Wafer pedestal, chemical vapor deposition apparatus and method of use
By adjusting the height and contact conditions of the bosses, the problem of uneven heating of the wafers was solved, achieving uniform heating and stress on the wafers, preventing scratches, and extending the service life of the equipment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ADVANCED MICRO FAB EQUIP INC CHINA
- Filing Date
- 2021-12-02
- Publication Date
- 2026-06-09
AI Technical Summary
In 3D NAND applications, during the CVD tungsten gate process, the wafer is bent into an irregular shape due to high stress, resulting in a large difference in height between the center and the edge of the wafer, uneven support of the bosses, uneven heating of the wafer and local scratches.
By adjusting the height of each boss exposed above the heater, the contact between the boss and the wafer can be adjusted. The threaded hole and threaded rod design allows the boss to support different types of wafers, ensuring uniform heat distribution.
It achieves uniform heating and stress on the wafer, prevents localized scratches, extends the service life of the wafer base, and adjusts the boss height in real time through a detection device to ensure uniform heat distribution.
Smart Images
Figure CN116230615B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to a wafer substrate, chemical vapor deposition equipment, and method of using it. Background Technology
[0002] In a wafer processing cavity, a heater is typically located above the substrate. The upper surface of the heater usually has multiple bosses fixed to it to support the wafer. In the traditional design of the bosses, all bosses have the same height. Bosses of the same height can support a completely flat wafer and ensure that the wafer is heated and stressed evenly.
[0003] However, in CVD tungsten gate deposition processes used in 3D NAND applications, high stress can cause the wafers entering the cavity to bend and exhibit irregular shapes, such as warped edges and a collapsed bowl shape in the center. Furthermore, the height difference between the wafer center and the edge may exceed 200 μm. In such cases, if bosses of uniform height are used to support the wafer, only the wafer center will contact the bosses, resulting in uneven stress on the wafer and a significantly higher temperature at the wafer center than at the edge. This further exacerbates uneven heating and severe localized scratches. Summary of the Invention
[0004] The purpose of this invention is to provide a wafer substrate, a chemical vapor deposition apparatus, and a method of using it. By adjusting the height of each protrusion exposed above the heater, the wafer substrate can support different types of wafers and adjust the heat distribution on the wafers, thereby ensuring that different types of wafers are heated and stressed evenly.
[0005] To achieve the above objectives, the present invention is implemented through the following technical solution:
[0006] A wafer substrate, comprising:
[0007] A heater, used to heat the wafer to be processed;
[0008] A plurality of protrusions are spaced apart on the heater; one end of each protrusion is connected to the heater; and the height of each protrusion exposed above the heater is adjustable so that the other end of each protrusion can support the wafer.
[0009] Preferably, the upper surface of the heater is provided with a plurality of threaded holes, and one end of the boss is screwed into the corresponding threaded hole.
[0010] Preferably, each of the bosses is a threaded rod; one end of the threaded rod is screwed into the corresponding threaded hole, and the other end contacts and supports the back of the wafer; and each threaded rod is screwed into or out of the corresponding threaded hole to adjust the height of the threaded rod exposed above the heater.
[0011] Preferably, each of the bosses further includes a fixing rod; one end of each fixing rod is disposed on the end of the corresponding threaded rod away from the heater, and the other end of the fixing rod contacts the back side of the wafer and supports the wafer.
[0012] Preferably, each of the fixed rods has a limiting portion at one end near the threaded rod.
[0013] Preferably, all the fixing rods are of the same height.
[0014] Preferably, all the threaded holes are arranged in a matrix.
[0015] Preferably, all the threaded holes are arranged in one or more concentric circle arrays, and all the threaded holes in each concentric circle array are spaced apart.
[0016] Preferably, both the threaded rod and the fixed rod are made of thermally conductive materials, and the coefficients of thermal expansion of both the threaded rod and the fixed rod are the same as the coefficient of thermal expansion of the heater.
[0017] Preferably, both the threaded rod and the fixing rod are made of ceramic coated with diamond-like carbon.
[0018] Preferably, purge gas is introduced into the gap formed between the boss and the wafer and into the area below the wafer where no boss is installed.
