JPS6129124A - Treating method of semiconductor wafer - Google Patents

Abstract

PURPOSE:To raise the effect of baking step in a short time by improving the heat resisting temperature of a positive resist higher than the temperature of the heater by emitting ultraviolet rays, and contacting a semiconductor wafer with a heater, to then heat it. CONSTITUTION:When a low voltage mercury lamp 4 is fired and raised to 140 deg.C or higher, a semiconductor wafer 6 is conveyed and stopped. At this time the water 6 and a heater 7 are spaced at the prescribed interval. Ultraviolet rays are emitted to a photoresist pattern to improve higher than the heat resisting temperature of the pattern. Then, the heater 7 is raised to contact with the wafer 6.

Description

[Detailed description of the invention] Unreleased F! A refers to a method for processing semiconductor wafers, and in an integrated manufacturing process a, oxide films, nitride films, metal films, etc. are generally formed by photochemical vapor deposition, etc., and they are deposited on the surface as a preliminary cleaning process. Ultraviolet irradiation is used to decompose and clean organic materials, but recently it has been used to
What about baking? This 6- is attracting attention for its textile use.
A photosensitive process is a photosensitive process in which a positive resist film is formed on a semiconductor wafer on which an oxide film is deposited, and a photosensitizer is coated on top of the oxide film, and the photosensitizer is partially removed by exposing the semiconductor wafer to light.
In the middle of the etching step, which removes the oxide film from the area where the photosensitive agent has been removed and forms a pattern, the etching process is performed at 120 to 200°C for the purpose of improving the adhesive strength of the oxide film, etc. This refers to the process of heating at a temperature of □, but the higher the temperature, the better the adhesive strength will be. If the temperature is 140° C. or higher, there are problems in that the surface of the photosensitive agent, vertical distortion, and LSI performance deteriorate. Furthermore, if the hardness of the formed pattern is insufficient, the formed pattern is also polished and reduced in weight during the etching process, resulting in a decrease in performance. Therefore, if the semiconductor wafer is irradiated with ultraviolet rays before the baking process, the formed pattern will be hardened, and the heating temperature will be increased to 140°C during the baking process.
It is known that the formed pattern does not become distorted even when the temperature is higher than 0.degree.

By the way, heating and betaening after irradiating ultraviolet rays increases the number of steps and increases the processing time, so attempts have been made to carry out irradiation of ultraviolet rays and baking in parallel. As mentioned above, the heat resistance temperature of the positive resist is about 140° C., so it is initially heated at a temperature below this temperature, and when the heat resistance temperature improves by irradiation with ultraviolet rays, the heater is switched to raise the heating temperature. However, the reality is that it is difficult to quickly change the temperature of the heater within a short process of 1 to 2 minutes to keep up with the improvement in heat resistance, and it is not possible to obtain sufficient effects.

Therefore, the present invention makes it possible to quickly change the heating temperature when irradiating the positive resist of a semiconductor wafer with ultraviolet rays and simultaneously performing heat treatment, thereby sufficiently increasing the effect of the baking process within a short time. The purpose is to provide a method for processing semiconductor wafers that can be used to process semiconductor wafers, and its structure is such that first, a semiconductor wafer is heated by a heater whose temperature is higher than about 140°C, which is the heat resistance temperature of positive resist, and a predetermined distance is left between the heater and the heater. The method is characterized by heating the positive resist at a temperature below its heat-resistant temperature and simultaneously irradiating it with ultraviolet rays to raise the heat-resistant temperature of the positive resist to a temperature above the temperature of the heater, after which the semiconductor wafer is brought into close contact with the heater and heated. do.

Embodiments of the present invention will be specifically described below based on the drawings.

A main mirror 2 is horizontally arranged above the center of the equipment box 1.
At both ends of the main mirror 2, vertical sub-mirrors 3 are disposed below to form a space.

In the space surrounded by the mirrors 2 and 3, a low-pressure mercury lamp 4 is installed in parallel to form a surface light source. mainly occurs. Below the low-pressure mercury lamp 4 is a front glass 5 made of quartz glass.
is provided, and ultraviolet rays from a low-pressure mercury lamp 4 are transmitted through this front glass 5 and irradiated downward. The semiconductor wafer which is the object 6 to be irradiated has a thickness of 0.5 inches and a diameter of 6 inches (approximately 1
53 m), and is transported by a transport tool (not shown) to a position 2.5 m from the low-pressure mercury lamp 4. A heater 7 is arranged below the irradiated object B so as to be able to move up and down, but the top surface of this heater 7 has the same shape as the semiconductor wafer 6, and the whistle part rim that is in close contact with it is also attached.
The semiconductor wafer 6 may be lowered and brought into close contact with the wafer 6 without moving.

A cooling fan 8 is provided on the side of the equipment box 1 to cool the low-pressure mercury lamp 4 and the mirror 2.3, but in particular, the bulb section surrounding the electrode section of the low-pressure mercury lamp 4 is strongly cooled. The temperature at the coldest point is adjusted to 20-40°C.

Then, the low-pressure mercury lamp 4 is turned on, and the heater 7 is turned on at 15
When the temperature is raised to 0° C., the semiconductor wafer-6 is transported to a predetermined position and stopped. At this time, the semiconductor wafer 6 and the heater 7 are spaced apart from each other by about 10 m, as shown in FIG. Therefore, the temperature of heater 7 is 150°C.
As shown in FIG. 6, the semiconductor wafer 6 is heated to a temperature of 120° C., but the temperature does not rise any further, and is heated while being held at this temperature. Since this temperature is lower than the heat resistance temperature of the positive resist, the pattern of the positive resist is not deformed by this heating. During this time, ultraviolet rays are irradiated, and the heat resistance temperature increases to 150° C. or higher within 30 seconds. Next, after 30 seconds have elapsed, the heater 7 rises and comes into close contact with the semiconductor wafer 6, as shown in FIG. Therefore, the heat of the heater 7 is conducted to the semiconductor wafer 7, but since the semiconductor wafer 6 is a metal plate with a thickness of 0.5 m and good heat conductivity, it is transferred within a few seconds as shown in FIG. The temperature is raised to 150°C and maintained. The process is completed in 60 seconds, and the semiconductor wafer 6 is carried out by the carrier.

In this way, although the heater 7 is always at a constant temperature, the semiconductor wafer 6 can be heated at two temperatures by quickly switching between heating at intervals and heating at close contact. Therefore, it is possible to quickly follow changes in the heat resistance temperature of the positive resist, and it is possible to efficiently bake at a temperature just below the heat resistance temperature, thereby hardening the pattern and improving the adhesive strength of oxide films and the like to the substrate. Furthermore, since the temperature of the semiconductor wafer changes rapidly, the process cycle can be shortened, making it suitable for manufacturing semiconductors, where there is a strong demand for improved productivity.

[Brief explanation of the drawing]

FIGS. 1 and 2 are process explanatory diagrams, and FIG. 6 is a diagram showing the relationship between processing time and temperature.

Claims (1)

[Claims] This is a processing method in which a positive resist on a semiconductor wafer is irradiated with ultraviolet rays and heat treated at the same time. First, the semiconductor wafer is heated by a heater with a temperature higher than the heat-resistant temperature of the positive resist, approximately 140°C, and a predetermined distance is left between the heater and the positive resist. heating the positive resist to a temperature below its heat-resistant temperature, raising the heat-resistant temperature of the positive resist to a temperature higher than the temperature of the heater by simultaneously irradiating it with ultraviolet rays, and then heating the semiconductor wafer by bringing it into close contact with the heater. A semiconductor wafer processing method characterized by: