JPH02246233A - Die bonder - Google Patents

Abstract

PURPOSE:To detect abnormalities which break semiconductor chips by especially enlarging the output of a pressure detector at a region where concentrated pushing force is applied when a foreign matter is present, and differentiating the value from a value when there is no foreign matter. CONSTITUTION:A sucking surface 1c of a vacuum sucking collet 11 is divided into four regions. A pressure detector 1e which detects pushing force that is received from a semiconductor chip C is provided beneath a silicone rubber 1d forming the sucking surface 1c at each region. When there are the differences exceeding a specified value among the outputs of four pressure detectors 1e or when the outputs of one or more pressure detectors 1e exceed a specified value, it is judged that there is abnormality. This is detected when the collet 11 sucks the semiconductor chip C or when the collect 11 is compressed to a package P. Thus, the abnormality which breaks the semiconductor chip can be detected.

Description

[Detailed Description of the Invention] [Summary] Regarding die bonders used for assembling semiconductor devices and bonding semiconductor chips to packages, semiconductor The purpose of the present invention is to detect abnormalities that may damage the chip.The collet is equipped with a vacuum suction collet that suctions the semiconductor chip by vacuum suction and presses and bonds the suctioned semiconductor chip to the chip mounting surface of the package. has a suction surface that makes surface contact with the suctioned semiconductor chip, and is configured to include a pressure detector for detecting the pressing force received from the semiconductor chip in each of a plurality of regions into which the suction surface is divided. .

[Industrial application field]

The present invention relates to a die bonder used for assembling semiconductor devices and bonding a semiconductor chip to a package.

A semiconductor device in which a semiconductor chip is sealed in a package requires the above-mentioned bonding during assembly. It is important that the die bonder, which is a device that performs this bonding, not damage the semiconductor chip during bonding.

[Conventional technology]

Figures 2 (a) to (C) are main part configuration diagrams of the conventional example of the die bonder, in which (a) shows the overall outline, (b) and (C).
) shows the cross section of the collet tip.

In FIG. 2(a), the die bonder is equipped with a vacuum suction collet 1, which adsorbs a semiconductor chip C to be bonded from a chip supply section 2 to its tip by vacuum suction, and places the chip C in a bonding section 3. Bonding is performed by pressing onto the chip mounting surface S of the package P.
Reference numeral 4 indicates an arm that supports the collet 1, and 5 indicates a collet drive mechanism that controls the vacuum suction and movement of the cholera l-1.

The tip of the collet 1 that attracts the chip C has a concave conical shape to avoid contact with the surface of the chip C, as shown in Figure 2 (B), and the other has a concave shape as shown in Figure 2 (C). As shown, there is one having a suction surface 1c with which the surface of the chip C makes surface contact.In the figure, 1a is the collet body, and lb is the suction hole for vacuum suction. The former contacts only the shoulder portion of the chip C and causes concentrated stress there, so there is a problem that fragments are generated from the chip C and the chip C is easily damaged. The latter alleviates this difficulty, and the surface of the silicone rubber film 1d attached to the tip of the main body 1a serves as the suction surface 1c.

When the collet 1 adsorbs the chip C, the collet 1 is stopped at a position where the tip of the collet L is directly above the chip C with a slight gap, and then the chip C is sucked by vacuum suction.
It sucks up and absorbs.

Also, the chip mounting surface S where the collet 1 presses the chip C
Apply adhesive such as silver paste in advance.

From this, in the case of the collet l shown in FIG. 2(C), the pressing force between the suction surface 1c and the chip C becomes as shown in the characteristic diagram of FIG. 3. This is the collet l shown in Figure 2(b).
The same applies to the case of .

In Fig. 3, the vertical axis is the above-mentioned pressing force, the horizontal axis is time, ■ is the force due to the impact when the chip C is sucked, ■ is the force during suction, ■ is the force during bonding, and ■ is the force during bonding. The force due to the initial impact of this crimping, ■ is the force when not adsorbed (-
0), (2) is set appropriately according to the size of the chip C, etc., and is about 50 to 20 g, and (2) can be prevented from protruding by adjusting the movement control of the collet 1. On the other hand, (2) is unavoidable, although it can be changed to some degree by adjusting the vacuum suction.

[Problem to be solved by the invention]

Therefore, if the collet 1 shown in FIG. 2(C) is used, the pressing force described in FIG. 3 will be dispersed on the surface of the chip C, and the chip C will not be fragmented or damaged.

However, if solid foreign matter is attached to the surface of the chip C or the suction surface 1b, and solid foreign matter is interposed between the suction surface 1b and the chip C when adsorbed, as shown in FIG. The situation is different.

That is, in that case, part of the pressing force shown in FIG. 3 is concentrated on the chip C at the point of the foreign object, and the chip C may be damaged due to the concentrated stress.According to the experience of the present inventors, The lower limit of the concentrated pressing force that can damage the chip C is about 50 g, and damage to the chip C occurs more frequently during adsorption prior to bonding than during crimping.

This damage causes defective products to be mixed into the loft that has been bonded, and when foreign matter is firmly attached to the suction surface 1b, defective products are continuously generated and the yield is reduced. significantly lowers

Therefore, the present invention aims to prevent abnormalities that damage semiconductor chips in a die bonder that is used for assembling semiconductor devices and to bond semiconductor chips to packages, in order to prevent defective products from being introduced and a decrease in yield due to semiconductor chip damage during bonding. The purpose is to make it detectable.

