KR200153296Y1 - Wafer boat - Google Patents

Abstract

The present invention discloses a boat for loading a wafer into a process tube to form a deposited film on the wafer surface.

Bow according to the present invention consists of a circular upper ring and lower ring located up and down, the upper and lower rings are integrated with each other by two or more coupling bars, the bottom surface of the upper ring and the upper surface of the lower ring a plurality of grooves Each was formed so that the outer portion of the wafer was accommodated in each of the grooves to be supported by the upper ring and the lower ring.

Description

Wafer Loading Boat

1 is a front sectional view of a process tube for general chemical vapor deposition.

2 is a detailed view of part B of FIG. 1;

3 is a front view of the present invention.

4 is a cross-sectional view taken along the line C-C of FIG.

Figure 5 is a front sectional view of a process tube showing a state loaded with the subject innovation.

* Explanation of symbols for main parts of the drawings

11: casing 12 and 30: boat

19: wafer 31 and 32: upper ring and lower ring

34: home

The present invention relates to a wafer support boat, and more particularly, to a wafer loading boat configured to uniformly supply a process gas to each wafer by loading the wafer vertically inside the process tube.

In the manufacturing process of a semiconductor device, for example, a chemical vapor deposition process in which a nitride film or a polysilicon film is deposited on a wafer surface, a plurality of wafers are loaded on a boat and then deposited. By spraying and supplying a gas, a film having a predetermined thickness is deposited on the wafer surface. Referring to the configuration of the process tube for chemical vapor deposition is carried out through the first and second as follows.

FIG. 1 is a cross sectional front view of a general chemical vapor deposition process tube in which a plurality of wafers 19 are loaded in a casing 11 constituting the process tube 10. The gas supply line 13 for supplying the deposition gas supplied from the outside into the casing 11 is located at one side of the boat 12, and the upper end of the casing 11 is connected to a vacuum pump at the lower end of the casing 11. From bottom to bottom. The heating means 16 is provided outside the casing 11 so that the inside of the casing 11 can maintain a temperature suitable for the process.

FIG. 2 is a detailed view of the portion B of FIG. 1 showing a plurality of slots 12A and a plurality of wafers 19 inserted in the slots 12A on both inner walls of the boat 12. FIG. The plurality of slots 12A are configured to be stacked vertically, so that each wafer 19 fitted in the corresponding slot 12A on both inner walls is also kept horizontal.

The functions of the process tube as described above will be briefly described with reference to FIGS. 1 and 2, and the vacuum pressure generated in the vacuum pump is first supplied to the casing 11 through the exhaust line 15 before the deposition process is performed. After the inside of the casing 11 to create a vacuum atmosphere, as shown in FIG. 1, the deposition gas is supplied into the casing 11 through the nozzle 14 mounted on the upper end of the gas supply line 13. The injected deposition gas flows from the top to the bottom of the boat 12 loaded with the wafer 19, and the flowing deposition gas flows on each wafer 19 through the side opening (not shown) of the boat 12. Is supplied. The deposition gas is activated by the heat provided by the heating means 16 and deposited on the surface of each wafer 19. Deposition gas not deposited on the surface of each wafer 19 flows to the lower end of the casing 11 and is exhausted to the outside through the exhaust line 15. The exhaust line 15 is supplied with a vacuum pressure to discharge the deposition gas and at the same time enable continuous downward flow of the deposition gas.

However, the following problems occur in the deposition process using the process tube as described above.

I. As can be seen from FIGS. 1 and 2, the flow of the deposition gas (vertical) is made in a direction opposite to the loading direction (horizontal) of the wafer 19, so that gas is supplied to each wafer 19 surface. This will not be smooth. That is, the deposition gas is supplied to the upper end of the inner space of the casing 11 and the vacuum pressure generated from the vacuum pump is supplied through the exhaust line 15 at the lower end of the inner space of the casing 11 so that the deposition path of the deposition gas flows (line). A) is represented by a substantially vertical line, and as a result, the deposition gas flowing vertically to the horizontally mounted wafer 19 surface cannot be sufficiently supplied.

II. In addition, since a plurality of wafers 19 are loaded with a narrow gap up and down, the flow of the deposition gas introduced through the narrow gap is converted into vortices to effectively deposit on the surface of the wafer 19. I can't.

