JP2901653B2 - Heat treatment method and heat treatment apparatus - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a heat treatment method and a heat treatment apparatus for an object to be processed.

[Problems to be solved by conventional technology and invention] In a photoresist processing step of a semiconductor manufacturing process,
Stabilization of resist physical properties such as removal of solvent of resist solution applied on the surface of semiconductor wafer for dehydration of cleaning water of semiconductor wafer, addition of heat resistance by increasing cross-linking of resist, deformation of pattern after exposure Baking is performed for the purpose of reduction. As the baking method, heat treatment is performed using a direct heating hot plate, an indirect heating hot plate, or a belt-conveying oven, a batch oven, or the like, but hot plates are often used for compactness and efficiency. ing. Baking using a hot plate includes a direct heating method and an indirect heating method called proximity.In the direct heating method, a semiconductor wafer is closely mounted on a hot plate and heated from below the semiconductor wafer, Alternatively, when cooling a semiconductor wafer that has been heated to a high temperature by a cooling device provided below the hot plate to room temperature, the temperature distribution over the entire semiconductor wafer is uniform and efficient, but the semiconductor wafer and the hot plate adhere to each other. Cause dust to adhere to the surface,
There was a problem of heavy metal contamination in hot plates made of steel. Also, in the proximity bake, contamination is not caused by the gap provided between the hot plate, but it is difficult to precisely adjust the gap to ensure uniform temperature distribution,
There are also problems such as a long processing time required due to a low heat transfer rate. In particular, it takes about 20 seconds to cool to room temperature after heating (for example, 90 ° C.), whereas the proximity method requires more than 60 seconds to cool down to room temperature.

The present invention has been made in order to solve the above-mentioned drawbacks, and there is provided a heat treatment method and a heat treatment apparatus which can prevent a semiconductor wafer from being contaminated, and which can respond particularly quickly to cooling and can reduce processing time. The purpose is to provide.

[Means for Solving the Problems] To achieve the above object, the heat treatment method of the present invention comprises:
An object to be processed disposed at an interval above the first temperature adjusting means for performing a heating process and a cooling process, and a heating process and a cooling process arranged at an interval facing the upper surface of the object to be processed The heat treatment is performed on the object to be processed by changing the distance between the object and the second temperature adjusting means.

The heat treatment apparatus according to the present invention includes a first temperature adjusting unit that is disposed at an interval facing the lower surface of the object and performs a heating process and a cooling process, and has an interval facing the upper surface of the object. A second temperature adjusting means arranged to perform a heating process and a cooling process, and a moving means for changing a distance between the second temperature adjusting means and the object to be processed, and comprising: The distance between the first temperature adjusting means and the first temperature adjusting means is smaller than the distance between the object to be processed and the second temperature adjusting means.
The distance between the object to be processed and the first temperature adjusting means is 0.1 to 0.5 mm
And the distance between the object to be processed and the second temperature adjusting means is
The temperature adjusting means is disposed at predetermined intervals so as to face the upper and lower surfaces of the object to be processed at 0.1 to 5 mm, respectively, and heat-treats the object.

[Operation] By arranging temperature adjusting means at predetermined intervals so as to face the upper surface and the lower surface of the object to be processed, respectively, and heat-treating the object to be processed, a length which is a drawback in the conventional proximity device is obtained. It is possible to reduce the processing time that was required for a long time. In addition, when a cooling device is provided by being stacked with a heating device, and a semiconductor wafer that has been heated to a high temperature after heating is cooled to room temperature, the cooling is rapidly performed at a desired target temperature or less. The heating device is operated so as not to be cooled below the temperature, and the semiconductor wafer is brought to the target temperature. Therefore, the processing time, especially the cooling time, can be greatly reduced without impairing the advantage that the back surface of the semiconductor wafer in the proximity device is not contaminated, and the manufacturing process can be performed with a high yield.

Example An example in which a heat treatment method and a heat treatment apparatus of the present invention are applied to heat treatment in a resist coating step of semiconductor wafer production will be described with reference to the drawings.

