TW202321533A - Preheating ring and wafer epitaxial growth equipment - Google Patents

Abstract

The invention provides a preheating ring and wafer epitaxial growth equipment, and belongs to the technical field of silicon product manufacturing. The preheating ring comprises an annular main body, the annular main body comprises a first surface for preheating reaction gas entering a reaction cavity of the wafer epitaxial growth equipment, and the annular main body comprises a first area corresponding to a gas inlet in the wafer epitaxial growth equipment in the circumferential direction of the annular main body, the orthographic projection of an air inlet in wafer epitaxial growth equipment on the annular main body is located in the corresponding first area, the first surface comprises second areas located on the two sides of the first area, and the second areas are provided with a plurality of pits. According to the technical scheme, the problem that the thickness of the epitaxial layer is not uniform can be solved.

Description

Preheating ring and wafer epitaxy growth equipment

The invention belongs to the technical field of silicon product production, in particular to a preheating ring and wafer epitaxy growth equipment.

During the epiwafer growth process, due to the heat field distribution heated by the lamp source and the characteristics of the technical gas flowing into the reaction chamber, the thickness distribution of the epitaxial layer is lower at about 50mm from the center point, and the above-mentioned depressions are not conducive to wafer growth. The improvement of chip quality will affect the yield rate of the product.

In order to solve the above technical problems, the present invention provides a preheating ring and wafer epitaxy growth equipment, which can solve the problem of uneven epitaxy layer thickness.

In order to achieve the above object, the technical solution adopted in the embodiment of the present invention is: A preheating ring, comprising an annular main body, the annular main body includes a first surface for preheating the reaction gas entering the reaction chamber of the wafer epitaxy growth equipment, and the annular main body includes along its circumferential direction The first area corresponding to the air inlet on the equipment, the orthographic projection of the air inlet on the wafer epitaxy growth equipment on the annular body is located in the corresponding first area, and the first surface includes two sides of the first area. The second area on the side is provided with a plurality of pits.

In some embodiments, in the second area, the plurality of pits are arranged in an array.

In some embodiments, along the direction away from the center of the second region, the distribution density of the pits decreases gradually.

In some embodiments, the distance between two adjacent pits is 1-1.5mm.

In some embodiments, the depth of the pit decreases gradually along the direction away from the center of the second region.

In some embodiments, the depth of the pit is 0.2-0.3 mm.

In some embodiments, the cross-section of the pit in a direction perpendicular to the first surface is an isosceles triangle, a rectangle, an inverted trapezoid, a semi-ellipse or a semi-circle.

In some embodiments, the plurality of pits are arranged in a row with the gas flow direction, and the pitches of the plurality of pits in the same row are the same.

In some embodiments, along the direction away from the center of the second region, the distance between two adjacent rows of pits increases gradually.

The present invention also provides a wafer epitaxy growth equipment, which includes a housing, a reaction chamber is formed in the housing, a base for carrying a wafer is arranged in the chamber, and the above-mentioned preheating ring is arranged on the inner wall of the housing , the preheating ring is arranged around the periphery of the base.

The beneficial effects of the present invention are: A plurality of pits are set in the second area on both sides of the first area corresponding to the gas inlet. Due to the existence of the pit structure, the reaction gas entering the reaction chamber will have a larger contact area with the preheating ring, so the temperature There will be a significant improvement, and then the growth rate at the corresponding position of the silicon wafer will be higher than that at other positions, thereby improving the thickness uniformity of the epitaxial layer.

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, but not to limit the present invention.

It should be noted that when an element is referred to as being “fixed” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

It is to be understood that the terms "length", "width", "top", "bottom", "front", "rear", "left", "right", "vertical", "horizontal", "top", The orientation or positional relationship indicated by "bottom", "inner" and "outer" are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying the referred device Or elements must have a certain orientation, be constructed and operate in a certain orientation, and thus should not be construed as limiting the invention.

