Heat-treating device and method

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Industrial application field]

The present invention relates to an apparatus for heat-treating a semiconductor wafer or a glass substrate and a method for heat-treating.

【0002】

[Conventional technology]

An exposure process is one of the processes for forming an integrated circuit on a semiconductor wafer. In the exposure step, as shown in FIG. 4A, light is applied to the resist film R formed on the surface of the semiconductor wafer W via the mask M. Then, as shown in FIG. 4 (b), by developing with a developing solution such as alkaline water after exposure, if the resist film R is a positive type, the portion not exposed to light is insoluble in the pattern R'. Leave as. After that, a metal thin film is formed on the surface of the semiconductor wafer W where there is no pattern R'by, for example, CVD. Further, the pattern R'is used as a mask when the surface of the semiconductor wafer W is etched and ion-doped.

【0003】

[Problems to be Solved by the Invention]

As shown in FIG. 4 (b), it is desirable that the side wall of the pattern R'used when forming a metal thin film on the semiconductor wafer W by CVD, etching or ion-doping is close to vertical. However, it often has a cross-sectional pattern with a protruding central part, as shown in FIG. 4 (c).

【0004】

The present inventor investigated the cause of the cross-sectional pattern as shown in FIG. 4 (c), and came to the conclusion that it was during the heat treatment after exposure. That is, when the heat treatment after exposure is performed by a continuous heating device for mass production, a cross-sectional pattern as shown in FIG. 4 (c) may occur, and when the patterns R'are close to each other, the patterns leak from each other. However, when the heat treatment is performed after exposure with an experimental heating device, the shape does not reach the shape of the above pattern.

【0005】

The difference between the continuous heating device for mass production and the heating device for experiments is whether the heating atmosphere is solvent-rich or not. In other words, in a continuous heating device for mass production, the heat reflector is placed above the hot plate, the wafer is floated from the hot plate by a pin, the wafer is brought closer to the heat reflector, and the wafer is radiated from the heat reflector. The structure is such that the heat is uniformly heated, or the distance between the lid of the heating device and the wafer is reduced to increase the heat treatment effect, but in the case of the experimental heating device, the heat reflector and lid are used. There is no body.

【0006】

When the wafer is brought close to the heat reflector as described above, the solvent volatilized from the coating liquid applied to the surface of the wafer remains in the space between the wafer and the heat reflector, creating a solvent-rich atmosphere. On the other hand, when the heat reflector is not provided, the volatile solvent easily escapes, and the solvent-rich atmosphere is not created.

【0007】

[Means for solving problems]

The present invention has been made based on the finding that an ideal exposure pattern can be obtained by scavenging a solvent-rich heating atmosphere when heat-treating a resist film applied to a wafer surface.

【0008】

That is, the heating device according to the present invention is a heat treatment device for carrying a plate-shaped object to be processed into the main body of the device and heat-treating the plate-shaped object to be processed with a hot plate, which is abbreviated as the heating temperature by the hot plate. A heated gas ejection means for ejecting gas having the same temperature and a scavenging means for ejecting gas in the main body of the apparatus are provided, and as the heating gas ejection means, a porous body is arranged above the hot plate, and the porous body is arranged. The body has a disk shape, a hollow portion is formed inside the body, and a gas supply pipe is connected from above the outside of the hollow portion.

【0009】

As another aspect, a heat reflector that also serves as a heating gas ejection means is provided above the hot plate in the main body of the apparatus, and the heat reflector is made hollow and has a temperature substantially equal to the heating temperature of the hot plate on the lower surface. A configuration that forms a hole for ejecting gas is conceivable. As yet another embodiment, a hollow ring having a large number of pores facing the center is arranged on the periphery of the hot plate, heating gas is ejected from the pores, and an exhaust port formed above the hot plate is used as a scavenging means. And vice versa.

【0010】

Further, in the heat treatment method according to the present invention, a plate-shaped object to be treated having a coating liquid coated on its surface is carried into a heat treatment apparatus provided with a hot plate, and the plate-shaped object to be treated is placed on the upper surface of the hot plate. In the method of placing or heat-treating while floating from the upper surface of the hot plate with a pin, a gas having a temperature substantially equal to the heating temperature of the hot plate is arranged above the hot plate and has a disk shape. The plate-like cover is forcibly supplied into the heat treatment apparatus by a porous body having a hollow portion formed inside the hollow portion and to which a gas supply pipe is connected from above the outside of the hollow portion. The solvent-rich atmosphere of the solvent volatilized from the coating liquid applied to the surface of the treated product was swept and heated.

【0011】

[Action]

N₂By forcibly supplying the gas such as N2 into the heat treatment device, the solvent-rich atmosphere due to the solvent volatilized from the coating liquid applied to the surface of the plate-shaped object to be treated can be scavenged, and the temperature of the gas such as N2 can be adjusted. By making it substantially equal to the heating temperature of the hot plate, an ideal cross-sectional pattern as shown in FIG. 4 (b) can be obtained when patterning is performed in a subsequent process without causing a temperature drop.

