JPH0289721A - Substrate conveyor device - Google Patents

Abstract

PURPOSE:To heighten carrier capacity by disposing double-lined plural gas exhaust nozzles with a line space appropriately narrower than the diameter or the width of the substrate to be conveyed, resulting in neither heightening the pressure of the gas jetted from the respective gas exhaust nozzles nor increasing the supply quantity of gas uselessly. CONSTITUTION:Semiconductor substrates are floatingly conveyed by double-lined gas exhaust nozzles 2a, 2b. In this case, the double-lined gas exhaust nozzles 2a, 2b are disposed such as to incline outward as their disposition goes down to the lower side. Accordingly, air current is generated to align to draw the substrate to the center part. As the other air current to agitate this air current is not generated, strong aligning force can be obtained.

Description

[Detailed description of the invention] The present invention will be described in the following order.

A. Industrial field of application B1 Overview of the invention C1 Prior art 1 Problem to be solved by the invention E1 Means for solving the problem F9 Effect G. Examples [Figures 1 to 5] H00 Invention Effects (A, Industrial Application Field) The present invention provides a substrate transport device, particularly a transport plate, in which a plurality of gas ejection holes are arranged along the transport direction and are arranged on a transport plate so as to be closer to the transport direction from top to bottom. The present invention relates to a substrate transfer device that ejects gas diagonally downward from a gas ejection hole.

(B. Summary of the Invention) The present invention is intended to increase the conveyance capacity and strengthen the centering force without increasing the pressure of the gas ejected from each gas ejection hole, in the substrate transfer apparatus described in -A.

There are two rows of a plurality of gas jet holes arranged along the transport direction on the transport plate, and the gas jet holes in each row are also inclined so as to move outward from the top to the bottom.

(C, Prior Art) There are substrate transport devices that transport wafer-shaped semiconductor substrates in a non-contact manner by utilizing the Bernoulli effect of airflow, and are disclosed in Japanese Patent Laid-Open No. 57-37847 and Japanese Patent Publication No. 61-77.
It is introduced in Publication No. 39, etc. A substrate transfer device that utilizes the Bernoulli effect has a plurality of gas ejection holes arranged on a transfer plate that are inclined from top to bottom in the transfer direction, and each gas ejector is arranged on the top surface of the transfer plate. A chamber is provided for sending pressurized gas to the nozzle, and by supplying pressurized gas to the chamber through the gas inlet, the pressurized gas is jetted diagonally downward from each gas nozzle, creating negative pressure under the conveyor plate. By using the fluid layer as a cushion, a wafer-shaped semiconductor substrate is levitated and moved in the transport direction.

The conveying device introduced in Japanese Patent Application Laid-Open No. 57-37847 had one row of gas jet holes.

On the other hand, in the conveying device introduced in Japanese Patent Publication No. 61-7739, there are three rows of gas nozzles, and each gas nozzle in the center row is arranged in three rows from top to bottom. It is tilted in the direction of conveyance.
This inclination allows the semiconductor substrate to be transported while floating. The gas ejection holes in the rows on both sides are inclined outward from the top to the bottom, and this inclination allows the semiconductor substrate to be centered in the center.

(D. Problems to be Solved by the Invention) By the way, the substrate transfer device described in Japanese Unexamined Patent Publication No. 57-37847 has the following problems. Semiconductor substrates tend to have larger diameters, and the weight of one semiconductor substrate tends to increase. Therefore, when a semiconductor substrate is transported by a substrate transport device, it is necessary to strengthen the negative pressure effect in response to an increase in the diameter of the semiconductor substrate. A possible way to enhance the negative pressure effect is to increase the flow rate of gas ejected from the gas ejection holes to increase the pressure. However, increasing the pressure of the gas ejected from each gas ejection hole increases the force with which dust mixed in the gas hits the semiconductor substrate, resulting in the problem that the surface of the semiconductor substrate is more likely to be contaminated. Furthermore, increasing the gas supply flow rate increases the amount of contamination, and in order to increase the gas supply amount without increasing the amount of contamination, it is necessary to strengthen the filter effect on the gas and increase the cleanliness of the gas. However, increasing the cleanliness of the gas is accompanied by a significant increase in the cost of filter equipment, which poses the problem of being undesirable or undesirable.

