JPS6060732A - Bonding device - Google Patents

Abstract

PURPOSE:To perform an always stable and secure fixation of a material to be bonded regardless of dispersion of the thickness thereof and to prevent the generation of bonding defect by a method wherein the material to be bonded is fixed at a prescribed position on a carrying surface by the applied pressure or suction force of a fluid. CONSTITUTION:A pellet 20 is bonded to a material to be bonded, lead frame 19, and after that, the lead frame 19 is carried to a prescribed position on the lead frame carrying surface of a heat block 16 along the carrying surface. Then, the lead part is held between a clamper 21 and the block 16, and at the same time, high-pressure air, which is sent from a high-pressure fluid source 18, is fed toward the lead frame 19 via a fluid passage 17 formed in the heat block 16 and the lead frame 19 is pressed to the clamper 21 by the high-pressure air flow.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to bonding technology, particularly to bonding semiconductor pellets onto lead frames, and bonding between pellet bonding bands and lead frames using wires. Regarding technology.

[Background technology] In the assembly process of semiconductor devices (hereinafter referred to as IC), pellets are bonded onto lead frames,
In order to connect the pellet and the lead frame with a wire, a bonding device called a pellet bonder or a wire bonder is used, respectively.

First, the wire bonder will be explained. FIG. 1 shows the main parts of a possible wire bonder. That is, there is a heat block 1, and an IC to which a pellet 6 is bonded.
A lead frame 5 is loaded. This heat block 1 is normally heated (around 350° C.) and heats the IC pellet and lead frame 5 placed thereon. The lead frame 5 is sandwiched and fixed between the clamper 2 and the heat block l. The bonding tool (capillary) 3 guides the wire into the hole of the capillary, hooks the ball-shaped thing at the tip, and lowers the bonding tool 3 to press the wire 7 against the electrode part of the pellet 6 or the lead frame 5, thereby generating so-called heat. Wire bonding is performed using the principle of crimping. In some cases, bonding may be performed by subjecting the capillary 3 to ultrasonic vibration or a minute displacement called scrubbing. In this case, the heating temperature by the heat block is reduced, and in some cases, the heating temperature may be room temperature.

Reference numeral 4 refers to a wire clamper, which clamps the wire 7. It serves to move the wire 7 up and down, and is also used to clamp and cut the wire after bonding.

FIG. 2 shows a principle diagram of bonding an integrated circuit (IC) using a wire bonder. Each part is exactly the same as in FIG.

Figure 2 +al shows that the pounding tool 3 is lowered and the pereso 1
- shows the case where the wire is bonded to the electrode part of the C element.

FIG. 2Cb) shows the case where the bonding tool 3 is separated from the pellet 6 and lowered to the lead frame 5, and the wire 7 is bonded to the lead frame 5.

FIG. 2 (C1 shows the wire clamper 4 clamping the wire and moving up together with the bonding tool 3, so that the wire is cut off a little distance from the bonding location of the lead frame 5.

However, in wire bonding, the leads of the lead frame to be bonded need to be reliably clamped at a location a little distance from the bonding location. This is because the reliability of the clamp is extremely important in bonding that involves scrubbing or bonding that uses ultrasonic waves. Therefore, as shown in Fig. 1, it is possible to fix the heat block and the clamper by mechanically sandwiching them between them (see Japanese Patent Publication No. 51-42666), but the flatness of the heat block and the clamper is different. Uncertain clamping may occur. Particularly, when there are dozens of leads such as in an IC, it sometimes happens that some of these leads are not clamped properly.

Particularly, if there are variations in thickness among several leads in a lead frame, the thinner leads will be unreliably clamped.

Unreliable clamping does not lead to many bonding defects in pure thermocompression bonding, which only applies heat and pressure, but in ultrasonic bonding, which involves applying ultrasonic waves to the bonding tool, or when the tool is rocked. In bonding that uses scrubbing, the vibration energy of the tool is absorbed due to the uncertainty in clamping the lead, which is the object to be crimped, resulting in bonding failures.

Further, even if the leads are reliably clamped, the bonding location is a little far away, and some bending occurs, which can cause bonding failures.

For this reason, the conventional method of mechanically clamping the leads with a heat block and clamper may result in uncertainties in the clamp itself, and even if it is reliable, the bonding location is not clamped. The inventor has revealed that this method has a drawback in that it may cause bonding defects.

Next, Pele/Tobonda will be explained.

FIG. 3 shows a cross-sectional view of the main part of a possible bullet bonding process using a possible pellet bonder. That is, the heat block 1 is loaded with the lead frame 5 in the same way as the wire bonder described above. The pellet 6 is bonded to the center point of the lead frame (tab>58).

