JP2003282558A - Heat treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat treatment apparatus in which the uniformity of substrate temperature is improved. <P>SOLUTION: In a heat treatment apparatus for performing heat treatment on a substrate 9, a lamp group for irradiating light to the substrate 9 and an annular shaped auxiliary ring 31 for supporting the substrate 9 are arranged. The auxiliary ring 31 has an annular support portion 311 projected inwardly from an inner circumferential surface 310, and the portion 311 supports the outer edge 91 of the substrate 9 while contacting with the bottom of the substrate. Assuming that the width of the substrate 9 overlapped with the portion 311 is a support width W, the thickness of the portion 311 is a support portion thickness T, and the thickness of the substrate is a substrate thickness Tw, the width W and the thickness T are determined such that ((T×W)≤(Tw×2)) is satisfied. This improves the uniformity of the temperature of a substrate to be heated. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment apparatus for performing a process involving heating a substrate.

[0002]

2. Description of the Related Art As the demand for fine processing of devices such as semiconductors increases, semiconductor substrates (hereinafter referred to as "substrates").
Rapid thermal process (Rapid Thermal
Process, hereinafter referred to as "RTP". ) Plays an important role. In RTP, a lamp is mainly used as a heating source, a substrate is heated to a predetermined temperature (for example, 1100 ° C.) on the order of seconds while maintaining a predetermined gas atmosphere in the processing chamber (heating process), and a predetermined time (for example, After the temperature is maintained for only a few tens of seconds (holding step), the lamp is turned off to perform rapid cooling.

The RTP prevents re-diffusion of impurities due to heat in the junction layer of the transistor built in the substrate,
A process such as thinning of an insulating film such as an oxide film, which is difficult to be realized by a conventional heat treatment for a long time in an electric furnace, is performed.

In the heat treatment apparatus for performing RTP, an auxiliary ring for supporting the substrate by contacting the outer edge of the substrate is provided. The auxiliary ring prevents the light from the lamp from entering the thermometer placed on the back side of the substrate to measure the temperature of the substrate during the RTP, and is heated integrally with the substrate so that the surface of the substrate is Improve temperature uniformity.

[0005]

However, since the combined thickness of the portion where the substrate and the auxiliary ring are in contact with each other is larger than the portion where only the substrate exists, the outer edge portion of the substrate is quasi unit area per unit area. Therefore, it becomes difficult to maintain the temperature uniformity of the substrate in both the temperature raising step and the holding step. As a result, for example, it becomes difficult to suppress the variation in film thickness when forming an oxide film or the like within a range that is required more strictly in the future. An example of oxide film formation by a conventional heat treatment apparatus will be shown below.

FIG. 1 is a diagram showing a temporal change of a substrate temperature in RTP. The horizontal axis represents time and the vertical axis represents substrate temperature. The process from time t1 to t2 in FIG. 1 is a temperature raising process for raising the substrate temperature, and the process from time t2 to t3 is a holding process for keeping the substrate temperature at the target temperature A. FIG. 2 shows the relationship between the position on the substrate and the film thickness of the oxide film when such RTP is performed using the conventional heat treatment apparatus. The horizontal axis shows the distance from the center of the substrate, and the vertical axis shows the average film thickness of the oxide film with respect to the distance.

As shown in FIG. 2, the film thickness is stable inside the vicinity of the distance R1 (on the center side of the substrate), but the film thickness rapidly increases as the distance R2 corresponding to the outer edge of the substrate is approached. It is considered that this is because the temperature of the auxiliary ring becomes higher than the substrate temperature in the holding step, and the temperature of the outer edge portion of the substrate becomes higher than that of the inner portion due to the heat conducted from the auxiliary ring. .

The present invention has been made in view of the above problems, and an object thereof is to improve the uniformity of substrate temperature in a heat treatment apparatus using a lamp.

[0009]

According to a first aspect of the present invention, there is provided a heat treatment apparatus for irradiating a substrate with light to perform a process involving heating, which comprises a lamp for irradiating the substrate with light from above and a substrate. A support width that has an annular support portion that abuts and supports the outer edge portion from below, and an auxiliary ring that spreads outward from the outer edge portion, and the support width and the support at which the outer edge portion of the substrate to be supported overlaps the support portion A value obtained by multiplying the thickness of the part is equal to or less than a value obtained by doubling the thickness of the substrate.

A second aspect of the present invention is the heat treatment apparatus according to the first aspect, wherein the multiplied value is 1.5 mm 2 or less.

The invention according to claim 3 is the heat treatment apparatus according to claim 1 or 2, wherein the support width is 3 mm or less.

A fourth aspect of the present invention is the heat treatment apparatus according to any one of the first to third aspects, wherein the thickness of the supporting portion is 0.5 mm or less.

A fifth aspect of the present invention is the heat treatment apparatus according to any one of the first to fourth aspects, wherein the auxiliary ring is made of silicon carbide.

The invention according to claim 6 is the heat treatment apparatus according to any one of claims 1 to 5, wherein the auxiliary ring has a cylindrical surface facing the outer peripheral surface of the substrate.

[0015]

3 and 4 are vertical cross-sectional views showing the structure of a heat treatment apparatus 1 according to an embodiment of the present invention. The cross section in FIG. 3 and the cross section in FIG. The heat treatment apparatus 1 intersects vertically with the central axis 1a facing the Z direction. In FIGS. 3 and 4, the illustration of parallel diagonal lines with respect to the detailed cross section is omitted.

The heat treatment apparatus 1 has a main body 1 which is the main body of the apparatus.
1, a lid portion 12 that covers the upper portion of the main body portion 11, and a reflection plate 13 that is disposed on the central bottom surface of the main body portion 11, and these forms an internal space. The inner space is vertically divided by a chamber window 21 made of quartz, and the substrate 9 is supported by a support ring group 30 described later in the lower processing space 10. The chamber window 21 and the body 11 are sealed by an O-ring (not shown),
The inner surface of is a cylindrical surface.

A plurality of gas inlets 1 are provided on the side wall of the main body 11.
11 and the exhaust port 112 are formed, the exhaust port 11
The gas in the processing space 10 is (forced) exhausted from 2,
The gas in the processing space 10 is replaced by introducing a gas (for example, nitrogen, oxygen) according to the type of processing performed on the substrate 9 through the gas introduction port 111. A quartz shower plate 22 having a large number of holes is provided between the substrate 9 and the chamber window 21.
The gas introduced from 11 is uniformly applied to the upper surface of the substrate 9 via the shower plate 22. The gas used for the treatment is guided to the exhaust port 112 from below the treatment space 10.

As shown in FIGS. 3 and 4, the support ring group 30 has a cylindrical cylindrical member 33 centered on the central axis 1a.
And the coupling member 331 is attached to the lower end of the cylindrical member 33. A coupling member 332 facing the coupling member 331 is provided below the outside of the main body 11, and the coupling member 331 and the coupling member 332 constitute a magnetic coupling mechanism. The coupling member 332 rotates about the central shaft 1a by the motor 333 shown in FIG. As a result, the coupling member 331 inside the main body 11 rotates by a magnetic action, and the substrate 9 and the support ring group 30 rotate about the central axis 1a.

The lower surface of the lid portion 12 is a reflecting surface (hereinafter referred to as "reflector") 121 which faces the upper surface of the substrate 9, and along the reflector 121, each faces in the X direction in FIG. A rod-shaped upper stage lamp group 41 is arranged. The light emitted upward from the light from the upper lamp group 41 is reflected by the reflector 121 and is irradiated on the substrate 9.

Below the upper lamp group 41 (that is, between the upper lamp group 41 and the substrate 9), rod-shaped lower lamp groups 42 are arranged so as to face the Y direction. That is, the upper lamp group 41 and the lower lamp group 42 are attached to the lid 12 so as to be orthogonal to each other.

Upper lamp group 41 and lower lamp group 42
Are divided into small groups according to the distance from the central axis 1a. In FIG. 4, the lamps of the upper lamp group 41 divided into groups are denoted by reference numeral 411 from the central axis 1a side.
412, 413, and 414 are attached, and in FIG. 3, the lamps of the lower lamp group 42 divided into groups are attached with reference numerals 421, 422, 423, and 424 from the central axis 1a side.

FIG. 5 is a block diagram showing a connection relationship between lamps divided into small groups and a lamp control unit 6 for supplying electric power to the lamps (even a plurality of lamps are shown by one block. .). As shown in FIG. 5, each group (lamps 411 to 414 of the upper lamp group 41, and lamps 421 to 424 of the lower lamp group 42) is individually connected to the lamp control unit 6 and supplied with power independently of each other. To be done. As a result, the intensity distribution of the light with which the upper surface of the substrate 9 is irradiated is controlled.

FIG. 6 is a view showing the inside from the cylindrical member 33 when viewed from the position of the arrow AA in FIG. 4, and FIG. 7 is an enlarged view showing a state in which the substrate 9 is supported by the support ring group 30. FIG.

As shown in FIGS. 6 and 7, the support ring group 30 is composed of an annular auxiliary ring 31 on which the substrate 9 is placed and an annular buffer ring 32 which supports the auxiliary ring 31 from the outside. . The auxiliary ring 31 and the buffer ring 32 are both made of silicon carbide (Si) having a specific heat close to that of the substrate 9.
C). The auxiliary ring 31 has an annular support portion 311 protruding on the inner peripheral surface 310 toward the central axis 1a,
The substrate 9 transported into the processing space 10 by the external transport mechanism is supported by the support portion 311 coming into contact with the outer edge portion 91 of the substrate 9 from below. Substrate 9 is auxiliary ring 3
In the state of being mounted on the substrate 1, the outer peripheral surface 90 of the substrate 9 and the inner peripheral surface 310 of the auxiliary ring 31 face each other, and the auxiliary ring 31 is positioned so as to spread outward from the outer edge portion 91 of the substrate 9. In the following description, as shown in FIG. 7, the thickness of the substrate 9 is called the substrate thickness Tw, the thickness of the supporting portion 311 is called the supporting portion thickness T, and the width at which the substrate 9 and the supporting portion 311 overlap is called the supporting width W. .

The auxiliary ring 31 is supported from the outside by a concentric annular buffer ring 32, and the buffer ring 32 is supported by the aforementioned cylindrical member 33. Then, as shown in FIG. 7, the engaging portion 391 of the auxiliary ring 31 and the buffer ring 32 and the engaging portion 392 of the buffer ring 32 and the cylindrical member 33 each have a gap (play), so that by heating. Even if the auxiliary ring 31 and the buffer ring 32 expand, cracks due to excessive stress are prevented.

As shown in FIGS. 4 and 6, a plurality of radiation thermometers 51 to 53 are attached below the substrate 9 from the central axis 1a toward the outside. Radiation thermometer 51-53
Measures the temperature of the substrate 9 by receiving infrared light from the substrate 9 through the window member 50 provided on the reflection plate 13. Since the substrate 9 placed on the support ring group 30 rotates, the temperature of the substrate 9 corresponding to the distance from the central axis 1a is measured by the plurality of radiation thermometers 51 to 53. that time,
Infrared rays from the lamp groups 41 and 42 are radiated by the substrate 9, the support ring group 30, and the cylindrical member 33.
Is prevented, and the radiation thermometers 51 to 53 accurately measure the temperature.

When the substrate 9 is heated, for example, the power supply to the lamps 411 and 421 is controlled according to the measurement result of the radiation thermometer 51. Similarly, the radiation thermometers 52 and 53 are controlled. Lamps 412 and 4 according to the measurement results of
22, the power supply to the lamps 413 and 423 is controlled respectively. Further, the lamps 414 and 424, which mainly irradiate infrared rays toward the auxiliary ring 31, are supplied with electric power according to a predetermined profile. At this time, the substrate 9 and the support ring group 30 are rotated by the rotating mechanism including the motor 333 and the coupling mechanism, and the heating of the substrate 9 is controlled so that the temperature of the substrate 9 becomes as uniform as possible.

FIG. 8 shows the case where the support portion thickness T and the support width W shown in FIG. 7 are changed as shown in FIG. It is a figure which shows the relationship between the film thickness difference D with the side (refer FIG. 2), and the product (TxW) of the support part thickness T and the support width W.

[0029]

[Table 1]

In the measurement, a substrate having a diameter of 200 mm and a substrate thickness Tw of 0.725 mm is rapidly heated to a target temperature of 1100 ° C. at about 100 ° C./s, and then the target temperature is maintained for 60 seconds. Further, in order to obtain the film thickness difference D, the film thickness is measured at a position 2 mm inward from the outer edge of the substrate (corresponding to the position of the distance R2 in FIG. 2) and a position 10 mm (corresponding to the position of the distance R1). There is. It should be noted that 10
It has been confirmed that the film thickness is substantially constant inside the position of mm, and the average film thickness is about 11 nm.

It can be seen from FIG. 8 that there is a proportional relationship indicated by the straight line Z between the film thickness difference D and (T × W).
Here, when the variation in the allowable film thickness is ± 1%, the allowable film thickness difference D is about 0.22 nm (average film thickness 11 nm
2%). Therefore, by the straight line Z (T × W)
It can be said that the variation of the film thickness can be set to ± 1% or less when is less than about 1.5 mm ² . Here, considering that the smaller the substrate thickness Tw is, the variation of the film thickness is influenced by the support portion thickness T and the support width W, and that the substrate 9 having the substrate thickness Tw of 0.725 mm is used in the measurement, If (T × W) is equal to or less than about twice the substrate thickness Tw, it is estimated that the variation in the film thickness can be set within ± 1% of the average film thickness. That is, ((T × W)
By satisfying the relation shown in ≦ (Tw × 2)),
It is realized that the temperature uniformity of the substrate 9 is improved.

When the RTP is actually performed by the heat treatment apparatus 1, the temperature raising step (time t1 to t2) in FIG.
In the above, in the portion where the substrate 9 and the auxiliary ring 31 overlap (that is, the outer peripheral portion of the substrate), the heat capacity per unit area is larger than that in the central portion of the substrate, and therefore the temperature rise is delayed. Therefore, in order to sufficiently heat the auxiliary ring 31, the power supplied to the lamps 414 and 424 is set higher than that of the other lamps.

However, in such a setting, the temperature of the auxiliary ring 31 becomes higher than the temperature of the substrate 9 in the holding step (time t2 to t3), the heat is transmitted from the auxiliary ring 31, and the substrate outer edge portion 91 is located at another portion. Will be hotter than In the heat treatment apparatus 1, by limiting the shape of the portion where the substrate 9 and the auxiliary ring 31 overlap (the shape indicated by the support portion thickness T and the support width W) by the substrate thickness Tw, the outer edge portion of the substrate and the substrate center in the holding step. It is possible to suppress the temperature difference from the side area. That is, the auxiliary ring 3
By limiting the heat transfer path from 1 to the substrate 9, the temperature uniformity of the substrate is improved.

From FIG. 8, it can be said that (T × W) is preferably 1.5 mm ² or less when forming a normal film thickness (about 10 nm), and this condition is shown in Table 1. Considering that it is derived from the measurement range, the thickness T of the supporting part is
Is preferably 0.5 mm or less and the support width W is preferably 3 mm or less. Further, from the viewpoint that a reliable measurement result is obtained, (T × W) is more preferably 1.2 mm ² or less, and the support portion thickness T is more preferably 0.4 mm or less. Can be said.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments and various modifications can be made.

In the above embodiment, the formation of the oxide film on the substrate 9 has been described as an example, but a process involving heating other than the formation of the oxide film may be performed by the heat treatment apparatus 1. Also,
The size and thickness of the substrate 9 may be various.

The support ring group 30 does not necessarily have to be the auxiliary ring 3.
1 and the buffer ring 32 do not have to be configured, and the buffer ring 32 may be omitted and only the auxiliary ring 31 may be provided.

Further, the shape of the auxiliary ring 31 is not limited to the above-mentioned embodiment, and for example, a simple plate-shaped circular ring without the inner peripheral surface 310 (that is, the support portion thickness is the auxiliary ring 3).
The thickness may be 1), and an annular protrusion having a surface facing the outer peripheral surface of the substrate 9 may be provided on the upper surface of a simple plate-shaped annular ring.

Although the substrate 9 rotates in the heat treatment apparatus 1, the rotation of the substrate 9 may be performed only when necessary.

The lamps for irradiating the substrate 9 do not necessarily have to be provided so that the upper lamp group 41 and the lower lamp group 42 are orthogonal to each other, and either the upper lamp group 41 or the lower lamp group 42 may be used. Further, lamp light may be emitted from the upper surface and the lower surface of the substrate 9.

[0041]

According to the present invention, in a heat treatment apparatus using a lamp, it is possible to improve the temperature uniformity of the substrate to be heated.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between substrate temperature and time.

FIG. 2 is a diagram showing the relationship between the distance from the center of the substrate and the film thickness of an oxide film.

FIG. 3 is a vertical sectional view of a heat treatment apparatus.

FIG. 4 is a vertical sectional view of a heat treatment apparatus.

FIG. 5 is a block diagram showing a lamp and a lamp control unit.

FIG. 6 is a plan view showing the inside of the cylindrical member.

FIG. 7 is an enlarged cross-sectional view showing how the substrate is supported by the support ring group.

FIG. 8 is a diagram showing a relationship between a film thickness difference D and (T × W).

[Explanation of symbols]

1 Heat treatment equipment 9 substrates 31 Auxiliary ring 90 outer peripheral surface 91 outer edge 310 inner surface 311 Support 411-414, 421-424 lamps T support thickness Tw substrate thickness W support width

Continued front page    (72) Inventor Yoshihiro Koyama             4 Horikawa-dori Teranouchi, Kamigyo-ku, Kyoto City, Kyoto Prefecture             No. 1 at Tenjin Kitamachi             Manufacturing Co., Ltd. (72) Inventor Mitsukazu Takahashi             4 Horikawa-dori Teranouchi, Kamigyo-ku, Kyoto City, Kyoto Prefecture             No. 1 at Tenjin Kitamachi             Manufacturing Co., Ltd. F term (reference) 5F045 AA20 AD15 DP02 DQ10 EM06

Claims (6)

[Claims] 1. A heat treatment apparatus for irradiating a substrate with light to perform a process involving heating, comprising: a lamp for irradiating the substrate with light from above; and an annular ring for supporting and supporting an outer edge portion of the substrate from below. An auxiliary ring having a support portion and extending outward from the outer edge portion, wherein a value obtained by multiplying a thickness of the support portion by a support width at which the outer edge portion of the substrate to be supported overlaps the support portion is Is less than or equal to twice the thickness of the heat treatment apparatus. 2. The heat treatment apparatus according to claim 1, wherein the multiplied value is 1.5 mm 2 or less. 3. The heat treatment apparatus according to claim 1, wherein the support width is 3 mm or less. 4. The heat treatment apparatus according to claim 1, wherein the supporting portion has a thickness of 0.5 mm or less. 5. The heat treatment apparatus according to claim 1, wherein the auxiliary ring is made of silicon carbide. 6. The heat treatment apparatus according to claim 1, wherein the auxiliary ring has a cylindrical surface facing the outer peripheral surface of the substrate.