Epitaxial equipment

Abstract

The invention relates to epitaxy equipment, which comprises a processing chamber; the heating device comprises an upper heating device located at the top of the processing chamber and a lower heating device located at the bottom of the processing chamber; a rotating support shaft; the base comprises a lower base body and an upper base body, the lower base body and the upper base body are connected through a connecting piece, the lower base body is located below the upper base body and directly connected with the rotary supporting shaft, the upper base body is used for placing a wafer, and the diameter of the lower base body is larger than that of the upper base body; and the lower base radiates the absorbed heat of the lower heating device to the upper base. According to the epitaxial equipment provided by the invention, the problem of non-uniform wafer heating is solved through the arrangement of the upper base and the lower base.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor equipment, and in particular to an epitaxial equipment. Background Art

[0002] In the field of semiconductor manufacturing, epitaxy equipment is a key device used to grow semiconductor materials. The epitaxy process requires extremely high temperature uniformity to ensure the consistency of deposition quality on the wafer surface. However, existing epitaxy equipment has some limitations, especially in terms of heating uniformity.

[0003] First, the heat radiation from the lower surface of the susceptor is often blocked due to the presence of the rotating support shaft. As a key mechanical component, the design and position of the rotating support shaft will inevitably affect the heat radiation of the lower heating device, resulting in a shadow area on the lower surface of the susceptor, which makes the area heated unevenly. This uneven heating will lead to inconsistent deposition quality on the wafer surface, which in turn affects the reliability of the final product.

[0004] Secondly, in the processing chamber of the existing epitaxial equipment, there is a gap between the preheating ring and the susceptor. These gaps may affect the deposition quality at the edge of the wafer. The edge area of ​​the wafer may be affected by the airflow in the gap, resulting in differences in the growth rate and quality of the edge area and the center area during the deposition process. This difference will cause the defect rate at the edge of the wafer to increase, thereby affecting the yield of the entire wafer. Not only that, the process gas will also flow from the gap to the bottom of the susceptor, forming a deposit on the lower surface of the susceptor. The falling of the deposit will produce particulate matter, affecting the deposition quality of the film.

[0005] In summary, existing epitaxial equipment has obvious technical defects in heating uniformity and deposition quality. These defects limit the efficiency of the epitaxial growth process and the performance of the final product. Therefore, it is necessary to develop a new type of epitaxial equipment to solve the above problems and achieve more uniform heating and higher quality wafer epitaxial layer deposition. Summary of the invention

[0006] The present invention aims to solve the problem of poor quality of wafer epitaxial layer caused by uneven wafer heating.

[0007] The present invention provides an epitaxial device, comprising:

[0008] a processing chamber;

[0009] A heating device, the heating device comprising an upper heating device located at the top of the processing chamber and a lower heating device located at the bottom of the processing chamber;

[0010] Rotating support shaft;

[0011] A base, the base comprising: a lower base and an upper base, the lower base is connected to the upper base through a connecting piece, the lower base is located below the upper base and is directly connected to the rotating support shaft, the upper base is used to place a wafer, and the diameter of the lower base is greater than the diameter of the upper base;

[0012] The lower base radiates the absorbed heat of the lower heating device to the upper base.

[0013] Preferably, a groove is provided on the bottom surface of the lower base, the groove is located at the projection formed by the rotation support shaft on the bottom surface of the lower base, and the groove has the same shape as the projection.

[0014] Preferably, the connecting member is an annular structure, and a plurality of connecting pins are arranged on the top surface of the annular structure; the diameter of the annular structure is greater than the diameter of the wafer;

[0015] The annular structure is fixedly connected to the lower base, and the plurality of connecting pins are connected to the bottom pins of the upper base.

[0016] Preferably, the base is made of graphite.

[0017] Preferably, the upper base is coaxially arranged with the lower base.

