High-temperature furnace temperature control silicon wafer and method for prolonging service life of high-temperature furnace temperature control silicon wafer
By setting an oxide layer on the substrate layer of the high-temperature furnace temperature-controlled silicon wafer and setting support sites to connect the crystal boat, combined with the method of rotating the silicon wafer regularly, the problem of deformation of the temperature-controlled silicon wafer in high-temperature environment is solved, extending its service life, improving production efficiency and reducing costs.
Patent Information
- Application Number
- CN202411801352.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-09
- Publication Date
- 2025-03-14
AI Technical Summary
The temperature-controlled silicon wafers in existing high-temperature diffusion furnaces are prone to soften in high-temperature environments, resulting in deformation, which in turn affects the manipulator grabbing and uniform oxidation of wafers, increasing production costs and reducing production efficiency.
An oxide layer is provided on the substrate layer of the high-temperature furnace temperature-controlled silicon wafer, and the thermal expansion coefficient of the oxide layer is smaller than the thermal expansion coefficient of the substrate layer, and several supporting sites are provided on the silicon wafer, through which the crystal boat is connected. Regularly rotate the high-temperature furnace temperature-controlled silicon wafer to change its stress point and direction to delay deformation.
Through the setting of the oxide layer, the thermal stress deformation of the high-temperature furnace temperature-controlled silicon wafer is reduced and its service life is extended. By rotating the silicon wafer regularly, changing the stress point and direction, the deformation is further delayed, and the service life of the silicon wafer is significantly improved.
Smart Images
Figure CN119626891A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of semiconductor chip manufacturing, and in particular relates to a high-temperature furnace temperature-controlled silicon wafer and a method for extending the service life of the high-temperature furnace temperature-controlled silicon wafer. Background Art
[0002] Since the working principle of the vertical high-temperature diffusion furnace is air intake at the furnace mouth and exhaust at the furnace tail, the uniformity of the oxide layer grown on the wafer surface that is directly impacted by the airflow in the furnace tube is often poor, far from meeting product requirements. In order to ensure the uniformity of the oxide layer, dummy wafers are needed to block the wafers in the middle of the dummy wafers, so the dummy wafers are also called temperature-controlled silicon wafers.
[0003] The temperature-controlled silicon wafers placed at the furnace mouth and furnace tail are used in an environment above 1050℃. In a high temperature environment, the texture of the temperature-controlled silicon wafers will become soft, and the places without support points of the temperature-controlled silicon wafers will deform downward under the influence of their own gravity. If the deformation is too large, it will cause accidents such as the robot arm being unable to grasp, the wafer hitting the wafer boat, or the temperature-controlled silicon wafer scratching the product. In order to reduce the risk, the temperature-controlled silicon wafers need to be replaced regularly, which increases production costs and reduces production efficiency. Therefore, it is necessary to extend the service life of the temperature-controlled silicon wafers used in high-temperature diffusion furnaces. Summary of the invention
[0004] In order to solve the above problems existing in the prior art, the present invention provides a high temperature furnace temperature control silicon wafer and a method for extending the service life of the high temperature furnace temperature control silicon wafer. The technical problem to be solved by the present invention is achieved by the following technical solutions:
[0005] The present invention provides a high-temperature furnace temperature-controlled silicon wafer, which can be adjusted and arranged on a wafer boat. The high-temperature furnace temperature-controlled silicon wafer comprises: a substrate layer and an oxide layer arranged in sequence, wherein the thermal expansion coefficient of the oxide layer is smaller than the thermal expansion coefficient of the substrate layer; and the thickness of the oxide layer is not less than 1% of the thickness of the substrate layer.
[0006] In one embodiment of the present invention, the oxide layer covers at least one side surface of the high temperature furnace temperature-controlled silicon wafer, so as to reduce thermal stress deformation of the high temperature furnace temperature-controlled silicon wafer during a high temperature diffusion process.
[0007] In one embodiment of the present invention, the material of the substrate layer is silicon, and the thickness of the substrate layer is 725 μm; the material of the oxide layer is silicon oxide, and the thickness of the oxide layer is 7 μm.
