Wafer annealing furnace and wafer annealing method

Abstract

The invention provides a wafer annealing furnace and a wafer annealing method.The wafer annealing furnace comprises an annealing furnace body and a sensor, the annealing furnace body comprises a rotary table rotating around a rotary shaft and a control module, n positioning holes are formed in the periphery of a wafer containing area of the rotary table, the tracks of the positioning holes rotating around the rotary shaft at least partially coincide, and the positioning holes are evenly distributed; the positioning hole penetrates through the rotary table, and n is larger than or equal to 3; the sensor is fixed below the overlapped area of the rotating tracks of the positioning holes, and the control module receives signals collected by the sensor in real time and processes the signals. According to the wafer annealing furnace, the structure of the wafer annealing furnace is improved, the positioning holes which are uniformly distributed and penetrate through the rotary table are formed in the rotary table, and the sensors are arranged below the positioning holes, so that the number of rotation turns and rotation angles of a wafer in the wafer annealing process are monitored in real time, and the initial position of the rotary table is accurately reset.

Description

Technical Field

[0001] The invention belongs to the field of semiconductor device manufacturing and relates to a wafer annealing furnace and a wafer annealing method. Background Art

[0002] High temperature annealing is an important process node in semiconductors, which directly determines the conductivity and capacity of the device. With the development of high-end processes, the uniformity requirements for wafers after annealing are getting higher and higher. The better the uniformity, the better the controllability of the wafer and the higher the yield.

[0003] At present, for high temperature annealing machines (RTP Mattson), there is a temperature deviation problem during the annealing process. The overall shift range is not large and is within the acceptable range of the process. However, with the upgrade of the process, these differences will gradually appear. The resistance value of the wafer after high temperature annealing is usually used to characterize the temperature at which the furnace chamber heats the wafer, such as Figure 1 and Figure 2 As shown in the figure, there are resistance distribution diagrams of one type of wafer after annealing and another type of wafer after annealing, respectively. The higher the annealing temperature, the lower the resistance after annealing. The values ​​in the figure are the resistance ranges obtained by measurement. The orange-red part is the area with lower resistance due to the higher annealing temperature. Usually, during the annealing process, the wafer rotates evenly in the chamber, and the heating lamp tube in the furnace cavity is composed of multiple ring-shaped bulbs. Figure 2 The temperature deviation in the same circle can be solved by adjusting the voltage of the corresponding ring bulb, but for Figure 1 However, it is unable to solve the unilateral temperature deviation in the wafer, which results in uneven resistance distribution of the wafer after annealing, seriously affecting the yield of the wafer.

[0004] Therefore, there is an urgent need to find a wafer annealing method that improves the problem of unilateral temperature deviation during wafer annealing. Summary of the invention

[0005] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a wafer annealing furnace and a wafer annealing method, which are used to solve the problem in the prior art that the temperature of the wafer is easily biased during the annealing process, resulting in uneven resistance distribution of the wafer.

[0006] To achieve the above-mentioned object and other related objects, the present invention provides a wafer annealing furnace, comprising:

[0007] The annealing furnace body includes a turntable rotating around a rotating axis and a control module, wherein n positioning holes are arranged at the periphery of a wafer placement area of ​​the turntable, and the trajectories of the positioning holes rotating around the rotating axis overlap and are evenly distributed, and the positioning holes penetrate the turntable, wherein n≥3;

[0008] The sensor is fixed below the overlapping area of ​​the rotation tracks of the positioning holes, and the control module receives and processes the signals collected by the sensor in real time.

[0009] Optionally, the length of the arc area formed by one positioning hole swept by the sensing area of ​​the sensor is different from the length of the arc area formed by other positioning holes; or the length of the arc area formed by different positioning holes swept by the sensing area of ​​the sensor is different.

[0010] Optionally, a reference hole is further provided in the turntable, and the reference hole is located at the periphery of the wafer placement area and passes through the turntable, and at least one sensor is fixed directly below the trajectory of the reference hole rotating around the rotation axis.

[0011] Optionally, the reference hole is collinear with the rotation axis and an adjacent positioning hole, and the reference hole is spaced apart from the positioning hole adjacent to the reference hole by a preset distance.

[0012] Optionally, the trajectory of the reference hole rotating around the rotation axis is spaced apart by a preset distance from the trajectory of the positioning hole rotating around the rotation axis, and the straight line where the positioning hole adjacent to the reference hole and the rotation axis are located intersects with the straight line where the reference hole and the rotation axis are located.

[0013] Optionally, the size of the sensor sensing area is not greater than the size of the minimum overlapping area that overlaps with each of the positioning holes in the overlapping portion of the rotation trajectory of each of the positioning holes.

[0014] Optionally, the sensor includes a combination of one or more of a photoresistor, a photoinductor, a photocapacitor, a photosensitive field transistor, and a photosensitive circuit.

[0015] The present invention also provides a wafer annealing method, comprising the following steps:

[0016] Provide a wafer annealing furnace as described above and a wafer, wherein the locating holes A1 are located in sequence along the rotation direction set by the turntable from one of the locating holes, wherein 1≤i≤n, start the wafer annealing furnace, and the turntable rotates the locating hole A1 to be directly above the sensor;

[0017] The control module receives a signal indicating that the sensor is located directly below the positioning hole A1, and sequentially controls the turntable to stop rotating, opens the furnace chamber of the annealing furnace, and the transfer arm to place the wafer in the wafer placement area and the turntable to rotate along the set direction;

[0018] After the turntable starts to rotate, each time the control module receives a signal that the positioning hole Ai rotates to the position directly below the sensor, it sequentially controls the turntable to stop rotating, wait for a preset time, and continue rotating;

[0019] Until the control module receives the signal that the positioning hole A1 moves to the position directly below the sensor for a predetermined number of times, the furnace chamber is controlled to be closed and the annealing process is performed.

[0020] Optionally, the preset time is the sum of the time taken by the transfer arm to place the wafer and the time taken to take out the wafer, and during the preset time when the turntable stops rotating, the wafer is located in the wafer placement area and remains stationary.

[0021] Optionally, during the preset time when the turntable stops rotating, the control module further controls the transfer arm to take out the wafer and put the taken out wafer back into the wafer placement area.

[0022] As described above, the wafer annealing furnace and the wafer annealing method of the present invention improve the structure of the wafer annealing furnace, and set n positioning holes that are evenly distributed and penetrate the turntable on the periphery of the wafer placement area of ​​the turntable, the trajectories of the positioning holes rotating around the rotating shaft at least partially overlap, and a sensor for collecting positioning hole signals is set below the overlapping area of ​​the positioning hole rotation trajectory, and the control module in the wafer annealing furnace receives and processes the signals collected by the sensor in real time, thereby realizing real-time monitoring of the number of rotations and the rotation angle of the wafer during the wafer annealing process; after the wafer is placed on the turntable and before the furnace chamber is closed for annealing, the wafer is preheated, and during the preheating process, the control module controls the turntable to stop rotating and wait for preheating each time it receives a signal from the positioning hole. The time is set and the turntable is controlled to continue to rotate, and then the lining of the wafer is heated at multiple angles in a tilted state during the entire wafer preheating process, which reduces the heat difference of various areas of the wafer due to the tilt of the lining during the annealing process, so that various areas of the wafer are heated more evenly during the annealing process, thereby improving the yield of the product, improving the uniformity and consistency of the entire heating of the product, achieving more precise control over the resistance value and long film thickness of the product, and improving the phenomenon of unilateral offset of the resistance distribution of the wafer after annealing; through simple structural improvements, the wafers can be put into the wafer annealing furnace at the same angle and taken out of the wafer annealing furnace at the same angle, which provides convenience for subsequent process steps and has high industrial utilization value. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Shown is a resistance distribution diagram of a wafer after annealing.

[0024] Figure 2 Shown is another resistance distribution diagram of the wafer after annealing.

[0025] Figure 3 Shown is a schematic structural diagram of the wafer annealing furnace of the present invention.

[0026] Figure 4 Shown is a schematic structural diagram of the turntable portion of the wafer annealing furnace of the present invention.

[0027] Figure 5 Shown is a structural schematic diagram of a turntable of the wafer annealing furnace of the present invention.

[0028] Figure 6 Another schematic structural diagram of the turntable of the wafer annealing furnace of the present invention is shown.

[0029] Figure 7 Shown is a third structural schematic diagram of the turntable of the wafer annealing furnace of the present invention.

[0030] Figure 8 Shown is a fourth structural schematic diagram of the turntable of the wafer annealing furnace of the present invention.

[0031] Fig. 9 It is a fifth structural schematic diagram of the turntable of the wafer annealing furnace of the present invention.

[0032] Fig.10 Display as Figure 6 Signal diagram collected by the sensors under the transfer platform.

[0033] Fig.11 Display as Figure 7 Signal diagram collected by the sensors under the transfer platform.

[0034] Fig.12 Display as Figure 8 Signal diagram collected by the sensors under the transfer platform.

[0035] Fig.13 Display as Fig. 9 Signal diagram collected by the sensors under the transfer platform.

[0036] Fig.14 The figure shows the resistance distribution of the wafer annealed by the wafer annealing method of the present invention.

[0037] Description of Figure Numbers

[0038] 1 Wafer annealing furnace body

[0039] 11 Teleporting Arm

[0040] 12 Lining

[0041] 2 Wafer

[0042] 3 Turntable

[0043] 31 Positioning hole

[0044] 32 Reference hole

[0045] 33 Quartz Air Cushion

[0046] 34 Speed ​​reduction components

[0047] 35 Gas supply components

[0048] 36 Wafer support DETAILED DESCRIPTION

[0049] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0050] See also Figures 3 to 14 It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0051] Embodiment 1

[0052] This embodiment provides a wafer annealing furnace, such as Figure 3 As shown, it is a structural schematic diagram of the wafer annealing furnace, including an annealing furnace body 1 and a sensor. The annealing furnace body 1 includes a turntable 3 rotating around a rotating axis and a control module. The periphery of the wafer placement area of ​​the turntable 3 is provided with n positioning holes 31 whose trajectories rotating around the rotating axis at least partially overlap and are evenly distributed. The positioning holes 31 pass through the turntable 3, wherein n≥3; the sensor is fixed below the overlapping area of ​​the rotation trajectory of each positioning hole 31, and the control module receives the signal collected by the sensor in real time and processes it.