Further, the substrate conveyance device introduced in Japanese Patent Publication No. 61-7739 has a problem in that alignment becomes unstable. This is because the two outer rows of gas nozzles create an airflow that aligns the semiconductor substrate to the center (center between the two rows of gas nozzles), but the airflow is caused by the middle row of gas nozzles. This is because the semiconductor substrate is disturbed, and as a result, the semiconductor substrate is likely to be horizontally dug when being transported. This is undesirable because it prevents the semiconductor substrate from being accurately transferred to a target position, for example, into a cassette. Therefore, it is necessary to provide a side wall on the side edge of the F screen of the transport plate to prevent the semiconductor substrate from deviating from the transport course. However, in this case, there is an undesirable problem that the semiconductor substrate collides with the side wall and generates dust, and there is also the problem that the shape of the transfer plate becomes complicated.

The present invention was made to solve these problems, and aims to increase the conveying capacity without increasing the pressure of the gas ejected from each gas ejection hole, and to strengthen the centering force. .

(E. Means for Solving the Problems) In order to solve the above-mentioned problems, the substrate transport apparatus of the present invention has two rows of gas ejection holes arranged along the transport direction on the transport plate.
They are arranged in rows, and each gas ejection hole in each row is inclined not only toward the front but also toward the outside as you go down from -F.

(F. Effect) According to the substrate transfer device of the present invention, since the semiconductor substrate is transported floating through two rows of gas injection holes, the number of gas injection holes can be doubled even if the arrangement pitch of the gas injection holes is the same. I can,
Even if the pressure of the gas ejected from each gas ejection hole is the same as that of the conventional method, it is possible to transport a semiconductor substrate that weighs about twice as much. That is, the conveying capacity (allowable weight of the substrate to be conveyed) can be increased without increasing the pressure of the gas ejected from each gas ejection hole or unnecessarily increasing the amount of gas supplied.

Since the two rows of gas ejection holes are both inclined outward as they go downwards, an airflow is created that aligns the substrate closer to the center, and other sources that disturb this airflow are created. Since no airflow is generated, strong centering force can be obtained.

(G. Embodiment) [FIGS. 1 to 5] The substrate transfer apparatus of the present invention will be described in detail below according to the illustrated embodiment.

The drawings show one embodiment of the substrate transfer device of the present invention, and Fig. 1 is a perspective view, and Fig. 2 is a plan view of the transfer plate (however, the figure is cut at a point slightly higher than the surface of the transfer plate). Figure 3 is a sectional view taken along line 3-3 of Figure 2, Figure 4 is a cross-sectional view of Figure 2.
In the sectional view taken along the line 4-4 in the figure, No. 513 is a sectional view for explaining the floating of the substrate.

In the drawings, reference numeral 1 denotes a conveying plate made of glass, for example, and gas ejection holes 2a, 2a, -2b, 2b.

...and 2c, 2c are formed. Gas outlet 2
a, 2a, . . . are arranged in a row along the substrate transport direction, and gas jet holes 2b, 2b, . . . are arranged in a row along the substrate transport direction. parallel to 1
arranged in columns.

The gas ejection holes 2a, 2a, . ing. On the other hand, the gas jet holes 2b, 2
b, . . . are gas ejection holes forming a row on the left side when the conveyance plate 1 is viewed along the conveyance direction, and are each inclined so as to go obliquely to the left front as going from top to bottom.

The gas ejection holes 2C12C are the gas ejection holes 2a, 2 of the conveyor plate 1.
The gas ejection holes are formed in the middle between the rows of gas ejection holes 2b, b, ... and the rows of gas ejection holes 2b, b, ..., and are slanted toward the front as you go from top to bottom. It plays the role of locally attracting the substrate and promoting smooth floating of the semiconductor substrate. The function of this gas ejection hole 2C12C will be explained in detail later with reference to FIG.