【0012】

[Example]

Examples of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an overall view of the heat treatment apparatus according to the present invention. The heat treatment apparatus is provided with a heat treatment apparatus main body 2 forming a box on the base 1, and a hot plate 3 is arranged in the heat treatment apparatus main body 2. ing.

【0013】

A cylinder unit 4 is fixed below the hot plate 3 with the shaft oriented in the vertical direction, an elevating plate 5 is attached to the upper end of the piston rod of the cylinder unit 4, and a pin 6 penetrating the hot plate 3 is attached to the elevating plate 5. The lower end of is attached.

【0014】

Further, a porous body 7 as a heating gas ejection means is arranged above the hot plate 3 in the heat treatment apparatus main body 2. The porous body 7 has a disk shape slightly larger than that of the semiconductor wafer W, and a hollow portion 8 is formed inside, and a gas supply pipe 9 is connected to the hollow portion 8 from above the outside.

【0015】

Further, a carry-in / carry-out port 10 for the semiconductor wafer W is formed on one side of the heat treatment device main body 2, and an opening 11 is formed on the other side of the heat treatment device main body 2. Then, in the present invention, the carry-in / carry-out outlet 10 and the opening 11 may act as an opening for scavenging.

【0016】

Further, a carry-in / carry-out robot 12 is provided outside the carry-in / carry-out outlet 10. The loading / unloading robot 12 provides a rail 14 on a support column 13, engages the arm 15 with the rail 14, and rotates the screw shaft by driving the motor 16 to move the arm 15 to the inside of the heat treatment device main body 2. To move forward and backward.

【0017】

In the above, the semiconductor wafer W whose surface is coated with the resist liquid is placed on the arm 15, and the arm 15 is moved to carry the semiconductor wafer W into the heat treatment apparatus main body 2.

【0018】

Next, the pin 6 is raised to pick up the semiconductor wafer W on the arm 15 with the pin 6, the arm 15 is retracted, the pin 6 is lowered, and the resist film on the surface of the semiconductor wafer W is exposed to the hot plate 3. Apply heat treatment.

【0019】

In performing the above prebaking treatment, in the present invention, a gas such as N2 heated to a temperature substantially equal to the heating temperature of the hot plate is supplied from the gas supply pipe 9 into the hollow portion 8 of the porous body 7. A gas heated downward is ejected from the porous body 7, and the solvent-rich atmospheric gas in the heat treatment apparatus 2 is exhausted from the carry-in / carry-out port 10 and the opening 11 with this gas to sweep the semiconductor wafer W. Is heat-treated.

【0020】

By prebaking while scavenging in this way, a cross-sectional shape close to the ideal pattern as shown in FIG. 4 (b) can be obtained.

【0021】

FIG. 2 is a diagram showing another embodiment of the heat treatment apparatus. In this embodiment, the heat reflector 20 is hollow, a heating gas supply pipe 23 is attached to the hollow portion, and the heat reflector is further formed. A heating gas ejection hole 25 is formed on the lower surface 24 of the 20.

【0022】

By using the heat reflector 20 as a heating gas ejection means as in this embodiment, the structure of the apparatus itself is simplified, and the semiconductor wafer W is heated by the pin 6 in a state where the semiconductor wafer W is floated from the hot plate 3. Even if the treatment is performed, the heating is not insufficient and uniform heating can be performed. The carry-in / carry-out port of the semiconductor wafer W is provided on a side surface (not shown).

【0023】

Although the semiconductor wafer has been described as the plate-shaped object to be processed in the embodiment, it may be a glass substrate. Further, the heat treatment is not limited to the heat treatment after exposure, but may be prebaking, heat treatment after development, or the like. Further, the heat treatment device may have a configuration in which the plate-shaped object to be treated is directly placed on the hot plate without providing a pin.

【0024】

[Effect of the invention]

As described above, according to the present invention, the gas whose temperature has been raised to the same level as that of the hot plate by the heating gas ejection means is forcibly supplied into the heat treatment apparatus, and at the same time, the inside of the apparatus main body by the scavenging means. Since the solvent-rich gas is discharged, an ideal cross-sectional pattern can be obtained when exposure is performed in a subsequent process without causing a temperature drop.

【0025】

In particular, by arranging a porous body as a heating gas ejection means above the hot plate, scavenging can be performed without disturbing the atmosphere, and when a heat reflector is provided above the hot plate in the main body of the apparatus, this heat reflector is provided. Is also more effective in terms of uniform heating by having a configuration that also serves as a heating gas ejection means.

[Simple explanation of drawings]

[Figure 1]

Overall view of the heat treatment apparatus according to the present invention [Figure 2]

The figure which shows another Example of the heat treatment apparatus [Fig. 3]

(a) is a diagram showing an exposure process of a resist film on a semiconductor wafer, (b) is a diagram showing an ideal resist pattern, and (c) is a diagram showing an unfavorable resist pattern. [Explanation of symbols]

2 ... heat treatment equipment body, 3 ... hot plate, 6 ... pin, 7 ... porous body, 10 ... carry-in / carry-out outlet, 11 ... opening, 20 ... heat reflection Plate, 21 ... heating gas ejection pipe, 22 ... scavenging pipe, 25 ... heating gas ejection hole, W ... semiconductor wafer.