[0053] Specifically, the annealing furnace body 1 is usually a high-temperature rapid annealing furnace for rapidly annealing the wafer 2 , and the size and shape of the annealing furnace body 1 can be selected according to actual process requirements.

[0054] Specifically, Figure 4 and Figure 5As shown, there are respectively a schematic diagram of the structure of the turntable 3 part of the wafer annealing furnace and a schematic diagram of the structure of the turntable 3. The turntable 3 is used to carry the wafer 2 to be annealed. At the same time, during the annealing process of the wafer 2, the turntable 3 usually rotates around the rotating axis along with the driving gear through the gear whose outer ring is meshed with the driving gear and drives the wafer 2 to rotate, so that the wafer 2 is evenly heated during the annealing process.

[0055] Specifically, a plurality of wafer support parts 36 for supporting wafers 2 are also provided on the wafer placement area of ​​the turntable 3. The wafer support parts 36 are used to support the wafers 2 so that the conveying arm 11 of the wafer annealing furnace can take out and place the wafers 2. In the case of facilitating the conveying arm 11 to take and place the wafers 2, the size, height, shape, number and distribution of the wafer support parts 36 can be selected according to actual conditions. In this embodiment, the wafer support parts 36 are commonly used PIN needle-shaped support structures, and the structure of the conveying arm 11 to take and place the wafers 2 is lifted and lowered by inserting the gaps between the PIN needles to achieve the taking and placing of the wafers 2.

[0056] Specifically, the turntable 3 is also provided with a plurality of quartz gas cushions 33 for supporting the wafer 2 and a gas supply component 35 for supplying gas to the quartz gas cushions 33. Usually, the quartz gas cushions 33 are evenly distributed on the turntable 3. It should be noted that the size, number and distribution of the quartz gas cushions 33 can be selected according to actual conditions; the size, shape and distribution of the gas supply component 35 can be selected according to actual conditions.

[0057] Specifically, the turntable 3 is further provided with a deceleration component 34 for decelerating the rotation of the wafer 2 through gas. It should be noted that the size, structure, number and distribution of the deceleration component 34 can be selected according to actual conditions.

[0058] Specifically, under the condition of ensuring the uniformity of heating during the wafer annealing process, the rotation speed, size, thickness and shape of the turntable 3 can be selected according to actual conditions; the size of the wafer placement area can be selected according to actual conditions.

[0059] Specifically, the turntable 3 is located in the furnace cavity of the annealing furnace body 1. Usually, the furnace cavity of the annealing furnace body 1 is also provided with an upper heating lamp tube, a lower heating lamp tube and a lining 12. The upper heating lamp tube is located above the turntable 3 and is spaced apart from the turntable 3 by a preset distance. The lower heating lamp tube is located below the turntable 3 and is spaced apart from the turntable 3 by a preset distance. The lining 12 is located between the upper heating lamp tube and the turntable 3 and is spaced apart from the upper heating lamp tube and the turntable 3, respectively.

[0060] It should be noted that only one layer of heating lamp tubes may be provided in the furnace chamber of the annealing furnace main body 1 , and the heating lamp tubes may be located below the turntable 3 or above the substrate 12 .

[0061] Specifically, the control module usually controls the extension and retraction of the cylinder to control the opening and closing of the cover of the wafer annealing furnace. When the furnace chamber of the wafer annealing furnace is opened, the cylinder lifts up the cover of the wafer annealing furnace, and at the same time, the lining 12 located above the turntable 3 is tilted on one side close to the furnace mouth to facilitate the removal and placement of the wafer 2. However, this structure also leads to uneven heating of various areas of the wafer 2 during the process of placing and removing the wafer 2 due to the tilt of the lining 12 during the process of placing and removing the wafer, which makes it easy for the temperature to shift unilaterally after the wafer is annealed.

[0062] Specifically, while ensuring uniform heating of the wafer 2 in the furnace chamber, the distance between the upper heating lamp tube and the turntable 3, the distance between the lining 12 and the turntable 3, the distance between the upper heating lamp tube and the lining 12, the distance between the lower heating lamp tube and the turntable 3, the thickness of the lining 12 and the material of the lining 12 can be selected according to actual conditions.

[0063] Specifically, the upper layer of heating lamp tubes is usually composed of a plurality of lamp tubes arranged in an array, and the arrangement of the lamp tubes in the upper layer of heating lamp tubes and the size of the lamp tubes can be selected according to actual conditions.

[0064] It should be noted that, generally, the structure of the upper layer heating lamp tubes is the same as or similar to that of the lower layer heating lamp tubes, that is, the lower layer heating lamp tubes are also composed of a plurality of lamp tubes arranged in an array.

[0065] Specifically, the arrangement of the lamps in the lower layer of heating lamps, the size of each lamp and the power of each lamp can be selected according to actual conditions; the number of lamps in the upper layer of heating lamps can be selected according to actual conditions; the number of lamps in the lower layer of heating lamps can be selected according to actual conditions.

[0066] Specifically, when the resistance in the wafer 2 after annealing appears to be unevenly distributed in a ring shape, the current of the corresponding upper heating lamp tube and the corresponding lower heating lamp tube can be adjusted to ensure uniform heating of various parts of the wafer 2 in the annealing furnace.

