KR0175051B1 - Hot-wall type high speed heat treatment device - Google Patents

Abstract

A novel hot-wall type high speed heat treatment apparatus is disclosed. A wafer for moving the wafer into the reactor, a donut-type wafer holder ring for mounting the wafer on the boat, and a wafer for the upper and lower crack fields, respectively; The ring is attached to the wafer backing so that the wafer can be mounted without being in direct contact thereon. The temperature uniformity in the wafer can be improved by reducing the temperature difference between the periphery and the center of the wafer.

Description

Hot-wall type high speed heat treatment device

FIG. 1A is a cross-sectional view of a conventional hot-wall type high speed heat treatment apparatus, and FIG. 1B is a cross-sectional view and a plan view of a wafer holder ring, and FIGS. 1C and 1D show a difference in temperature and temperature profile of light at the wafer periphery and the center. Representative Schematics.

2A and 2B are schematic diagrams showing a donut wafer holder ring and a temperature profile by another conventional method.

3A and 3B are schematic views for explaining a wafer holder ring in a hot-wall type high speed heat treatment apparatus according to the present invention.

4A and 4B are wafer maps and Rs distribution diagrams showing Rs values of wafers annealed by a hot-wall type high speed heat treatment apparatus using a conventional wafer holder ring.

5A and 5B are wafer maps and Rs distribution charts showing Rs values of wafers annealed by a hot-wall type high speed heat treatment apparatus using a wafer holder ring according to the present invention.

6 is a graph showing the difference between Rs values for each slot of a wafer annealed by a hot-wall type high speed heat treatment apparatus using a conventional wafer holder ring.

7 is a graph showing the relationship between the inner diameter of the wafer holder ring and the Rs value in the wafer annealed by the hot-wall type high speed heat treatment apparatus using the wafer holder ring according to the present invention.

* Explanation of symbols for main parts of the drawings

1: wafer 2: heater

4,6,21,34: Boat 5,7,35: Wafer holder ring

11: upper heater 12: lower heater

13: heat insulation material 14: reflector

15: upper crack field 16: lower crack field

17 exhaust pipe 18 booster pump

19: dry pump 20: magnet

21: boat 22: the second mobile unit

23: first mobile unit 24: reactor

25: manifold 26: door plate

29: wafer stand

The present invention relates to a rapid thermal processing (hereinafter referred to as RTP) apparatus, and more particularly to a hot-wall type RTP apparatus capable of improving temperature uniformity in a wafer.

In the process of making integrated circuits from silicon, various heat treatment techniques are used. For example, the silicon substrate may be oxidized into a silicon oxide film (SiO ₂ ) to be used as an insulating layer, an etching mask, or a gate oxide film for a transistor. In addition, after implanting trivalent or pentavalent ions into the silicon substrate, the implanted ions are rearranged from invasive to substituted in the silicon crystal to generate extra holes or electrons that may contribute to the conduction of electricity. Heat treatment is used after ion implantation as a means to make it possible. It may also be used for silicidation and for annealing thin films formed by various methods. It is also used in a reflow process for planarization of flowable films, such as BPSG films. In addition, for various purposes, a heat treatment process is used in the manufacturing process of a semiconductor device.

An apparatus commonly used in such a heat treatment process is an electric furnace. However, in recent years, as semiconductor devices have been increasingly integrated, the size of devices has become smaller, and there is a tendency for heat treatment using an RTP device to reduce the overall thermal budget received in the manufacturing process. The RTP apparatus has the advantage of reducing the thermal history received by the wafer by processing at a high temperature by short heating time and lamp heating, which are divided into two types according to the heating method. That is, it is divided into a lamp heating heat treatment apparatus using a halogen lamp or an arc lamp as a heat source, and a hot-wall heat treatment apparatus using a resistance heating heater as a heat source.

Lamp-heated RTP apparatus has several problems as follows.

First, because of the cold type, the temperature uniformity in the wafer is bad.

Second, since the emissivity of the back side of the heated wafer is measured by the pyrometer and converted into temperature, accurate temperature control is difficult because the emission rate varies depending on the state of the wafer surface. Third, the slippage of the wafer occurs due to the rapid temperature change.

Recently, a lamp-heating RTP device has been developed that improves the above-mentioned problems, but since this device uses dozens of halogen lamps, uneven deterioration of the lamp that occurs when several of the dozens of lamps fail or over time This degrades the temperature uniformity in the wafer. In addition, the device is expensive and expensive to operate and maintain.

On the other hand, the hot-wall type RTP device is expected to expand its use in the future because the equipment price is low, maintenance is easy, and temperature uniformity is easy to secure.

Figure 2a is a schematic cross-sectional view of a conventional hot-wall type RTP apparatus, each using a separate heater in one tube, batch processing of the wafer is possible (Applicant Korean Utility Model Application No. 94-02402 Filed under No. 1, and is still pending with the Patent Office). Here, reference numeral 24 is a capsule-shaped semi-finished furnace (quartz tube) for heat treatment of the wafer, 11 is an upper heater located at the upper end of the outer surface of the reaction vessel for RTP treatment, 12 is located at the lower end of the outer surface of the reactor for preheating The lower heater, 13 and 14 are the heat insulating material and the reflector located between the upper heater and the lower heater, 15 is the upper crack field located at the upper end of the reactor, 16 is the lower crack field located at the lower end of the reactor, 17 is Exhaust pipes connected to the top of the reactor, 18 and 19 are mechanical booster and drying pumps located at the end of the exhaust pipe, 21 is a boat carrying wafers, 23 is the boat from the lower crack field to the upper crack field A first mover for moving, 22 a second mover for moving the boat to the lower cracking field, 20 a magnet attached to the first mover, 25 a supporter for supporting the reactor (Manifold), and 26 is located at the bottom of the reactor, and shows the door plate which keep the air-tightness of the reactor. Reference numeral 27 denotes the length of the upper crack field 15.

Hereinafter, a problem according to a conventional hot-wall RTP apparatus will be described with reference to FIGS. 1B to 1D. Here, reference numeral 1 denotes a wafer, 2 a heater, 3 a shade of light, 4 a boat, 5 a wafer holder ring supporting the wafer, 9 a temperature profile in the wafer, and 10A a periphery of the wafer. The angle of arrival of the light, 리고 riB0B, represents the angle of arrival of light at the center of the wafer.

FIG. 1b shows a top view of the wafer holder ring, FIG. 1c shows the difference in the angle of arrival of light at the periphery and the center of the wafer, and FIG. 1d shows the temperature profile in the wafer.

Conventional hot-walled RTP apparatus suffers from temperature non-uniformity problems in the wafer as shown in FIG. 1D as the size of the wafer becomes larger.

The reason for this is that as shown in FIG. 1C, the heats received by the wafers are different because the angles of arrival l0A and l0B of the light in the heater 2 reaching the periphery and the center of the wafer 1 are different. As a result, a wafer heat-treated with a hot-walled RTP device receives more heat at the periphery than at the center, resulting in a larger sheet resistance (hereinafter referred to as Rs) at the periphery. In addition, since the inner diameter of the wafer holder ring 5 is about 90% of the diameter of the wafer 1, it hardly blocks light from the heater 2 to the periphery of the wafer 1, and the heat mass is not so large. .

As a conventional method for solving the above-mentioned problems, there is a technique disclosed in Korean Patent Application No. 91-21816 (Notification No. 95-9940), which will be described with reference to FIGS. 2a and 2b. .

FIG. 2A shows the wafer holder ring according to the conventional method, and FIG. 2B shows the temperature profile in the wafer. In Fig. 2, the same reference numerals as those in Fig. 2 denote the same members. Reference numeral 6 denotes a boat, 7 a wafer holder ring, and 8 a shade of light.

Referring to FIGS. 2A and 2B, the donut-shaped wafer holder ring 7 is widened (ie, reduces the inner diameter of the ring) so as to properly block light reaching the periphery of the wafer. 7) By placing the wafer 1 on contact, the heat capacity of the wafer periphery is increased to reduce the amount of heat that the periphery receives. Therefore, the temperature of the peripheral portion of the wafer drops so that the temperature difference between the peripheral portion and the center portion can be reduced. However, since the wafer holder ring 7 takes heat away from the wafer 1 in contact with the wafer 1, not only the heat capacity of the wafer periphery increases, but also the heat loss from the wafer increases, conversely, the temperature of the wafer periphery drops much. As a result, the temperature uniformity in the wafer becomes worse, as shown in FIG. 2B.

Accordingly, an object of the present invention is to provide a hot-wall type RTP apparatus that can solve the problems of the conventional methods described above and improve the temperature uniformity in the wafer.

In order to achieve the above object, the present invention, the reactor and the upper crack field and the lower crack field is located in the upper and lower, respectively; A vogue for moving a wafer into the reactor; And a donut-type wafer holder ring for mounting a wafer in the boat, wherein the wafer holder ring has a wafer support attached to it so that the wafer can be mounted without being in direct contact thereon. to provide.

Preferably, the wafer support is located at three points on the wafer holder ring.

The boat and wafer holder rings are formed of a material that does not transmit light, and are preferably made of quartz or SiC. In addition, the boat and the wafer holder ring are preferably treated such that its surface is not transparent.

In addition, in order to achieve the above object, the present invention, the upper and the lower crack field is located in the reactor, respectively; A wafer transport boat having a plurality of slots formed therein for heat treatment of the wafer in a batch; And a donut wafer holder ring for mounting a wafer on the boat, wherein the width of the wafer holder ring is adjusted differently for each slot of the boat.

The outer diameter of the wafer holder ring is preferably 105% of the wafer diameter.

The inner diameter of the wafer holder ring is preferably 90% of the wafer diameter in the uppermost slot and the lowermost slot of the boat, and is adjusted to 50 to 90% for each slot in the inner slot.

According to the present invention, by allowing the wafer to be mounted in a floating state supported by a small support positioned at three points on the wafer holder ring, the temperature uniformity in the wafer can be improved by reducing the temperature difference between the periphery and the center of the wafer.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3A and 3B are schematic views for explaining the wafer holder ring in the hot-wall type high speed heat treatment apparatus according to the present invention. Here, reference numeral 1 denotes a wafer, 2 a heater, 28 an angle of arrival of light added from a boat, 29 a wafer support, 33 'a shade angle of light, 34 a boat, and 35 a wafer holder ring.

The hot-walled RTP apparatus according to the present invention is identical to the conventional hot-walled RTP apparatus shown in FIG. 2A except for the wafer holder ring attached to the boat.

That is, the hot-wall type RTP apparatus of the present invention, the inside of the vacuum treatment and the capsule-shaped reactor (quartz tube) for heat treating the wafer, the upper heater located in the upper end of the outer surface of the reactor and heats the hot portion for RTP treatment (Can control 600 ~ 1200 ℃), the lower heater located in the lower end of the outer surface of the reactor to heat the low temperature part for preheating (can control 400 ~ 800 ℃), between the upper heater and the lower heater Insulation material and reflector located, upper crack field located at the upper end of the reactor, lower crack field located at the lower end of the reactor, exhaust pipe connected to the upper end of the reactor, mechanical booster pump located at the end of the exhaust pipe and drying A pump, a boat having a plurality of slots formed therein for heat treatment in a batch, a first mover for moving the boat from a lower crack field to an upper crack field, and the boat And a second mover for moving to the lower crack field, a magnet attached to the first mover, a manifold supporting the reactor, and a door plate positioned at the bottom of the reactor to maintain airtightness of the reactor.

In the hot-wall type RTP apparatus of the present invention configured as described above, the boat 34 and the wafer holder ring 35 are also formed of a material that does not transmit light, such as quartz or SiC. In addition, the boat 34 and the wafer holder ring 35 may be treated such that its surface is not transparent so as not to transmit light.

In the present invention, as shown in FIG. 3A, the wafer 1 is not placed in contact with the wafer holder ring 35, but rather as a small wafer support 29 positioned at three points on the wafer holder ring 35. It is supported and mounted floating on the ring. In this state, since the wafer 1 hardly contacts the wafer holder ring 35 directly, there is almost no heat loss around the wafer compared with the conventional method. In addition, since the width of the wafer holder ring 35 using a material that does not transmit light, such as quartz or SiC, is wide, a shadow is formed at the periphery of the wafer to block radiant heat transmitted through the light, so that the periphery of the wafer is the central portion. Compared to this, it is possible to reduce the temperature difference by reducing the amount of radiant heat that is relatively received. In addition, since the wafer holder ring 35 reflects a part of radiant heat to reach the center of the wafer, the angle of arrival of light reaching the center of the wafer is increased as compared with the conventional method, thereby increasing the temperature of the center and increasing the temperature of the center. The temperature difference can be reduced.