The tab 5a is sandwiched between the clamper 2 and the heat block 1 and fixed. The pellet 6 is vacuum-adsorbed by the collet 8, pressed against the tab 5a of the lead frame, and is swung (scrubbed) in a horizontal plane to be joined. Beret 6
There are cases in which an adhesive is used or not used between the and tab 5a, and there are two cases in which the heat block is heated and cases in which it is not heated.

However, the pellet bonder has the following problems in addition to the above.

In the pellet bonder, the portion (tab) to which the pellet is to be attached is fixed in the same way as in the wire bonder described above, in that it is sandwiched and fixed between the clamper and the heat block. There is usually one tab, and wire bonding can be performed relatively reliably, unlike the case of fixing dozens of IC leads. However, the size of the tab is only slightly thicker than that of the pellet in order to reduce the number of ICs and to prevent the next wire bonding wire from touching the tab. For this reason, there are restrictions on where to clamp, and sometimes the clamper cannot fit.

In this case, since the tab is not clamped securely, vibration energy of the collet may be absorbed, resulting in pellet bonding failure. The inventor has discovered that the wetted area between the pellet and the tab needs to be at least 95% of the bottom area of the pellet, and that if this is too small, pellet cranking may occur when an IC is mounted.

[Object of the Invention] An object of the present invention is to provide a technique that can prevent the occurrence of bonding failures due to failures in fixing objects to be bonded in a bonding apparatus.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Summary of the Invention] A brief overview of typical inventions disclosed in this application is as follows.

In other words, by fixing the object to be bonded at a predetermined position on the conveying surface using the pressurizing force or suction force of the fluid, stable and reliable fixation is always achieved regardless of variations in the thickness of the object to be bonded. The occurrence of bonding defects can be prevented.

[Embodiment I] FIG. 4 is a diagram schematically showing an example of a bonding device according to the present invention, and FIG. 5 is a schematic sectional view of a main part of a feeding and fixing mechanism 111 incorporated therein.

In this embodiment, the bonding apparatus is, for example, a wire honda, and this apparatus includes a loader IO1 for supplying a lead frame as an object to be bonded, a transport mechanism II for transporting the lead frame from this loader 10 through a bonding position, A bonding mechanism 12 that bonds the same frame J8 and a pellet bonding pad with a wire, a recognition mechanism 13 that detects the bonding position by recognition, an unloader 14 that stores the lead frame after bonding, and controls the operation of each of the above mechanisms. It consists of a control section 15.

As shown in the embodiment of FIG. 5, the heat block 16 forming the lead frame transport surface of the transport mechanism 11 has a fluid passage 17 formed therein. This fluid passage 1
7 communicates with the high-pressure fluid source 18 at its proximal end, and opens into the lead frame conveying surface of the heat block 16 at its distal end.

That is, when a high-pressure fluid such as pressurized air is supplied from the high-pressure fluid source 18 through the fluid passage 17, the high-pressure fluid is supplied to the lead frame 1i on the upper surface of the heat block 16.
ft is ejected upward from the feeding surface.

Therefore, according to this embodiment, after bonding the pellet 20 to the lead frame 19, the lead frame 19 is transported to a predetermined position along the lead frame transport surface of the heat block 16, and then the lead portion is lifted up by the clamper 21. When high pressure air is supplied from the high pressure fluid source 18 through the fluid passage 17, the lead frame 19 is pressed against the clamper 21 by the high pressure air flow jetted from the fluid passage 17, so that the thickness of the lead frame 19 is Even if there are variations in the thickness, not only thick ones but also thin ones can always be reliably clamped and a stable fixed state can be obtained.

As a result, the wire bonder of this embodiment can always perform reliable wire bonding regardless of the thickness of the lead frame 19.

[Embodiment 2] FIG. 6 is an enlarged partial cross-sectional view of the main parts of a bonding apparatus according to Embodiment 2 of the present invention.

In this embodiment, in addition to the clamper 21, in order to fix the lead frame 19 on the conveying surface of the heat block 16,
This uses the vacuum suction force from the vacuum source 22. That is, in the case of this embodiment, the high pressure fluid source 18 of the first embodiment
Unlike the above, a vacuum source 22 is connected to the fluid passage 17 in the heat block 16, and the combination of the vacuum suction force from the vacuum source 22 and the clamping force of the clamper 21 causes the lead frame 19 to be attached to the conveying surface of the heat block 16. It is fixed tightly on top.

Therefore, even in this case, the lead frame 19 always reliably connects to the heat block 1 even if there are variations in its thickness.
Since it is closely fixed on the conveyance surface of No. 6, stable wire bonding performance can be ensured.

Further, in this embodiment, even an end portion that cannot be clamped by the clamper 21, such as the portion A in FIG. 6, can be easily fixed by forming the fluid passage 17.

[Embodiment 3] FIG. 7 is an enlarged partial cross-sectional view of the main parts of a bonding apparatus as Embodiment 3 of the present invention.