[0067] Specifically, the control module is usually a control mechanism of the annealing furnace body 1. For example, it can control the start and stop of the annealing furnace, the annealing temperature of the wafer 2, the annealing time, the rotation speed of the turntable 3 and other related annealing parameters. It can be a control circuit that controls and monitors the entire annealing process, or it can be an intelligent control unit that controls and monitors the entire annealing process based on a set program.

[0068] Specifically, the positioning hole 31 and the sensor are combined to determine the position of the wafer 2 placed in the wafer placement area, so as to accurately monitor the angle and number of rotations of the wafer.

[0069] As an example, the length of the arc area formed by the sensing area of ​​the sensor sweeping through a positioning hole 31 is different from the length of the arc area formed by sweeping through other positioning holes 31. The arc area formed here refers to the arc area of ​​the sensor's sensing area moving relative to the positioning hole 31 from the initial receipt of the signal passing through the positioning hole 31 to the end of receiving the signal of the positioning hole 31 (i.e., the period during which the sensor collects the signal of the positioning hole 31).

[0070] It should be noted that the number of positioning holes 31 on the turntable 3 is usually between 3 and 20, and more positioning holes 31 may be provided according to the size of the turntable 3. However, a larger number of positioning holes 31 will cause the preheating process of the wafer 2 before annealing to take up more time, which is not conducive to mass production of the production line during the production process. Considering the preheating time of the wafer 2, the annealing time, and the mass production requirements of the production line, preferably, 3 to 12 positioning holes 31 may be provided on the turntable 3.

[0071] In order to explain the advantages of the improved wafer annealing furnace, the following explanation is given by taking the arrangement of four positioning holes 31 on the turntable 3 as an example.

[0072] Specifically, Figure 6 As shown in the figure, it is a schematic diagram of the structure of a turntable 3 having a positioning hole 31 whose size is larger than that of the other positioning holes 31. By making the size of the arc area formed by the sensing area of ​​the sensor in the n positioning holes 31 scanning over one positioning hole 31 different from the size of the arc area formed by scanning over the other positioning holes 31, the signal of the positioning hole 31 of the special size collected by the sensor can be different from the signals of the other positioning holes 31, so that the rotation angle and the number of revolutions of the wafer 2 in the furnace chamber of the annealing furnace main body 1 can be judged based on the signal collected by the sensor without opening the furnace chamber of the annealing furnace main body 1.

[0073] As an example, the sensing area of ​​the sensor sweeps different lengths of arc areas formed by different positioning holes 31. It should be noted that when the sensor sweeps different lengths of arc areas formed by different positioning holes 31, the overall shapes of the positioning holes 31 can be the same or different.

[0074] Specifically, Figure 7As shown, it is a schematic diagram of the structure of the turntable 3 with positioning holes 31 of different sizes. By making the sizes of the positioning holes 31 different (the size here refers to the arc length of the arc area formed by the sensor scanning the positioning holes 31), during the annealing process of the wafer 2, the signals collected by the sensor can be different, and then, without opening the furnace chamber of the annealing furnace main body 1, the rotation angle and the number of revolutions of the wafer 2 can be more conveniently judged based on the signals collected by the sensor. For example, an initial positioning hole 31 can be selected, and with the initial positioning hole 31 as a reference, the size of the arc area formed in each positioning hole 31 scanned by the sensing area of ​​the sensor is gradually increased or decreased in a clockwise or counterclockwise direction. In order to facilitate identification and not affect the measurement accuracy, the size of the arc area formed by each positioning hole 31 scanned by the sensor is gradually decreased by 0.1 to 10 times in a clockwise or counterclockwise direction starting from the initial positioning hole, or increased by 0.1 to 10 times, and then the width of the signal collected by the sensor is also reduced or increased accordingly. Preferably, the size of the arc area formed by each positioning hole 31 scanned by the sensor is gradually increased by 1 time in a clockwise or counterclockwise direction starting from the initial positioning hole.

[0075] It should be noted that, in order to save costs, the sensor used under the turntable 3 does not have high requirements on the size and intensity changes of the light signal, has better stability, and has a simple structure after combining with the positioning hole 31. Therefore, it is more advantageous to work in the furnace chamber of a wafer annealing furnace with stable light intensity (the power of the heating lamp is stable, so that the light intensity in the furnace chamber is also stable).

[0076] As an example, a reference hole 32 is further provided in the turntable 3. The reference hole 32 is located at the periphery of the wafer placement area and passes through the turntable 3. At least one sensor is fixed directly below the trajectory of the reference hole 32 rotating around the rotation axis.

[0077] Specifically, a sensor is arranged directly below the track of the reference hole 32 rotating around the rotation axis, so that when the reference hole 32 rotates to directly above the sensor, a signal of one rotation of the wafer 2 is collected. For example, starting from the initial position, the wafer 2 rotates x circles, and the sensor directly below the rotation track of the reference hole 32 generates x+1 signals, wherein the first signal is the signal of the initial position.

[0078] As an example, the reference hole 32 is colinear with the rotation axis and an adjacent positioning hole 31 , and the reference hole 32 is spaced apart from the adjacent positioning hole 31 by a preset distance.