[0008] In one embodiment of the present invention, the high temperature furnace temperature-controlled silicon wafer is evenly provided with a plurality of supporting sites along the circumference, and the wafer boat is connected via at least two of the supporting sites.
[0009] In one embodiment of the present invention, the angular interval between any two adjacent support sites is 90°.
[0010] The present invention also provides a method for extending the service life of a high-temperature furnace temperature-controlled silicon wafer, using the high-temperature furnace temperature-controlled silicon wafer, the method comprises:
[0011] Step 1: preparing an oxide layer on a silicon wafer provided with a plurality of supporting sites to obtain a high-temperature furnace temperature-controlled silicon wafer;
[0012] Step 2: Loading a plurality of the high temperature furnace temperature-controlled silicon wafers and a plurality of product wafers onto a wafer boat through a plurality of the supporting sites, and performing a high temperature diffusion process in a high temperature diffusion furnace along with the wafer boat;
[0013] Step 3: Rotate a plurality of the high temperature furnace temperature-controlled silicon wafers and reload them onto the wafer boat through a plurality of the supporting sites.
[0014] In one embodiment of the present invention, the step 1 comprises:
[0015] A silicon wafer provided with a plurality of supporting sites is placed in an oxidation furnace, a first reaction gas is introduced, and the oxidation temperature is set to 1200°C to form a dense oxide layer on the surface of the silicon wafer to obtain a high-temperature furnace temperature-controlled silicon wafer; wherein the first reaction gas is oxygen.
[0016] In one embodiment of the present invention, the step 2 comprises:
[0017] A plurality of the high temperature furnace temperature-controlled silicon wafers and a plurality of product wafers are loaded onto the wafer boat together, wherein at least one of the high temperature furnace temperature-controlled silicon wafers is located at the head end of the wafer boat, and at least one of the high temperature furnace temperature-controlled silicon wafers is located at the tail end of the wafer boat; a plurality of the product wafers are located between the high temperature furnace temperature-controlled silicon wafer at the head end of the wafer boat and the high temperature furnace temperature-controlled silicon wafer at the tail end of the wafer boat, and the oxide layer of each of the high temperature furnace temperature-controlled silicon wafers is placed away from the product wafers.
[0018] In one embodiment of the present invention, step 3 comprises:
[0019] After the warpage on any of the high-temperature furnace temperature-controlled silicon wafers exceeds 50 μm, the high-temperature furnace temperature-controlled silicon wafer with the warpage exceeding 50 μm is rotated 90° and reloaded onto the wafer boat through a plurality of the supporting sites until the high-temperature furnace temperature-controlled silicon wafer with the warpage exceeding 50 μm is rotated at least 360°.
[0020] In one embodiment of the present invention, the step 3 further includes:
[0021] The plurality of high temperature furnace temperature controlled silicon wafers are rotated 90° regularly and reloaded onto the wafer boat through the plurality of supporting sites until the plurality of high temperature furnace temperature controlled silicon wafers are rotated at least 360°.
[0022] Compared with the prior art, the present invention has the following beneficial effects:
[0023] The high-temperature furnace temperature-controlled silicon wafer of the present invention is provided with an oxide layer on the substrate layer. Since the thermal expansion coefficient of the oxide layer is smaller than that of the unoxidized substrate layer, under the same temperature conditions, the deformation of the oxide layer is smaller than that of the substrate layer. Therefore, the oxide layer exerts a force opposite to the deformation direction on the high-temperature furnace temperature-controlled silicon wafer as a whole, thereby delaying the deformation occurring on the high-temperature furnace temperature-controlled silicon wafer.
[0024] The method for extending the service life of a high-temperature furnace temperature-controlled silicon wafer of the present invention, under the premise of ensuring the normal use of the high-temperature furnace temperature-controlled silicon wafer, changes the force points and force directions on the high-temperature furnace temperature-controlled silicon wafer by periodic rotation, thereby delaying the deformation of the high-temperature furnace temperature-controlled silicon wafer and extending the service life of the high-temperature furnace temperature-controlled silicon wafer.
[0025] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following specifically cites a preferred embodiment and describes it in detail with the accompanying drawings as follows. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 It is a structural schematic diagram of an existing crystal boat;
[0027] Figure 2 is a cross-sectional schematic diagram of a temperature-controlled silicon wafer in a high-temperature furnace provided by an embodiment of the present invention;
[0028] Figure 3a 0° position schematic diagram of a temperature-controlled silicon wafer in a high-temperature furnace provided by an embodiment of the present invention;
[0029] Figure 3b It is a schematic diagram of the 90° position of a temperature-controlled silicon wafer in a high-temperature furnace provided by an embodiment of the present invention;
[0030] Figure 4 The present invention provides a flowchart of a method for extending the service life of a silicon wafer controlled by a high temperature furnace.
[0031] Icons: 1- high temperature furnace temperature controlled silicon wafer; 11- substrate layer; 12- oxide layer; 13- support site; 10- wafer boat. DETAILED DESCRIPTION
[0032] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the following is a detailed description of a high-temperature furnace temperature-controlled silicon wafer and a method for extending the service life of a high-temperature furnace temperature-controlled silicon wafer proposed in accordance with the present invention in combination with the accompanying drawings and specific implementation methods.
[0033] The above and other technical contents, features and effects of the present invention are clearly presented in the following detailed description of the specific implementation modes in conjunction with the accompanying drawings. Through the description of the specific implementation modes, the technical means and effects adopted by the present invention to achieve the predetermined purpose can be more deeply and specifically understood. However, the attached drawings are only for reference and explanation purposes and are not used to limit the technical solutions of the present invention.
[0034] The structural diagram of an existing crystal boat is as follows Figure 1 As shown, the temperature-controlled silicon wafer is loaded on the wafer boat and located at the furnace mouth and furnace tail of the vertical high-temperature diffusion furnace. The temperature-controlled silicon wafer blocks the front impact of the airflow in the furnace tube to ensure the uniformity of the oxide layer grown on the surface of the wafer. However, the texture of the temperature-controlled silicon wafer will become soft in a high-temperature environment. If the deformation is too large, it will affect normal production and need to be replaced regularly. In order to extend the service life of the temperature-controlled silicon wafer, the present invention provides a high-temperature furnace temperature-controlled silicon wafer and a method for extending the service life of the high-temperature furnace temperature-controlled silicon wafer.
[0035] Embodiment 1
[0036] like Figure 1 and Figure 2 As shown, Figure 1 It is a structural schematic diagram of an existing crystal boat; Figure 2 It is a cross-sectional schematic diagram of a temperature-controlled silicon wafer in a high-temperature furnace provided in an embodiment of the present invention.
[0037] The present embodiment provides a high-temperature furnace temperature-controlled silicon wafer 1, which can be adjusted on a wafer boat 10. The high-temperature furnace temperature-controlled silicon wafer 1 includes: a substrate layer 11 and an oxide layer 12 arranged in sequence, wherein the thermal expansion coefficient of the oxide layer 12 is smaller than the thermal expansion coefficient of the substrate layer 11; and the thickness of the oxide layer 12 is not less than 1% of the thickness of the substrate layer 11.
[0038] In an optional embodiment, the material of the substrate layer 11 is silicon (Si), and the thickness of the substrate layer 11 is 725 μm.
[0039] In an optional embodiment, the material of the oxide layer 12 is silicon oxide (SiO), and the thickness of the oxide layer 12 is 7 μm.
[0040] like Figure 3a and Figure 3b As shown, Figure 3a 0° position schematic diagram of a temperature-controlled silicon wafer in a high-temperature furnace provided by an embodiment of the present invention; Figure 3bIt is a schematic diagram of the 90° position of a temperature-controlled silicon wafer in a high-temperature furnace provided in an embodiment of the present invention.
