JPS6181648A - Quartz glass jig for conveying wafer boat - Google Patents

Abstract

PURPOSE:To prevent a wafer boat from being bent or curved, by composing the wafer boat of quartz glass which contains 5,000 or more approximately spherical air bubbles having a diameter of 10-50mum per 1cm<3>, and has an OH radical content of 150ppm or less. CONSTITUTION:A generally tubular conveying jig body 1 is provided at the tip thereof with a notch which is curved and straight in the vertical section, for forming wafer boat holding portion 2. The wafer boat holding portion is formed of translucent quartz glass having an OH radical content of 150ppm or less and containing 5,000 or more approximately spherical air bubbles having a diameter of 10-50mum, per 1cm<3>. A semiconductor wafer is placed on the wafer boat 2 to be conveyed and put in or taken out of a furnace core tube.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in a soft landing type quartz glass wafer boat transport jig used for loading and unloading a wafer boat containing semiconductor wafers into and out of a furnace core tube.

[Technical background of the invention and its problems] When a wafer boat with semiconductor wafers placed thereon is taken in and out of the furnace core tube, a notch is provided at one end of a tubular or rod-shaped heat-resistant material to form a wafer boat holding part. A wafer boat transport jig is used. Conventionally, this type of wafer boat transport jig has mainly been made of quartz glass from the viewpoint of purity.

However, when using a transport jig made of quartz glass, when one end of the wafer boat holder is inserted into a high-temperature furnace and the other end is fixedly supported at room temperature, if a temperature gradient occurs within the transport jig, this temperature The gradient generates thermal stress within the conveying jig, which acts as residual stress and reduces the mechanical strength of the material. For this reason, conventional wafer boat transport jigs made of quartz glass have the drawback of being broken or bent. This folding or bending is particularly likely to occur in areas where the bending moment is large.

In order to eliminate these drawbacks, it is conceivable to make the entire quartz glass wafer boat transport jig thicker, but if this is done, thermal deformation is likely to occur due to the own weight of the transport jig.

[Object of the Invention] The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a quartz glass glass/port feed jig with high mechanical strength.

[Summary of the invention]

The great invention of the quartz glass wafer boat transport jig is such that at least the quartz glass constituting the wafer port holding part has a diameter of 1
5000 approximately spherical bubbles of 0 to 50 pm per cm
PpII, and the OH group content is l 50 PpII.
It is characterized by the following.

According to such a wafer boat transfer jig made of quartz glass, the quartz glass constituting the wafer boat holding section contains appropriate air bubbles, making it lightweight.

The wafer boat holding portion can be made thicker, and its mechanical strength is increased. In addition, it has O and H groups at a moderate content rate, and 1
Since the molecular structure of quartz glass is stable and the bubbles are almost spherical, there is almost no variation in viscosity depending on direction at high temperatures, thermal deformation due to its own weight is reduced, and the strength is relatively high.

Furthermore, due to the presence of air bubbles, infrared rays and the like are scattered and refracted without being directly transmitted, so WI thermal properties are improved.

Temperature control inside the furnace core tube becomes easier.

In the present invention, at least the quartz glass constituting the wafer boat holder has a shape of one bubble.

The number and content of OH groups were defined as above because
This is due to the following reasons. That is, the diameter of the bubble is 10
If it is less than gm, the effect of weight reduction will be small; on the other hand, if it is less than 50p
When m is raised, the strength decreases. Furthermore, if the shape of the bubble deviates significantly from a spherical shape, the viscosity will vary depending on the direction. Also.

If the number of bubbles is less than 5000 per cm', the weight reduction effect will be small, and furthermore, the content of OH groups will be 150p.
When p■ is exceeded, the molecular structure of quartz glass becomes unstable and the strength decreases.

[Embodiments of the invention] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a partially cross-sectional side view showing the vicinity of the wafer boat holding part of the quartz glass wafer boat transfer jig according to the present invention;
FIG. 2 is a plan view.

In Fig. 1 and Fig. i42, the transfer jig main body l has a tubular shape as a whole, and the wafer boat holding part 2 is formed by providing a notch with a vertical cross-sectional shape of an arc and a straight line at the tip thereof. There is. This wafer boat holding part 2 has a diameter of lO~5
It is made of translucent quartz glass containing 500 () or more approximately spherical bubbles of 0 am per cm' and an OH group content of 150 ppm or less.

The base end of the conveying jig main body l of the quartz glass wafer port conveying jig is the same as that of the conventional one.

It is fixed at a predetermined position on a transport device (not shown).

Also, the wafer boat holding part? A semiconductor wafer boat is placed on top of the wafer and transported, and the wafer is taken in and out of the furnace core tube.

However, according to the quartz glass wafer port transfer coin, the wafer boat holder 2 does not bend or bend even when the wafer boat holder 2 is inserted into and taken out from the furnace core tube compared to the conventional one. The deflection of the tip can be reduced.

In addition, as shown in Fig. 3, the deflection due to its own weight when a glass sample 4 with a length of 70 mm from the 41251 fixed support end to the tip was supported on the support member 3 and heated at 1350°C for 1 hour with a force α. The amount was measured for 3@ quartz glass by changing the wall thickness of the sample.

The results are shown in Figure 4.
) is elongated in the pipe manufacturing direction, and the short axis is 10 to 504
Opaque quartz glass containing at least 500 m bubbles per lea' and an OH group content of approximately 120 pp■, in the same figure.
(Comparative Example 2) is a transparent quartz glass that contains almost no bubbles and has an OH group content of about 200 ppm or less.
5,000 or more per ', and the OH group content is about 1
The results are shown for 10 ppm translucent quartz glass.

As is clear from FIG. 4, the shape of the bubbles contained in the quartz glass of Comparative Example 1 deviates greatly from the spherical shape.
In addition, the silica glass of Comparative Example 2 has a large amount of deflection, as it contains almost no air bubbles and the content of OH groups exceeds 150 pp. The deflection strength is smaller than that of the comparative example.

In addition, in the quartz glass wafer boat transfer jig of the present invention, the bending moment is greatest near the boundary A between the circular arc and the straight line of the notch where the vertical cross-sectional shape of the wafer holding part is circular and straight; Therefore, as shown in Figure 5 and iSS diagram, the area near A is made thicker.
The wall may become thinner toward the tip.

Further, the main body of the conveyance jig is not limited to the tubular shape as in the above embodiment, but may be rod-shaped.

Furthermore, the main body of the transport jig may also be made of the same material as the wafer holder.

[Effects of the Invention] As detailed above, according to the quartz glass wafer boat transfer jig of the present invention, bending and bending of the wafer boat holder can be eliminated, and the deflection of the tip of the wafer boat holder can be reduced. This has remarkable effects, such as the ability to

[Brief explanation of drawings]

FIG. 1 is a side view partially showing the vicinity of the wafer boat holding part of the quartz glass port transfer jig in the present invention, FIG. 2 is a top view of the same transfer jig, and FIG. 3 is a deflection view. An explanatory diagram showing a method of testing quantity. FIG. 4 is a diagram showing the relationship between sample wall thickness and deflection amount for the quartz glasses of Examples and Comparative Examples 1.2, and FIG. 5 is a diagram showing the relationship between the sample wall thickness and the amount of deflection for the quartz glasses of Example and Comparative Example 1.2, and FIG. 5 is the quartz glass wafer boat transportation in another example of the present invention. FIG. 6 is a side view partially showing the vicinity of the wafer boat holding part of the jig in cross section, and FIG. 6 is a plan view of the same transfer jig. l... Transfer jig main body, 2... Wafer boat holding section. 3... Support member 24... Quartz glass sample. Applicant's representative Patent attorney Takehiko Suzue Procedural amendments Showa J30/1/31 Director General of the Patent Office Michibe Uga 1, Indication of case Patent application No. 181886/1986 2, Title of invention: Quartz glass wafer boat Transportation jig 3, relationship with the person making the amendment Patent applicant Toshiba Ceramics Co., Ltd. 4, attorney 6, drawings subject to amendment 7, content of amendment

Claims (1)

[Claims] In a quartz glass wafer boat transfer jig in which one end is fixed and the other end forms a wafer boat holder for holding a wafer boat on which a semiconductor wafer is mounted, the quartz glass constituting the wafer boat holder has a diameter of at least 10 mm. ~
A wafer boat transport jig made of quartz glass, characterized in that it contains 5000 or more approximately spherical bubbles of 50 μm per cm^3, and has an OH group content of 150 ppm or less.