[0019] On the other hand, the present invention also provides a chemical vapor deposition apparatus, comprising: a chemical vapor deposition reaction chamber; a wafer substrate as described above, wherein the wafer substrate is disposed at the bottom of the interior of the chemical vapor deposition reaction chamber; and a detection device, which includes a laser emitter, a pyrometer, and a signal detection device.
[0020] On the other hand, the present invention also provides a method of using a wafer substrate in a chemical vapor deposition apparatus as described above, comprising:
[0021] The light emitted by the laser emitter is reflected by the wafer surface;
[0022] The signal detection device receives the light intensity signal of the reflected light to determine the degree of warping of the crystal surface, and adjusts the height of each protrusion based on the obtained warping information so that one end of the protrusion supports the wafer.
[0023] A pyrometer detects the heating condition of the wafer surface, and adjusts the contact or non-contact of each boss with the wafer based on the obtained heating information.
[0024] Preferably, when the wafer warps, the height of each of the bosses exposed above the heater is equal to the height between the corresponding back surface of the wafer and the upper surface of the heater, so that each of the bosses supports the warped wafer.
[0025] Preferably, the boss includes a fixing rod and a limiting portion near one end of the fixing rod near the threaded rod. When the wafer is flat, the limiting portion of each fixing rod abuts against the heater so that each boss supports the flat wafer.
[0026] Preferably, when a local area of the wafer is overheated, the corresponding protrusion in that area is adjusted to move away from the wafer; when a local area of the wafer is underheated, the corresponding protrusion in that area is adjusted to move closer to or contact the wafer.
[0027] Compared with the prior art, the present invention has at least one of the following advantages:
[0028] The present invention provides a wafer substrate, a chemical vapor deposition apparatus and a method of using it. The height of each protrusion exposed above the heater is adjustable, so that each protrusion can contact the back side of the flat or warped wafer, thereby supporting different types of wafers and ensuring that different types of wafers are heated and stressed evenly.
[0029] In this invention, the threaded holes arranged in a matrix or in a concentric circle array can be evenly distributed on the heater, so that the bosses screwed into the corresponding threaded holes are also evenly distributed on the heater, so as to evenly support the wafer, thereby making the wafer heated and stressed evenly.
[0030] In this invention, when the wafer warps, the height of each protrusion exposed above the heater can be equal to the height between the corresponding back surface of the wafer and the upper surface of the heater, so that each protrusion can support the warped wafer.
[0031] In this invention, all the fixing rods are at the same height, so when the wafer is flat, the limiting part of the fixing rod in each boss can abut against the heater, so that each boss can support the flat wafer and effectively improve the adjustment efficiency of the boss.
[0032] In addition, the contact between each protrusion and the wafer can be adjusted according to the heating condition of the wafer surface to adjust the heat distribution on the wafer, thereby preventing local areas of the wafer from being overheated or underheated, and thus ensuring the uniformity of the wafer heating.
[0033] Each boss in this invention is easy to replace, and replacing the boss can effectively extend the service life of the wafer substrate. Attached Figure Description
[0034] Figure 1 This is a schematic diagram of the structure of a wafer base during wafer warpage according to an embodiment of the present invention;
[0035] Figure 2 This is a schematic diagram of the structure of a wafer substrate during wafer planarization according to an embodiment of the present invention;
[0036] Figure 3 This is a schematic diagram of the structure of a boss in a wafer substrate provided in an embodiment of the present invention. Detailed Implementation
[0037] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a further detailed explanation of the wafer substrate, chemical vapor deposition equipment, and method of use proposed in this invention. The advantages and features of this invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, intended only to facilitate and clarify the illustration of the embodiments of this invention. Please refer to the drawings to make the objectives, features, and advantages of this invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for illustrative purposes to aid those skilled in the art and are not intended to limit the implementation conditions of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effects and objectives achieved by this invention, should still fall within the scope of the technical content disclosed in this invention.
[0038] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0039] Combined with appendix Figures 1-3This embodiment provides a wafer substrate, including: a heater 120 for heating a wafer 100 to be processed; a plurality of protrusions 110 spaced apart on the heater 120; one end of each protrusion 110 is connected to the heater 120; and the height of each protrusion 110 exposed above the heater 120 is adjustable so that the other end of each protrusion 110 can contact the lower surface of the wafer 100 to support the wafer 100 or change the distance between the upper surface of the protrusion 110 and the lower surface of the wafer 100.
[0040] Please also refer to Figure 1 and Figure 2 The heater 120 has a plurality of threaded holes on its upper surface, and one end of each boss 110 is screwed into the corresponding threaded hole.
[0041] It is understood that in some other embodiments, all the said threaded holes are arranged in a matrix.
[0042] In some embodiments, all the threaded holes are arranged in one or more concentric circle arrays, and all the threaded holes in each concentric circle array are spaced apart.
[0043] In some embodiments, a purge gas, such as argon, is introduced into the gap formed between the boss 110 and the wafer 100 and into the area below the wafer 100 where no boss is installed, to provide back pressure to the wafer 100.
[0044] Specifically, the heat generated by the heater 120 can be transferred to the wafer 100 through both radiative and contact heat transfer, allowing a thin film to form on the surface of the wafer 100 during the deposition process. The contact heat transfer between the heater 120 and the wafer 100 is achieved by the bosses 110 fixed to the heater 120 and supporting the wafer 100. More specifically, the threaded holes arranged in a matrix or concentric array can be evenly distributed on the heater 120, and the bosses 110 screwed into the corresponding threaded holes are also evenly distributed on the heater 120, providing uniform support for the wafer 100. This ensures uniform heating and stress on the wafer 100, thereby guaranteeing the uniformity of the thin film formed on the surface of the wafer 100 during the deposition process and preventing severe localized scratches on the back side of the wafer 100. However, this invention is not limited to these limitations.
[0045] In other embodiments, all the threaded holes can also be uniformly distributed on the heater in other ways, but the invention is not limited thereto.
[0046] Please also refer to Figure 1 , Figure 2 and Figure 3 Each of the bosses 110 is a threaded rod 1101; one end of the threaded rod 1101 is screwed into the corresponding threaded hole, and the other end contacts and supports the back of the wafer 100; and each of the threaded rods 1101 is screwed into or out of the corresponding threaded hole to adjust the height of the threaded rod 1101 exposed above the heater 120.
[0047] Specifically, in this embodiment, the height of the corresponding boss 110 exposed above the heater 120 can be adjusted by adjusting the screw-in depth of each threaded rod 1101. If the wafer 100 is flat, the height of all the bosses 110 exposed above the heater 120 is the same, so that each boss 110 can support the flat wafer, thereby making the flat wafer heated and stressed evenly. If the wafer 100 is warped, the height of each boss 110 exposed above the heater 120 is equal to the height between the back surface of the corresponding wafer 100 and the upper surface of the heater 120, so that each boss 110 can support the warped wafer, thereby making the warped wafer also heated and stressed evenly. However, the present invention is not limited thereto.
[0048] Specifically, in this embodiment, if a localized area of the wafer 100 is overheated, the screw-in depth of the threaded rod 1101 in that area can be adjusted so that the corresponding boss 110 is no longer in contact with the wafer 100. This means the boss 110 in that area no longer supports the wafer 100, thus changing the contact heat transfer between the boss 110 and the wafer 100 to radiative heat transfer, thereby reducing the heat transfer rate in that area and ensuring uniform heating of the wafer 100. Conversely, if a localized area of the wafer is underheated, the screw-in depth of the threaded rod 1101 in that area can be adjusted so that the corresponding boss 110 is closer to or in contact with the wafer 100. This means the boss 110 in that area supports the wafer 100, thereby enhancing radiative heat transfer between the boss 110 and the wafer 100 or changing radiative heat transfer to contact heat transfer, thereby increasing the heat transfer rate in that area and ensuring uniform heating of the wafer 100. More specifically, when the protrusion 110 corresponding to the overheated area does not contact the wafer 100, there will be a gap between each protrusion 110 and the wafer 100. The size of the gap can be determined according to the specific temperature of the wafer and the specific temperature adjustment measures, but the present invention is not limited thereto.
[0049] Please continue to refer to this. Figure 3Each of the bosses 110 further includes a fixing rod 1102; one end of each fixing rod 1102 is disposed on the end of the corresponding threaded rod 1101 away from the heater 120, and the other end of the fixing rod 1102 contacts the back side of the wafer 100 and supports the wafer 100.
[0050] It is understood that in some other embodiments, each of the fixed rods 1102 is provided with a limiting part 1103 at one end near the threaded rod 1101.
[0051] In some embodiments, all of the fixing rods 1102 have the same height.