[0041] In an optional embodiment, a plurality of supporting sites 13 are evenly arranged along the circumference of the high temperature furnace temperature-controlled silicon wafer 1 , and the wafer boat 10 is connected via at least two supporting sites 13 .
[0042] In an optional embodiment, the angular interval between any two adjacent supporting sites 13 is 90°.
[0043] Exemplarily, only three supporting points are provided on the wafer boat 10, which are used to connect the supporting points 13 of the high-temperature furnace temperature-controlled silicon wafer 1. The angle interval between two adjacent supporting points on the wafer boat 10 is 90°. When the high-temperature furnace temperature-controlled silicon wafer 1 is loaded on the wafer boat 10, at least one supporting point 13 will be left without support. Under the action of the high temperature in the vertical high-temperature diffusion furnace, the texture of the high-temperature furnace temperature-controlled silicon wafer 1 will become soft, thereby causing deformation of the position that loses support.
[0044] In view of this, a high-temperature oxidation furnace is used to grow an oxide layer 12 of about 1% of its own thickness on the upper surface of the high-temperature furnace temperature-controlled silicon wafer 1. After the oxide layer 12 is grown, it is used according to the normal process. Since the thermal expansion coefficient of silicon oxide is smaller than that of silicon, under the same temperature conditions, the deformation of silicon will be slightly greater than that of silicon oxide. Therefore, growing a thicker oxide layer 12 on the surface of the silicon substrate layer 11 can exert a force on the high-temperature furnace temperature-controlled silicon wafer 1 as a whole, and the direction of the force is opposite to the deformation direction of the substrate layer 11, thereby delaying the deformation of the silicon wafer.
[0045] For example, the thermal expansion coefficient of silicon oxide is 0.5×10 -6 / K, the thermal expansion coefficient of silicon is 2.5×10 -6 / K.
[0046] For example, when a high-temperature diffusion process is performed, the temperature in the vertical high-temperature diffusion furnace is 1050° C.; when a high-temperature oxidation process is performed, the temperature in the high-temperature oxidation furnace is above 1200° C.
[0047] The high-temperature furnace temperature-controlled silicon wafer of the present invention is provided with an oxide layer on the substrate layer. Since the thermal expansion coefficient of the oxide layer is smaller than that of the unoxidized substrate layer, under the same temperature conditions, the deformation of the oxide layer is smaller than that of the substrate layer. Therefore, the oxide layer exerts a force opposite to the deformation direction on the high-temperature furnace temperature-controlled silicon wafer as a whole, thereby delaying the deformation occurring on the high-temperature furnace temperature-controlled silicon wafer.
[0048] Embodiment 2
[0049] like Figure 4As shown, this embodiment provides a method for extending the service life of a high-temperature furnace temperature-controlled silicon wafer, using the high-temperature furnace temperature-controlled silicon wafer of embodiment 1, the method includes:
[0050] Step 1: Prepare an oxide layer on a silicon wafer provided with a plurality of supporting sites to obtain a high-temperature furnace temperature-controlled silicon wafer.
[0051] It should be noted that the thickness of the oxide layer prepared on a silicon wafer provided with a plurality of support sites can be determined according to the actual processing machine used or the required oxide layer thickness. Generally, when the thickness of the oxide layer 12 is not less than 1% of the thickness of the substrate layer 11, the effect of extending the service life can be achieved.
[0052] In an optional embodiment, step 1 comprises:
[0053] A silicon wafer with several supporting sites is placed in an oxidation furnace, a first reaction gas is introduced, and the oxidation temperature is set to 1200°C to form a dense oxide layer on the surface of the silicon wafer to obtain a high-temperature furnace temperature-controlled silicon wafer; wherein the first reaction gas is oxygen.
[0054] Step 2: Load several high-temperature furnace temperature-controlled silicon wafers and several product wafers onto the wafer boat through several supporting positions, and perform a high-temperature diffusion process in a high-temperature diffusion furnace along with the wafer boat.