[0079] Specifically, Figure 8As shown, it is a structural schematic diagram of a turntable 3 having a reference hole 32 which is colinear with the rotation axis and a neighboring positioning hole 31. When the shapes and sizes of the n positioning holes 31 are the same, the position of the wafer 2 is determined by counting the number of signal peaks one by one through the signal collected by the sensor below the rotation trajectory of the positioning hole 31 around the rotation axis, which makes it more troublesome to determine the position of the wafer 2. By setting a reference hole 32 on the periphery of the wafer placement area in the turntable 3, the reference hole 32 is colinear with the rotation axis of the turntable 3 and the positioning hole 31 adjacent to the reference hole 32, and then the signals collected by the two sensors below the rotation trajectory of the positioning hole 31 and the reference hole 32 are convenient for simply determining the rotation angle of the wafer 2 and the number of revolutions of the wafer 2. At the same time, it is relatively convenient to install the sensors located below the rotation trajectory of the reference hole 32 and the positioning hole 31.

[0080] It should be noted that when the reference hole 32 is colinear with the rotating shaft and an adjacent positioning hole 31 , the shapes of the positioning holes 31 can be the same or different, and the sizes of the arc areas formed by the sensor scanning the positioning holes 31 can be the same or different.

[0081] As an example, the reference hole 32 is connected to the positioning hole 31 adjacent to the reference hole 32 , which is equivalent to that one positioning hole 31 is different from the other positioning holes 31 , but compared with the other positioning holes 31 , the sensing areas of the two sensors can simultaneously scan the positioning hole 31 .

[0082] Specifically, when the reference hole 32 and the positioning hole 31 adjacent to the reference hole 32 are connected, the sensing area of ​​the sensor for collecting the reference hole 32 signal sweeps across the arc area formed by the reference hole 32 and the sensing area of ​​the sensor for collecting the positioning hole 31 signal sweeps across the arc area formed by the positioning hole 31 at a preset distance to avoid the sensor for collecting the reference hole 32 signal being affected by the positioning hole 31 and erroneously collecting the signal.

[0083] As an example, the trajectory of the reference hole 32 rotating around the rotation axis is separated from the trajectory of the positioning hole 31 rotating around the rotation axis by a preset distance, and the straight line where the positioning holes 31 adjacent to the reference hole 32 and the rotation axis are located intersects with the straight line where the reference hole 32 and the rotation axis are located, that is, the reference hole 32, the positioning holes 31 adjacent to the reference hole 32 and the rotation axis are not colinear.

[0084] It should be noted that when the reference hole 32, the positioning hole 31 adjacent to the reference hole 32 and the rotating shaft are not colinear, the shapes of the positioning holes 31 can be the same or different, and the sizes of the arc areas scanned by the sensors in the positioning holes 31 can be the same or different.

[0085] Specifically, Fig. 9As shown, it is a structural schematic diagram of a turntable 3 having a reference hole 32 which is not colinear with the rotation axis and the positioning hole 31 adjacent to the reference hole 32. When the sizes of the n positioning holes 31 are the same and the reference hole 32 in the turntable 3 and the positioning holes 31 adjacent to the reference hole 32 and the rotation axis are not colinear, before the wafer 2 is placed in the wafer placement area, the reference hole 32 needs to be rotated to be directly above the sensor corresponding to the reference hole 32 (i.e., the sensor below the trajectory of the reference hole 32 rotating around the rotation axis), and at the same time, a positioning hole 31 also needs to be rotated to be directly above the sensor corresponding to the positioning hole 31 (i.e., the sensor below the trajectory of the positioning hole 31 rotating around the rotation axis), so that the two sensors can simultaneously collect the initial signal and the signal of the number of revolutions of the wafer 2, and then facilitate the determination of the rotation angle and the number of revolutions of the wafer 2 based on the signals collected by the two sensors during the annealing process of the wafer 2.

[0086] Specifically, under the condition that the accuracy of the sensor collecting signals is ensured, the size and shape of each positioning hole 31 can be selected according to the actual situation; the distance between each positioning hole 31 and the rotating shaft can be selected according to the actual situation; the size and shape of the reference hole 32 can be selected according to the actual situation; the distance between the reference hole 32 and the rotating shaft can be selected according to the actual situation; the distance between the reference hole 32 and the adjacent positioning hole 31 can be selected according to the actual situation. The rotating shaft here is equivalent to the center of the turntable 3. For example, when the reference hole 32, the positioning hole 31 adjacent to the reference hole 32 and the rotating shaft are collinear, the distance between the reference hole 32 and the positioning hole 31 can be 3mm or 5mm.

[0087] As an example, the size of the sensor sensing area is not greater than the size of the minimum overlapping area overlapping with each positioning hole 31 in the overlapping portion of the rotation trajectory of each positioning hole 31 .

[0088] Specifically, by making the sensing area of ​​the sensor smaller than the size of the minimum overlapping area overlapping with each positioning hole in the overlapping part of the rotation trajectory of each positioning hole 31, the signal of the positioning hole 31 collected by the sensor changes based on the change in the size of the arc area formed by the sensing area of ​​the sensor scanning the positioning hole 31, which facilitates the judgment of the rotation angle of the wafer 2 based on the signal collected by the sensor.