In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, a feature defined as "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

In the present invention, terms such as "installation", "connection", "connection" and "fixation" should be interpreted in a broad sense, for example, it can be a fixed connection or a detachable connection, unless otherwise clearly specified and limited. , or integrated; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediary, and it can be the internal communication of two components or the interaction relationship between two components. Those with ordinary knowledge in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

Silicon epitaxial growth technology is an important technology in semiconductor wafer manufacturing. It refers to the method of growing a layer of silicon single crystal layer with resistivity, thickness controllable and oxygen-free precipitation on the polished wafer as the substrate under certain conditions. , mainly including vacuum epitaxy deposition, vapor phase epitaxy deposition and liquid phase epitaxy deposition and other methods. Among them, vapor phase epitaxy deposition is the most widely used. In a high-temperature environment, the epitaxial layer is obtained by reacting silicon source gas with hydrogen to form single crystal silicon and depositing it on the surface of the silicon wafer. required resistivity.

The structure of the wafer epitaxy growth equipment is shown in FIG. 1 , and the external structure includes an upper quartz bell jar 1 , a lower quartz bell jar 2 , an air inlet, an exhaust outlet, and a mounting part 7 . The internal structure includes a halogen lamp 3, a pin 5, a pin support rod 6, a base 8 for placing a silicon wafer, a base support rod 4 and a wafer support rod, wherein the base 8 plays the role of placing a silicon wafer, and the base supports The rod 4 plays the role of fixing the base 8 and driving the base 8 to rotate, so that the epitaxial growth can be carried out uniformly on the substrate, and the preheating ring 9 is mainly used to heat the reaction gas, so that it can achieve a chemical reaction when it reaches the silicon wafer. the desired temperature. Outside the quartz bell jar, there is a heating bulb responsible for providing reaction energy, which provides heat for the reaction through thermal radiation.

The flatness of silicon wafer is an important index to measure the quality of silicon wafer, which is directly related to the thickness of epitaxial layer. The temperature during the chemical vapor deposition process, the concentration of the silicon source gas, and the gas flow rate will have a very obvious impact on the performance.

During the epiwafer growth process, due to the thermal field distribution and the characteristics of the technical gas flowing into the reaction chamber, the thickness distribution of the epitaxial layer is lower than the center point of 50 mm, as shown in Figure 2, where the ordinate is the epitaxial wafer Thickness, the abscissa is the distance from the center point of the epitaxial wafer, and the above-mentioned depression is not conducive to the improvement of the quality of the wafer, and will affect the yield of the product.

The invention provides a preheating ring and wafer epitaxy growth equipment, which can solve the problem of uneven epitaxy layer thickness.

As shown in FIG. 3 and FIG. 4 , the surface of the annular body 10 of the related art preheating ring is flat, which leads to the thickness distribution of the epitaxial layer as shown in FIG. 2 .

An embodiment of the present invention provides a preheating ring, as shown in FIG. 5 , including an annular body 10, the annular body 10 includes a first surface for preheating the reaction gas entering the reaction chamber of the wafer epitaxy growth equipment, the The annular body 10 includes a first area S1 corresponding to the air inlet on the wafer epitaxy growth equipment along its circumferential direction, and the orthographic projection of the air inlet on the wafer epitaxy growth equipment on the annular body is located at the corresponding The first area S1 , the first surface includes a second area S2 located on both sides of the first area S1 , and the second area S2 is provided with a plurality of pits 11 .

In this embodiment, a plurality of dimples are provided in the second area on both sides of the first area corresponding to the gas inlet. Due to the existence of the dimple structure, there will be a greater gap between the reaction gas entering the reaction chamber and the preheating ring. Therefore, the temperature will be significantly increased, and the growth rate at the corresponding position of the silicon wafer will be higher than that at other positions, thereby improving the thickness uniformity of the epitaxial layer.

After the silicon wafer enters the chamber and undergoes epitaxial deposition, the surface temperature will not be exactly the same, and the chemical reaction will be more intense in places with high temperature, and the deposition speed will be relatively faster; the distribution of the temperature field is roughly in the middle area and The near-edge area is relatively high, so that the thickness of the wafer epitaxial layer is uneven. In this embodiment, the second area S2 is symmetrically distributed on both sides of the first area S1, and a plurality of pits are set in the second area S2, so that The second area S2 can increase the contact area between the reaction gas entering the reaction chamber and the preheating ring, so that the temperature of the reaction gas in the second area S2 will be significantly increased, and then the growth at the corresponding position of the silicon wafer will be better than other positions. Higher growth rate, thereby improving the thickness uniformity of the epitaxial layer.

