for die bonding in the manufacturing process of semiconductor devices, and a plurality of nozzles used in this device have a cross-sectional shape. They are characterized by being arranged in a radial pattern centered on the center. The configuration in which the nozzles are arranged radially does not necessarily have to be linear, but also includes a configuration in which the nozzles are distorted in a spiral shape. Further, the diameters of the nozzles may be different from each other. For example, the diameter of the nozzle may be reduced toward the center of the radial arrangement. The center of the central portion may be set at two or more points, or it may be configured to have two or more sets of radially arranged nozzles.

(Function) By adopting the configuration of the present invention, air bubbles are not trapped during chip mounting, and the liquid resin can be spread over the entire surface.

(Example 1) An embodiment of the present invention will be described with reference to the drawings.

Figures 1 (a) to (c) show the state in which liquid resin is discharged onto a lead frame made of a material such as Cu or N1 (42%)-Fe alloy by the multi-point device of Example 1. FIG. FIG. 1(a) shows, for example, Ag
This is a state immediately after a liquid resin such as an epoxy resin contained in powder is discharged, and the resin is arranged radially in all directions from the center.

This condition reveals the number and arrangement of nozzles in the multipoint device used here. In other words, nine nozzles having the same diameter are used and are arranged radially. When a semiconductor chip is placed on top of this liquid resin and pressure is applied, the dots of the resin are combined and integrated to form an adhesive layer 2 (Fig. 1(c)) - dots as in the conventional example. The resin is the first
As shown in Figure (b), at first they are joined in a cross shape, but as the joining progresses, this joined part expands toward one periphery as shown by the arrow. In other words, with this type of bonding, the air between the resin dots is pushed out to the periphery without forming bubbles, and the adhesive layer 2 without bubbles is formed as shown in FIG. 1(c). It is formed.

(Example 2) Next, Example 2 will be described with reference to FIGS. 2(a) to (c).

The adhesive layer 2 shown in FIG. 1(c) has a substantially square shape, but each side is recessed in some direction. this is,
This is because no nozzles are arranged around this area, and therefore there is a relatively wide area where resin is not initially discharged. In Example 1, since the nozzles are arranged in a straight radial manner, it is natural that the above-mentioned dents occur, and for this reason, it is suitable to use a relatively small chip for this adhesive layer 2.

In this way, if the radiation state is linear, a relatively wide area is created where the resin is not discharged, and as a result, formation of a good adhesive layer cannot be expected. Embodiment 2 is an improvement on this point, in which the radial straight line is slightly distorted to form a curved line with a constant curvature. Figure 2 (
The resin arrangement shown in a) is the same as the nozzle used in Example 1.
This was obtained by arranging the radial straight lines with some distortion and using them in a multi-point device. When the resin is arranged in this way, the area without resin is reduced, and the air between the resins is pushed outward as shown by the arrow, as shown in Figure 2 (b). However, these four arrows point outward in a counterclockwise rotation. As a result, the resin spreads uniformly, and the formed adhesive layer 2 has no dents on the sides as described above and becomes more square.

(Example 3) Next, Example 3 will be described with reference to FIGS. 3(a) to (c).

The shape of a semiconductor chip is not only square but also rectangular. With such a shape, it is difficult to maintain the radial arrangement of the nozzles, so two groups of nozzles that form resin in the shape shown in FIG. 2(a) may be stacked or used. Partially use one of them.

As a result, a resin arrangement as shown in FIG. 3(a) is obtained.

In this case, although the shape is complicated, it is basically a radial shape, so as the bonding between the resins progresses, the resin Since the air in between is expelled toward the periphery as shown by the arrow, the completed adhesive layer 2 is free of air bubbles and has the intended rectangular shape.

(Example 4) Next, Example 4 will be described with reference to FIGS. 4(a) to (c).

In Examples 2 and 3, the nozzles are arranged so that the radial straight lines are somewhat distorted in order to eliminate the relatively wide area where there is no resin as in Example 1. In No. 4, a relatively large area without resin is eliminated by changing the diameter of the nozzle. That is, the nozzles are combined so that the resin arrangement is as shown in FIG. 4(a).

The nozzles are arranged such that the nozzle with the smallest diameter is placed in the center and the diameter of the nozzle increases as it goes outward. The distance between the resins increases as you go outward, so you can make the resins larger and reduce the distance between them (
Figure 4(a)). The adhesive layer 2 formed from this resin has no dents on each side and is a good layer free of bubbles.

In addition, forming a rectangular adhesive layer with an aspect ratio close to 1 can be easily done by appropriately changing the aspect ratio of the nozzle arrangement shown in Figure 1 (a) or Figure 2 (a). It's about getting. In order to form an extremely flat rectangular adhesive layer, several nozzle groups having radial cross sections may be combined, as shown in Example 3.

Further, in all the examples so far, the nozzles are arranged radially around one point, but the present invention also includes two points at the center and the nozzles arranged radially from each point. However, at that time, care must be taken to ensure that the length between the two center points and other resins is not too long. In the above embodiments, the number of nozzles was nine, that is, a nine-point type was basically used; however, the present invention is not limited to this number, and is basically a 13-point type, a 17-point type, or more. It is also possible to do this. Although an epoxy resin containing Ag powder was used as the resin adhesive, this is just an example; for example, metal powder may be made of Au, or silicone resin or polyimide may be used as the resin. Also,
In the embodiment, die bonding to a lead frame has been described, but it is also possible to target an alumina substrate or other ceramic substrate.

Furthermore, it goes without saying that the present invention is applicable not only to the bonding of semiconductor elements but also to the dispensing of any adhesive that requires uniform spreading while avoiding the inclusion of air bubbles.

〔Effect of the invention〕

By having the above-described structure, the present invention eliminates air bubbles from being trapped in the resin adhesive layer for die-bonding chips and the resin does not spread properly, thereby increasing the bonding area and increasing the bonding strength. Eliminates chip cracking due to impact during wire bonding due to the gap under the chip or stress from surroundings during package encapsulation.
Remarkable effects such as being able to prevent product defects due to the trapping of moisture in air bubbles, etc., have been observed.

[Brief Description of the Drawings] Figure 1 (a) is a plan view of the resin discharged by the multi-point fine wave resin discharge device used in Example 1 of the present invention, and Figure 1 (b) is a plan view of the resin that has been bonded together. Figure 2(c) is a plan view of the adhesive layer made of the resin, and Figure 2(a) is Example 2.
Figure 3(b) is an explanatory diagram of the state in which the resin is bonded; Figure 3(c) is a plan view of the adhesive layer made of the resin; Figure 3(a) ) is a plan view of the resin discharged by the apparatus of Example 3, FIG. FIG. 4(a) is a plan view of the resin discharged by the device of Example 4, FIG. 4(b) is an explanatory diagram of the state in which the resin is bonded, and FIG. 4(c) is an adhesive made of the resin. FIG. 5(a) is a plan view of the resin discharged by the conventional device, FIG. 5(b) is an explanatory diagram of the state in which the resin is bonded, and FIG. FIG. 6(a) is a cross-sectional view of the resin discharged onto a lead frame using a conventional device, and FIG. 6(b) is a plan view of the adhesive layer made of the resin. A cross-sectional view is shown. 1... Semiconductor element (chip), 2... Adhesive layer, 3
...Lead frame, 4...Bubble.

Claims (1)

[Claims] In a resin discharging device equipped with a plurality of nozzles for discharging liquid resin used for a resin adhesive for bonding semiconductor elements, the cross-sectional shape of the arrangement of the plurality of nozzles is formed radially outward from the center. A resin discharging device characterized by the following.