As shown in the configuration diagram of FIG. 1, a heat treatment apparatus S1 as a first temperature adjusting means includes a hot plate 1 and a cooling apparatus 2 as a heating apparatus for heating a semiconductor wafer W as an object to be processed. In the figure, a thin-film resistance heating element 4 and an insulator 5 having an extremely small heat capacity are sequentially laminated and integrated on a base 3 which is a circular flat insulator and is a heat insulating material. The thin-film resistance heating element 4 is made of a metal simple substance such as nickel, chromium, platinum, tungsten or the like, a carbon simple substance, an alloy such as nichrome or stainless steel SUS, a polymer composite material such as polymer graft carbon, or a composite ceramic such as molybdenum silicide. Any material having conductivity including a material, which can be a resistance heating element when energized, can be suitably used, an appropriate material can be selected according to the heating temperature, and an electrode such as copper is attached,
It is formed to a thickness of 0.1 to 100 μm. The insulator 5 provided on these thin-film resistance heating elements 4 has excellent electrical insulation and good thermal conductivity, such as ceramics such as alumina, zirconia, and silicon carbide; metal oxides such as quartz and rutile; Any material that easily emits far infrared rays, such as plastics such as Teflon or the like, can be used. The base 3 provided below the thin-film resistance heating element 4 has an appropriate heat insulating property so that the semiconductor wafer W can be efficiently heated without the heat of the thin-film resistance heating element 4 being unilaterally diffused downward. It is made of a resin such as Teflon or polyimide having both heat conductivity and ceramics such as alumina and silicon carbide, or a metal material such as aluminum or SUS having these materials coated on the upper surface.

The cooling device 2 provided below the hot plate 1 is provided with a circulation path 6 for a cooling medium formed by using a cooling medium such as a compressor and an evaporator (not shown).
The vertical drive mechanism 7 allows the hot plate 1 to removably move up and down so that the semiconductor wafer W can be efficiently heated.

In order to control the temperature of the semiconductor wafer W, a temperature sensor 8 is provided on the insulator 5, and a temperature control device 9 transmits a control signal based on a temperature detected by the temperature sensor 8, and a power supply device.
10 is controlled to operate the thin-film resistance heating element 4 and the cooling device 2.

Above description is a heat treatment apparatus S ₁ similar second temperature adjusting means of the heat treatment apparatus S ₂ is also provided on the upper surface of the semiconductor the wafer W, the vertical heat treatment apparatus S ₂ causes the detaching of the cooling device 2 to the hot plate 1 driven as you can hold other preferably during transport and during heat treatment of the semiconductor wafer W gap d ₁ mechanism 7, and is moved up and down by the vertical drive mechanism 71 is moving means.

A heat treatment apparatus provided below the semiconductor wafer W;
As the hot plate 1 of S ₁ is shown in the sectional view of FIG. 2 3
A sphere 12 made of ceramic or the like is provided so as to have a box-shaped hole 11, which is substantially inscribed in each side wall of the hole 11, and whose upper surface slightly projects from the surface of the hot plate 1. when placing the semiconductor wafer W to, so as to hold the gap d _2. The hot plate 1 also includes a walking beam (not shown) for carrying in from a sender or a pre-processing device and carrying out to a post-processing device or a receiver, or a semiconductor for mounting on a predetermined position of the hot plate 1 at the time of carrying in / out. A vertically movable pin or the like for raising the wafer from the hot plate 1 is provided.

A heat treatment method of the present invention employing the heat treatment apparatus having the above-described configuration will be described. FIG. 3 shows a processing line of the resist coating apparatus, and the semiconductor wafer W stored in a cassette or the like by the sender 13 is transferred to the adhesion unit 14 by the transfer means. The adhesion unit 14 improves the adhesion between the resist film and the semiconductor wafer (C
H ₃ ) ₃ SiNHSi (CH ₃ ) ₃ or other vapor applied and heated (100 ° C)
Then, it is cooled to normal temperature in the next cooling device 15. Thereafter, the wafer is transported to the coater 16, where the resist film is applied, and then transported to the above-described heat treatment apparatus S. Before the semiconductor wafer W is loaded, the heat treatment apparatus S lowers the cooling device 2 from the position shown in FIG.
After further detachment, the thin-film resistance heating element 4 is supplied with electric power from the power supply 10 so as to be heated to a desired temperature (for example, 100 ° C.) in advance to generate heat. Thereafter, when the pins are projected from the hot plate 1 and the semiconductor wafer W transported by the beam is placed on the hot plate 1 while holding the gap d ₂ (for example, 0.1 to 0.5 mm), similarly to the heat treatment apparatus S _1. holding the gap d ₁ (e.g., 0.5 to 5 mm) preheated (eg 100 ° C.) has been heat treatment apparatus S ₂ of the hot plate is disengaged cooling apparatus by the vertical driving mechanism 7 and the semiconductor wafer W by the vertical drive mechanism 71 Be placed.

