KR20200071276A - Wafer carrier for large wafer - Google Patents

Abstract

According to one embodiment, provided is a wafer carrier for supporting a wafer in a chemical vapor deposition device, wherein the wafer carrier includes: a carrier lower surface; a carrier upper surface; a plurality of pockets surrounded by the carrier upper surface; and a spindle receiving groove surrounded by the carrier lower surface. The plurality of pockets include at least two pockets capable of receiving the wafer having 12 inches or more. The plurality of pockets are spaced apart from the spindle receiving groove to be arranged to have a rotational symmetrical structure around the spindle receiving groove.

Description

Wafer carrier for large diameter wafers{WAFER CARRIER FOR LARGE WAFER}

The present invention relates to a wafer carrier of a chemical vapor deposition apparatus, and more particularly, to a wafer carrier for a large diameter wafer having a pocket for receiving the wafer on the upper surface.

Generally, a gallium nitride based semiconductor layer is grown on a growth substrate using chemical vapor deposition equipment. A wafer such as a sapphire substrate is placed on a wafer carrier and mounted in a chamber capable of high temperature heating, and source gases are introduced into the chamber at a temperature of 500 to 1200° C., and gallium nitride-based epi layers are grown on the substrate. The wafer carrier also has a pocket for receiving the substrate. Typically, a wafer carrier has a plurality of pockets, so that multiple wafers can be placed on a wafer carrier to simultaneously grow the same epitaxial layer on multiple wafers through a single deposition process.

In order to grow a uniform epitaxial layer on multiple wafers, it is important to maintain uniform conditions at all points of the multiple wafers on the wafer carrier. Variations in the composition of the reaction gas and the temperature of the wafer surface lead to non-uniform growth of the epi layer, consequently degrading the uniformity of the semiconductor device.

For example, when a gallium indium nitride layer is deposited, fluctuations in the surface temperature on the wafer or concentration of the reaction gas result in fluctuations in the composition and bandgap of the deposited layer. Since indium has a high vapor pressure, it will have a wider bandgap, resulting in a lower indium composition ratio in areas of the wafer with higher surface temperatures. When a light emitting diode is formed using a deposited epi layer, light emitting diodes manufactured from regions having different band gaps will emit light of different wavelengths.

The wafer carrier is supported on a spindle in the reaction chamber such that the pockets receiving the substrate are directed upwards toward the gas distribution element, and while the spindle is rotating, gas is directed downwards onto the top surface of the wafer carrier and arriving at the top surface of the wafer carrier. Gas flows to the outside of the wafer carrier. The gas used is vacuum evacuated through an exhaust port distributed near the periphery of the chamber.

On the other hand, the heating element of the wafer carrier is disposed under the wafer carrier to mainly heat the wafer carrier by thermal radiation, and heats the wafers disposed thereon through the wafer carrier. Generally, an electrical resistive heating element is used and is placed over a large area of the wafer carrier to uniformly heat the wafer carrier. However, since the heating element cannot be arranged near the spindle receiving groove for receiving the spindle, the center of the carrier will usually be cooler than the other parts.

On the other hand, the process temperature in the reaction chamber is configured to measure the temperature of the carrier during the processing process, and if the temperature difference according to the position of the carrier occurs by measuring the process temperature during the processing process in the reaction chamber, heating elements are selectively Control. In order to compensate for local temperature changes, the heating elements of the wafer carrier are provided divided into a plurality of parts so as to be operable independently of each other.

The process temperature in the reaction chamber can be measured using a contactless pyrometer configured to measure the temperature of the carrier.

1 shows a schematic cross-sectional view of a reaction chamber for measuring the temperature of a carrier using a non-contact pyrometer.

The carrier 10 is supported on the spindle 30, and a heating element 20 is located under the carrier 10. A plurality of pyrometers P1, P2, and P3 are disposed on the carrier 10, respectively. The pyrometers P1, P2, P3 can be disposed on top of a gas distribution element (not shown) and can measure the temperature on the carrier 10 through a plurality of observation ports. In order to keep the temperature of the carrier 10 uniform using the temperature measured by the pyrometers P1, P2, P3, the pyrometers P1, P2, P3 are relatively wide on the carrier 10. They are arranged spaced apart from one another to cover the area. For example, the pyrometer P1 may be disposed on a position spaced apart by a distance D1 from the center of the carrier 10 that the spindle 30 contacts, and the pyrometer P2 may be a distance D2. ). Also, the pyrometer P3 may be disposed on a position spaced apart by the distance D1.