[0018] Preferably, the processing chamber comprises: an air inlet, an exhaust port and a preheating ring arranged around the susceptor, the air inlet is used to introduce process gas, and the exhaust port is used to discharge the process gas after process treatment from the processing chamber;

[0019] The bottom surface of the preheating ring is higher than the top surface of the lower base, and the preheating ring extends radially to the inner side of the lower base, a transverse gap is formed between the bottom surface of the preheating ring and the top surface of the lower base, a protrusion structure is arranged in the gap, and the protrusion structure is arranged on the top surface of the lower base.

[0020] Preferably, a protrusion is provided on the bottom surface of the preheating ring, and the protrusion extends around the lower edge of the bottom surface of the preheating ring.

[0021] Preferably, the cross section of the protrusion is a right-angled trapezoid, and the upper side of the right-angled trapezoid is parallel to the top surface of the lower base.

[0022] Preferably, the protruding structure is a plurality of annular bodies, and the plurality of annular bodies are concentric with the center of the circle of the lower base.

[0023] Preferably, the oblique waist of the right-angled trapezoid is located directly above the outer edge of the lower base.

[0024] Preferably, the rotating support shaft includes a plurality of arms and a plurality of support pins, the plurality of arms are distributed in an umbrella shape, the lower portion of the support pin is arranged above the end of the arm, and the upper portion of the support pin is located in a non-uniform projection area, which is a downward projection area between the outer edge of the preheating ring and the connecting piece.

[0025] The present invention has the following beneficial effects:

[0026] The separation design of the upper and lower bases ensures the uniformity of the wafer temperature.

[0027] By improving the structure of the preheating ring and the base, the temperature uniformity of the wafer edge is further optimized to ensure that the wafer is subjected to uniform heat radiation;

[0028] The quality of the epitaxial layer at the edge of the wafer is improved, and the consistency of the epitaxial layer on the surface of the wafer is ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of the structure of an epitaxial device according to an embodiment of the present invention;

[0030] Figure 2 A schematic structural diagram of a base according to an embodiment of the present invention;

[0031] Figure 3 It is a structural schematic diagram of a lower base according to an embodiment of the present invention;

[0032] Figure 4 A bottom view of a lower base according to an embodiment of the present invention;

[0033] Figure 5 It is a schematic structural diagram of a base and a preheating ring according to an embodiment of the present invention;

[0034] Figure 6 This is a schematic structural diagram of a base and a preheating ring according to another embodiment of the present invention. DETAILED DESCRIPTION

[0035] The following is a further detailed description of an epitaxial device proposed by the present invention in conjunction with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the drawings are in a very simplified form and use non-precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In order to make the purposes, features and advantages of the present invention more obvious and easy to understand, please refer to the accompanying drawings. It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no technical substantive significance. Any structural modification, change in proportional relationship or adjustment of size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope of the technical content disclosed by the present invention.

[0036] See also Figure 1 , is a schematic diagram of the structure of an epitaxial device according to an embodiment of the present invention. The epitaxial device includes a processing chamber, a heating device, a rotating support shaft 110 and a base. The processing chamber is used to provide a vacuum environment for reaction, and contains a process gas for reaction. The heating device is used to provide the temperature of the reaction, which is located outside the processing chamber and provides heat energy to the processing chamber by thermal radiation. The processing chamber includes a side wall, an upper dome 108 and a lower dome 109. The upper dome 108 is arranged above the side wall, and the lower dome 109 is arranged below the side wall. The upper dome 108 and the lower dome 109 are both made of quartz material, which can transmit most visible light and infrared rays, and can allow the heat radiation of the heating device to enter the processing chamber. The upper dome 108 is roughly circular, the lower dome is funnel-shaped, and the side wall is roughly annular. The heating device includes an upper heating device 101 located above the upper dome 108 and a lower heating device 102 located below the lower dome 109. The rotating support shaft 110 passes through the lower dome 109 upward from the bottom of the lower dome 109 and extends into the processing chamber. The rotating support shaft 110 is used to hold the susceptor and can rotate and lift. The susceptor is used to carry the wafer 107, and the upper surface of the wafer 107 is completely exposed to the heat radiation of the upper heating device 101. An upper temperature meter 103 and a lower temperature meter 104 are also provided outside the processing chamber for detecting the temperature near the susceptor.