3f and 3r are partition walls with an arcuate cross-section that are fixed to the upper surface of the conveyor plate l, and are made of glass like the conveyor plate.
It forms a gas circulation space on top that is closed off from the outside, and the planar shape is U-shaped to create a U-shaped gas circulation space. In the gas circulation space formed by the partition wall 3f, the right row of gas jet holes 2a, 2a,
. . , the front gas ejection holes 20, and the front portions of the left row of gas ejection holes 2b, 2b, . . . communicate with each other. In addition, in the gas circulation space formed by the partition wall 3, the right row of gas jet holes 2a, 2a, .
. . , the rear gas jet holes 2c, and the left row of gas jet holes 2b, 2b, . . . are in communication. One gas supply port 4f, 4r is formed in each of the partition walls 3f, 3f, and gas supply vibrators 5f, 5r are connected to the gas supply ports 4f, 4r,
The gas supplied to the gas supply ports 4f, 4r through the vibrators 5f, 5r passes through the gas circulation spaces in the partition walls 3f, 3r to the respective gas jet holes 2a, 2a, . . . , 2b, 2b, .
, 2C12C to the lower side of the conveyor plate 1.

According to such a substrate transfer device, the gas jet holes 2a, 2a, -, 2b, 2b, .
-2b, 2b, . . . by blowing out gas, for example, air or nitrogen gas, the gas layer is floated on the lower surface of the conveying plate 1 as a cushion, and the conveying plate 1 can be conveyed forward while being aligned. This is because first of all, each of the gas ejection holes 2a, 2a, . . . and 2b, 2b, . It is ejected diagonally downward and forward. Therefore, due to the Bernoulli effect, the semiconductor substrate is made to float directly below the transfer plate 1 and receives a negative pressure that pushes it forward. And each gas ejection hole 2a, 2a, -12b,
2b, . . . also have an inclination toward the outside as they go from top to bottom, so that the center of the semiconductor substrate is located between the rows of gas injection holes 2a, 2a, . 2
It also receives negative pressure located in the center with the columns b,...,
Centering is achieved by the negative pressure. Moreover, the special public service 1986-7
As in the substrate transfer device introduced in Publication No. 739, the airflow that generates negative pressure for aligning the semiconductor substrate generated by the gas jetting holes in the rows on both sides is caused by the airflow generated by the gas jetting holes in the middle row. Disturbance cannot occur in this substrate transfer device. Therefore, the conductor substrate is conveyed under the alignment force of the airflow, and there is no risk of lateral deflection. Therefore, there is no need to provide side walls on both sides of the lower surface of the carrier plate to prevent the semiconductor substrate from swinging laterally, so the structure of the carrier plate is simple, and there is no possibility that dust will be generated due to collision between the semiconductor substrate and the side walls. Nothing can happen.

Furthermore, the present substrate transfer device reduces the gas pressure required to transfer a semiconductor substrate of the same weight compared to the substrate transfer device introduced in Japanese Patent Application Laid-Open No. 57-37847 that has only one row of gas ejection holes. Can be done. This is because the present substrate transfer apparatus has two rows of gas ejection holes, so if the arrangement pitch of the gas ejection holes is the same, the number of gas ejection holes that contribute to the transportation of the semiconductor substrate can be doubled. Therefore, the pressure of the gas ejected from the five external gas ejection holes can be reduced to about one-half. And this brings about two important advantages. First, the pressure of the gas blown onto the surface of the semiconductor substrate being transported is weakened, making the semiconductor substrate less susceptible to damage. Also, the degree of contamination by trash is reduced. This is of great significance. This is because the substrate transport device is ideal for taking out the semiconductor substrate from the susceptor of the vapor phase growth system and transporting it to the cassette. Since this directly leads to deterioration of the characteristics of the semiconductor element and the occurrence of defects, it is very desirable that the degree of contamination by dust is low.

Secondly, there is an advantage that the amount of gas supplied is small and the ability of the filter to remove dust from the supplied gas is also small. This leads to a reduction in equipment costs.