III. In particular, when the diameter of the wafer 19 is relatively large, the deposition gas introduced into the space between the wafer and the wafer cannot be sufficiently introduced into the center of the wafer, so that the thicknesses of the deposition film formed on the edge and the center of the same wafer surface are different from each other. It acts as a factor that lowers uniformity.

IV. In addition to these problems, since the deposition gas is introduced into the space between the wafer and the wafer as described above, the front and rear surfaces of the wafer are exposed to the deposition gas together, and eventually, the gas is also deposited on the back side of the wafer. The deposited film formed on the back surface of the wafer not only acts as a cause of particle generation in the later process but also becomes a factor of defocus during the exposure process.

V. The deposition gas flows from the upper portion to the lower portion of the inner space of the casing 11 so that an amount of deposition gas corresponding to the surface of the wafer loaded under the boat 12 is provided to the wafer loaded thereon. The thickness of the deposited film is different depending on the loading position (difference in vertical height) of the wafer because it is relatively smaller than the amount of gas.

The present invention is to solve the above-mentioned problems caused by the bow loaded in the process tube while supporting the wafer to form a deposition film on the wafer surface, supplying the deposition gas in the state in which the wafer is loaded vertically It is an object of the present invention to provide a wafer loading boat capable of uniformly supplying deposition gas to each wafer surface to obtain a deposition film of uniform thickness.

The present invention for realizing the above object consists of a circular upper ring and a lower ring positioned up and down, the upper and lower rings are integrated with each other by two or more coupling bars, the upper surface of the lower surface and the lower ring of the upper ring A plurality of grooves, each of which can accommodate a circumferential surface of the wafer, is formed so that the wafer can be supported by the upper ring and the lower ring by the respective grooves.

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

5 is a front sectional view of a process tube loaded with the present invention, and the overall configuration of the process tube loaded with the present invention is similar to that of the general chemical vapor deposition process tube shown in FIG. That is, in the casing 11, a plurality of boats 30 on which a plurality of wafers 19 are loaded are positioned, and one side of the boat 30 is configured to supply the deposition gas supplied from the outside into the casing 11. The gas supply line 23 is located. In addition, the lower end of the casing 11 is connected to the vacuum pump exhaust line 15 for discharging the residual gas in the casing 11 to the outside is located. Meanwhile, the upper portion of the gas supply line 23 described above is bent toward the upper center portion of the boat 30, so that the deposition gas injection nozzle 24 mounted on the upper portion of the gas supply line 23 is the upper end of the boat 30. Corresponds to. The heating means 16 is installed outside the casing 11 so that the inside of the casing 11 is always maintained at a constant temperature.

The biggest feature of the present invention is that a plurality of wafers 19 are loaded on each boat 30 in a vertical state rather than horizontally, and the boat 30 is configured differently to mount the wafer 19 vertically. It is a feature of. Referring to the configuration of the boat 30 according to the present invention in more detail as follows.

FIG. 3 is a front view of the present invention, and FIG. 4 is a cross-sectional view taken along the line CC of FIG. 3, showing the configuration of the boat 30 on which the wafer 19 is loaded, and FIG. Although the boat 30 is positioned inside the casing 11 in a stacked state, only one boat is illustrated in FIGS. 3 and 4 by way of example.

The bolt 30 is composed of a circular upper and lower ring 31 and the lower ring 32, the upper and lower rings 31 and 32 are integrated with each other by two or more vertical coupling bar (33). . A plurality of grooves 34 are formed on the bottom of the upper ring 31 and the upper surface of the lower ring 32 to accommodate a part of the circumferential surface of the wafer 19, so that the wafer 19 is formed with these grooves ( 34 is supported by the upper ring 31 and the lower ring (32). At this time, in order to support the plurality of wafers 19 to the upper ring 31 and the lower ring 32 without interfering with each other, the configuration direction (lengthwise direction) of each groove 34 is determined by each ring 31 and 32. It is preferable to face the center, so that a plurality of wafers 19 are loaded onto the boat 30 in a radial manner as shown in FIG.

On the other hand, as shown in FIG. 4, each groove 34 is configured to have a width that can accommodate the thickness of two wafers 19. Therefore, each groove 34 of the upper and lower rings 31 and 32 is formed. Two wafers 19 are supported by 34. Here, the two wafers 19 supported by one groove 34 have grooves 34 in a state where each back side faces each other, that is, the front surface of the wafer to be formed with the film is exposed to the outside. It is desirable to be supported by.