[0052] Specifically, in this embodiment, when the wafer 100 is flat, the limiting part 1103 of the corresponding fixing rod 1102 can be made to abut against the heater 120 by adjusting the screw-in depth of each threaded rod 1101. At this time, the height of each boss 110 exposed above the heater 120 is the height of the corresponding fixing rod 1102. Since the height of all fixing rods 1102 is the same, the height of each boss 110 exposed above the heater 120 is also the same, so that each boss 110 can support the flat wafer and effectively improve the adjustment efficiency of the boss 110. However, the present invention is not limited thereto.
[0053] Please also refer to Figure 1 and Figure 2 The threaded rod 1101 and the fixed rod 1102 are both made of thermally conductive materials, and the coefficients of thermal expansion of the threaded rod 1101 and the fixed rod 1102 are the same as the coefficients of thermal expansion of the heater 120.
[0054] In some embodiments, the threaded rod 1101 and the fixing rod 1102 are both made of ceramic coated with diamond-like carbon.
[0055] Specifically, in this embodiment, the threaded rod 1101 and the fixing rod 1102 in each of the bosses 110 are made of thermally conductive material, so that each boss 110 has good thermal conductivity, thereby enabling contact heat transfer between the heater 120 and the wafer 100. Simultaneously, the threaded rod 1101 and the fixing rod 1102 in each of the bosses 110 have similar or the same coefficient of thermal expansion as the heater 120, so that under the same temperature change conditions, each boss 110 and the heater 120 exhibit the same volume change. This ensures that each boss 110 can always be stably fixed in the corresponding threaded hole on the heater 120, thereby stably supporting the wafer 100. However, this invention is not limited to this.
[0056] On the other hand, this embodiment also provides a chemical vapor deposition apparatus, including: a chemical vapor deposition reaction chamber; a wafer substrate as described above, wherein the wafer substrate is disposed at the bottom of the interior of the chemical vapor deposition reaction chamber; and a detection device, which includes a laser emitter, a pyrometer, and a signal detection device.
[0057] Specifically, in this embodiment, the laser emitter is used to emit a laser beam toward the wafer 100; the signal detection device can receive the light intensity signal of the laser beam reflected from the surface of the wafer 100 to obtain the degree of warpage of the wafer 100 surface, thereby facilitating the adjustment of the height of each protrusion 110 in the wafer pedestal exposed above the heater 120. The pyrometer is used to detect the heating condition of the wafer 100 surface to adjust the contact condition between each protrusion 110 and the wafer 100, thereby preventing local areas of the wafer 100 from being overheated or underheated, but the present invention is not limited thereto.
[0058] On the other hand, this embodiment also provides a method for using a wafer pedestal in a chemical vapor deposition apparatus as described above, including: step S1, light emitted by a laser emitter is reflected by the surface of wafer 100; step S2, a signal detection device receives the light intensity signal of the reflected light to determine the degree of warping of the crystal surface, and adjusts the height of each protrusion 110 based on the obtained warping information so that one end of the protrusion 110 supports the wafer 100; step S3, a pyrometer detects the heating condition of the surface of wafer 100, and adjusts each protrusion 110 to contact or not contact the wafer 100 based on the obtained heating condition information.
[0059] It is understood that in some other embodiments, when the wafer 100 warps, the height of each of the bosses 110 exposed above the heater 120 is equal to the height between the corresponding back surface of the wafer 100 and the upper surface of the heater 120, so that each of the bosses 110 supports the warped wafer.
[0060] In some embodiments, the boss 110 includes a fixing rod 1102 and a limiting portion 1103 of the fixing rod 1102 near one end of the threaded rod 1101. When the wafer 100 is flat, the limiting portion 1103 of each fixing rod 1102 abuts against the heater 120 so that each boss 110 supports the flat wafer.
[0061] In other embodiments, when a local area of the wafer 100 is overheated, the corresponding protrusion 110 is adjusted to move away from the wafer; when a local area of the wafer 110 is underheated, the corresponding protrusion 110 is adjusted to move closer to or contact the wafer.