[0037] Due to the existence of the rotating support shaft 110, the heat radiation received by part of the lower surface of the base is blocked by the rotating support shaft 110, affecting the uniformity of heating on the lower surface of the base, and further affecting the temperature uniformity of the wafer 107 above the base, affecting the subsequent deposition of the wafer epitaxial layer.

[0038] In the deposition process, the uniformity of temperature will affect the quality of epitaxial layer deposition. In order to provide the wafer with a stable heat source, the present invention optimizes the structure of the base that supports the wafer. Figure 2 The base includes a lower base 105 and an upper base 106. The lower base 105 is connected to the upper base 106 through a connector 115. The lower base 105 is located below the upper base 106 and is directly connected to the rotating support shaft 110. The upper base 106 is used to place a wafer 107. The lower base 105 and the upper base 106 are both circular, and the diameter of the lower base 105 is larger than the diameter of the upper base 106. This size difference design can make the base more stable. In addition, the lower base 105 radiates the heat absorbed by the lower heating device 102 to the upper base 106. The large-sized lower base 105 can generate uniform heat radiation to the upper base 106, reducing the impact of the rotating support shaft 110 blocking.

[0039] As mentioned above, temperature uniformity will affect process quality. In order to further improve the temperature uniformity of the susceptor, Figure 4 As shown, the bottom surface of the lower base 105 is provided with a groove 151, and the groove 151 is located at the projection formed by the rotating support shaft 110 on the bottom surface of the lower base 105, and the groove 151 has the same shape as the projection. The position where the groove 151 is provided is thinner than the position without the groove, so it can heat up faster due to thermal radiation. By controlling the depth of the groove 151, the temperature of each position of the lower base 105 can be uniform, thereby compensating for the uneven heat distribution caused by the shielding of the rotating support shaft 110.

[0040] Furthermore, the connecting member 115 is located between the lower base 105 and the upper base 106, and the connecting member 115 is an annular structure, and the center of the annular structure is concentric with the center of the lower base. Figure 3 As shown, the connection between the connecting member 115 and the upper base 106 is connected by a pin. Specifically, the connecting member 115 is an annular structure, and a plurality of connecting pins 125 are arranged on the top surface of the annular structure. The annular structure is fixedly connected to the lower base 105, and the plurality of connecting pins 125 are connected to the bottom surface of the upper base 106 by pins, that is, the connecting pins 125 are inserted into the corresponding holes on the bottom surface of the upper base 106 to form a pin connection.

[0041] Furthermore, the diameter of the annular structure is larger than the diameter of the wafer 107. Since there are complex components below the wafer 107, including components on the rotating support shaft 110 and components of the base, the heat distribution below the wafer 107 is uneven. In order to reduce the influence of these components on the heat distribution, the annular structure is set to be larger than the diameter of the wafer 107. When the wafer 107 is located on the upper base 106, the orthographic projection position of the wafer 107 is located within the annular structure, thereby ensuring that there is no influence of the annular structure below the wafer 107, ensuring that the lower base 105 with uniform medium is directly below the wafer 107, and further ensuring that the wafer 107 is subjected to uniform heat radiation.

[0042] Optionally, the upper base 106 is coaxially arranged with the lower base 105. The advantage of the coaxial arrangement is that it improves the stability of the base while ensuring the uniformity of heat distribution. When the wafer is placed at the center of the base, the surrounding heat is symmetrically distributed, which makes it easier to control the uniformity of heat radiated to the wafer. Optionally, the base is made of graphite.