Bonding ■ in this example is Bere Nodobonda,
Since a pellet is not bonded to the tab 19a of the lead frame 19, the clamper 21a is attached to the tab 19a.
Clamp by pressing the top of a.

Also in this embodiment, a fluid passage 17a is provided inside the heat processor 16a, and this fluid passage 1
7a communicates with a high pressure fluid source 18a.

Therefore, in this example, the above-mentioned Example 1 (FIG. 5)
Similarly, by pressing the tab 19a, which is the pellet bonding surface, from below toward the clamper 21a with the jet force of high-pressure fluid from the high-pressure fluid source 18a, the clamper 21
Coupled with the clamping force of a, stable fixing is always achieved without being affected by variations in the thickness of the lead frame 19, and good bullet bonding performance can be ensured.

[Embodiment 4] FIG. 8 is an enlarged partial sectional view of a main part of a bonding apparatus according to Embodiment 4 of the present invention.

This embodiment also applies the present invention to a wire bonder, and as in the case of the second embodiment (FIG. 6), a vacuum source 22a is connected to a tab 19a via a fluid passage 17a formed in a heat block 16a. By applying the vacuum suction force of , in combination with the clamping force from the clamper 21a, even if there are variations in the thickness of the lead frame 19, stable close fixation can be performed at all times, and defective adhesion of the pellets can be prevented.

In this case, as shown in the figure, the fluid passage 17a is connected to the tab 1.
By forming the clamp 9a at a position corresponding to the lower center of the clamp 9a, there is an advantage that it can be easily tightly fixed even in a position that cannot be clamped by the clamper 21a.

[Effects] (1) By fixing the object to be bonded using the pressurizing force or adsorption force of the fluid, stable fixation is always achieved without being affected by variations in the thickness of the object to be bonded.
Good bonding performance can be obtained.

(2) By appropriately selecting the positions of the fluid passages provided in the heat block, even parts to which mechanical clamping force cannot be applied can be easily and reliably fixed.

(3) Can be fixed without applying any mechanical force,
It is possible to avoid damaging the object to be bonded.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. Nor.

For example, the formation position and structure of the fluid passage can be changed to various other shapes. In addition, by providing a fluid passage in the clamper,
The lead may be fixed by applying pressure.

Furthermore, it is also possible to use only the suction force or pressurizing force of a fluid without using any mechanical clamping force from the clamper. Especially when pellet bonding is performed using a vacuum suction fixing method, the clamper is used to hold the bond. This is very advantageous because it does not get in the way.

[Field of Application] In the above explanation, the invention made by the present inventor was mainly applied to the field of application which is the background thereof, pellet bonding and wire bonding of Lee I frame, but the present invention is not limited thereto. For example, it can be applied to bonding to a substrate such as a ceramic, and it can be applied particularly advantageously to ultrasonic bonding or bonding by scrubbing, but it can also be applied to other bonding.

[Brief explanation of the drawing]

Fig. 1 is a schematic explanatory diagram showing a possible example of wire bonding; Fig. 2 is a schematic explanatory diagram showing sequential steps of wire bonding; Fig. 3 is a schematic explanatory diagram showing a possible example of pellet bonding. , FIG. 4 is a schematic explanatory diagram of a bonding apparatus according to the present invention, FIG. 5 is an enlarged partial cross-sectional view of the main part of a bonding apparatus according to a first embodiment of the present invention, and FIG. 6 is a schematic illustration of a bonding apparatus according to a first embodiment of the present invention. FIG. 7 is an enlarged partial cross-sectional view of the main parts of the bonding apparatus according to the third embodiment of the present invention. FIG. 8 is an enlarged partial cross-sectional view of the main parts of the bonding apparatus according to the fourth embodiment of the present invention. 10... Loader, 11... 1 collection mechanism, 12...
Bonding mechanism, 13...Transportation mechanism, 14...Unloader, 15...Control unit, 16°168...Heat block, 17.17a...19a...Tab, 20
... Pellet, 21°218 ... Clamper, 22,
222...Vacuum source. Figure 1 Figure 2 (C Figure 3 Figure 4 Figure 5 Figure 20 Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] (1) Used for bonding pellets onto an object to be bonded while transporting the object on a conveyance mechanism, or for bonding the bonding pad of the pellet and the object to be bonded with a wire. In the bonding apparatus, a fluid passage is formed in the conveyance surface through which the object to be bonded is transported, and a pressurizing force or adsorption force of the fluid is applied to the object to be bonded through this fluid passage, thereby bonding the object. A bonding device characterized by being configured to be fixed at a predetermined position on a conveying surface. 2. Claim 1, characterized in that the fluid passage is formed within the heat block and communicates with a high pressure fluid source.
The bonding device described in Section 1. 3. The bonding apparatus according to claim 1, wherein a fluid passage is formed within the heat block and communicates with a vacuum source.