[0055] In an optional embodiment, step 2 comprises:
[0056] A plurality of high temperature furnace temperature-controlled silicon wafers and a plurality of product wafers are loaded onto a wafer boat together, wherein at least one high temperature furnace temperature-controlled silicon wafer is located at the head end of the wafer boat, and at least one high temperature furnace temperature-controlled silicon wafer is located at the tail end of the wafer boat; a plurality of product wafers are located between the high temperature furnace temperature-controlled silicon wafer at the head end of the wafer boat and the high temperature furnace temperature-controlled silicon wafer at the tail end of the wafer boat, and the oxide layer of each high temperature furnace temperature-controlled silicon wafer is placed away from the product wafer.
[0057] Step 3: Rotate several high temperature furnace temperature controlled silicon wafers and reload them onto the wafer boat through several supporting sites.
[0058] In an optional embodiment, step 3 includes:
[0059] When the warpage on any of the high temperature furnace temperature controlled silicon wafers exceeds 50 μm, the high temperature furnace temperature controlled silicon wafer with the warpage exceeding 50 μm is rotated 90° and reloaded onto the wafer boat through a plurality of supporting positions until the high temperature furnace temperature controlled silicon wafer with the warpage exceeding 50 μm is rotated at least 360°.
[0060] In an optional implementation, step 3 further includes:
[0061] Several high temperature furnace temperature controlled silicon wafers are rotated 90 degrees regularly and reloaded on the wafer boat through several supporting positions until the several high temperature furnace temperature controlled silicon wafers are rotated at least 360 degrees.
[0062] For example, Figure 3a and Figure 3b As shown, the high-temperature diffusion furnace dummy sheet is loaded on the wafer boat at the 0° position. When the warpage on the high-temperature diffusion furnace dummy sheet increases by about 50μm, the dummy sheet is turned clockwise or rotated 90° and reloaded on the wafer boat for continued use to change the force position distribution on the high-temperature diffusion furnace dummy sheet, so that the deformation of the high-temperature diffusion furnace dummy sheet is not accumulated in the same area, thereby extending the service life of the high-temperature diffusion furnace dummy sheet.
[0063] In addition, the high-temperature diffusion furnace dummy wafer can be rotated regularly to change the force points and force directions on the high-temperature furnace temperature-controlled silicon wafer. Specifically, when it is found that the high-temperature diffusion furnace dummy wafer has obvious warping, the force points and force directions acting on it can be changed by rotation; when the high-temperature diffusion furnace dummy wafer has not yet produced obvious warping, the force points and force directions acting on it can also be changed by active rotation.
[0064] The method for extending the service life of a high-temperature furnace temperature-controlled silicon wafer of the present invention, under the premise of ensuring the normal use of the high-temperature furnace temperature-controlled silicon wafer, changes the force points and force directions on the high-temperature furnace temperature-controlled silicon wafer by periodic rotation, thereby delaying the deformation of the high-temperature furnace temperature-controlled silicon wafer and extending the service life of the high-temperature furnace temperature-controlled silicon wafer.
[0065] It should be noted that the processes used in the present embodiment in the process of preparing the high temperature furnace temperature controlled silicon wafer are all existing mature processes, and the corresponding parameter settings can be realized by referring to the existing related technologies. In addition, for the technical details not disclosed in the embodiment of the method of the present invention, please refer to the description of the device embodiment for understanding.
[0066] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the term "include", "comprise" or any other variant is intended to cover non-exclusive inclusion, so that the article or device including a series of elements includes not only those elements, but also other elements that are not explicitly listed. In the absence of more restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the article or device including the elements. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The orientation or position relationship indicated by "up", "down", "left", "right", etc. is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.
[0067] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.
Claims
1. A high temperature furnace temperature controlled silicon wafer, characterized in that: The high-temperature furnace temperature-controlled silicon wafer can be adjusted and arranged on the wafer boat, and the high-temperature furnace temperature-controlled silicon wafer includes: a substrate layer and an oxide layer arranged in sequence, wherein the thermal expansion coefficient of the oxide layer is smaller than the thermal expansion coefficient of the substrate layer; the thickness of the oxide layer is not less than 1% of the thickness of the substrate layer.