Since the carrier 10 is rotated by the spindle 30 during the process, the pyrometers P1, P2, P3 annularly measure the carrier 10 temperature on the carrier 10. However, since the wafers placed on the carrier 10 have a different temperature from the surface of the carrier 10, the temperature measured by the pyrometers P1, P2, P3 is limited to the area between the wafers. Accordingly, when the area between the wafers is narrow, temperature measurement by a pyrometer is difficult or impossible.

The problem to be solved by the present invention is to provide a wafer carrier capable of uniformly controlling the temperature of a large-diameter wafer of 12 inches or more in a chemical vapor deposition apparatus.

Another problem to be solved by the present invention is to provide a wafer carrier for a large-diameter wafer having a plurality of pockets on the upper surface and capable of temperature measurement by a pyrometer.

A wafer carrier according to an embodiment of the present invention is for supporting a wafer in a chemical vapor deposition apparatus, the carrier lower surface; Carrier top surface; A plurality of pockets surrounded by the upper surface of the carrier; And a spindle accommodating groove surrounded by a lower surface of the carrier, wherein the plurality of pockets include at least two pockets capable of accommodating a wafer of 12 inches or more, and the plurality of pockets are spaced apart from the spindle accommodating groove. It is arranged to have a rotationally symmetrical structure around the receiving groove.

According to embodiments of the present invention, it is possible to prevent the pocket from being disposed on the spindle receiving groove, so that the temperature of the wafer placed in the pockets can be uniformly controlled.

Furthermore, certain embodiments of the present invention provide a wafer carrier capable of measuring the temperature of the carrier by a pyrometer.

1 shows a schematic cross-sectional view of a reaction chamber for measuring the temperature of a carrier using a non-contact pyrometer.
2 is a schematic plan view for explaining a wafer carrier according to an embodiment of the present invention.
3 shows a schematic cross-sectional view of FIG. 1.
4 is a schematic plan view for explaining a wafer carrier according to another embodiment of the present invention.
5 is a schematic plan view for explaining a wafer carrier according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments introduced below are provided as examples in order to sufficiently convey the spirit of the present invention to those skilled in the art. Therefore, the present invention is not limited to the embodiments described below and may be embodied in other forms. In addition, in the drawings, the width, length, and thickness of components may be exaggerated for convenience. Throughout the specification, the same reference numbers refer to the same components.

According to one embodiment of the present invention, a wafer carrier for supporting a wafer in a chemical vapor deposition apparatus is provided. The wafer carrier includes: a carrier lower surface; Carrier top surface; A plurality of pockets surrounded by the upper surface of the carrier; And a spindle accommodating groove surrounded by a lower surface of the carrier, wherein the plurality of pockets include at least two pockets capable of accommodating a wafer of 12 inches or more, and the plurality of pockets are spaced apart from the spindle accommodating groove. It is arranged to have a rotationally symmetrical structure around the receiving groove.

Since the plurality of pockets are separated from the spindle receiving groove, wafers can be uniformly heated by a heating element.

The plurality of pockets may include only two pockets that can accommodate the wafer of 12 inches or more, and at least two pockets that can accommodate wafers of less than 12 inches disposed between the two pockets. By including only two pockets that can accommodate a wafer of 12 inches or more, a sufficient gap between the pockets and the pockets can be secured, thereby increasing the reliability of temperature measurement by a pyrometer.

On the other hand, by arranging small-sized pockets in the area between the two large pockets, it is possible to secure sufficient spacing between pockets for temperature measurement by a pyrometer and to increase productivity.

The wafer less than 12 inches may be a 2 inch, 4 inch, 6 inch or 8 inch wafer.

In certain embodiments, at least two pockets capable of accommodating the 12-inch or larger wafer hold the 12-inch wafer.

In addition, in one embodiment, the wafer carrier may have a diameter of approximately 700mm.

