JPH01261827A - Optical asher - Google Patents

Abstract

PURPOSE:To approximately uniformize an ashing rate over an entire surface of a wafer by a method wherein amount of ozone to be supplied from nozzles which supply ozone and the positions of nozzles are specified so that ozone can flow on the wafer within time that concentration of ozone does not drop too low by being thermally decomposed due to processing temperature. CONSTITUTION:A quartz plate 3 which permits ultraviolet rays of 185nm and 254nm irradiated from a low pressure mercury lamp 2 to transmit and forms a uniform flow gap G on a wafer 5 surface is equipped with a number of nozzles 4 which supply reaction gas containing ozone, and reaction gas containing ultraviolet rays and ozone is supplied to the wafer 5 on a rotary stage 6. When amount of gas flowing from one of a plurality of nozzles 4 is assumed to be MM (cc/sec), a distance from the adjacent nozzle 4 is R (cm), the flow gap of reaction gas is G (cm) and temperature of a material to be processed is T( deg.C), conditions which satisfy M/RG>=T-100 are realized if the material to be processed is rotated with G<=0.05(cm) or less. This enables uniformity of an ashing rage on the wafer 5 to be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an apparatus for ashing an organic resist.
In particular, the present invention relates to an optical asher suitable for ashing at a uniform rate on a wafer surface.

[Conventional technology]

Conventional equipment removes organic resist using light and ozone, as described in Japanese Patent No. 1,214,135.

[Problem to be solved by the invention]

The above-mentioned conventional technology does not take into consideration the point of reducing the difference in ashing rate at different locations on the wafer surface, and has the problem of requiring overashing.

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical asher that can make the ashing rate substantially uniform over the entire surface of a wafer.

[Means to solve the problem]

The above object is achieved by making the time for ozone to pass over the wafer within a predetermined time depending on the temperature.

In other words, by specifying the amount of ozone supplied from the nozzle that supplies ozone and the arrangement of the nozzle, 3!1!
The ozone is made to flow over the wafer within a time that does not cause the ozone concentration to drop too much due to thermal decomposition due to temperature.

(Function) Ozone becomes radical oxygen by ultraviolet rays of 254 nm and reacts with the organic resist to generate COz and H2O, which are removed by ashing.
has the effect of breaking the chemical bonds in the organic resist.
It acts to speed up the ashing rate. In addition, the processing temperature has the effect of promoting the above chemical reaction, but it also has the effect of decomposing ozone, and if ozone is exposed to high temperatures on the wafer for a long time, the ozone concentration will decrease due to thermal decomposition. In areas far from the ozone supply port, the ashing effect is poor and the ashing time becomes uneven, which has the opposite effect. Therefore, uniform processing is achieved by selecting the amount of ozone supplied from the nozzle and the arrangement of the nozzles so as to shorten the time that the ozone passes over the wafer surface. Furthermore, not increasing the gas flow gap increases the gas flow speed on the wafer surface and allows more ultraviolet rays to reach the wafer, which has the effect of increasing the ashing rate. Also, by rotating the wafer, uniformity is further increased.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1(a) and 1(b). A quartz plate 3 that transmits 185 nm and 254 nm emitted from a low-pressure mercury lamp 2 and forms a uniform gas flow gap G on the wafer 5 surface is provided with a plurality of nozzles 4 for supplying a reactive gas containing ozone and is rotated. A reactive gas containing ultraviolet rays and ozone is supplied onto the wafer 5 on the stage 6. Each treatment temperature T (℃) various experiments were conducted. Experiments were conducted with R kept constant at 31 and M varied. A 5-inch wafer was used as wafer 5, and G was constant at 0.05 cm. The results are shown in Figure 2, where the horizontal axis shows M/
RG is shown on the vertical axis as the ratio of the maximum value to the minimum value of the ashing rate on the five wafer surfaces. By creating a condition that approximately satisfies M/RG≧T-100 from the results shown in FIG.

At a processing temperature of 200 to 300° C., the ashing rate on the wafer 5 was able to achieve a uniformity within 20%.

According to this embodiment, there is an effect that uniformity of the ashing rate on the wafer 5 surface can be obtained from low humidity to high temperature.

〔Effect of the invention〕

According to the present invention, the ashing rate of the organic resist on the wafer surface is made uniform, so there is no need for extreme overashing, and the quality of semiconductor devices can be made uniform, while at the same time, throughput can be improved. be.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are diagrams showing the configuration of an embodiment of the present invention, and FIG. 2 is a diagram showing the effects of the present invention. 1... Processing chamber, 2... Low pressure mercury lamp, 3... Quartz plate, 4... Nozzle, 5... Wafer, 6... Rotating table. 1st mouth 2nd prisoner

Claims (1)

[Claims] 1. An apparatus for ashing and removing organic resist, etc. on the surface of a workpiece using ultraviolet light, a reaction gas containing ozone, and heat, including a plurality of nozzles for supplying the reaction gas containing ozone. The flow rate of gas from one of the nozzles is M (cc/sec),
When the distance from the nozzle to the next nozzle is R (cm) and the flow gap G (cm) of the reaction gas, and the temperature of the object to be treated is T (°C), M/RG
An optical atsher characterized by having a relationship of ≧T-100. 2. The above flow gap G≦0.05 (cm) or less,
2. The optical atsher according to claim 1, wherein the object to be processed is rotated.