In this embodiment, there are two partition walls (3f and 3r), but this is done so that semiconductor substrates arranged on two concentric circles of one susceptor can be transported. In other words, when two semiconductor substrates are spaced apart in the transport direction under the transport plate, only the semiconductor substrate on the side closer to the target position is transported first, and then the other semiconductor substrate is transported. It is possible to transport by this substrate transport device. Specifically, first, gas is supplied into the gas circulation space within the partition wall 3f through the gas supply port 4f, but no gas is supplied to the gas supply port 4r. Therefore, since a negative pressure for floating and transporting the semiconductor substrate is not generated in the lower part of the partition wall 3r, only the semiconductor substrate near the target position below the partition wall 3f is transported. Next, when gas is also supplied to the gas supply port 4r, the semiconductor substrate located below the partition wall 3r and far from the target position is transported.

FIG. 5 is a cross-sectional view for explaining that the substrate can be easily floated by the gas jet holes 2c, 2c. When there are no gas ejection holes 2c, 2c, the semiconductor substrate 8 placed on the four parts 7 of the susceptor 6 has several gas ejection holes 2a, 2a, . . . A substantially uniform negative pressure is applied to the entire area by the gas ejection holes 2b, 2b, . . . . A considerably large negative pressure is required to start floating the semiconductor substrate 8 substantially uniformly over the entire semiconductor substrate 8. However, if there is a gas nozzle 2c, the part immediately below the gas nozzle 2c will receive stronger negative pressure than the other parts, and a moment will work around the part opposite to that part, as shown by the solid line in FIG. Rotate to. If the semiconductor substrate 8 rises even slightly from the surface of the recess 7 of the susceptor 6, air rapidly enters the back surface of the semiconductor substrate 8 from there, causing the semiconductor substrate 8 to float. Therefore,
The semiconductor substrate 8 is smoothly floated and transported.

(Effects of the H2 invention) As described above, the substrate transfer apparatus of the present invention arranges two rows of gas jet holes along the transfer direction so that the row spacing is appropriately smaller than the diameter or width of the substrate to be transferred. It is characterized in that the gas ejection holes in each row are inclined not only toward the surface side but also toward the outside as they go from top to bottom.

Therefore, according to the substrate transfer apparatus of the present invention, since the semiconductor substrate is transported floating through two rows of gas injection holes, the number of gas injection holes can be doubled even if the arrangement pitch of the gas injection holes is the same, and each Even if the pressure of the gas ejected from the gas ejection holes is the same as that of the conventional method, it is possible to transport a semiconductor substrate that weighs about twice as much. That is, it is possible to increase the conveying capacity (allowable weight of substrates to be transported by ffi) without increasing the pressure of the gas jetted from each gas jetting hole or unnecessarily increasing the amount of gas supplied.

Since the two rows of gas ejection holes are both inclined so that they approach not only the surface side but also the outside as they go downwards, an airflow is generated that aligns the substrate closer to the center.
Since no other airflow is generated to disturb this airflow, a strong centering force can be obtained.

[Brief explanation of the drawing]

1 to 5 are for explaining one embodiment of the substrate transfer device of the present invention, FIG. 1 is a perspective view of the substrate transfer device, and FIG. 2 is a perspective view of the substrate transfer device, which is slightly smaller than the transfer plate. Fig. 3 is a sectional view taken along the line 3-3 in Fig. 2, Fig. 4 is a sectional view taken along the line 4-4 in Fig. 2, and Fig. 5 is a plan view taken at a high point. It is a sectional view for explanation. Explanation of symbols 1...Transportation plate, 2a, 2b...Gas ejection holes, 8...Substrate. applicant

Claims (1)

[Claims] (1) A plurality of gas ejection holes are arranged along the transfer direction so that the gas ejection holes are inclined toward the transfer direction side as you go from top to bottom, so that gas is ejected downward from each gas ejection hole. In a substrate transfer device, two rows of gas ejection holes along the transfer direction are arranged approximately parallel to each other with an interval appropriately smaller than the diameter or width of the substrate to be transferred, and the gas ejection holes of each row are arranged from top to bottom. A substrate transfer device characterized in that the device is inclined so that it approaches the outside as it goes to the top.