The semiconductor wafer W is cooler 2 approximately to be 40 seconds heat treatment heat treatment apparatus S ₁ and S ₂ are attached to each hot plate 1 in order to cool to room temperature 23 ° C.. At this time, by circulating freon at −20 to −40 ° C. through the passage 6 of the cooling medium of the cooling device, as shown in FIG.
The cooling time of the semiconductor wafer W in the case of circulating the cooling water of ° C. was much shorter than the time required for cooling the semiconductor wafer W (indicated by a broken line), as indicated by the solid line, and the temperature reached about room temperature by the temperature sensor 8 after ₁ second from T. When this is detected, the power supply device 9 is automatically driven by the temperature control device 9 and the thin-film resistance heating element 4 is activated.
When turned on, the cooling device 2 and the thin-film resistance heating element 4 are simultaneously used to prevent overcooling to a temperature lower than normal temperature. Thus the rapid cooling process is a heat treatment apparatus S ₂ and ends is raised upward by the vertical drive mechanism 71, the semiconductor wafer W is supported above the hot plate 1 by a pin or the like (not shown) walking beam, etc. It is transported to the receiver 17 and stored in a cassette or the like. The above description described a method of cooling to room temperature after heating to 100 ° C., for example, a cooling device capable of controlling from −20 ° C. to 30 ° C. and a heating device having a temperature control range of 30 ° C. to 250 ° C., −20 ° C. The temperature can be controlled over a temperature range from to 250 ° C., and a wide range of desired temperatures can be controlled.

In addition, a refrigeration cycle (for example, including a compressor, an evaporator, and a condenser) generally widely used in industrial machines may be employed as the cooling device in the present invention. In this case, high reliability and safety can be ensured.

The above description is one embodiment of the heat treatment method of the present invention, and the present invention is not limited to this. That is, the heating device and the cooling device can be used simultaneously and can be operated at any time, and the cooling and heating devices of the upper and lower devices can be used in combination. Further, the number of heat treatment devices to be installed is not limited to two in the vertical direction, and a large number of heat treatment devices can be used. Further, the heating device and the cooling device are not limited thereto, and known devices can be used.

[Effects of the Invention] As is clear from the above description, according to the heat treatment method and the heat treatment apparatus of the present invention, there is no contamination of the back surface of the semiconductor wafer and no heavy metal contamination, clean processing can be performed, and both in the up and down directions. Since the cooling device is detachably provided on the heating device, heating can be efficiently performed even during heating, and the cooling time is rapidly cooled to achieve the target temperature by using the heating device together, so that the processing time can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a heat treatment apparatus according to one embodiment to which the heat treatment method of the present invention is applied, FIG. 2 is a cross-sectional view showing a main part of the embodiment shown in FIG. 1, and FIG. FIG. 4 is a view showing a heat treatment step using one embodiment shown in FIG. 4, and FIG. 4 is a view explaining one embodiment. S ₁ , S ₂ … heat treatment device W… semiconductor wafer 1… hot plate (heat treatment device) 2… cooling device d ₁ , d ₂ … gap

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Koji Matsumura 2655 Tsukurei, Kikuyo-cho, Kikuchi-gun, Kumamoto Prefecture Inside Tel Kyushu Co., Ltd. Inside (72) Inventor Tetsuya Oda 2655 Tsukurei, Kikuyo-cho, Kikuchi-gun, Kumamoto Prefecture Inside Tel Kyushu Co., Ltd. (72) Inventor Tomomi Yamaguchi 2655 Tsukurei, Kikuyo-cho, Kikuchi-gun, Kumamoto Prefecture Inside Tel Kyushu Corporation (56) References JP-A-1-168026 (JP, A) JP-A 63-75032 (JP, U) JP-A 63-79636 (JP, U) (58) Fields investigated (Int. Cl. ⁶⁾ , DB name) H01L 21/027 G03F 7/26

Claims (4)

(57) [Claims] An object to be processed disposed at an interval above a first temperature adjusting means for performing a heating process and a cooling process, and an object to be disposed at an interval facing an upper surface of the object to be processed. A heat treatment method for heat-treating the object to be processed with a variable interval between the heat treatment and the second temperature adjusting means for performing a cooling treatment. 2. A first temperature adjusting means which is disposed at an interval facing a lower surface of an object to be processed and performs a heating process and a cooling process, and has an interval facing an upper surface of the object to be processed. A second temperature adjusting unit arranged to perform a heating process and a cooling process, and a moving unit for changing a distance between the second temperature adjusting unit and the object to be processed is provided. apparatus. 3. The apparatus according to claim 2, wherein an interval between said object to be processed and said first temperature adjusting means is smaller than an interval between said object to be processed and said second temperature adjusting means. Heat treatment equipment. 4. The distance between the object to be processed and the first temperature adjusting means is 0.1 to 0.5 mm, and the distance between the object to be processed and the second temperature adjusting means is 0.1 to 5 mm. The heat treatment apparatus according to claim 3, wherein: