Preheating ring, wafer epitaxial growth equipment, epitaxial growth method and epitaxial silicon wafer
By designing a symmetrically distributed groove area in the preheating ring of the epitaxial silicon wafer growth device, increasing the contact area and temperature of the silicon source gas, the problem of large differences in the epitaxial layer thickness and the central region in the edge area of the epitaxial silicon wafer is solved, and the uniformity and flatness of the epitaxial layer thickness are improved.
Patent Information
- Application Number
- CN202510354656.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-25
- Publication Date
- 2025-06-27
AI Technical Summary
The thickness of the epitaxial layer in the edge region of the epitaxial silicon wafer differs greatly from the epitaxial layer thickness in the central region, which affects the uniformity of the epitaxial layer thickness of the epitaxial silicon wafer.
A preheating ring is designed, with the first surface including a first and a second region symmetrically distributed, with a distance between the two regions ranging from 240 mm to 300 mm, and grooves are provided in these regions to increase the contact area and temperature of the silicon source gas and increase the epitaxial growth rate of the edge region.
By increasing the epitaxial growth rate of the edge region, the thickness difference between the epitaxial layer of the edge region and the central region of the epitaxial silicon wafer is reduced, the thickness uniformity of the epitaxial layer is improved, and the flatness of the epitaxial silicon wafer is improved.
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Figure CN120210953A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of semiconductor manufacturing, and particularly relates to a preheating ring, a wafer epitaxial growth device, an epitaxial growth method, and an epitaxial silicon wafer. Background Art
[0002] Epitaxial growth refers to a process of growing a single crystal thin film (the crystal direction is the same as that of the substrate crystal) on a single crystal silicon substrate through epitaxy technology. The entire production process of an epitaxial silicon wafer includes crystal growth (pulling a silicon crystal rod from polysilicon material) → forming (slicing and grinding) → polishing (double-sided polishing) → cleaning (removing surface particles, metal ions, and organic substances) → epitaxy (chemical vapor deposition). Among them, epitaxy, as the last important process, can improve the crystal properties, native defects, resistivity, and flatness of the polished wafer.
[0003] As Figure 1 shown, an epitaxial growth device generally includes: an upper quartz bell jar 1, a lower quartz bell jar 2, an air inlet, an air outlet, a halogen lamp 3, and a mounting member 4. In the reaction chamber surrounded by the upper quartz bell jar 1 and the lower quartz bell jar 2, a pedestal 6 for placing a silicon wafer, a pedestal support rod 7, and a silicon wafer support rod are provided. After the silicon wafer 8 is input into the reaction chamber and placed on the pedestal 6 in the reaction chamber, the silicon wafer 8 is heated by an upper heating module provided on the upper side of the pedestal 6 and a lower heating module provided on the lower side of the pedestal 6, and a raw material gas 5 is supplied to the surface of the silicon wafer 8, thereby performing vapor phase epitaxial growth, and the epitaxial wafer obtained through vapor phase epitaxial growth is output out of the reaction chamber. During the growth process, the pedestal support rod 7 plays a role in fixing the pedestal 6 and driving the pedestal 6 to rotate, so that epitaxial growth can be uniformly performed on the substrate 6.
[0004] In the related art, the thickness of the epitaxial layer in the edge region of the epitaxial silicon wafer is quite different from the thickness of the epitaxial layer in the central region of the epitaxial silicon wafer, which affects the uniformity of the thickness of the epitaxial layer of the epitaxial silicon wafer. Summary of the Invention
[0005] In order to solve the above technical problems, the present invention provides a preheating ring, a wafer epitaxial growth device, an epitaxial growth method, and an epitaxial silicon wafer, which can improve the uniformity of the thickness of the epitaxial layer of the epitaxial silicon wafer.
[0006] In order to achieve the above object, the technical solution adopted in the embodiment of the present invention is:
[0007] A preheating ring includes an annular main body. The annular main body includes a first surface for preheating a reaction gas entering a reaction chamber of a wafer epitaxial growth device. The first surface is on the same side as the bearing surface of a pedestal for carrying a silicon wafer in the wafer epitaxial growth device.
[0008] Wherein, the first surface includes a first region and a second region that are symmetrically distributed with respect to the first central axis of the annular body, and the distance between the first region and the second region is
[0009] 240 mm - 300 mm;
[0010] At least one groove is respectively provided in the first region and the second region, and the extending direction of the groove is parallel to the first central axis.
[0011] In some embodiments, a plurality of grooves are respectively provided in the first region and the second region.
[0012] In some embodiments, 5 - 6 grooves are respectively provided in the first region and the second region.
[0013] In some embodiments, the longitudinal cross - section of the groove is semi - circular.
[0014] In some embodiments, the radius of the semi - circle is 2.5 - 3.5 mm.
[0015] In some embodiments, when a plurality of grooves are respectively provided in the first region and the second region, the distance between two adjacent grooves is 0 - 0.5 mm.
[0016] An embodiment of the present invention further provides a wafer epitaxial growth device, including the above - mentioned pre - heating ring and a base for carrying a silicon wafer, and the carrying surface of the base is located inside the pre - heating ring.
[0017] An embodiment of the present invention further provides an epitaxial growth method, which is applied to the wafer epitaxial growth device as described above. The method includes:
[0018] Placing the silicon wafer on the base such that the central axis of the silicon wafer is aligned with the first central axis;
[0019] Transporting a silicon source gas into the reaction chamber through the gas inlet of the wafer epitaxial growth device to grow an epitaxial layer on the silicon wafer;
[0020] The temperature and flow rate of the silicon source gas flowing through the first region and the second region are greater than the temperature of the silicon source gas flowing through other regions of the pre - heating ring, so as to make the thickness of the epitaxial layer grown on the silicon wafer uniform;
[0021] Discharging the reaction tail gas generated by the epitaxial growth out of the reaction chamber through the exhaust port of the wafer epitaxial growth device.
[0022] An embodiment of the present invention also provides an epitaxial silicon wafer, which is prepared by the epitaxial growth method as described above. The difference between the thickness of the epitaxial layer in the edge region of the epitaxial silicon wafer and the thickness of the epitaxial layer in the central region of the epitaxial silicon wafer is not greater than 0.02 microns.
[0023] The beneficial effects of the present invention are:
[0024] In this embodiment, the first surface includes a first region and a second region that are symmetrically distributed with respect to the first central axis of the annular body. The distance between the first region and the second region is 240 mm - 300 mm; at least one groove is provided in each of the first region and the second region, and the extending direction of the groove is parallel to the first central axis. During the epitaxial deposition process, when introducing a silicon source gas into the reaction chamber, due to the arrangement of the grooves in the first region and the second region, the silicon source gas will have a larger contact area with the first region and the second region, more silicon source gas will flow through the first region and the second region, and the temperature of the silicon source gas flowing through the first region and the second region will also increase significantly. The silicon source gas flowing through the first region and the second region is used for epitaxial growth at the edge of the silicon wafer, which can improve the epitaxial growth rate at the edge position of the silicon wafer, reduce the difference between the thickness of the epitaxial layer in the edge region of the epitaxial silicon wafer and the thickness of the epitaxial layer in the central region of the epitaxial silicon wafer, and an epitaxial silicon wafer with better flatness of the epitaxial layer can be obtained through the present invention. Description of the Drawings
[0025] Figure 1 Schematic structural diagram showing an existing epitaxial growth device;
[0026] Figure 2 Schematic diagram showing the thickness of the epitaxial layer of an existing epitaxial silicon wafer;
[0027] Figure 3 Schematic structural diagram showing the preheating ring of an embodiment of the present invention;
[0028] Figure 4 Schematic cross-sectional diagram showing the first region and the second region of an embodiment of the present invention;
[0029] Figure 5 Schematic diagram showing the groove of an embodiment of the present invention.
[0030] Reference Signs
[0031] 1 Upper quartz bell jar
[0032] 2 Lower quartz bell jar
[0033] 3 Halogen lamp
[0034] 4 Mounting component
[0035] 5 Process gas
[0036] 6 Base
[0037] 7 Base Support Rod
[0038] 8 Silicon Wafer
[0039] 11 Silicon Chip
[0040] 12 Preheating Ring
[0041] 13 Groove
[0042] 14 First Region
[0043] 15 Second Region
[0044] 16 First Central Axis Detailed Implementation Manner
[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention fall within the scope of protection of the present invention.
[0046] Figure 2 It shows a schematic diagram of the epitaxial layer thickness of an existing epitaxial silicon wafer. Among them, the abscissa is the distance between each position point on the diameter of the silicon chip and the center of the silicon chip, with the unit of mm; the ordinate is the thickness of the epitaxial layer at each position point, with the unit of um. It can be seen that in the edge region where the distance from the center of the silicon chip is 120 mm to 150 mm, due to the combined influence of the temperature, the concentration of the silicon source gas, and the gas flow rate during the chemical vapor deposition process, the epitaxial layer thickness in the edge region is relatively small, and finally the thickness uniformity of the epitaxial layer is very poor, seriously affecting the product quality.
[0047] The present invention provides a preheating ring, a wafer epitaxial growth device, an epitaxial growth method, and an epitaxial silicon wafer, which can improve the thickness uniformity of the epitaxial layer of the epitaxial silicon wafer.
[0048] An embodiment of the present invention provides a preheating ring 12, as Figure 3 shown, including an annular body. The annular body includes a first surface for preheating the reaction gas entering the reaction chamber of the wafer epitaxial growth device. The first surface and the bearing surface of the base for carrying the silicon chip 11 in the wafer epitaxial growth device are on the same side.
[0049] Among them, the first surface includes a first region 14 and a second region 15 that are symmetrically distributed with respect to the first central axis 16 of the annular body. The distance between the first region 14 and the second region 15 is 240 mm - 300 mm.
[0050] The first region 14 and the second region 15 are respectively provided with at least one groove 13 , and an extending direction of the groove 13 is parallel to the first central axis 16 .
[0051] In this embodiment, the preheating ring extends the range of the heat control zone outside the silicon wafer, and during the silicon wafer manufacturing process, the introduced silicon source gas is first heated in the preheating ring, which can improve the uniformity of the deposit.
[0052] In this embodiment, the first surface of the preheating ring includes a first area and a second area symmetrically distributed relative to the first central axis of the annular body, and the distance between the first area and the second area is 240mm-300mm; the first area and the second area are respectively provided with at least one groove, and the extension direction of the groove is parallel to the first central axis. During the epitaxial deposition process, when the silicon source gas is introduced into the reaction chamber, due to the arrangement of the grooves in the first area and the second area, the silicon source gas will have a larger contact area with the first area and the second area, and more silicon source gas will flow through the first area and the second area. The temperature of the silicon source gas flowing through the first area and the second area will also be significantly increased. The silicon source gas flowing through the first area and the second area is used for epitaxial growth at the edge of the silicon wafer, which can increase the epitaxial growth rate at the edge of the silicon wafer, reduce the difference between the epitaxial layer thickness of the edge area of the epitaxial silicon wafer and the epitaxial layer thickness of the central area of the epitaxial silicon wafer, and through the present invention, an epitaxial silicon wafer with better epitaxial layer flatness can be obtained.
[0053] In some embodiments, the first region 14 and the second region 15 may each be provided with one groove 13 , or may each be provided with a plurality of grooves 13 .
[0054] In this embodiment, the distance between the first area 14 and the second area 15 is 240mm-300mm, that is, the distance between the center of the first area 14 and the center of the second area 15 is 240mm-300mm. The silicon source gas flowing through the first area 14 and the second area 15 will perform epitaxial growth at the edge of the silicon wafer. By setting a plurality of grooves 13 in the first area 14 and the second area 15, more silicon source gas can flow through the first area 14 and the second area 15 at the same time during the epitaxial deposition process, and the temperature of the silicon source gas flowing through the first area 14 and the second area 15 can be increased, thereby leading to an increase in the epitaxial growth rate, and then when the corresponding edge position of the silicon wafer grows, it has a higher growth rate than other positions, which will offset the problem of the small thickness of the epitaxial layer in the edge area, and ultimately improve the thickness uniformity of the epitaxial layer.