2. The high temperature furnace temperature controlled silicon wafer according to claim 1, characterized in that: The oxide layer at least covers one side surface of the high temperature furnace temperature-controlled silicon wafer, and is used to reduce thermal stress deformation of the high temperature furnace temperature-controlled silicon wafer during a high temperature diffusion process.
3. The high temperature furnace temperature controlled silicon wafer according to claim 1, characterized in that: The material of the substrate layer is silicon, and the thickness of the substrate layer is 725 μm; the material of the oxide layer is silicon oxide, and the thickness of the oxide layer is 7 μm.
4. The high temperature furnace temperature controlled silicon wafer according to claim 1, characterized in that: The high temperature furnace temperature control silicon wafer is evenly provided with a plurality of supporting sites along the circumference, and the wafer boat is connected via at least two of the supporting sites.
5. The high temperature furnace temperature controlled silicon wafer according to claim 4, characterized in that: The angular interval between any two adjacent support sites is 90°.
6. A method for extending the service life of a high temperature furnace temperature controlled silicon wafer, characterized in that: Using the high temperature furnace temperature control silicon wafer according to any one of claims 1 to 5, the method comprises: Step 1: preparing an oxide layer on a silicon wafer provided with a plurality of supporting sites to obtain a high-temperature furnace temperature-controlled silicon wafer; Step 2: Loading a plurality of the high temperature furnace temperature-controlled silicon wafers and a plurality of product wafers onto a wafer boat through a plurality of the supporting sites, and performing a high temperature diffusion process in a high temperature diffusion furnace along with the wafer boat; Step 3: Rotate a plurality of the high temperature furnace temperature-controlled silicon wafers and reload them onto the wafer boat through a plurality of the supporting sites.
7. The method for extending the service life of a high temperature furnace temperature controlled silicon wafer according to claim 6, characterized in that: The step 1 comprises: A silicon wafer provided with a plurality of supporting sites is placed in an oxidation furnace, a first reaction gas is introduced, and the oxidation temperature is set to 1200°C to form a dense oxide layer on the surface of the silicon wafer to obtain a high-temperature furnace temperature-controlled silicon wafer; wherein the first reaction gas is oxygen.
8. The method for extending the service life of a high temperature furnace temperature-controlled silicon wafer according to claim 6, characterized in that: The step 2 comprises: A plurality of the high temperature furnace temperature-controlled silicon wafers and a plurality of product wafers are loaded onto the wafer boat together, wherein at least one of the high temperature furnace temperature-controlled silicon wafers is located at the head end of the wafer boat, and at least one of the high temperature furnace temperature-controlled silicon wafers is located at the tail end of the wafer boat; a plurality of the product wafers are located between the high temperature furnace temperature-controlled silicon wafer at the head end of the wafer boat and the high temperature furnace temperature-controlled silicon wafer at the tail end of the wafer boat, and the oxide layer of each of the high temperature furnace temperature-controlled silicon wafers is placed away from the product wafers.
9. The method for extending the service life of a high temperature furnace temperature controlled silicon wafer according to claim 6, characterized in that: The step 3 comprises: After the warpage on any of the high-temperature furnace temperature-controlled silicon wafers exceeds 50 μm, the high-temperature furnace temperature-controlled silicon wafer with the warpage exceeding 50 μm is rotated 90° and reloaded onto the wafer boat through a plurality of the supporting sites until the high-temperature furnace temperature-controlled silicon wafer with the warpage exceeding 50 μm is rotated at least 360°.
10. The method for extending the service life of a high temperature furnace temperature controlled silicon wafer according to claim 9, characterized in that: The step 3 further includes: The plurality of high temperature furnace temperature controlled silicon wafers are rotated 90° regularly and reloaded onto the wafer boat through the plurality of supporting sites until the plurality of high temperature furnace temperature controlled silicon wafers are rotated at least 360°.