A wafer fixing device and an annealing method using the same

Abstract

A wafer fixing device and an annealing method using the same, at least comprising: a quartz boat; a fixing frame arranged above the quartz boat and capable of being clamped with the wafer when the wafer is vertically arranged in the quartz boat, so that all the wafers are placed in the placement space formed between the quartz boat and the fixing frame without shaking. The fixing frame is hollowed out and arranged at the upper end surface of the wafer, and the fixing frame and the underlying quartz boat jointly improve the stability of wafer placement, prevent wafer shaking, and reduce the probability of wafer breakage. Meanwhile, a guide plate for guiding flow is arranged on both sides of each wafer, which can further improve the fixation of the wafer, make the cold air flow into the guide warehouse formed by the guide plate, accelerate the cooling speed and the uniformity of cooling, further reduce the generation of oxygen donors, and improve the accuracy of resistivity measurement. The annealing time is saved, the energy is saved, and the production cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of silicon wafer annealing process, in particular to a fixing device for wafer and an annealing method using the fixing device. BACKGROUND

[0002] In the wafer manufacturing process, the resistivity needs to be monitored, because the resistivity is affected by temperature, oxygen donors are generated, the oxygen donors have a great influence on the resistivity, and rapid annealing needs to be performed in an annealing furnace to reduce the amount of oxygen donors and improve the accuracy of the resistivity.

[0003] However, the quartz boat in the existing annealing furnace is an open bottom disc structure, the lower part of the wafer is vertically placed on the quartz boat, and the upper part is suspended; in the annealing process, affected by the speed of the cold air flow, the wafer is easy to shake on the quartz boat, which is easy to cause the wafer to be broken. Moreover, because the wind direction is divergent blowing, the wind force on the surface of the wafer is weak, so that the surface temperature of the wafer cannot be quickly cooled, the time for generating oxygen donors is prolonged, and the difficulty of testing the resistivity of the wafer is increased; moreover, the temperature and air volume utilization rate of the wafer is low, and the energy is wasted seriously. SUMMARY

[0004] The present application provides a fixing device for wafer and an annealing method using the fixing device, in particular to the fixing of wafer in the annealing furnace, how to set a fixing device for placing wafer in the annealing furnace is proposed, which can ensure stable placement and quickly blow cold air to the surface of the wafer.

[0005] To solve at least one of the above technical problems, the technical solution adopted by the present application is:

[0006] A fixing device for wafer, at least comprising:

[0007] A quartz boat;

[0008] A fixing frame placed above the quartz boat, which can be in clamping cooperation with the wafer when the wafer is vertically placed in the quartz boat, so that all the wafers are placed in the placement space formed between the quartz boat and the fixing frame without shaking.

[0009] Further, the fixing frame is a hollow rectangular structure, which is provided with a surrounding rod around, and the surrounding rod is provided with a clamping groove for clamping the wafer; and the clamping groove corresponds to the insertion slot in the quartz boat for placing the wafer.

[0010] Further, the tangent line of each wafer and the two connection points of the surrounding rod is vertically arranged.

[0011] Further, the card slot is perpendicular to the axis of the longer surrounding rod.

[0012] Further, the length of the fixing frame is the same as the length of the supporting rod in the quartz boat, and the width of the fixing frame is not greater than the maximum width of the quartz boat.

[0013] Further, the guide plates are inserted into the quartz boat and connected with the fixing frame; the guide plates divide the quartz boat into several bottom-communicating placement spaces, and the wafer is placed in the placement spaces in isolation.

[0014] Further, the upper and lower ends of the guide plate are detachably connected with the card slot on the fixing frame and the insertion slot on the quartz boat.

[0015] Further, the height of the guide plate is less than the diameter of the wafer.

[0016] Further, the guide plates are uniformly arranged on the quartz boat.

[0017] Further, the guide plate is a square structure or a circular structure.

[0018] A wafer annealing method using the fixing device as claimed in any one of the above, comprising the steps of: vertically placing the wafer on the quartz boat, and placing the fixing frame on the upper end of the wafer until the annealing is completed and the wafer is taken out of the annealing furnace.

[0019] Further, before placing the fixing frame, the wafer is placed in the placement space formed by the guide plate inserted into the quartz boat, and the fixing frame is clamped to all the guide plates and wafers; during the annealing, the air flow enters the placement space along the periphery of the guide plate, is gathered in the placement space, and directly contacts the surface of the wafer, so that the wafer is rapidly cooled.

[0020] Further, the fixing frame and all the guide plates are made of quartz material; and all the placement spaces are communicatively arranged.