[0055] In some embodiments, the first region 14 and the second region 15 may be respectively provided with 5 to 6 grooves 13. Of course, the first region 14 and the second region 15 are not limited to being provided with 5 to 6 grooves 13, and other numbers of grooves 13 may also be provided. When the first region 14 and the second region 15 are respectively provided with 5 to 6 grooves 13, the growth rate of the epitaxial layer at the edge position of the silicon wafer can be effectively improved.
[0056] The longitudinal cross-section of the groove 13 may be an inverted triangle, an inverted trapezoid, a rectangle or a semi-circle. In some embodiments, as Figure 4 and Figure 5 shown, the longitudinal cross-section of the groove 13 may be a semi-circle.
[0057] In some embodiments, the radius of the semi-circle may be 2.5 - 3.5 mm, such as 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm, 2.9 mm, 3.0 mm, 3.1 mm, 3.2 mm, 3.3 mm, 3.4 mm, 3.5 mm. When the radius of the semi-circle takes the above values, during the epitaxial deposition process, more silicon source gas flowing through the first region 14 and the second region 15 at the same time can be achieved, and the temperature of the silicon source gas flowing through the first region 14 and the second region 15 can be increased, thereby resulting in an increase in the epitaxial growth rate. As a result, when growing at the corresponding edge position of the silicon wafer, it has a higher growth rate than other positions, which will offset the problem of the smaller thickness of the epitaxial layer in the edge region, and finally improve the thickness uniformity of the epitaxial layer.
[0058] In some embodiments, when the first region 14 and the second region 15 are respectively provided with a plurality of grooves 13, the distance between two adjacent grooves 13 is 0 - 0.5 mm, such as 0 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm or 0.5 mm.
[0059] The embodiment of the present invention also provides a wafer epitaxial growth device, including the above-mentioned preheating ring 12 and a pedestal for carrying the silicon wafer 11, and the carrying surface of the pedestal is located within the preheating ring.
[0060] In the wafer epitaxial growth equipment of this embodiment, the first surface of the preheating ring includes a first region and a second region that are symmetrically distributed with respect to the first central axis of the annular body. The distance between the first region and the second region is 240 mm - 300 mm. At least one groove is provided in each of the first region and the second region, and the extending direction of the groove is parallel to the first central axis. During the epitaxial deposition process, when a silicon source gas is introduced into the reaction chamber, due to the grooves provided in the first region and the second region, the silicon source gas will have a larger contact area with the first region and the second region, and more silicon source gas will flow through the first region and the second region. The temperature of the silicon source gas flowing through the first region and the second region will also increase significantly. The silicon source gas flowing through the first region and the second region is used for epitaxial growth at the edge of the silicon wafer, which can improve the epitaxial growth rate at the edge position of the silicon wafer and reduce the difference in the epitaxial layer thickness between the edge region and the central region of the epitaxial silicon wafer. An epitaxial silicon wafer with better epitaxial layer flatness can be obtained through the present invention.
[0061] An embodiment of the present invention also provides an epitaxial growth method, which is applied to the wafer epitaxial growth equipment as described above. The method includes:
[0062] Place the silicon wafer on the base such that the central axis of the silicon wafer is aligned with the first central axis;
[0063] Transport the silicon source gas into the reaction chamber through the gas inlet of the wafer epitaxial growth equipment to grow an epitaxial layer on the silicon wafer;
[0064] The temperature and flow rate of the silicon source gas flowing through the first region and the second region are greater than the temperature of the silicon source gas flowing through other regions of the preheating ring, so as to make the thickness of the epitaxial layer grown on the silicon wafer uniform;
[0065] Discharge the reaction tail gas generated by the epitaxial growth out of the reaction chamber through the exhaust port of the wafer epitaxial growth equipment.
[0066] In this embodiment, the silicon wafer is placed on the base such that the central axis of the silicon wafer is aligned with the first central axis. During the epitaxial deposition process, when introducing the silicon source gas into the reaction chamber, due to the grooves provided in the first region and the second region, the silicon source gas will have a larger contact area with the first region and the second region, more silicon source gas will flow through the first region and the second region, and the temperature of the silicon source gas flowing through the first region and the second region will also increase significantly. The silicon source gas flowing through the first region and the second region is used for epitaxial growth at the edge of the silicon wafer, thereby increasing the epitaxial growth rate at the edge position of the silicon wafer, while the growth rate of the epitaxial layer in other regions of the silicon wafer remains unchanged. In this way, the difference in the thickness of the epitaxial layer between the edge region and the central region of the epitaxial silicon wafer can be reduced, and an epitaxial silicon wafer with better epitaxial layer flatness can be obtained through the present invention.