Meanwhile, the pocket may be circular, but is not limited thereto, and may have a fan shape or a polygonal shape.

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

2 is a plan view illustrating a wafer carrier 100 according to an embodiment of the present invention, and FIG. 3 is a schematic cross-sectional view of FIG. 2.

2 and 3, the wafer carrier 100 includes a carrier lower surface 10l, a carrier upper surface 10u, a pocket 17 surrounded by the upper surface 10u of the carrier, and a lower surface 10l of the carrier ) Is provided with a spindle receiving groove 19 surrounded by. The pocket 17 includes a bottom surface 13 and a wafer (not shown) is placed in the pocket 17. A rim (not shown) is formed at the end of the bottom surface, and the wafer may be placed on the rim and spaced apart from the bottom surface 13. The upper surface of the rim is located below the upper surface 10u of the carrier 100, so the lower surface of the wafer is located inside the pocket 17.

Each wafer can be a sapphire substrate, a silicon carbide substrate, a silicon substrate, a GaN substrate, an AlN substrate, an AlGaN substrate or other crystalline substrate. In addition, the carrier 100 may be a susceptor for epi layer growth for manufacturing a light emitting diode, or a solar epi layer or a susceptor for supporting a wafer for growing a compound semiconductor for HEMT or other uses. .

The carrier 100 may be integrally formed of the same material, for example, formed by processing graphite. In addition, SiC or the like may be coated on the graphite body.

On the other hand, the spindle receiving groove 19 is formed on the lower surface 10l side of the carrier 100. The carrier 100 is disposed on a spindle (30 in FIG. 1) in a chamber, wherein the spindle receiving groove 19 accommodates the spindle. When driving, the spindle is rotated by a rotary driver, and the carrier 100 is rotated by rotation of the spindle.

On the other hand, the carrier 100 has a plurality of pockets 17 on the upper surface. For example, as shown in FIG. 2, the carrier 100 may have three pockets 17. The pockets 17 accommodate large diameter wafers of 12 inches or larger. The pockets 17 are spaced from the spindle receiving groove 19. To this end, the diameter of the carrier 100 is greater than 600 mm, and may be approximately 700 mm.

The pockets 17 are radially arranged at regular intervals around the spindle receiving groove 19 and are arranged to have a rotationally symmetrical structure. The spindle receiving groove 19 is located in the center of the carrier 100, and the pockets 17 have a rotationally symmetrical structure, so that the carrier 100 can be safely rotated by the spindle. The carrier 100 can be rotated generally at 500 to 1500 rpm.

Meanwhile, the carrier 100 is disposed on a heating element, for example, a heater (20 in FIG. 1), and is heated by the heater. Since the spindle 30 extends vertically from the bottom of the carrier 100 toward the carrier 100, the heating element cannot be disposed under the spindle receiving groove 19. That is, there is a limitation that the center of the carrier 100 cannot be directly heated by the heating element. Therefore, when the pockets 17 overlap the spindle receiving groove 19, it is difficult to uniformly heat the wafer in the pocket. In this practical example, as a solution to this problem, the pockets 17 are spaced apart from the spindle receiving groove 19 in the horizontal direction.

According to the present embodiment, three pockets 17 capable of accommodating a 12-inch wafer may be disposed using a carrier 100 having a diameter of approximately 700 mm. If the size of the carrier 100 is increased, it may accommodate a wafer larger than 12 inches.

On the other hand, in this embodiment, the three annular (C1, C2, C3) shows the annular lines on the carrier 100 whose temperature is measured by the pyrometers (P1, P2, P3) of FIG. The temperature is measured annularly by pyrometers P1, P2, P3 disposed on points arranged at intervals of D1, D2, D3 from the center of the carrier 100. However, since the wafers are placed on the pocket 17, the pyrometer measures the temperature of the carrier 100 in the area between the pockets.

If the distance between the pockets 17 is narrow, the pyrometers P1, P2, or P3 cannot properly measure the temperature of the carrier 100, and accordingly, errors in temperature recognition may occur. In particular, since the distance between the pockets 17 on the annular line C3 measured by the pyrometer P3 is narrow, it may be difficult to measure the temperature of the pyrometer P3. In particular, certain chemical vapor deposition equipment is configured to control heating elements at a time when all of the pyrometers P1, P2, and P3 can read the temperature normally, and thus, any one pyrometer If a problem occurs in the temperature measurement, thin film growth itself becomes impossible, and thus it is difficult to grow a high-quality uniform epitaxial layer.