[0043] In this example, please continue to refer to Figure 1 The processing chamber includes: an air inlet 112, an exhaust port 113 and a preheating ring 111 arranged around the susceptor. The air inlet 112 is used to introduce process gas, the exhaust port 113 is used to discharge the process gas after process treatment from the processing chamber, and the preheating ring 111 is used to heat the outer edge area of ​​the susceptor. Figure 1 It can be seen that the air inlet 112 is arranged opposite to the exhaust port 113, and the exhaust port 113 is connected to a pump for extracting the process gas after the reaction. The main reaction area of ​​the epitaxial process is concentrated above the upper base, and the lower base is used to introduce the purge gas. The height of the air inlet 112 is slightly higher than the height of the wafer 107. After the process gas enters through the air inlet 112, it passes over the surface of the wafer and forms an epitaxial layer on the surface of the wafer. At the same time, the preheating ring 111 heats the passing process gas. Among them, the preheating ring 111 can be made of graphite. Graphite has good heat absorption efficiency and heat radiation efficiency. After absorbing heat, it can radiate heat energy outward. In order to prevent the temperature difference at various locations on the preheating ring 111 from affecting the process gas, the present invention improves the structure and position of the preheating ring 111.

[0044] In the epitaxial process, in addition to the temperature affecting the quality of the epitaxial layer, the disturbance of the airflow is also one of the key factors. In this embodiment, when improving the preheating ring 111, the problem of airflow disturbance in the gap between the preheating ring 111 and the base is also taken into account.

[0045] In this embodiment, please refer to Figure 5, a specific positional relationship is maintained between the preheating ring 111 and the base. Specifically, the bottom surface of the preheating ring 111 is higher than the top surface of the lower base 105, and the preheating ring 111 extends radially to the inner side of the lower base 105, and a transverse gap is formed between the bottom surface of the preheating ring 111 and the top surface of the lower base 105.

[0046] Optional, such as Figure 5 As shown, a protrusion structure 152 is provided in the gap, and the protrusion structure 152 is provided on the top surface of the lower base 105. The protrusion structure 152 is mainly used to weaken the airflow in the gap, reduce the process gas in the reaction area from entering the bottom of the base through the gap, thereby affecting the purity of the bottom of the base. In order to further weaken the airflow in the gap, the protrusion structure 152 is a plurality of annular bodies, and the plurality of annular bodies are concentric with the center of the circle of the lower base 105.

[0047] In other embodiments, Figure 6 As shown, a portion of the lower surface of the preheating ring 111 is blocked by the lower base 105, so that the upper and lower surfaces of the preheating ring 111 at this position are heated unevenly. In particular, after the lower surface is blocked, it cannot directly obtain heat radiation from the lower heating device 102, thereby forming a temperature difference between the blocked area and the non-blocked area. In order to solve this problem, Figure 6 As shown, it is a structural schematic diagram of a preheating ring 111 and a base in another embodiment, a protrusion 153 is provided on the bottom surface of the preheating ring 111, and the protrusion 153 extends around the lower edge of the bottom surface of the preheating ring 111, and the protrusion 153 can obtain heat radiation supplement from the lower base 105. Compared with the area without a protrusion (non-blocking area), the protrusion 153 has a thicker thickness and a closer distance to the lower base 105, so the protrusion 153 can absorb more heat energy to make up for the less absorbed heat radiation. Therefore, the protrusion can be made to protrude toward the lower base 105 by thickening the protrusion, so as to receive more heat, so as to ensure that the preheating ring 111 has a relatively uniform radiation efficiency everywhere. In addition, the protrusion can also solve the above-mentioned gap airflow disturbance problem.

[0048] Of course, in other embodiments, Figure 5 The raised structure 152 and Figure 6 The middle protrusions 153 may exist simultaneously in the same embodiment.

[0049] Optionally, the cross section of the protrusion 153 is a right-angled trapezoid, and the upper side of the right-angled trapezoid is parallel to the top surface of the lower base. The heat radiation of the lower base can be evenly received, and the waist of the right-angled trapezoid is located just above the outer edge of the lower base, and the waist can receive part of the heat radiation of the lower heating device and the heat radiation of the outer edge of the lower base. The protrusion 153 with a trapezoidal design can control the uniform heat radiation of various parts of the preheating ring.