[Means to solve the problem]

The above object includes a vacuum suction collet that suctions a semiconductor chip by vacuum suction and presses and bonds the suctioned semiconductor chip to a chip mounting surface of a package, and the collet has a suction surface that makes surface contact with the suctioned semiconductor chip. The problem is solved by the die bonder of the present invention, which is equipped with a pressure detector for detecting the pressing force received from the semiconductor chip in each of a plurality of regions in which the suction surface is divided.

[For production]

When foreign matter is present, which causes damage to the semiconductor chip, a pressing force, which is a reaction to the concentrated pressing force applied to the semiconductor chip, is concentrated on the part of the suction surface where the foreign matter is present.

On the other hand, when there is no intervening foreign matter, the pressing force from the semiconductor chip is distributed almost uniformly on the suction surface.

The suction surface is divided into a plurality of regions, and each region is provided with the pressure detector.

From this, when a foreign object is present, the output of the pressure detector in the area where concentrated pressing force is applied becomes particularly large, resulting in a large difference between the outputs of multiple pressure detectors, and Since the outputs are different from those in the absence of foreign matter when the outputs are almost uniform, it is possible to detect an abnormality that may damage the semiconductor chip. However, this detection occurs before the bonding of the semiconductor chip is completed.

Therefore, when this abnormality is detected, stop the die bonder work, remove the foreign matter, and if the semiconductor chip is damaged, remove it as well before restarting the work. It is possible to prevent the introduction of defective products and a decrease in yield due to damage to semiconductor chips.

〔Example〕

Embodiments of the present invention will be described below with reference to main part configuration diagrams shown in FIGS. 1(a) to 1(C). FIG. 1(a) shows the overall outline, and FIGS. 1(b) and 1(C) show the cross section and front view of the tip of the collet, and the same reference numerals indicate the same objects throughout the figures.

This embodiment is shown in FIG. 2(a) as shown in FIG. 1(a).
The vacuum suction collet 1 and collet drive mechanism 5 of the conventional example described in ) are replaced with the vacuum suction collet 11 and collet drive mechanism 15 described below.

As shown in FIGS. 1(B) and (C), the vacuum suction collet 11 divides the suction surface 1c of the vacuum suction collet 1 shown in FIG. A pressure detector 1e, which is made of, for example, a piezo element and detects the pressing force exerted by the attracted semiconductor chip C, is provided under the silicone rubber film 1d forming the attraction surface 1c.

The collet drive mechanism 15 detects the above-described abnormality that damages the semiconductor chip C from the outputs of the four pressure detectors 1e, and when detecting the abnormality, stops the operation of the collet 11 and issues an alarm. This function is added to the conventional collet drive mechanism 5.

This detection is performed when there is a difference of more than a certain value between the outputs of four pressure detectors 1e, or when the output of one or more pressure detectors 1e exceeds a certain value. This abnormality is mainly detected when the collet 11 picks up the semiconductor chip C or presses it onto the package P. Since the above-mentioned constant value varies depending on the case, it is set based on a trial for damage to the semiconductor chip C.

From the above, this die bonder detects an abnormality and stops the work of the die bonder when a solid foreign object is present between the adsorption surface 1c of the collet 11 and the adsorbed chip C, as explained in Fig. 4. do. Therefore, the stop is chip C
If it is before crimping the semiconductor chip C to the package P, remove the foreign matter and if the semiconductor chip C is damaged, remove it as well before restarting the work, or if the stop is after the semiconductor chip C is crimped. For example, the bonding can be completed by checking the bonded semiconductor chip C and, if it is damaged, removing the entire package P as a defective product, and restarting the work after removing foreign matter adhering to the suction surface 1c. It is also possible to prevent defective products from entering the loft, and also to prevent the yield from decreasing due to continuous generation of defective products.

In the example, the suction surface 1c is divided into four areas and four pressure detectors 1e are provided, but the number is not limited to the example, and if possible, it is preferable to have as many as possible. desirable.

〔Effect of the invention〕

As explained above, according to the configuration of the present invention, in a die bonder used for assembling semiconductor devices and bonding a semiconductor chip to a package, it is possible to detect an abnormality that may damage a semiconductor chip. This has the effect of making it possible to prevent the introduction of defective products and a decrease in yield due to chip damage.

[Brief explanation of drawings]

Figures 1 (a) to (C) are main part configuration diagrams of the embodiment, and Figure 2 (
a) to (C) are main part configuration diagrams of the conventional example, and Figure 3 shows the suction surface and
FIG. 4 is a characteristic diagram of the pressing force between semiconductor chips. FIG. 4 is an explanatory diagram of the problem in the conventional example. lb is the intake hole, 1c is the suction surface, ld is the silicone rubber membrane, le is the pressure detector, 2 is the chip supply part, 3 is the bonding part, 4 is the arm, 5.15 is the collet drive mechanism, C is the semiconductor chip, D is a solid foreign substance, P is a package, and S is a chip mounting surface. In the figure, 1 and 11 are the vacuum suction collets, 1a is the collet body, Cα) The whole body is cold (O2)

Claims (1)

[Claims] A vacuum suction collet is provided that suctions a semiconductor chip by vacuum suction and presses and bonds the suctioned semiconductor chip to a chip mounting surface of a package, the collet having a suction surface that makes surface contact with the suctioned semiconductor chip. ,
A die bonder comprising a pressure detector for detecting a pressing force received from a semiconductor chip in each of a plurality of divided regions of the suction surface.