JPH0313735B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat treatment apparatus suitable for modifying a coating formed on an object.

Etching is one of the manufacturing processes for semiconductor devices, and in order to perform this etching, it is necessary to form a photoresist film on the surface of an object such as a silicon wafer, and then photoprocess this. In forming this photoresist film, a photoresist liquefied using a solvent is applied onto a wafer as a photoresist film, and then a photoresist is applied to improve the photosensitivity, phenomenon processing characteristics, or etching processing characteristics of this film. The membrane is heat-treated to perform so-called modification. This modification also includes removing solvents, strengthening adhesion, and improving etching resistance.

Heat treatment equipment such as infrared baking equipment, hot air circulation baking equipment, dielectric heating baking equipment, etc., and vacuum baking equipment are used as means for performing this type of reforming, but the former is preferred in terms of productivity and automation. is advantageous.

However, in conventional heat treatment equipment, since the baking action is performed with the photoresist film exposed inside the processing equipment, there is a drawback that foreign matter (dust, etc.) present inside the equipment tends to adhere to the photoresist film. . If such foreign matter adheres to the photoresist film, the light will be blocked by the foreign matter during the exposure process, and the photoresist film under the foreign matter will not be exposed. As a result, a desired semiconductor element pattern cannot be obtained on the wafer, and especially if foreign matter adheres to the segmented line portion, the wire may be disconnected.

Therefore, in the past, it was considered essential to conduct a visual inspection after the heat treatment process of the photoresist film, and in fact, a large number of defective products were discovered during this inspection, reducing the product yield and reducing man-hours in the manufacturing process. This has become an obstacle to reduction.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a heat treatment apparatus that can prevent foreign matter from adhering to a coating formed on an object such as a wafer and perform heat treatment with a good yield.

For this reason, the inventors of the present invention investigated the cause of the generation (adhesion) of foreign matter and found that foreign matter was generated from the drive unit for transporting objects on which a film was formed inside the heat treatment equipment, and objects were transferred from outside the equipment into the equipment. It was found that most of this was due to foreign matter contained in the outside air that entered during transport.

Based on the results of this investigation, the present invention is designed to expel foreign matter from the drive unit to the outside of the processing chamber and to prevent outside air from entering the processing chamber.

Hereinafter, the present invention will be explained based on the drawings.

1 and 2 are a front sectional view and a side sectional view of an embodiment of the present invention, showing an infrared baking device. In the figure, reference numeral 1 denotes the main body of the device, inside which a partition wall 2 is erected at a position near the back side to define a circulation chamber 3 on the back side, which includes an inert gas source (not shown). A gas supply pipe 4 connected to the gas supply pipe 4 is open and continuous. Mesh plates 5 and 6 are disposed on the upper and lower sides of the front side of the partition wall 2, respectively, defining a ventilation chamber 7, a baking chamber (processing chamber) 8, and an exhaust chamber 9 in order from the top. There are through holes 1 in the upper and lower parts of the partition wall 2.
0 and 11, and an air supply fan 12 and an exhaust fan 13 are installed inside the circulation chamber 3 as shown by the arrow in the figure.
The gas is circulated along the following route: → ventilation room 7 → bake room 8 → exhaust room 9 → circulation room 3. A pre-filter 14 is disposed at the through hole 10 that communicates the circulation chamber 3 and the ventilation chamber 7, and a main filter 15 is disposed between the ventilation chamber 7 and the baking chamber 8.

On the other hand, in the lower part of the baking chamber 8, a conveying means 16 having a belt conveyor as a driving unit is disposed in both directions, and conveys the wafer 17 from left to right in FIG. A loader section 18 and an unloader section 19 are arranged on the left and right sides of the main body 1, and the loader section 1
The 8 wafers 17 are transferred to the transport means 16 through the loading port 20 of the main body side wall 1a, and the transport means 16
The upper wafer 17 is transferred to the unloader section 19 through the outlet 21 of the main body side wall 1a. Furthermore, three infrared lamps 22 are provided in the upper part of the bake chamber 8 in parallel with the transport means 16, so that the wafers transported by the transport means 16 can be heated. 23 is a reflecting plate.

According to the above configuration, the inert gas supplied into the circulation chamber 3 from the gas supply pipe 4 is transferred to the prefilter 1.
The air enters the ventilation chamber 7 through the air filter 4, is purified through the main filter 15, and flows into the baking chamber 8. In the bake chamber 8, the gas flow is directed downward by the action of the mesh plate 5, resulting in a so-called down flow. Here, the foreign matter generated by the drive section of the conveyance means 16 is carried by the flow and moved downward, passed through the mesh plate 6 to the exhaust chamber 9, and then passed back to the circulation chamber 3. This gas will be circulated again through the same route as described above, and will be purified by the pre-filter 14 and main filter 15, respectively, and will flow into the bake chamber 8 to remove foreign substances in the bake chamber 8. Become.