4 is a schematic plan view illustrating a wafer carrier 200 according to an embodiment of the present invention.

4, the wafer carrier 200 according to this embodiment is substantially similar to the wafer carrier 100 described with reference to FIGS. 2 and 3, but only has pockets 17 for accommodating 12 inch wafers. There is a difference in including only two.

The wafer carrier 200 can have a diameter of approximately 700 mm, and the pockets 17 can accommodate a wafer of 12 people, as described above.

The two pockets 17 are spaced apart from the spindle receiving groove 19 around the spindle receiving groove 19 and arranged in a rotationally symmetrical structure.

Since only two pockets 17 are arranged, it is possible to secure a sufficient gap between the pockets 17 on the annular lines C1, C2, C3. In this embodiment, the circumferential length of the annular line C3 whose temperature is measured by the pyrometer P3 is the shortest, but one circumferential length located between the pockets 17 is approximately 1/ 3 or more. Accordingly, the pyrometers P1, P2, and P3 can stably read the temperature of the carrier 100.

5 is a schematic plan view illustrating a wafer carrier 300 according to another embodiment of the present invention.

Referring to FIG. 5, the carrier 300 according to this embodiment is similar to the carrier 200 described with reference to FIG. 4, but has a smaller size between two pockets 17 for accommodating 12 wafers. There is a difference in including the pockets 21 of the.

The pockets 21 are provided to accommodate wafers smaller than 12 inches, for example, 2 inches, 4 inches, 6 inches or 8 inches in size.

The pockets 17 and the pockets 21 are arranged in a rotationally symmetrical structure around the spindle receiving groove 19. For example, the pockets 17 are arranged to face each other around the spindle receiving groove 19, and the pockets 21 are arranged to face each other between the pockets 17. In addition, the pockets 21 may be disposed centrally between the pockets 17, respectively. Therefore, the carrier 200 can be stably rotated by the spindle.

In this embodiment, the annular line C2 of the annular lines C1, C2, C3 whose temperature is measured by the pyrometer P2 has the shortest circumferential length between the pockets 17,21. However, this circumferential length can also provide sufficient spacing for the pyrometer P2 to measure the temperature by placing a small sized pocket 21 between the pockets 17.

On the other hand, in the above-described embodiments, the pockets 17 and 21 are illustrated and described as being circular, but the present invention is not limited thereto, and may be of any shape as long as the wafer (or substrate) can be disposed. For example, the pockets 17 and 21 may have a fan shape or a polygonal shape.

The wafer carriers 100, 200, 300 according to this embodiment can be used to support wafers, particularly in metal organic chemical vapor deposition equipment.

Although various embodiments have been described above, the components described in the specific embodiments may be applied to other embodiments without departing from the scope of the invention.

Claims (6)

In a wafer carrier for supporting a wafer in a chemical vapor deposition apparatus,
Carrier bottom surface;
Carrier top surface;
A plurality of pockets surrounded by the upper surface of the carrier; And
Comprising a spindle receiving groove surrounded by the lower surface of the carrier,
The plurality of pockets includes at least two pockets capable of accommodating a wafer of 12 inches or more,
The plurality of pockets are spaced apart from the spindle receiving groove, the wafer carrier disposed to have a rotationally symmetrical structure around the spindle receiving groove. The method according to claim 1,
The plurality of pockets includes only two pockets capable of accommodating the wafer of 12 inches or more and at least two pockets capable of accommodating wafers of less than 12 inches disposed between the two pockets. The method according to claim 2,
The wafer of less than 12 inches is a 2 inch, 4 inch, 6 inch or 8 inch wafer. The method according to claim 1,
At least two pockets capable of accommodating the 12-inch or larger wafer are wafer carriers that accommodate the 12-inch wafer. The method according to claim 1,
The wafer carrier is a wafer carrier having a diameter of 700mm. The method according to claim 1,
The pocket is a wafer carrier having a circular, flat or polygonal shape.

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