[0050] In this embodiment, the rotating support shaft 110 includes a plurality of arms and a plurality of support pins, the plurality of arms are distributed in an umbrella shape, the lower portion of the support pin is arranged above the end of the arm, and the arm is distributed in an umbrella shape to ensure that the support pin can effectively support the base while minimizing the shielding of the thermal radiation in the space below the wafer. The upper portion of the support pin is located in the non-uniform projection area, which is the downward projection area between the outer edge of the preheating ring and the connector.

[0051] Since there is no thermal interference from the support pins directly below the wafer, the uniformity of the radiation received by the wafer can be ensured. The position and layout of the support pins can reduce the shielding of the thermal radiation in the space below the wafer, which is crucial for maintaining the precise temperature control required in the semiconductor manufacturing process. In this way, the quality of epitaxial process production can be improved.

[0052] In summary, the epitaxial equipment provided by the present invention has a more uniform temperature control function, and solves the problem of uneven heating of the wafer by setting the upper and lower bases; further, by improving the structure and positional relationship of the preheating ring and the base, the influence of airflow disturbance on the wafer edge is solved, and the quality of the wafer epitaxial layer is improved; and the design of the protrusion on the preheating ring further optimizes the uniformity of thermal radiation.

[0053] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. An epitaxial device, characterized in that: include: a processing chamber; A heating device, the heating device comprising an upper heating device located at the top of the processing chamber and a lower heating device located at the bottom of the processing chamber; Rotating support shaft; A base, the base comprising: a lower base and an upper base, the lower base is connected to the upper base through a connecting piece, the lower base is located below the upper base and is directly connected to the rotating support shaft, the upper base is used to place a wafer, and the diameter of the lower base is greater than the diameter of the upper base; The lower base radiates the absorbed heat of the lower heating device to the upper base.

2. The epitaxial device according to claim 1, characterized in that: The bottom surface of the lower base is provided with a groove, the groove is located at the projection formed by the rotation support shaft on the bottom surface of the lower base, and the groove has the same shape as the projection.

3. The epitaxial device according to claim 1, characterized in that: The connecting piece is an annular structure, and a plurality of connecting pins are arranged on the top surface of the annular structure; the diameter of the annular structure is greater than the diameter of the wafer; The annular structure is fixedly connected to the lower base, and the plurality of connecting pins are connected to the bottom pins of the upper base.

4. The epitaxial device according to claim 1, characterized in that: The base is made of graphite.

5. The epitaxial device according to claim 1, characterized in that: The upper base is coaxially arranged with the lower base.

6. The epitaxial device according to claim 1, characterized in that: The processing chamber comprises: an air inlet, an exhaust port and a preheating ring arranged around the susceptor, the air inlet is used to introduce process gas, and the exhaust port is used to discharge the process gas after process treatment from the processing chamber; The bottom surface of the preheating ring is higher than the top surface of the lower base, and the preheating ring extends radially to the inner side of the lower base, a transverse gap is formed between the bottom surface of the preheating ring and the top surface of the lower base, a protrusion structure is arranged in the gap, and the protrusion structure is arranged on the top surface of the lower base.

7. The epitaxial device according to claim 6, characterized in that: A protrusion is provided on the bottom surface of the preheating ring, and the protrusion extends around the lower edge of the bottom surface of the preheating ring.

8. The epitaxial device according to claim 7, characterized in that: The cross section of the protrusion is a right-angled trapezoid, and the upper side of the right-angled trapezoid is parallel to the top surface of the lower base.

9. The epitaxial device according to claim 6, characterized in that: The protruding structure is a plurality of annular bodies, and the plurality of annular bodies are concentric with the center of the circle of the lower base.

10. The epitaxial device according to claim 8, characterized in that: The oblique waist of the right-angled trapezoid is located directly above the outer edge of the lower base.

11. The epitaxial device according to claim 8, characterized in that: The rotating support shaft includes multiple arms and multiple support pins, the multiple arms are distributed in an umbrella shape, the lower part of the support pin is arranged above the end of the arm, and the upper part of the support pin is located in the non-uniform projection area, which is the downward projection area between the outer edge of the preheating ring and the connecting piece.

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