In some embodiments, as shown in FIG. 6 , in the second area, the plurality of pits 11 are arranged in an array. In this way, the arrangement of the pits 11 can be made more regular, and the air flow disorder can be avoided.

In some embodiments, as shown in FIG. 6 , along the direction away from the center of the second region, the distribution density of the pits 11 gradually decreases. Since the thickness of the epitaxial layer is the lowest in the center of the second region, the thickness of the pits 11 decreases as it goes to both sides. High, so this structural design can achieve better thickness uniformity improvement effect.

In some embodiments, the distance between two adjacent pits 11 can be 1-1.5mm, for example, it can be 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, and the present invention does not do this limited. Of course, the distance between two adjacent pits 11 may also be greater than 1.5 mm, or less than 1 mm, which is not limited in the present invention.

In some embodiments, along the direction away from the center of the second region, the depth of the pit 11 gradually decreases. Since the thickness of the epitaxial layer is the lowest in the center of the second region, and becomes higher towards both sides, this structural design A better thickness uniformity improvement effect can be achieved.

In some embodiments, the depth of the pit 11 is 0.2-0.3mm, such as 0.21mm, 0.22mm, 0.23mm, 0.24mm, 0.25mm, 0.26mm, 0.27mm, 0.28mm, 0.29mm, 0.3mm, The present invention is not limited thereto. Of course, the depth of the pit 11 may also be greater than 0.3 mm, or less than 0.2 mm, which is not limited in the present invention.

In some embodiments, the cross-section of the pit 11 in the direction perpendicular to the first surface may be an isosceles triangle, rectangle, inverted trapezoid, semi-ellipse or semicircle. Of course, the pit 11 is vertical to the first surface. The cross-section in the direction of a surface can also have other shapes. Figure 7 shows an enlarged schematic view of a pit in an embodiment of the present invention, and Figure 8 shows a schematic cross-sectional view of a pit in an embodiment of the present invention, as shown in Figure 8, the cross section of the pit 11 in a direction perpendicular to the first surface can be inverted trapezoidal.

In some embodiments, as shown in FIG. 6 , the plurality of pits 11 are arranged in a row with the gas flow direction, and the pitches of the plurality of pits 11 in the same row are the same. The number of pits 11 in a row can be set according to actual needs, and the number of pits 11 in each row can also be consistent. Since the thickness distribution of the epitaxial layer in the related art is relatively low at 50 mm from the central point, the pit 11 can be arranged at a distance of 50 mm from the central axis of the preheating ring and extend to both sides, along the In the direction of the center of the dimples 11 , the distance between two adjacent rows of dimples 11 increases gradually, and this kind of structural design can achieve a better effect of improving the thickness uniformity. As shown in FIG. 6, a first row of pits 111 is provided at the center of the second region S2, and a second row of pits 112 and a third row of pits 113 are provided on one side of the first row of pits 111. A fourth row of pits 114 and a fifth row of pits 115 are disposed on the other side of the first row of pits 111 . The distance between the second row of pits 112 and the first row of pits 111 can be 1mm, the distance between the third row of pits 113 and the second row of pits 112 can be 1.2mm, and the distance between the third row of pits 113 The distance between a row of pits away from the second row of pits 112 and the third row of pits 113 may be 1.4 mm, and so on. The distance between the fourth row of pits 114 and the first row of pits 111 can be 1 mm, the distance between the fifth row of pits 115 and the fourth row of pits 114 can be 1.2 mm, and the distance between the fifth row of pits 115 and the fourth row of pits 114 can be 1.2 mm. The distance between a row of pits away from the fourth row of pits 114 and the fifth row of pits 115 may be 1.4 mm, and so on.

When installing the preheating ring, align the central axis with the middle of the air inlet. The airflow passing through the preheating ring will have a larger contact area with the preheating ring due to the existence of the dimple structure, so the temperature will increase significantly. , and then have a higher growth rate when growing at the corresponding position of the silicon wafer than other positions, thereby obtaining better uniformity of the thickness of the epitaxial layer.