[0021] The fixing device for wafer and the annealing method using the fixing device are designed, the fixing frame is arranged on the upper end surface of the wafer, the fixing frame and the quartz boat arranged below can jointly improve the stability of the wafer, prevent the wafer from shaking, and reduce the wafer breakage probability; meanwhile, the guide plate for guiding the flow is arranged on both sides of each wafer, the guide plate can further improve the fixing of the wafer, the cold air is blown into the flow guiding space formed by the guide plate along the flow guiding, the cooling speed and the cooling uniformity are improved, the generation of oxygen donors is further reduced, the accuracy of the resistivity measurement is improved, the annealing time is saved, the energy is saved, and the production cost is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 This is a schematic diagram of the structure of a wafer fixing device according to an embodiment of the present invention;

[0023] Figure 2 This is a side view of a wafer fixing device according to an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the structure of a quartz boat according to one embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of the structure of the fixing frame in one embodiment of the present invention;

[0026] Figure 5 This is a schematic diagram of the structure of a wafer fixing device according to another embodiment of the present invention;

[0027] Figure 6 This is a side view of a wafer fixing device according to another embodiment of the present invention.

[0028] In the picture:

[0029] 10. Quartz boat; 11. Support rod; 12. End plate

[0030] 13. Slot 20. Fixture 21. Enclosure rod

[0031] 22, Card slot 30, Guide plate 40, Wafer Detailed Implementation

[0032] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0033] This embodiment proposes a wafer fixing device, such as... Figure 1 As shown, it includes at least: a quartz boat 10 and a mounting bracket 20 placed above the quartz boat 10. The mounting bracket 20 can engage with the wafer 40 when the wafer 40 is placed upright in the quartz boat 10, so that all the wafers 40 are placed in the placement space formed between the quartz boat 10 and the mounting bracket 20 without shaking.

[0034] like Figure 2 As shown, the quartz boat 10 includes a semi-circular structure with several support rods 11 arranged side by side and staggered. The end face of the support rod 11 is provided with an end plate 12, and the end plate 12 is provided with a through hole in the middle to facilitate airflow. In this embodiment, there are four symmetrically arranged support rods 11, wherein the connection points between these four support rods 11 and the wafer 40 are all in the lower section of the wafer 40, that is, in the lower semicircle of the wafer 40.

[0035] Preferably, the tangent line of the outermost two support rods 11 in the quartz boat 10 and the support point of the wafer 40 is vertically arranged, that is, the included angle between the tangent line of the outermost two support rods 11 and the support point of the wafer 40 is 90°, at this time, the support force of the outermost two support rods 11 to the wafer 40 is the largest, and the support force directly converges on the center of the wafer 40; the support force of the outermost two support rods 11 to the wafer 40 is the largest, so that the support to the wafer 40 is the most stable.

[0036] Further, the tangent line of the two innermost support rods 11 and the connection point of the wafer 40 is 45°, the intersection point of the support force of the two innermost support rods 11 to the wafer 40 is lower than the height of the center of the wafer 40, so that the support force of the two innermost support rods 11 to the wafer 40 can further improve the stability of the quartz boat 10 supporting the lower section of the wafer 40.

[0037] A plurality of insertion slots 13 are arranged on the length direction of the support rod 11, each insertion slot 13 on the support rod 11 is arranged towards the longitudinal center axis of the vertically arranged wafer 40, and is arranged perpendicular to the length axis of the support rod 11. The quartz boat 10 made of only four support rods 11 and two end plates 12 not only has a simple structure, but also is easy for airflow to pass through and contact with the wafer 40, and is easy to process, and can provide the wafer 40 with the least and most stable support force.

[0038] As shown in Figure 3 The fixed frame 20 is a hollow rectangular structure in the middle, and is provided with a surrounding rod 21 around, and the surrounding rod 21 in the length direction is provided with a clamping slot 22 for clamping the wafer 40; and the clamping slot 22 corresponds to the insertion slot 12 on the support rod 11 in the quartz boat 10 one by one, and all the clamping slots 22 are arranged perpendicular to the axis of the longer surrounding rod 21, which is easy to process and easy to clamp with the wafer 40.

[0039] In order to ensure the stability of the wafer 40 placed at the upper end position, and to make the fixing force of each wafer 40 the largest and most stable, preferably, the tangent line of the two connection points of each wafer 40 and the surrounding rod 21 is vertically arranged, as shown in Figure 4 Furthermore, in this structure, the fixing force of the wafer 40 by the fixed frame 20 and the support force of the outermost two support rods 11 in the quartz boat 10 are symmetrically arranged and diagonally arranged, and the support force and the fixing force penetrate the center diameter of the wafer 40, so that the two forces along the diameter of each wafer 40 can be counteracted, thereby reducing the stress degree of the wafer 40, further improving the stability of the wafer 40 standing on the quartz boat 10, not being shaken by the wind, and reducing the fragmentation of the wafer 40 due to shaking.