In addition, when the wafer holder ring is used, the wider the wafer holder ring or the smaller the inner diameter of the ring, the less heat the wafer receives. Therefore, since the amount of heat received by the wafer can be adjusted by adjusting the width of the wafer holder ring, as shown in FIG. 3B, the arrangement according to the difference in the amount of heat received by the wafer 1 for each slot in the boat 34 is shown. The problem of uniformity for the wafer-to-wafer can be improved. That is, by mounting the wafer holder ring 35 with a small ring width in the slot on the side where the wafer receives less heat, and attaching the wafer holder ring 35 with the wide width of the ring in the slot on the side receiving sufficient heat, The amount of heat received by the wafer for each slot can be controlled uniformly. Thus, it is possible to improve uniformity for wafer-to-wafer in a batch in a hot-walled RTP apparatus.

4A and 4B are wafer maps and Rs distribution diagrams showing the Rs values of the wafers in the case where the dopant is ion implanted into the wafer and then annealed with a hot-wall type RTP apparatus using a conventional wafer holder ring to activate the dopant. to be. Here, ○ indicates a case where the inner diameter of the wafer holder ring is 85% of the wafer size, □ indicates a case where the inner diameter of the ring is 75% of the wafer size, and Δ indicates a case where the inner diameter of the ring is 50% of the wafer size. In addition, the heating temperature of the upper heater and the lower heater is 950 ℃ and 700 ℃, annealing was performed for 120 seconds.

Referring to FIGS. 4A and 4B, in the case of using a conventional wide and large heat capacity wafer holder ring, the heat capacity of the wafer periphery becomes too large because the wafer holder ring is deprived of heat in contact with the wafer. do. As a result, the temperature around the wafer drops a lot so that the Rs value is lower than that of the center portion. In addition, as a result of measuring the Rs value for each position of the wafer, that is, for each slot of the boat, it can be seen that the temperature uniformity in the wafer is reduced.

5A and 5B are wafers showing the Rs value of the wafer in the case of annealing the wafer with a hot-wall type RTP device using the wafer holder ring according to the present invention to activate the dopant after ion implantation into the wafer. Map and Rs distribution map. Here, ○ denotes a case where the inner diameter of the wafer holder ring is 101% of the wafer size, □ denotes a case where the inner diameter of the ring is 87.5% of the wafer size, and Δ denotes a case where the inner diameter of the ring is 75% of the wafer size, × Indicates the case where the inner diameter of the ring is 62.5% of the wafer size. In addition, the heating temperature of the upper heater and the lower heater is 950 ℃ and 700 ℃, annealing was performed for 120 seconds.

Referring to FIGS. 5A and 5B, since the wafer is supported by a small wafer support located at three points on the wafer holder ring and is mounted floating on the ring, radiant heat in which the periphery of the wafer is received relatively more than the center part In addition to reducing the amount of light, the angle of light reaching the center of the wafer is also increased, thereby reducing the temperature difference between the periphery and the center of the wafer.

As a result, the temperature distribution in the wafer becomes uniform to obtain a uniform Rs distribution.

6 is a graph showing the difference between Rs for each slot of a wafer annealed by a hot-wall type high speed heat treatment apparatus using a conventional wafer holder ring. Here,? And? Indicate the case of annealing at 950 ° C. for 120 seconds, and ▲ and? Indicate the case of annealing at 1000 ° C. for 40 seconds, and data when the intervals between slots are changed under the same annealing conditions are displayed.

Referring to FIG. 6, according to the conventional hot-wall type high-speed heat treatment apparatus using a wafer holder ring, there is a difference in the amount of heat received by the wafer according to the slots in a boat, so that uniformity of wafer-to-wafer in a batch is achieved. Appears bad. There are two reasons for this. First, as shown in FIG. 1A, since the length of the upper crack field 27 is finite, wafers close to the top slot and the bottom slot in the boat are located in the center slot. This is because they receive relatively less calories than wafers. Secondly, except for the top and bottom wafers, there are one wafer in each of the front and rear slots to transfer the received heat back to the radiant heat, but the top and bottom wafers are either front or back. This is because only the wafers receive less heat than other wafers, so they receive relatively less heat. This phenomenon can be seen that the narrower the gap between the slots.