[0089] Specifically, under the condition of ensuring the accuracy of the sensor collecting signals, the position where the sensor is fixed below the turntable 3 can be selected according to actual conditions.

[0090] It should be noted that the size of the sensing area of ​​the sensor may also be larger than the size of the maximum overlapping area that overlaps with each positioning hole 31 in the overlapping part of the rotation trajectory of each positioning hole 31. However, in this case, when each positioning hole 31 passes directly above the sensor, the signal collected by the sensor is the same. Therefore, it is necessary to add an additional unit for processing the sensor signal in the control module to determine the rotation angle of the wafer 2 and perform related annealing operations based on the signal collected by the sensor.

[0091] As an example, the sensor includes a combination of one or more of a photoresistor, a photoinductor, a photocapacitor, a photosensitive field transistor, and a photosensitive circuit, or other suitable devices or circuits that are convenient for collecting signals at high temperatures. Preferably, a photoresistor is used as the sensor.

[0092] Specifically, while ensuring the accuracy of the sensor's collected signals, the model, size and shape of the sensor can be selected according to actual conditions.

[0093] It should be noted that, generally, the smaller the size of the positioning hole 31 is, the higher the sensitivity of the sensor is.

[0094] Specifically, a positioning hole 31 is set in the turntable 3 of the annealing furnace body 1, and a sensor is set below the overlapping area of ​​the trajectory of the positioning hole 31 rotating around the rotation axis, and the sensor transmits the collected signal to the control module of the annealing furnace body 1 in real time, and then the rotation angle of the wafer 2 can be monitored in real time without opening the furnace chamber of the annealing furnace body 1.

[0095] Specifically, through the combination of the positioning hole 31, the sensor and the control module, when the turntable 3 is not in the set initial position, the control module in the wafer annealing furnace can perform a self-check and reset the control turntable 3 to rotate the turntable 3 to the set initial position.

[0096] The wafer annealing furnace of this embodiment improves the structure of the turntable 3, and sets a plurality of positioning holes 31 that are evenly distributed and penetrate the turntable 3 on the periphery of the wafer placement area of ​​the turntable 3. The trajectories of the positioning holes 31 rotating around the rotation axis at least partially overlap, and a sensor for collecting signals is set directly below the overlapping area of ​​the trajectories of the positioning holes 31 rotating around the rotation axis. Through the combination of these three simple structures of the control module, the positioning holes 31 and the sensor, real-time monitoring and precise control of the number of rotations and the rotation angle of the wafer 2 during the annealing process of the wafer 2 are achieved. At the same time, the improved wafer annealing furnace can also have the ability of position self-detection and reset.

[0097] Embodiment 2

[0098] This embodiment provides a wafer annealing method, the annealing method comprising the following steps:

[0099] S1: Provide a wafer annealing furnace and a wafer as described above, and start the wafer annealing furnace, wherein the locating holes A1 are located directly above the sensor, from one of the locating holes along the rotation direction set by the turntable.

[0100] S2: the control module receives a signal indicating that the sensor is located directly below the positioning hole A1, and sequentially controls the turntable to stop rotating, opens the furnace chamber of the annealing furnace, and the transfer arm places the wafer in the wafer placement area and the turntable to rotate along the set direction;

[0101] S3: After the turntable starts to rotate, each time the control module receives a signal that the positioning hole Ai rotates to the position directly below the sensor, it sequentially controls the turntable to stop rotating, wait for a preset time, and continue rotating;

[0102] S4: until the control module receives the signal that the positioning hole A1 moves to the position directly below the sensor for a predetermined number of times, the furnace chamber is controlled to be closed and the annealing process is performed.

[0103] Specifically, please perform step S1: provide a wafer annealing furnace and a wafer 2 as described above, and use positioning holes Ai in sequence from a positioning hole 31 along the set rotation direction of the turntable 3, where 1≤i≤n, start the wafer annealing furnace, and rotate the positioning hole A1 to be directly above the sensor.

[0104] Specifically, since the turntable 3 of the wafer annealing furnace is provided with n positioning holes 31 evenly distributed on the periphery of the wafer placement area, a sensor is arranged directly below the overlapping part of the rotation trajectory of the positioning hole 31 around the rotation axis, a positioning hole is selected as the positioning hole A1, and then each positioning hole 31 is numbered in sequence as positioning hole Ai (1≤i≤n) along the rotation direction set by the turntable 3, so as to determine the position of the wafer 2 based on the signal collected by the sensor in real time during the subsequent annealing of the wafer 2.

[0105] Specifically, after starting the wafer annealing furnace, the upper heating lamp tube and the lower heating lamp tube begin to preheat, the sensor begins to collect signals and transmits the collected signals to the control module in real time, the control module receives the signals transmitted by the sensor, and determines the position of the turntable 3 in real time.

[0106] It should be noted that when the wafer annealing furnace is started, the wafer annealing furnace also needs to perform a reset self-check. When the control module does not receive the signal that the positioning hole A1 is directly above the sensor, it controls the turntable 3 to rotate, and controls the turntable 3 to stop rotating after the positioning hole A1 rotates to directly above the sensor, so as to achieve the reset of the turntable 3; when the wafer annealing is started, the control module receives the signal that the positioning hole A1 is directly above the sensor, and directly skips the step of resetting the turntable 3.

