JPH0671031B2 - Bonding device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a parallelizing mechanism for providing parallelism between a bonding tool and a sample to be bonded in a bonding apparatus used in a semiconductor manufacturing process.

[Conventional technology]

FIG. 7 is a front view of a main part of a conventional bonding apparatus of this type. The bonding apparatus 1 is equipped with a tool holder 3 supported by a support 2 and movable up and down. And this tool holder 3 has
The bonding tool 4 is supported via another tool holder 5. 6 is a parallelism adjusting screw in the Y-axis direction provided between the tool holders 3 and 5, and 7 is a parallelism adjusting screw in the X-axis direction provided between the support 2 and the tool holder 3. Is. On the other hand, a bonding stage 9 is fixed on a fixing plate 8 below the bonding apparatus 1, and a bonding target sample 10 (hereinafter, simply referred to as sample 10) is vacuum-adsorbed on the bonding stage 9. It is fixed.

With this structure, a gap gauge having a constant thickness, such as a Kapton tape, is placed on the bonding stage 9 in place of the sample 10 before the bonding work. Then, the heated bonding tool 4 is lowered and brought into contact with the clearance gauge, and the parallelism adjusting screws 6 and 7 are adjusted to adjust the parallelism between the bonding tool 4 and the clearance gauge. In this case, look at the indentation of the bonding tool 4 attached to the gap gauge,
It is assumed that the parallelism is obtained when the indentation has the same shape as the pressing surface shape of the bonding tool 4. After preparing in this manner, the sample 4 is fixed on the bonding stage 9 instead of the gap gauge, the leads on the carrier tape are placed on the protruding electrodes, and the bonding tool 4 is bonded by pressure and heat for bonding. If an adhesion failure occurs in the actual adhesion, the parallelism is adjusted again.

[Problems to be solved by the invention]

However, in such a paralleling mechanism of the conventional bonding apparatus, the parallelism of the surface of the bonding tool is limited to 4 μm, while the variation in the thickness between the lots of the semiconductor element as the sample is about 10 μm to 20 μm. Therefore, it may be necessary to make adjustments every time the lot changes, and in the conventional adjustment method, it is necessary to replace the clearance gauge and the sample before parallelism is achieved. There was a problem that it took time.

The present invention has been made in view of the above points, and an object thereof is to obtain a bonding apparatus capable of performing parallel alignment between the sample and the bonding tool in a short time regardless of the variation in the thickness of the sample. There is.

[Means for solving problems]

In order to achieve such an object, a bonding apparatus according to the present invention, a sample placed on a bonding stage provided on a fixed plate and a lead placed on the sample are mounted on the bonding stage by a descending bonding tool. In pressing and bonding, a bonding stage is provided so as to be movable up and down with respect to a fixed plate, and this bonding stage is loaded with a tilt absorbing spring member that is compressed by the descending contact of the bonding tool with the descending contact of the sample. By the paralleling mechanism, the target sample mounting surface of the bonding stage is tiltably supported so as to follow the pressing surface of the bonding tool.

[Action]

According to the present invention, when the sample and the lead are placed on the bonding stage and the heated bonding tool is lowered, the sample and the bonding stage are pushed and lowered. At this time, if there is variation in the thickness of the sample, the sample on the bonding stage is pushed by the bonding tool and tilts. This tilt is absorbed by the compressed spring member for tilt absorption, so The abutting surfaces of the samples are in contact with each other almost all over.

〔Example〕

1 to 4 show one embodiment of a bonding apparatus according to the present invention, FIG. 1 is a front view showing a partially cutaway main part of a bonding apparatus for carrying out this, and FIG. FIG. 3 is a sectional view taken along the line AA, FIG. 3 is an operation explanatory view, and FIG. 4 is a partially cutaway front view showing a main part of the bonding apparatus shown with a bonding tool lowered. In the figure, the bonding tool and its holding device have the same structure as the conventional device shown in FIG. 7, so the same reference numerals are given and their explanation is omitted. The fixing plate 12 fixed on the base 11 is provided with a spring hole 12a concentrically with the bonding tool 4, and in the spring hole 12a, a spring fixing metal member formed in a flat columnar shape. 13 is fitted and placed on the substrate 11, and four holes are bored from the top surface at equally spaced circumferential positions. Each of these holes is loaded with a spring 14 having the same spring characteristic that elastic force is accumulated by compression. On the spring 14, that is, at the upper end of the spring hole 12a, circles that are vertically stacked. Bonding stage 15 on board
The lower plate 16 and the lower plate 16 are fitted into the spring hole 12a and placed.
A sample 17 for bonding is placed at the center of the bondage stage 15, and this sample 17 is connected to a suction air source, and a tube 18 for vacuum suction is opened to the center of the bonding stage 15. Adsorbed by negative pressure air.

The operation of the bonding apparatus configured as above will be described. Prior to the bonding work, before inserting all the illustrated members 13 to 18 into the spring hole 12a, a block gauge formed in a cylindrical shape and having the correct parallelism of the upper and lower surfaces,
The spring hole 12a is loaded into the bottom. Then, the bonding tool 4 is lowered and brought into contact with the upper surface of the block gauge, and as described above, the parallelism adjusting screws 6 and 7 are rotated to adjust the parallelism of the lower surface of the bonding tool 4. After adjusting the parallelism, the block gauge is removed and, instead, the members 13 to 18 are put into the spring holes 12a as shown in the figure, and the sample 17 carried by the transfer arm is aligned and adsorbed on the bonding stage 15. At the same time, the leads on the carrier tape are placed on the sample 17.

After this, the heated bonding tool 4 is
When the sample 17 and the bonding stage 15 and the lower plate 16 are pushed down by the bonding tool 4 and are sunk into the hole 12a when they are lowered by the reference numeral l in the figure, the protruding electrodes on the surface of the sample 17 and the leads on the tape And are connected by heat and a pressing load. The amount of sinking of the sample 17 at this time is obtained by the descending distance 1 of the bonding tool 4 and the height of the sample 17. When the surface of the bonding tool 4 and the surface of the sample 17 are not parallel to each other when the bonding tool 4 is lowered (exaggeratedly shown in FIG. 3), FIGS. ), The bonding stage 15 begins to sink while compressing the spring 14 from the part where the bonding tool 4 first contacts the sample 17, and subsequently the sample 17 and the bonding stage 15 are separated as shown in FIG. Follow the inclination of the bonding tool 4 and keep sinking. Here, it is necessary to set the subduction amount so that the surface of the bonding tool 4 and the surface of the sample 17 are entirely in contact with each other before the bonding tool 4 reaches the lowest point. It must be larger than the value obtained by adding the variation in the thickness of the sample 17 to the inclination of the bonding tool 4. According to the experiment, 3 to 5 times the value obtained by adding the variation of the thickness of the sample 17 to the inclination of the bonding tool 4 is suitable. However, if the inclination of the bonding tool 4 is 20 μm or more, bonding cannot be performed, so this inclination is kept within 15 μm. Spring 14
The spring constant of is the load during bonding and the bonding tool 4
It is found by calculation from the slope and the amount of subduction. However, the inclination is calculated to be 15 μm and the spring 14 is designed. From the experiment, the elastic force of all springs 14 against the load at the time of adhesion,
By setting the spring constant so as to be 1 to 1.3 times, the result that the defective bonding is eliminated was obtained. Further, the number of springs 14 is preferably three or more as shown in FIG. 2 and FIGS. 5 and 6 as another embodiment, and further, the springs 14 are arranged at equal positions in the circumferential direction. is necessary.

〔The invention's effect〕

As described above, according to the bonding apparatus of the present invention, the bonding stage is provided so as to be vertically movable with respect to the fixed plate, and the bonding stage is
A tilting absorption spring member that is compressed by the descending contact of the bonding tool is tiltably supported by a parallelizing mechanism that is loaded, and the sample and leads are stacked on the bonding stage, and the heated bonding tool is lowered. At this time, the sample and the bonding stage are pushed down and lowered, and the inclination of the bonding tool with respect to the sample is absorbed by the spring member, and the target sample of the bonding stage is placed on the pressing surface of the bonding tool. Since the surface is configured so as to be imitated, the following various excellent effects can be obtained despite the simple structure.

That is, when the thickness of the sample varies, the sample on the bonding stage is pushed by the bonding tool and tilts, but the tilt absorbing spring member that constitutes the paralleling mechanism described above acts to separate the bonding tool and the target sample. The contact surfaces are in contact with each other almost over the entire surface.

Therefore, according to the present invention, even if there is some variation in the thickness of the sample, the parallel alignment of the bonding tool can be performed easily and in a short time, the work efficiency is improved, and the labor is reduced. Further, according to the present invention, since the surface of the bonding tool and the surface of the sample are not unevenly contacted with each other, the bonding is surely performed and the yield is improved.

In particular, according to the present invention, since the spring member is adopted as the parallelizing mechanism, the only movement is the vertical movement of the bonding stage, which does not generate frictional force or the like for tilt adjustment, and stabilizes. Then, the inclination is adjusted. Also,
Since it has a spring structure, there are advantages that it is extremely simple mechanically, that parts can be easily replaced, and that handling is easy.

Further, according to the present invention, by changing the bonding stage jig and tool, the coarse adjustment of the inclination of the bonding tool is performed in advance, so that the automatic alignment range of the inclination of the bonding tool can be narrowed and more reliable bonding can be performed. There is also the advantage that

[Brief description of drawings]

1 to 6 show an embodiment of a bonding apparatus according to the present invention, FIG. 1 is a partially cutaway front view of a main portion of the bonding apparatus, FIG. 2 is a sectional view taken along the line AA of FIG. 1, and FIG. (A) ~
(C) is an operation explanatory view, FIG. 4 is a partially cutaway front view of the main part of the bonding device shown in a state where the bonding tool is lowered, and FIGS. 5 and 6 respectively show other embodiments of the present invention. FIG. 7 is a cross-sectional view corresponding to FIG. 2, and FIG. 7 is a partially cutaway front view of an essential part of a conventional bonding device. 1 ... Bonding device, 4 ... Bonding tool,
11 …… Base, 12 …… Fixing plate, 12a …… Spring hole, 13 …… Fixing bracket, 14 …… Spring, 15 …… Bonding stage, 16
…… Lower plate, 17 …… Target sample.

Claims (1)

[Claims] 1. A bonding apparatus in which a target sample placed on a bonding stage provided on a fixed plate and a lead placed on the target sample are pressed on the bonding stage by a bonding tool that is moved down. A stage is provided on the fixed plate so as to be movable up and down, and the bonding stage can be tilted by a paralleling mechanism equipped with a tilt absorbing spring member that is compressed by the lowering of the target sample by the lowering contact of the bonding tool. A bonding apparatus characterized by being supported by.