JPS5990937A - Torch for semiconductor wire bonding - Google Patents

Abstract

PURPOSE:To prevent the blow-off of flame and instabilization due to the influence of ambient and high speed operation of torch by protecting the torch flame with the blast of air layer to the circumference thereof through formation of a double-tube structure edge of torch with the flammable gas ejected from the internal tube and the air from the external tube. CONSTITUTION:A torch 11 has the double-tube structure where the main cylindrical part 12 is mounted vertically to the bonding machine. The internal tube 12a is formed with the upper end located at the connecting part 12b of flexible tube, which is connected with a rubber tube indicated as an example guided from the oxygen and hydrogen gas source, and the flammable gas for torch is pressurized in the internal tube. The lower part of main cylindrical part 12 is bent deviating from the axis line BB' of the cylindrical part and the end of internal tube 12a is formed at the nozzle 12c. The external tube 12d of the double-tube structure is connected to the flexible connecting part 12e at the comparatively upper part of the main cylindrical part and the lower end is a little protruded from the nozzle 12c.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an improvement of a torch for semiconductor wire bonding, and particularly relates to an improvement of a torch that takes measures to extinguish the torch flame and prevent instability for high-speed operation of pole bonding assembly. .

[Technical background of the invention]

In assembling a semiconductor device, there is a step in which electrodes of a semiconductor chip are electrically connected to leads using bonding wires. In this process, after the stacked bonding wires are connected, the bonding wires are fused and a ball is formed at the starting end of the bonding wires, and the next bonding step is carried out. A torch as shown in FIGS. 1 and 2 is used to melt and cut the bonding wire. In this torch, the main cylinder part (1a) is vertically attached to a bonding machine (not shown) at the attachment part (lb), the upper end is provided with a flexible tube connection part (IC), and the lower part is the main cylinder part (1a). axis 1
The nozzle part (1d) is bent away from the product.

Therefore, when the main cylinder part is rotated around the axis A-A, the nozzle part oscillates following the rotation, and a torch with oxyhydrogen gas is applied at the fusing position in time with the timing of bonding. .

[Problems with background technology]

The above conventional technology has the following drawbacks.

(1) The torch flame may disappear or become unstable due to the influence of the flow of atmospheric gas (see Figure 2 (2)) to make the bonding atmosphere non-oxidizing.

(2) Because the torch nozzle moves at high speed, the torch flame may disappear or become unstable.

As a result of the above, (a) the torch flame goes out, which significantly impedes the flow of the process, resulting in poor quality and decreased yield.

(b) If the torch flame is unstable and the ball formed is large, it will cause a bonding short (due to contact with an adjacent part), and if it is small, it will cause chip cracks or capillary clogging. Furthermore, it causes variations in bonding strength.

This causes bonding defects and reduces yield.

There are problems such as:

[Purpose of the invention]

The present invention provides a structure for a torch for semiconductor wire bonding which improves the above-mentioned conventional problems.

[Summary of the invention]

In this invention, the tip of a torch used for wire bonding to semiconductor chips has a double-tube structure, and the inner tube blows out twisting gas, and the outer tube blows out air. This layer is used to improve the effects of the atmosphere and the extinguishing and destabilization caused by high-speed operation of the torch.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be explained in detail with reference to the drawings.

The torch 0 shown in Fig. 3 has a double-tube structure in which the main cylinder part (121) is vertically attached to a bonding machine (not shown), and the upper end of the inner tube (12a) is connected to a flexible tube. Part (12b) is connected to an example of a rubber tube led from an oxyhydrogen gas source (not shown), and combustible gas for the torch is pressurized into the inner tube. is bent away from the axis BB of the main cylinder part, and the tip of the inner pipe (12a) is formed into a nozzle part (12c).Next, it forms a double pipe structure with the inner pipe (12a) in the main cylinder part. The outer tube (12d) is connected to the flexible tube connection section (12d) at a relatively upper part of the main cylinder section.
e), and its lower width is more effective if it is slightly protruded from the nozzle part (12c). That is, when the outer diameter of the inner tube is III+1, the inner diameter of the outer tube with a wall thickness of 1 inch is l,
In the case where 8 liters of sake were used and the desired air was jetted therein at a flow rate of 0.05 to 317 ml, it was optimal to set the protrusion length to 0.5 liters. Note that this protrusion length may vary depending on usage conditions and atmosphere (waste flow).
etc., the preferred width is in the range of 0 to 1 am. This range [/11] is a value determined because if it is too small, the effect will be poor, and if it is too thick, the tip will be burnt, deformed, or become brittle.

In addition, in Fig. 4, (2) represents the flow of atmospheric gas, (
3) is a bonding wire, and (3a) is a ball portion formed by a torch.

Next, in the present invention, the relative positions of the inner tube and the outer tube do not necessarily have to be coaxial. That is, as shown in FIG. 5, the inner tube (22a) and the outer tube (22d) may be configured so as to be in contact with each other at part of their circumferential surfaces, or even at an intermediate position between the coaxial lines.

〔Effect of the invention〕

According to this invention, since the atmosphere in which the torch flame is formed is covered by the air flow jetted from the outer cylinder, the torch flame does not extinguish or become unstable even when the atmosphere changes or in an atmosphere of non-oxidizing gas. There is no. In addition, the tip of the inner tube where the torch flame is formed is cooled as the torch moves at high speed, preventing the torch flame from changing, extinguishing the flame, and preventing it from becoming unstable. By this method, the size of the ball formed on the bonding wire can be made constant, and problems such as bonding short due to large ball, chip clap and clogging of bonding capillary due to small ball, etc., and bonding strength due to l゛I: Lucky etc. Bad bonding,
This has a significant effect in countermeasures such as reduction in yield.

[Brief explanation of drawings]

1 and 2 relate to a conventional torch, FIG. 1 is a sectional view, FIG. 2 is a sectional view for explaining the torch, and FIG. 3 and subsequent figures relate to a torch of an embodiment of the present invention. The figure is a cross-sectional view of the torch, and Figure 4 is cross-section 1 for explaining the torch.
g (, Fig. 5 is a sectional view showing the nozzle part of the torch. !, 11) - Chi 3 Bonding wire 33 Ball 12 ) - Chi's main cylinder portion 12a, 22a Inner tube 12b, 12e Flexible! ? Greetings i;71
: Part 12C Inner tube light "Ifij nozzle part t2d, 22d Outer tube Fig. 1 Fig. 2 Fig. 3

Claims (1)

[Claims] A torch for semiconductor wire bonding that has a single double tube and blows out torch gas from the inner tube and air from the outer tube.