7 is a graph showing the relationship between the inner diameter of the wafer holder ring and the Rs value in the wafer annealed by the hot-wall type high speed heat treatment apparatus using the wafer holder ring according to the present invention. Here, ○ denotes a case where the inner diameter of the wafer holder ring is 101% of the wafer size, □ denotes a case where the inner diameter of the ring is 87.5% of the wafer size, and Δ denotes a case where the inner diameter of the ring is 75% of the wafer size, × Indicates the case where the inner diameter of the ring is 62.5% of the wafer size.

In addition, the heating temperature of the upper heater and the lower heater is 950 ℃ and 700 ℃, annealing was performed for 120 seconds. The spacing between slots was set to 24 mm.

Referring to FIG. 7, in the present invention, the wafer holder ring is used with different widths according to slots so as to properly block light reaching the wafer to ensure temperature uniformity. The amount of heat received by the wafer for each slot can be controlled uniformly. That is, the smaller the inner diameter of the wafer holder ring (the wider the width of the wafer holder ring), the smaller the amount of heat received by the wafer and the larger the Rs value. Therefore, if the width of the wafer holder ring is adjusted for each slot, the amount of heat the wafer receives Can be adjusted. According to this experiment, the outer diameter of the wafer holder ring is preferably 105% of the wafer diameter. The inner diameter of the wafer holder ring is preferably adjusted to 90% of the wafer diameter at the top and bottom slots of the boat and 50-90% per slot in the inner slots.

Thus, according to the hot-wall high speed heat treatment apparatus according to the present invention as described above, by using a boat in which the wafer is mounted in a floating state supported by a small support located at three points on the wafer holder ring, By reducing the temperature difference in the center, the temperature uniformity in the wafer can be improved. In addition, by using a boat mounted by varying the width of the wafer holder ring for each slot so as to appropriately block the light reaching the wafer, the uniformity of the wafer-to-wafer can be improved in one batch.

The present invention is not limited to the above embodiments, and it is apparent that many modifications are possible by those skilled in the art within the technical idea of the present invention.

Claims (13)

A reactor in which an upper crack field and a lower crack field are respectively positioned above and below; A boat for moving a wafer into the reactor; And a donut-type wafer holder ring for mounting a wafer on the boat, wherein the wafer holder ring has a wafer support attached thereto so that the wafer can be mounted without directly contacting the wafer thereon. . The hot-wall high speed heat treatment apparatus according to claim 1, wherein the wafer support is located at three points on the wafer holder ring. The hot-wall high speed heat treatment apparatus according to claim 1, wherein the boat and the wafer holder ring are formed of a material that does not transmit light. The hot-wall high speed heat treatment apparatus according to claim 3, wherein the boat and the wafer holder ring are formed of a material such as quartz or SiC. The hot-wall high speed heat treatment apparatus according to claim 1, wherein the boat and wafer holder rings are treated so that their surfaces are not transparent. A reactor in which an upper crack field and a lower crack field are respectively positioned above and below; A wafer transport boat having a plurality of slots formed therein for heat treatment of the wafer in a batch; And a donut-type wafer holder ring for mounting a wafer on the boat, wherein the width of the wafer holder ring is adjusted differently for each slot of the boat. 7. The hot-wall high speed heat treatment apparatus according to claim 6, wherein the wafer holder ring is attached with a wafer support to mount the wafer without directly contacting the wafer thereon. 8. The hot-wall high speed heat treatment apparatus according to claim 7, wherein the wafer support is located at three points on the wafer holder ring. 7. The hot-wall high speed heat treatment apparatus according to claim 6, wherein an outer diameter of the wafer holder ring is 105% of a wafer diameter. 7. The hot-wall high speed of claim 6, wherein an inner diameter of the wafer holder ring is adjusted to 90% of the wafer diameter at the uppermost slot and the lowermost slot of the boat and 50 to 90% for each slot in the inner slot thereof. Heat treatment device. The hot-wall high speed heat treatment apparatus according to claim 6, wherein the boat and the wafer holder ring are formed of a material that does not transmit light. 12. The hot-wall high speed heat treatment apparatus according to claim 11, wherein the boat and the wafer holder ring are formed of a material such as quartz or SiC. 7. The hot-wall high speed heat treatment apparatus according to claim 6, wherein the boat and wafer holder rings are treated so that their surfaces are not transparent.