Referring to the functions of the present invention configured as described above with reference to the drawings, a plurality of wafers 19 are loaded on the boat 30 consisting of the upper ring 31 and the lower ring 32 as shown in FIG. In the state of making a plurality of bolts 30 are placed in the casing 11 in a stacked form. Thereafter, the heating means 16 installed on the outer side of the casing 11 is operated to raise the inside of the casing 11 to a constant temperature, and also inside the casing 11 through the exhaust line 15 located at the bottom of the casing 11. The vacuum pressure is supplied to make the casing 11 inside into a vacuum atmosphere. Thereafter, the deposition gas supply apparatus is operated to supply the deposition gas into the casing 11. Here, the upper portion of the gas supply line 23 is configured to face the upper center portion of the boat 30, so that the deposition gas injected through the injection nozzle 24 installed at the end of the gas supply line 23 moves to the upper portion of the boat 30. Supplied. The upper portion of the boat 30 flows downward in the vertical direction by the vacuum pressure. Therefore, the deposition gas flows horizontally with respect to the surface of all the wafers 19 loaded perpendicular to each boat 30, so that the entire surface of the wafer 19 is in uniform contact with the gas, and consequently the surface of the wafer 19 The thickness of the film deposited on can be kept uniform. In particular, unlike the state of FIG. 1 in which a plurality of wafers 19 are stacked in a horizontal state with a narrow gap, each wafer whose front surface is completely exposed to the outside is supported on the boat in a vertical state. Of course, the effect can be maximized. As the deposition gas is supplied to the surface of each wafer as described above, the deposition gas is active molecules by heat provided by the heating means 16 to form a deposition film on the surface of the wafer 19, and the deposition remaining around each wafer 19. The gas is absorbed by the exhaust line 15 located at the bottom of the casing 11 and discharged to the outside of the casing 11.

The effects obtained in the process of forming the deposition film on the wafer surface by using the present invention as described above are as follows.

I. As shown in FIG. 3 and FIG. 4, the two wafers 19 are supported in a state where the back surface is in close contact with each groove 34 of each boat 30, so that the back surface of each wafer 19 It is not exposed to the deposition gas to be injected, and eventually the deposition film cannot be formed on the back surface of the wafer 19.

II. In addition, the deposition gas is supplied through the gas supply line 23 positioned at the upper portion of the boat 30 so that the flow of gas is almost vertical in the downward direction from the upper portion of the boat 30, and thus a uniform amount is applied to all wafer surfaces. The deposition gas may be supplied to maintain a uniform thickness of the deposited film.

III. Since each wafer 19 is independently supported by the upper ring 31 and the lower ring 32, it maintains a sufficient distance from another adjacent wafer, so that the deposition gas is not influenced by the wafers. It can be supplied sufficiently to the entire surface of the wafer. This feature is more effective for wafers with relatively large diameters. That is, even in a wafer having a large area, the thickness of the deposited film formed on the edge and the center surface thereof becomes uniform, thereby improving the uniformity of the deposited film.

Claims (4)

In the casing, the deposition gas is connected to the gas supply line and the vacuum pump, which is installed on the exhaust line for discharging residual gas in the casing to the outside, and the inside of the process tube having heating means for maintaining the casing at a constant temperature at all times. A boat for loading a wafer in a supported state, comprising a circular upper ring and a lower ring positioned up and down, wherein the upper and lower rings are integrated with each other by two or more coupling bars, and the bottom and the bottom of the upper ring A plurality of grooves are formed on the upper surface of the ring, so that the outer periphery of the wafer is accommodated in the respective grooves, characterized in that configured to be supported in the upper ring and the lower ring. The boat of claim 1, wherein a plurality of wafers are radially supported such that a configuration direction (length direction) of each groove formed in the upper ring and the lower ring is directed toward the center of each ring. The boat of claim 1, wherein each of the grooves has a width capable of accommodating two wafers, and each groove of the upper and lower rings is supported with each rear surface of the wafer facing each other. The boat of claim 1, wherein two or more boats are loaded in a casing of the tube in a stacked form and the gas exposed portion of the deposition gas supply line is located at the center of the upper end of the boat.