JPS6145377B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a semiconductor device, and in particular, after a desired active region is formed, mainly to facilitate the latter half of the assembly process, etc.
This invention relates to an improvement in the bonding method between a wafer and a jig in the process of controlling the overall thickness of a semiconductor wafer (hereinafter simply referred to as a wafer).

Conventionally, in the process of controlling wafer thickness,
Apiezon wax has been mainly used when bonding a wafer and a jig. The bonding method using this Apiezon wax will be explained below with reference to FIGS. 1a and 1b.

A disk-shaped jig with good flatness precision (e.g. made of glass or stainless steel) 1 is approximately 80
When the temperature rises above ℃, Apiezon wax 3 is formed on the surface.
and spread it to a size corresponding to the wafer 2 (Fig. 1a).

The wafer 2 is placed on the Apiezon wax 3 with the back side of the wafer 2 (the part to be scraped) facing upward (FIG. 1b).

After completing the step in item 1, the wafer 2 and jig 1 are naturally cooled to harden the Apiezon wax 3 and complete the bonding.

The excess portion of the Apiezon wax 3 on the wafer 2 is wiped off with a solvent such as trichloride or methylene chloride.

The entire wafer 2 is controlled to have a desired thickness using a desired known technique (etching method, wrapping method, etc.).

After completing the step in section 1, place the jig 1 on the hot plate for approx.
Heat it to 80°C or higher to melt the Apiezon wax 3, and remove the wafer 2 from the jig 1 using tweezers or the like.

Apiezon Wax 3 with a solvent such as trichlene
The wafer 2 is washed with a desired solvent.

As mentioned above, in the bonding method using Apiezon Wax 3, (a) If Apiezon Wax 3 melts, the viscosity is too high, so the wafer 2 must be pressed against the jig 1 with moderate force. The entire wafer 2 is not properly bonded.

(b) Since Apiezon Wax 3 is difficult to be completely removed even with cleaning such as Triclean boiling, defects in post-processes due to Apiezon Wax 3 residue (such as defective wire bonding during the assembly process) occur. There are things to do.

(c) In the process described in item 1 above, when the wafer 2 is removed from the jig 1, the Apiezon wax 3 immediately begins to harden when it is separated from the hot plate, so the wafer 2, which has become thinner, It may break when handled with tweezers.

(d) If the temperature is too high when Apiezon Wax 3 is melted on a hot plate, it may burn and become impossible to remove.

There were other drawbacks.

This invention was made to eliminate the above-mentioned drawbacks, and provides a method of using phenyl salicylate (C ₁₃ H ₁₀ O ₃ ), commonly known as Zalor, in place of Apiezon wax. The present invention will be explained below based on the drawings.

First, the characteristics of phenyl salicylate will be outlined. Phenyl salicylate is a white crystal or powder at room temperature, with a specific gravity of 1.25 and a melting point of 41-43°C. It is difficult to dissolve in water, and it takes 6,670 ml of water to dissolve 1 g, but it is easily soluble in organic solvents such as alcohol, benzene, acetone, and chloroform.

An example in which this phenyl salicylate is applied to the wrapping work of silicon semiconductor wafers will be described below with reference to FIGS. 2a, b, and c.

Heat a disc-shaped jig (for example, a glass disc) 1 with good flatness to about 45°C or higher on a hot plate, place an appropriate amount of phenyl salicylate 4 on it, and melt it. , the shape of the wafer 2 is expanded to at least a size that can be covered (FIG. 2a).

The wafer 2 that has undergone the desired process is placed on the phenyl salicylate 4 in the state described in item 1 with the surface to be scraped facing upward.

After completing the process in item 1, remove the wafer 2 and the jig 1 from the hot plate, place a filter paper 5 larger than the wafer 2 on top of the wafer 2, place an appropriate weight 6 on top of it, and leave it for about 20 minutes. let cool,
The wafer 2 and the jig 1 are bonded together (FIG. 2b).

After a predetermined period of time, the weight 6 and filter paper 5 are removed, and the wafer 2 is wrapped and shaved to a desired thickness using a known technique (FIG. 2c).

After completing the step in item 1, the jig 1 with the wafer 2 still attached is heated to about 45°C or higher on a hot plate to melt the phenyl salicylate 4 again.
Lower jig 1 from above the hot plate, and from above wafer 2,
For example, after adding a few drops of an organic solvent such as acetone and melting it, remove the wafer from jig 1 to wafer 2 using tweezers or the like.
Remove.

After completing the step in item 1, the wafer 2 is cleaned with a solvent such as acetone.

The above describes the bonding of the wafer 2 and the jig 1 by the method using phenyl salicylate 4 according to the present invention,
The removal process is completed.

Although the above embodiment describes an example in which the thickness of a silicon semiconductor wafer is controlled by wrapping, the present invention is not limited to this.
It is also applicable to other semiconductor wafers such as wafers, etc., and can be applied not only to mechanical polishing methods such as wrapping, but also to cases where the thickness is controlled by chemical etching.

As explained above, in the present invention, Apiezon wax does not melt unless heated to a high temperature of about 80°C or higher, but phenyl salicylate melts at a relatively low temperature of about 45°C. In addition, apiezon wax tends to leave a residue relatively easily no matter what kind of organic solvent is used, whereas phenyl salicylate leaves almost no residue when used with an organic solvent such as acetone. Furthermore, since phenyl salicylate has a lower viscosity after melting than Apiezon wax, it has the advantage that by using an appropriate weight, it is possible to reduce variations in the thickness of the final semiconductor wafer.

[Brief explanation of the drawing]

Figures 1a and b are cross-sectional views showing the steps of a conventional bonding method using Apiezon wax, and Figures 2a and 2
b and c are cross-sectional views showing steps in an embodiment of the present invention. In the figure, 1 is a jig, 2 is a semiconductor wafer, 4 is phenyl salicylate, 5 is a filter paper, and 6 is a weight.
Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A method for manufacturing a semiconductor device, in which a semiconductor wafer is bonded onto a jig, and then the semiconductor wafer is processed to a required thickness, characterized in that phenyl salicylate is used to bond the semiconductor wafer and the jig. A method for manufacturing a semiconductor device.