[0040] Correspondingly, the length of the fixed frame 20 is the same as the length of the supporting rods 11 in the quartz boat 10, and the width of the fixed frame 20 is not greater than the maximum width of the quartz boat 10; that is, the length of the longer surrounding rod 21 is the same as the length of the supporting rod 11, so that the fixing of all the wafers 40 inserted in the quartz boat 10 can be ensured; the length of the shorter surrounding rod 21 is not greater than the maximum width of the quartz boat 10. Since the end plate 12 of the quartz boat 10 needs to completely fix the end faces of all the supporting rods 11 in the same plane, the width of the end plate 12 must be greater than the width of the outermost two supporting rods 11, so as to ensure the uniformity of the stress on the wafers 40, the length of the shorter surrounding rod 21 is required to be the same as the width of the outermost supporting rod 11.

[0041] Preferably, all the supporting rods 11 and all the surrounding rods 21 are quartz material supporting round rods, the diameters of which are the same, and the structures of the insertion slots 13 on the supporting rods 11 and the structures of the clamping slots 22 on the surrounding rods 21 are the same and have the same depth.

[0042] Another embodiment of the present application, as shown in Figure 5 and Figure 6 Further, the quartz boat 10 is divided into a plurality of placement compartments which are in communication with each other by the guide plates 30, and the wafers 40 are placed in the placement compartments in isolation. The setting of the guide plates 30 can guide all the cold air to converge in the placement compartments, so as to improve the cooling of the surfaces of the wafers 40 by the cold air, quickly take away the heat blown away, and thus accelerate the annealing speed of the wafers 40 and save the annealing time.

[0043] Further, the upper and lower ends of the guide plates 30 are detachably connected to the clamping slots 22 on the fixed frame 20 and the insertion slots 22 on the quartz boat 10, respectively, and all the guide plates 30 are uniformly arranged on the quartz boat 10, and the lower end faces of the guide plates 30 are arranged in communication with the bottom of the quartz boat 10.

[0044] Further, the height of the guide plates 30 is less than the diameter of the wafers 40, so as to improve the contact between the upper and lower surfaces of the wafers 40, and thus improve the guidance of the air volume and the intercommunication of the air volume.

[0045] Further, the guide plates 30 can be square or circular structures, as long as they can guide the flow and be stably placed between the quartz boat 10 and the fixed frame 20, and the drawings are omitted.

[0046] The fixed frame 20 can form a stable placement space with the quartz boat 10 to fix the wafer 40, so that the position of the wafer 40 can be ensured not to shake during annealing and after the wafer 40 is taken out of the furnace, thereby reducing the generation of fragments and improving the whole wafer rate of the wafer 40; and the time for taking and placing the waste wafer can also be reduced. The guide plate 30 can increase the guiding effect and guide the cold air to flow along the surface of the wafer 40 in a direction, which can not only accelerate the cooling speed, but also improve the uniformity of the wafer 40 cooling; at the same time, the width between the guide plates 30 can be adjusted at will according to the wind direction, so that the wafer 40 can be quickly cooled to reduce the generation of oxygen donors and ensure the accuracy of the resistivity measurement; not only the annealing time is saved, but also the energy is saved and the production cost is reduced.

[0047] A wafer annealing method using the fixing device according to any one of the above, the steps comprising:

[0048] The wafer 40 can be first vertically placed on the quartz boat 10, and the fixed frame 20 is arranged at the upper end of the wafer 40 until the annealing is completed and the wafer 40 is taken out of the furnace.

[0049] When placed, the fixed frame 20 is arranged in overlap with the length axis of the quartz boat 10, and the tangent line of the outermost two supporting rods 11 in the quartz boat 10 and the supporting point of the wafer 40 is arranged vertically, that is, the included angle between the outermost two supporting rods 11 and the tangent line of the supporting point of the wafer 40 is 90°, at this time, the supporting force of the outermost two supporting rods 11 on the wafer 40 is the largest, and the supporting force is directly converged on the center of the wafer 40; the supporting force of the outermost two supporting rods 11 on the wafer 40 is the largest, so that the support of the wafer 40 is the most stable.

[0050] At the same time, in order to ensure the stability of the upper end position of the wafer 40 and make the fixing force on each wafer 40 the largest and most stable, preferably, the tangent line of the two connecting points of each wafer 40 and the surrounding rod 21 is arranged vertically, as shown in Figure 4 Moreover, in this structure, the fixing force of the wafer 40 by the fixed frame 20 and the supporting force of the outermost two supporting rods 11 in the quartz boat 10 are symmetrically arranged and diagonally arranged, and the supporting force and the fixing force penetrate the center diameter of the wafer 40, so that the two forces along the diameter of each wafer 40 can be offset, thereby reducing the stress degree of the wafer 40, further improving the stability of the vertically placed wafer 40 on the quartz boat 10, and reducing the shaking of the wafer 40 due to the blowing force of the wind, and also reducing the fragmentation of the wafer 40 due to the shaking.

[0051] Further, before placing the fixing frame 20, each wafer 40 is placed in the placing cavity formed by the guide plate 30 inserted in the quartz boat 10, and the fixing frame 20 is clamped to all the guide plates 30 and the wafers 40. During annealing, the air flow enters the placing cavity around the guide plate 30 and directly contacts the surface of the wafer 40, so that the wafer 40 is rapidly cooled.

[0052] The guide plate 30 divides the quartz boat 10 into several placing cavities in communication with each other, and the wafer 40 is placed in the placing cavity in isolation. The guide plate 30 is arranged to guide all the cold air to the placing cavity, so that the cooling of the wafer 40 is improved, the heat is rapidly removed, and the annealing speed of the wafer 40 is accelerated, and the annealing time is saved.

[0053] Further, the fixing frame 20 and all the guide plates 30 are made of quartz material; and all the placing cavities are arranged in communication with each other.

[0054] The fixing device for the wafer and the annealing method using the fixing device are used. The fixing frame with hollow structure is arranged on the upper end surface of the wafer. The fixing frame and the quartz boat arranged below can jointly improve the stability of the wafer, prevent the wafer from shaking, and reduce the probability of wafer breakage. The guide plate for guiding air flow is arranged on both sides of each wafer. The guide plate can further improve the fixation of the wafer, make the cold air blow into the guide cavity formed by the guide plate, accelerate the cooling speed and the cooling uniformity, further reduce the generation of oxygen donors, improve the accuracy of the resistivity measurement, save the annealing time, save the energy, and reduce the production cost.

[0055] The above detailed description of the embodiments of the present application is only a preferred embodiment of the present application, and cannot be considered as limiting the scope of the present application. Any equivalent changes and improvements made according to the scope of the present application should still belong to the scope of the present application.

Claims

1. A wafer fixing device, characterized in that, At least including: quartz boat; A fixing frame, placed above the quartz boat, can engage with the wafers when they are placed upright in the quartz boat, so that all the wafers are placed in the placement space formed between the quartz boat and the fixing frame without shaking; It also includes several guide plates inserted into the quartz boat and connected to the fixing frame; The guide plate divides the quartz boat into several interconnected placement compartments, and isolates the wafers within the placement compartments.

2. The wafer fixing device according to claim 1, characterized in that, The fixing frame is a rectangular structure with a hollow center and surrounding rods. The surrounding rods are equipped with slots for securing the wafers. The slots correspond to the slots in the quartz boat where the wafers are placed.

3. The wafer fixing device according to claim 2, characterized in that, The tangents at the two connection points of each wafer and the surrounding rod are set perpendicularly.

4. A wafer fixing device according to claim 2 or 3, characterized in that, The slot is positioned perpendicular to the axis of the longer section of the retaining rod.

5. A wafer fixing device according to claim 4, characterized in that, The length of the fixing frame is the same as the length of the support rod in the quartz boat, and its width is not greater than the maximum width of the quartz boat.

6. A wafer fixing device according to any one of claims 2-3 and 5, characterized in that, The upper and lower ends of the guide plate are detachably connected to the slot on the fixing frame and the slot on the quartz boat, respectively; the height of the guide plate is smaller than the diameter of the wafer.

7. A wafer annealing method, characterized in that, Using the fixing device as described in any one of claims 1-6, the steps include: placing the wafer upright on a quartz boat and mounting the fixing frame on the upper end of the wafer until the annealing is completed and the wafer leaves the annealing furnace.

8. The wafer annealing method according to claim 7, characterized in that, Before placing the fixing frame, each wafer is placed in a placement chamber formed by a guide plate inserted on the quartz boat, and the fixing frame secures all the guide plates and wafers; during annealing, the airflow enters the placement chamber along the perimeter of the guide plate and converges and directly contacts the surface of the wafer, rapidly cooling the wafer.

9. A wafer annealing method according to claim 8, characterized in that, The mounting frame and all the guide plates are made of quartz material; and all the placement compartments are interconnected.

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