[0062] In summary, this embodiment provides a wafer substrate, a chemical vapor deposition apparatus, and a method of use. All protrusions are spaced apart on the heater, and the height of each protrusion exposed above the heater is adjustable, allowing each protrusion to contact the flat or warped back side of the wafer, thereby supporting different types of wafers. In this embodiment, the threaded holes arranged in a matrix or concentric array can be evenly distributed on the heater, ensuring that the protrusions screwed into the corresponding threaded holes are also evenly distributed on the heater, thus uniformly supporting the wafer and ensuring uniform heating and stress on the wafer. In this embodiment, the contact between each protrusion and the wafer can be adjusted according to the heating condition of the wafer surface to adjust the heat distribution on the wafer, thereby preventing excessive or insufficient heating in local areas of the wafer and ensuring uniform heating of the wafer.
[0063] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.
Claims
1. A wafer substrate, characterized in that, include: A heater, used to heat the wafer to be processed; A plurality of protrusions are spaced apart on the heater; one end of each protrusion is connected to the heater; and the height of each protrusion exposed above the heater is adjustable so that the other end of each protrusion may or may not contact the wafer. The heater has several threaded holes on its upper surface. Each boss is a threaded rod, and one end of each boss is screwed into the corresponding threaded hole.
2. The wafer substrate as described in claim 1, characterized in that, One end of the threaded rod is screwed into the corresponding threaded hole, and the other end contacts and supports the back of the wafer; and each threaded rod is screwed into or out of the corresponding threaded hole to adjust the height of the threaded rod exposed above the heater.
3. The wafer substrate as described in claim 2, characterized in that, Each of the bosses further includes a fixing rod; one end of each fixing rod is disposed on the end of the corresponding threaded rod away from the heater, and the other end of the fixing rod contacts the back side of the wafer and supports the wafer.
4. The wafer substrate as described in claim 3, characterized in that, Each of the fixed rods has a limiting part at one end near the threaded rod.
5. The wafer substrate as described in claim 3, characterized in that, All the aforementioned fixing rods are at the same height.
6. The wafer substrate as described in claim 1, characterized in that, All the threaded holes are arranged in a matrix.
7. The wafer substrate as described in claim 1, characterized in that, All the threaded holes are arranged in one or more concentric circle arrays, and all the threaded holes in each concentric circle array are spaced apart.
8. The wafer substrate as described in claim 3, characterized in that, Both the threaded rod and the fixed rod are made of thermally conductive materials, and their coefficients of thermal expansion are the same as those of the heater.
9. The wafer substrate as described in claim 3, characterized in that, Both the threaded rod and the fixing rod are made of ceramic coated with diamond-like carbon.
10. The wafer substrate as claimed in claim 1, characterized in that, Purge gas is introduced into the gap formed between the boss and the wafer and into the area below the wafer where no boss is installed.
11. A chemical vapor deposition apparatus, characterized in that, include: Chemical vapor deposition reaction chamber; The wafer substrate as described in any one of claims 1 to 10, wherein the wafer substrate is disposed at the bottom of the interior of the chemical vapor deposition reaction chamber; The detection device includes a laser emitter, a pyrometer, and a signal detection device.
12. A method of using a wafer substrate in a chemical vapor deposition apparatus as described in claim 11, characterized in that, include: The light emitted by the laser emitter is reflected by the wafer surface; The signal detection device receives the light intensity signal of the reflected light to determine the degree of warping of the crystal surface, and adjusts the height of each protrusion based on the obtained warping information so that one end of the protrusion supports the wafer. A pyrometer detects the heating condition of the wafer surface, and adjusts the contact or non-contact of each boss with the wafer based on the obtained heating information.
13. The method of using a wafer substrate in a chemical vapor deposition apparatus as described in claim 12, characterized in that, When the wafer warps, the height of each of the bosses exposed above the heater is equal to the height between the corresponding back surface of the wafer and the upper surface of the heater, so that each of the bosses supports the warped wafer.
14. The method of using a wafer substrate in a chemical vapor deposition apparatus as described in claim 12, characterized in that, The boss includes a fixing rod and a limiting part near one end of the fixing rod. When the wafer is flat, the limiting part of each fixing rod abuts against the heater so that each boss supports the flat wafer.
15. The method of using a wafer substrate in a chemical vapor deposition apparatus as described in claim 12, characterized in that, When a local area of the wafer is overheated, the corresponding protrusion in that area is adjusted to move away from the wafer; when a local area of the wafer is underheated, the corresponding protrusion in that area is adjusted to move closer to or in contact with the wafer.