On the other hand, the wafer 17 is supplied from the loader section 18 through the loading port 20 into the bake chamber 8, and while being conveyed by the conveying means 16, it is heated (baked) by the radiant heat of the infrared lamp 22 and the heat of the heated gas in the bake chamber. After the heat treatment, it is carried out from the carrying out port 22 to the unloader section 19. At this time, by adjusting the flow rate of the gas and maintaining the inside of the bake chamber 8 at a positive pressure (relative to the outside air), outside air can be removed from the inlet 20 and the outlet 21 even when loading and unloading the wafers. There is no intrusion into the chamber 8, and therefore no foreign matter contained in the outside air can enter. The pressure inside the baking chamber 8 can be adjusted by adjusting the flow rate of the gas supplied from the gas supply pipe 4, the rotational speed of the air supply fan 12, and the like.

As a result of the above, foreign matter generated from the drive unit of the conveying means is removed in the baking chamber 8, and foreign matter contained in the outside air is prevented from entering together with the outside air.
It is possible to prevent foreign matter from adhering to the photoresist film formed on the surface of the wafer 17, thereby improving the yield of products.

FIGS. 3 to 5 show other different embodiments. In these figures, the same parts as those in the embodiment described above are designated by the same reference numerals, and the explanation thereof will be omitted.

Figure 3 shows the configuration as a hot air circulation system.
In place of the infrared lamps 22 in the previous example, heaters 24 are arranged on both side walls of the circulation chamber 3 to heat the gas as it flows through the circulation chamber 3 and ventilate it to the baking chamber 8.
The wafer 17 is heated.
The gas supply pipe 4 is connected to the lower part of the circulation chamber 3.

FIG. 4 shows a plate heating system in which a heater 25 is installed inside a belt conveyor serving as a conveying means 16, and wafers conveyed thereon are heated from a close distance.

Figure 5 shows a configuration using a dielectric heating (microwave heating) method, with two magnetrons installed in the ventilation room 7.
6 is placed in the baking chamber 8, and the wafer 17 is dielectrically heated by radiating microwaves into the baking chamber 8.

As mentioned above, although each example has a different heating method,
The points of downflowing the inert gas into the baking chamber and the positive pressure inside the baking chamber are the same as in the previous example, and it goes without saying that the adhesion of foreign matter can be prevented in the same way as in the previous example.

Here, the apparatus of the present invention can be applied to other apparatuses as long as they have a processing space and require cleanliness between processing chambers, such as a photoresist pre-beta furnace, a photoresist post-bake furnace, etc. It can be applied to automatic coating baking equipment and automatic phenomenon baking equipment.

As described above, according to the heat treatment apparatus of the present invention, the gas is caused to flow down into the processing chamber and the pressure inside the processing chamber is made positive, so that foreign matter generated from the drive unit inside the processing chamber or foreign matter contained in the outside air is removed. It can be prevented from adhering to the processing object, and the yield of products can be improved.

[Brief explanation of the drawing]

1 and 2 are front sectional views and side sectional views of one embodiment of the present invention, and FIGS. 3 to 5 are side sectional views of other different embodiments. 1... Apparatus main body, 3... Circulation room, 5, 6... Mesh plate, 7... Ventilation room, 8... Processing room (bake room),
9... Exhaust chamber, 12... Air supply fan, 13... Exhaust fan, 14... Prefilter, 15... Main filter, 16... Transfer means, 17... Wafer, 18... Loader section, 19... Unloader section, 22... Infrared lamp, 24 ...heater, 25...heater, 26...magnetron.

Claims (1)

[Scope of Claims] 1. A heat treatment chamber, a means for transporting an object to be heated in the heat treatment chamber, a means for heat treating the object to be heated in the heat treatment chamber, and an upper part of the heat treatment chamber. A filter unit for supplying purified gas, a means for dispersing and supplying the supplied gas into the room, and a filter unit for making the supplied clean gas into a substantially uniform downflow state over the object to be heated. and a means for dispersing and evacuation provided below the heat treatment object, and the supply amount of clean gas supplied from the dispersion supply means at the upper part of the heat treatment chamber and the clean gas exhausted from the dispersion and evacuation means. A heat treatment device that controls the amount of gas exhausted and makes the pressure inside the heat treatment chamber more positive than the outside air of the treatment chamber. 2. The heat treatment apparatus according to claim 1, wherein the means for conveying the object to be heated is located below the object to be heated. 3. The heat treatment apparatus according to claim 1, wherein the distributed supply means and the distributed exhaust means are each constituted by a mesh plate.