The present invention also provides a wafer epitaxy growth equipment, which includes a housing, a reaction chamber is formed in the housing, a base for carrying a wafer is arranged in the chamber, and the above-mentioned preheating ring is arranged on the inner wall of the housing , the preheating ring is arranged around the periphery of the base.

In the wafer epitaxy growth equipment of this embodiment, the preheating ring is provided with a plurality of pits in the second area on both sides of the first area corresponding to the air inlet. Due to the existence of the pit structure, the The reaction gas has a larger contact area with the preheating ring, so the temperature will be significantly increased, and the growth rate at the corresponding position of the silicon wafer will be higher than that at other positions, thereby improving the thickness uniformity of the epitaxial layer.

It should be noted that each embodiment in this specification is described in a progressive manner, the same and similar parts of each embodiment can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, as for the embodiment, since it is basically similar to the product embodiment, the description is relatively simple, and for related parts, please refer to the description of the product embodiment.

It should be noted that each embodiment in this specification is described in a progressive manner, the same and similar parts of each embodiment can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, as for the embodiment, since it is basically similar to the product embodiment, the description is relatively simple, and for related parts, please refer to the description of the product embodiment.

In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in an appropriate manner.

It is obvious that those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the patent scope of the present invention and the scope of equivalent technologies, the present invention is also intended to include these modifications and variations.

1: Upper quartz bell jar 10: ring body 11: Pit 111: The first row of pits 112: The second row of pits 113: The third row of pits 114: The fourth row of pits 115: The fifth row of pits 2: Lower quartz bell jar 3: Halogen lamp 4: Base support rod 5: Pin 6: Pin support rod 7: Install parts 8: Base 9: preheating ring S1: the first area S2: second area

FIG. 1 shows a schematic structural diagram of wafer epitaxy growth equipment; Fig. 2 shows the schematic diagram of epitaxial layer thickness topography; Fig. 3 shows the schematic top view of the related art preheating ring; Fig. 4 shows the schematic side view of the related art preheating ring; Fig. 5 shows the schematic top view of the preheating ring of the embodiment of the present invention; FIG. 6 shows an enlarged schematic view of the second region of the embodiment of the present invention; Fig. 7 shows the enlarged schematic diagram of the pit of the embodiment of the present invention; Fig. 8 shows a schematic cross-sectional view of a pit in an embodiment of the present invention.

10: ring body

11: Pit

S1: the first area

S2: second area

Claims (10)

A preheating ring, comprising an annular main body, the annular main body includes a first surface for preheating the reaction gas entering the reaction chamber of the wafer epitaxy growth equipment, and the annular main body includes along its circumferential direction The first area corresponding to the air inlet on the equipment, the orthographic projection of the air inlet on the wafer epitaxy growth equipment on the annular body is located in the corresponding first area, and the first surface includes two sides of the first area. The second area on the side is provided with a plurality of pits. The preheating ring as claimed in claim 1, wherein, in the second area, the plurality of pits are arranged in an array. The preheating ring as claimed in claim 2, wherein, along the direction away from the center of the second region, the distribution density of the pits gradually decreases. The preheating ring according to claim 3, wherein the distance between two adjacent dimples is 1-1.5 mm. The preheating ring as claimed in claim 2 or 3, wherein, along the direction away from the center of the second region, the depth of the pit gradually decreases. The preheating ring as claimed in item 5, wherein the depth of the pit is 0.2-0.3mm. The preheating ring according to claim 1, wherein, the cross-section of the dimple in a direction perpendicular to the first surface is an isosceles triangle, a rectangle, an inverted trapezoid, a semi-ellipse or a semi-circle. The preheating ring as claimed in claim 2, wherein the plurality of pits are arranged in a row with the gas flow direction, and the pitches of the plurality of pits in the same row are the same. The preheating ring as claimed in claim 8, wherein, along the direction away from the center of the second region, the distance between two adjacent rows of pits gradually increases. A wafer epitaxy growth equipment, comprising a casing, a reaction chamber is formed in the casing, a base for carrying a wafer is arranged in the reaction chamber, and any One item of the preheating ring, the preheating ring is arranged around the periphery of the base.

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