[0107] See also Figures 10 to 14 , please execute step S2, step S3 and step S4: the control module receives the signal that the sensor is located directly below the positioning hole A1, and controls the turntable 3 to stop rotating, open the furnace chamber of the annealing furnace, and the transfer arm 11 to place the wafer 2 in the wafer placement area and the turntable 3 to rotate along the set direction in sequence; after the turntable 3 starts to rotate, each time the control module receives the signal that the positioning hole Ai rotates to the bottom of the sensor, it controls the turntable 3 to stop rotating, wait for a preset time, and continue to rotate the turntable 3 in sequence; until the control module receives the signal that the positioning hole A1 rotates to the bottom of the sensor for a predetermined number of times, controls the furnace chamber to close and performs the annealing process.

[0108] Specifically, when the positioning hole A1 rotates to be directly above the sensor, the sensor detects a signal and transmits the detected signal to the control module. The control module controls the turntable 3 to stop rotating and uses the position where the turntable 3 stops as the position for placing the wafer 2, thereby determining the initial position of the wafer 2 placed in the wafer placement area.

[0109] Specifically, before placing the wafer 2 in the wafer placement area, a step of waiting for the furnace chamber to be preheated is also included to raise the temperature of the upper heating lamp tube and the lower heating lamp tube to a preset temperature and stabilize the power of the upper heating lamp tube and the lower heating lamp tube.

[0110] Specifically, under the condition that the temperature in the furnace chamber of the wafer annealing furnace reaches the preset temperature and the machine works stably, the preset preheating time of the furnace chamber can be selected according to actual conditions; the temperature value of the preset temperature can be selected according to actual conditions.

[0111] It should be noted that before the transfer arm 11 transfers the wafer 2 to the wafer placement area, the wafer annealing furnace needs to complete the preparatory work before annealing, such as self-checking and resetting the turntable 3 and preheating the furnace chamber, and after placing the wafer 2 in the wafer placement area, the wafer 2 is first preheated and then annealed.

[0112] Specifically, the time when the control module controls the conveying arm 11 to convey the wafer 2 to the wafer placement area and the time when the control module controls the conveying arm 11 to take out the wafer 2 from the wafer placement area are usually pre-set fixed times. At the same time, the time when the control module controls the opening and closing of the furnace cover of the wafer annealing furnace is also fixed. Since the lining 12 is in an inclined state during the process of placing the wafer 2, the wafer 2 will be heated unevenly during the process of placing the wafer 2, taking out the wafer 2, opening the furnace cover and closing the furnace cover.

[0113] It should be noted that before preheating the wafer 2, the number of revolutions of the wafer 2 during preheating needs to be preset, that is, the number of times the control module receives the signal of the positioning hole A1; during the preheating of the wafer 2, the rotation direction of the turntable 3 can be selected according to the actual situation, but the rotation direction of the turntable 3 remains unchanged during the entire preheating process of the wafer 2. The number here refers to the number of times the wafer 2 receives the signal of the positioning hole A1 after the preheating of the wafer 2 in the furnace chamber begins.

[0114] As an example, the preset time is the sum of the time it takes for the transfer arm 11 to place the wafer 2 and the time it takes for the transfer arm 11 to take out the wafer 2, and during the preset time when the turntable 3 stops rotating, the wafer 2 is located in the wafer placement area and remains motionless, that is, during the preheating process of the wafer 2, the control module starts to process the signal transmitted by the sensor during the preheating process after the wafer 2 is placed in the wafer placement area and starts to rotate. When the number of times the control module receives the signal of the positioning hole A1 does not reach the preset number of times, the control module repeats the operation of stopping the turntable 3, waiting for the transfer arm 11 to take out the wafer 2 and the time it places the wafer 2, and continuing to rotate the turntable 3 for preheating each time it receives the signal of the positioning hole Ai, until the control module receives the signal of the positioning hole A1 the number of times the control module controls the annealing furnace main body 1 to close the furnace chamber for the annealing process.

[0115] Specifically, the size of the arc area formed by the sensing area of ​​the sensor sweeping across the positioning hole A1 is different from the size of the arc area formed by sweeping across other positioning holes Ai, that is, the size of the area swept across by the sensing area of ​​the sensor in the initial positioning hole A1 is different from the size of the area swept across by the sensing area of ​​the sensor in other positioning holes Ai.

[0116] Specifically, by making the size of the area swept by the sensing area of ​​the sensor in the positioning hole A1 different from the size of the area swept by the sensing area of ​​the sensor in other positioning holes Ai, the signal of the positioning hole A1 collected by the sensor is different from the signals of other positioning holes Ai, which can facilitate the control module to count the number of times the signal of the positioning hole A1 collected by the sensor is received, so as to simplify the workload of the control module in processing the received signal of the positioning hole Ai and simplify the control mechanism of the control module. Taking the four positioning holes 31 as an example, if Fig.10 and Fig.11 As shown, they are Figure 6 Signal diagram of the sensor collected under the relay station 3 structure and Figure 7 The signal diagram collected by the sensor under the turntable 3 structure shows that during the preheating process of the wafer 2, the wafer 2 is set to rotate one circle on the turntable 3. After the preheating starts, when the control module receives the positioning hole A1 signal that is different from the signals of other positioning holes A2, A3 and A4, it can directly trigger the instruction to control the conveying arm 11 to take the wafer 2, so as to simplify the control mechanism of the control module.

