JPH04304652A - Boat for heat treating device - Google Patents

Abstract

PURPOSE:To facilitate maintenance upon occurrence of a dislocation of a thermal stress at the time of treating a large-diameter wafer at a high temperature, damage or deformation of a wafer holder and to further prevent a local application of a load to the vicinity of the holder by employing a member in contact with the wafer, having the same physical properties as those of the wafer. CONSTITUTION:A boat body in which a top plate 1 and a bottom plate 2 made of quartz or SiC are integrated by connecting round rods 3a, 3b, 3c of the same material by welding, of a boat used for a vertical bottom-open type heat treating device, is obtained, groove rods 4a, 4b, 4c, 4d having grooves 5a formed at a predetermined interval in a longitudinal direction and the same physical properties as those of a wafer are detachably mounted between the plates 1 and 2, and the wafer is supported to the grooves 5a of the rods 4a-4d.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for holding a wafer, and more particularly to a technique effective for use in a heat treatment apparatus for oxidation, diffusion, etc. employed in the manufacture of semiconductor devices.

0002

[Prior Art] When performing oxidation, diffusion, etc., it is necessary to hold a large number of wafers at the same time without covering the processing surface of the wafers and install them in a heat treatment chamber using a quartz reaction tube or the like. A jig called a boat is used.

[0003] As a specific example, for example, Japanese Patent Application Laid-Open No. 1983-
No. 65369 discloses a structure in which four pillars are arranged around the periphery, and the upper and lower ends are fixed by a top plate and a bottom plate made of the same material as the pillars. Proposed.

[0004] Also, in Japanese Patent Application Laid-open No. 56-53266,
A configuration has been proposed in which a pillar, a top plate, and a bottom plate are individually made using a silicon material, and then assembled together.

[0005] The vertical diffusion device can be roughly divided into two types: the top-open type with the boat insertion port on the top and the bottom-open type with the boat insertion port on the bottom.The top-open type allows the boat to be suspended. Insert it into the device with the bottom-opening type by pushing up the boat placed on the cap from below.

[0006]

[Problems to be Solved by the Invention] However, the above-mentioned Japanese Patent Application Laid-Open No. 58-65369 and Japanese Patent Application Laid-Open No. 56-53266
The present inventor found that the prior art described in the publication has the following problems.

[0007] That is, when a large diameter (for example, 6 to 8 inch) wafer is placed in a high temperature atmosphere of 1000°C or higher,
Temperature distribution (=temperature difference) occurs within the wafer surface, which leads to the generation of thermal stress dislocations, which causes crystal defects in the wafer and I
The inventor of the present invention has discovered that there is a problem in that the electrical characteristics of C products are adversely affected.

[0008]Furthermore, in the structure described in Japanese Patent Application Laid-open No. 58-65369, since it is an integral structure, maintenance becomes difficult if deformation or damage occurs.

[0009] Also, since a large diameter wafer set on a boat has a part of its periphery held in a dotted manner by a columnar body, the wafer's own weight is applied to several parts of its periphery, causing local loads to be applied. This will deform the wafer.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a technique that can prevent the occurrence of thermal stress dislocation during high-temperature processing of large-diameter wafers.

Another object of the present invention is to provide a technique that allows easy maintenance in the event of damage or deformation of the wafer holder.

Still another object of the present invention is to provide a technique that can prevent a load from being locally applied to the vicinity of a wafer holding section.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[0014]

[Means for Solving the Problems] Among the inventions disclosed in this application, a brief overview of typical inventions is as follows.

[0015] That is, the boat is used in a vertical and downwardly open type heat treatment apparatus, and the boat body has a top plate and a bottom plate connected and integrated by a plurality of connecting members, and each of which is made of the same material. and a wafer holding member which has a groove for supporting the wafer, is detachably attached between the top plate and the lower plate, and has physical characteristics equal to those of the wafer.

[0016]

[Operation] According to the above-mentioned means, the top plate, the bottom plate, and the connecting member are integrated by welding or the like to form a main body, which is detachably attached to the main body, and whose physical characteristics are the same as those of a wafer. The wafer is supported only by the wafer holding member. Therefore, the occurrence of thermal stress dislocations in the wafer can be reduced.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a perspective view showing an embodiment of a boat for heat treatment equipment according to the present invention. Moreover, FIG. 2 is a sectional view showing the mounting state of the grooved rod.

A disk-shaped top plate 1 and a bottom plate 2 having a slightly larger diameter than the wafer to be processed are formed using quartz or SiC, and both are made of three cylindrical round rods 3 made of quartz or SiC.
They are fixed by a, 3b, and 3c (connecting members) as shown in FIG. Top plate 1, bottom plate 2 and round bars 3a, 3b, 3
c is integrally fixed by welding. Round bar 3a,
Each of 3b and 3c is erected at the same radial position with respect to the center of the lower plate 2, and a space corresponding to the width of the wafer is secured in one direction so that there is no problem in loading and unloading the wafer from the horizontal direction. has been done.

Further, four groove rods 4a, 4b, 4c, and 4d (wafer holding members) are loosely fitted into the top plate 1 and the bottom plate 2 in an upright position at positions corresponding to the outer shape of the wafer. This groove rod 4
A, 4b, 4c, and 4d are also provided with a wafer loading/unloading space corresponding to the wafer loading/unloading space secured in the round bars 3a, 3b, and 3c.

FIG. 3 is a perspective view showing the detailed structure of the groove rods 4a, 4b, 4c, and 4d.

Groove bars 4a, 4b, 4c, and 4d each have grooves 5a having a width slightly wider than the thickness of the wafer at regular intervals in the length direction of the portion facing the center of the top plate 1 and bottom plate 2. It is provided perpendicular to the circumferential direction. These groove rods 4a, 4b
, 4c, and 4d, as shown in FIG. 4, are provided with a plate-shaped projection 5b at the bottom to prevent the groove 5a from rotating from the front. and groove rods 4a, 4b, 4
A counterbore hole 6 is provided in the upper surface of the lower plate 2, and a through hole 7 is provided in the top plate 1 to hold the parts 4c and 4d. The lower ends of the grooved rods 4a, 4b, 4c, and 4d are inserted into the counterbore holes 6, and the upper ends are inserted into the through holes 7.

The groove bars 4a, 4b, 4c, and 4d are made of polysilicon, which has approximately the same physical characteristics as the wafer. When polysilicon, quartz, and SiC are compared with silicon, which is the material of the wafer, they have the following characteristics.

[0023]

[Table 1]

As described above, since polysilicon has almost the same physical properties as the wafer material, there is no difference in heat conduction and heat capacity, which was a problem in the past, and the temperature distribution of the wafer during high-temperature processing becomes uniform. However, polysilicon has drawbacks such as not being able to be welded and having lower strength than quartz. Therefore, in the present invention, in addition to the grooved bars 4a, 4b, 4c, and 4d, round bars 3a, 3b, which can be welded and have sufficient strength, are provided.
, 3c are provided to integrally fix the top plate 1 and the bottom plate 2 to obtain the necessary strength.

When assembling the above embodiment, first, groove rods 4a, 4b, 4c, and 4d are attached one by one to the top plate 1 and bottom plate 2, which are integrated by round rods 3a, 3b, and 3c. . If you install the groove rod 4a first,
First, the upper part (the side where the protrusion 5b is not provided) is deeply inserted into the through hole 7, and then the groove rod 4a is made vertical on the lower plate 2, and the groove 5a is directed toward the center. Further, in this state, the groove rod 4a is lowered and the protrusion 5b is inserted into the through hole 7 of the top plate 1. Similarly, groove rods 4b, 4
If c and 4d are attached in sequence, the state shown in Fig. 1 will be obtained.

When mounting a wafer, the peripheral edge is inserted into each of the grooves 5a of the groove rods 4a, 4b, 4c, and 4d located at the same height. By inserting each wafer into a different groove 5a, a large number of wafers can be stacked and set on the boat.

According to this embodiment, since the wafer and the polysilicon groove rods 4a, 4b, 4c, and 4d have the same heat transfer coefficient and heat capacity, the temperature distribution of the wafer is uniform over the entire surface, and the heat is Since stress can be reduced, crystal defects will not occur. In addition, in this embodiment, the groove rod 4a is provided in the boat body.
, 4b, 4c, and 4d are assembled, so
Even if damage or deformation occurs, parts can be easily replaced or repaired.

FIG. 5 is a plan view showing another embodiment of the boat for heat treatment equipment according to the present invention, and FIG. 6 is a front view of FIG. FIG. 6 shows a state in which wafers are mounted on a boat.

In this embodiment, the groove rods 4a and 4b of the previous embodiment are used.
, 4c, and 4d to hold the wafer at several points around its periphery.In contrast, the wafer 12 is placed on a polysilicon disc-shaped holding member 8 having a diameter larger than that of the wafer. It has characteristics. In this embodiment, instead of the round bars 3a, 3b, 3c of the previous embodiment, these round bars 3a, 3
a grooved wafer holding column 9a made of quartz or SiC, which has the functions of the grooved rods 4a, 4b, 4c, and 4d;
A top plate 10 and a lower plate 11 are installed above and below the wafer holding columns 9a, 9b, 9c, and 9d using the wafer holding columns 9b, 9c, and 9d (connecting members).
(both made of quartz or SiC) are fixed by welding. Groove rods 4 are provided in the wafer holding columns 9a, 9b, 9c, and 9d.
Similarly to a, 4b, 4c, and 4d, grooves are provided at regular intervals in the length direction, and each of the holding members 8 is locked into the grooves as shown in FIG.

As shown in FIG. 8, the holding member 8 has an opening 13 formed from the center toward the periphery. This opening 13 is provided so that the wafer 12 can be placed on or taken out from the holding member 8 using an automatic machine. Wafer holding columns 9a and 9b are located in a range of 90 degrees left and right with respect to the center in the direction in which the opening 13 is provided.
, 9c, 9d are not provided, and the wafer holding columns 9a, 9b, 9c are not provided.
, 9d and the wafer 12 can be freely taken in and taken out.

In this embodiment, as shown in FIG. 7, the boat body has wafer holding columns 9a, 9 made of quartz (or SiC).
b, 9c, and 9d, the top plate 10 and the bottom plate 11 are made of the same material.
It can be manufactured by integrally fixing them using welding. Wafer holding column 9 of the boat body completed in this way
The boat is completed by inserting one holding member 8 into each of the grooves a, 9b, 9c, and 9d. In such a boat, the wafers 12 are placed on the upper surface of each of the holding members 8. The boat installed in the diffusion device in this state is processed in a high temperature atmosphere, but the wafer 12 and the holding member 8
Since the physical properties of the wafers 12 and 12 are the same, no temperature difference occurs in the wafer 12. Therefore, similar to the embodiments described above, no crystal defects occur in the wafer. In addition, the wafer 12
Since the entire surface is supported by the holding member 8, local application of load can be prevented, and crystal defects can also be prevented from occurring.

[0032] Above, the invention made by the present inventor has been specifically explained based on examples, but the present invention is not limited to the above-mentioned examples, and can be modified in various ways without departing from the gist thereof. Needless to say.

For example, in the above embodiment, the top plate and the bottom plate are disk-shaped, but they may also be square, hexagonal, or the like. Similarly, although the round bars 3a to 3c, the groove bars 4a to 4d, and the wafer holding columns 9a to 9d are shaped like round bars, they are not limited thereto and may be shaped like a square column.

Further, although the grooved rods 4a to 4d are shown as round rods, they may be formed by providing grooves on long plates. moreover,
Although the grooves are provided only in part of the groove rods 4a to 4d and the wafer holding columns 9a to 9d, they may be made to circulate in a ring shape. If this is done, there is no need to consider directionality, so there is no need to provide the protrusion 5b.

[0035]

[Effects of the Invention] Among the inventions disclosed in this application, the effects obtained by the typical inventions are briefly explained as follows.
It is as follows.

That is, the boat is a boat used in a vertical and downwardly open type heat treatment apparatus, and the boat body has a top plate and a bottom plate connected and integrated by a plurality of connecting members, and each of which is made of the same material. and a wafer holding member which has a groove for supporting the wafer, is detachably attached between the top plate and the bottom plate, and has the same physical properties as the wafer, so that the thermal conductivity can be improved. In addition to reducing thermal stress dislocations that occur in wafers due to differences, it also reduces deformation and damage, and makes it easy to replace parts.
Its maintenance is also extremely easy.

[0037] Further, the boat is used in a vertical and downwardly open type heat treatment apparatus, and has a top plate and a bottom plate made of the same material, and is processed using the same material, and has a top plate and a bottom plate made of the same material. A plurality of connecting members connecting the plates and having grooves continuously formed in the longitudinal direction thereof, and a disk-shaped holding member supported by the grooves of the wafer holding part and on which the wafer is placed are provided. As a result, the wafer can be supported over the entire surface, and local loads can be prevented from being applied to the wafer, thereby making it possible to prevent the occurrence of crystal defects.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of a boat for a heat treatment apparatus according to the present invention.

FIG. 2 is a sectional view showing a mounting state of the grooved bar according to the present invention.

FIG. 3 is a perspective view showing the detailed configuration of the groove rod.

FIG. 4 is a sectional view showing how the groove rod is attached.

FIG. 5 is a plan view showing another embodiment of the boat for heat treatment equipment according to the present invention.

FIG. 6 is a front view of the embodiment of FIG. 5;

7 is a perspective view showing details of the boat body in FIG. 6. FIG.

8 is a perspective view showing details of the holding member shown in FIG. 6. FIG.

[Explanation of symbols]

1 Top plate 2 Lower plate 3a, 3b, 3c Round bar (connecting member) 4a, 4b, 4
c, 4d Groove rod (wafer holding member) 5a Groove 5b Protrusion 6 Counterbore hole 7 Through hole 8 Holding member 9a, 9b, 9c, 9d Wafer holding column (connecting member)
10 Top plate 11 Lower plate 12 Wafer 13 Opening

Claims (4)

[Claims] Claim 1: A boat used in a vertical, downward-opening heat treatment apparatus, in which a top plate and a bottom plate are connected and integrated by a plurality of connecting members, and each boat is made of the same material. A heat treatment method comprising: a main body; and a wafer holding member having a groove for supporting a wafer, detachably attached between the top plate and the bottom plate, and having physical properties equal to those of the wafer. equipment boat. 2. The boat for a heat treatment apparatus according to claim 1, wherein the material of the wafer holder is polysilicon. 3. A boat used in a vertical, downward-opening heat treatment apparatus, comprising a top plate and a bottom plate made of the same material, and a boat processed using the same material, the bottom plate and the top plate made of the same material. It includes a plurality of connecting members that connect the plates and have grooves continuously formed in the longitudinal direction thereof, and a disk-shaped holding member that is supported by the grooves of the wafer holding part and on which the wafer is placed. A boat for heat treatment equipment, characterized by: 4. The boat for a heat treatment apparatus according to claim 3, wherein the material of the holding member is polysilicon.