[0067] An embodiment of the present invention further provides an epitaxial silicon wafer, which is prepared by using the above-described epitaxial growth method. The uniformity of the thickness of the epitaxial layer of the epitaxial silicon wafer prepared in this embodiment is better, and the thickness uniformity of the epitaxial silicon wafer can be reduced by 0.4%. The difference between the thickness of the epitaxial layer in the edge region and the thickness of the epitaxial layer in the central region of the epitaxial silicon wafer is not greater than 0.02 microns, and at the same time, the flatness of the epitaxial silicon wafer is also greatly improved.
[0068] It should be noted that the various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other, and the key point of each embodiment is to illustrate the differences from other embodiments. In particular, for the method embodiment, since it is basically similar to the product embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the product embodiment.
[0069] Unless otherwise defined, the technical terms or scientific terms used in this disclosure should have the ordinary meaning understood by those of ordinary skill in the field to which this disclosure belongs. The "first", "second" and similar terms used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. The terms such as "including" or "comprising" mean that the elements or objects appearing before this term cover the elements or objects listed after this term and their equivalents, without excluding other elements or objects. The terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left" and "right" are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.
[0070] It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" or "under" another element, the element can be "directly" on or under the other element, or intervening elements may be present.
[0071] 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 a suitable manner.
[0072] As described above, the specific embodiments of the present disclosure are only provided, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present disclosure, and all such changes or substitutions should be covered by the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.
Claims
1. A preheating ring, comprising an annular body, characterized in that: The annular body comprises a first surface for preheating the reaction gas entering the reaction chamber of the wafer epitaxial growth device, and the first surface is located on the same side as the bearing surface of the base for bearing the silicon wafer in the wafer epitaxial growth device. Wherein, the first surface includes a first area and a second area symmetrically distributed relative to a first central axis of the annular body, and a distance between the first area and the second area is 240 mm-300 mm; The first region and the second region are respectively provided with at least one groove, and an extending direction of the groove is parallel to the first central axis.
2. The preheating ring according to claim 1, characterized in that: The first area and the second area are respectively provided with a plurality of grooves.
3. The preheating ring according to claim 2, characterized in that: The first area and the second area are respectively provided with 5-6 grooves.
4. The preheating ring according to any one of claims 1 to 3, characterized in that: The longitudinal section of the groove is semicircular.
5. The preheating ring according to claim 4, characterized in that: The radius of the semicircle is 2.5-3.5 mm.
6. The preheating ring according to claim 1, characterized in that: When the first area and the second area are respectively provided with a plurality of grooves, the interval between two adjacent grooves is 0-0.5 mm.
7. A wafer epitaxial growth device, characterized in that: It comprises the preheating ring according to any one of claims 1 to 6 and a base for carrying a silicon wafer, wherein the carrying surface of the base is located inside the preheating ring.
8. An epitaxial growth method, characterized in that: Applied to the wafer epitaxial growth device as claimed in claim 7, the method comprising: placing a silicon wafer on the susceptor such that a central axis of the silicon wafer is aligned with the first central axis; Delivering a silicon source gas into a reaction chamber through a gas inlet of the wafer epitaxial growth device to grow an epitaxial layer on the silicon wafer; The temperature and flow rate of the silicon source gas flowing through the first area and the second area are greater than the temperature of the silicon source gas flowing through other areas of the preheating ring, so that the thickness of the epitaxial layer grown on the silicon wafer is uniform; The reaction tail gas generated by the epitaxial growth is discharged from the reaction chamber through the exhaust port of the wafer epitaxial growth equipment.
9. An epitaxial silicon wafer, characterized in that: Prepared by the epitaxial growth method according to claim 8, the difference between the thickness of the epitaxial layer in the edge area of the epitaxial silicon wafer and the thickness of the epitaxial layer in the central area of the epitaxial silicon wafer is no more than 0.02 microns.