[0117] As an example, a reference hole 32 passing through the turntable 3 is also provided on the periphery of the wafer placement area, and a sensor is provided directly below the overlapping area of ​​the trajectory of the reference hole 32 rotating around the rotating axis. The control module controls the wafer annealing furnace body 1 to perform corresponding operations based on the signal of the reference hole 32 collected by the sensor. For example, at the beginning of preheating, the furnace chamber is controlled to be opened; at the end of preheating, the furnace chamber is controlled to be closed; at the end of the annealing process, the furnace chamber is controlled to be opened, etc.

[0118] Specifically, by setting a reference hole 32 and setting a sensor below the rotation track of the reference hole 32, the reference hole 32 and the positioning hole 31 are combined to jointly determine the initial position of the wafer 2 (when the turntable 3 is reset, the two sensors are respectively located directly below the reference hole 32 and the positioning hole 31), which can further simplify the workload of the control module in processing signals and facilitate more accurate reset of the turntable. Taking the four positioning holes 31 as an example, Fig.12 and Fig.13 As shown, they are Figure 8 Signal diagram collected by the sensor under the relay station 3 structure and Fig. 9 The signal diagram collected by the sensor under the turntable 3 structure shows that during the preheating process of the wafer 2, the wafer 2 is set to rotate one circle during the preheating process. When the control module only receives the signal of the positioning hole 31, the wafer annealing furnace repeats the operation of stopping the turntable and waiting for the preset time and the turntable rotation. When the control module receives the signals of the positioning hole 31 and the reference hole 32 at the same time, it can directly trigger the instruction of the annealing furnace main body 1 to close the furnace chamber for the annealing process, thereby further simplifying the control mechanism of the control module.

[0119] It should be noted that when the wafer 2 needs to rotate multiple times in the annealing furnace, the complexity of the control module processing signals needs to be increased. For example, when only positioning hole 31 is set on the turntable 3, it is necessary to identify and count the number of signals received from the positioning hole A1 to trigger the instruction to close the furnace chamber.

[0120] Specifically, by improving the structure of the turntable 3, a plurality of positioning holes 31 for positioning are provided on the turntable 3, and the positioning holes 31 are evenly distributed on the periphery of the wafer placement area of ​​the turntable 3. The positioning holes 31 are combined with the sensor and the control module, and the sensor collects the positioning hole 31 signal and transmits it to the control module. The control module counts and processes the received positioning hole 31 signal. When the signal received by the control module is the positioning hole Ai signal of each intermediate process, the turntable 3 is controlled to stop rotating and wait for the time to take out the wafer 2 and the time to put the wafer 2, and then continue to rotate the turntable 3 until the turntable 3 rotates a preset number of circles, and the furnace chamber is closed for annealing process, so that the wafer 2 undergoes a heating process in which the lining is in a tilted state for multiple times at the same time since it is placed in the wafer annealing furnace, and then the difference in heating of the wafer 2 caused by the tilt of the lining 12 during the process of taking and placing the wafer 2 can be reduced.

[0121] As an example, during the preset time when the turntable 3 stops rotating, the control module further controls the transfer arm 11 to take out the wafer 2 and put the taken out wafer 2 back into the wafer placement area.

[0122] Specifically, during the entire preheating process of the wafer 2, based on the number of revolutions of the wafer 2, the control module processes and counts the number of received positioning holes A1 after controlling the turntable 3 to rotate. When the received positioning hole 31 signal is an intermediate process signal, the turntable 3 stops rotating, and controls the transfer arm 11 to take out the wafer 2 from the furnace chamber and put it back into the wafer placement area. At the same time, after the wafer 2 rotates a preset number of times, it returns to the original position and closes the furnace chamber for annealing process, so that the wafer 2 also has one operation of taking out the wafer 2 and one operation of placing the wafer 2 at the initial position, so that the wafer 2 experiences one operation of taking and placing the wafer 2 as each positioning hole Ai rotates to the sensor, and then the heating conditions of the wafer 2 as each positioning hole 31 rotates to the sensor are the same, further reducing the heating error of the wafer 2 during the process of taking and placing the wafer, so that each area of ​​the wafer 2 is heated more evenly during the preheating process.

[0123] Specifically, Fig.14 As shown in FIG. 1 , it is a resistance distribution diagram of wafer 2 after annealing, wherein the result is measured after the wafer is rotated one circle in an annealing furnace with a turntable 3 having four positioning holes 31 for preheating and then annealing, and during the preheating process of the test wafer, the turntable 3 stops rotating and waits for a preset time, and does not take out the wafer, but waits for the time for the transfer arm 11 to take and put the wafer, and then continues to rotate the turntable 3 until the furnace chamber is closed for annealing process, and the relevant parameters in the whole annealing process are Figure 1 The relevant annealing parameters in are the same. The values ​​in the figure are the resistance ranges obtained by measurement. It can be seen from the figure that the resistance distribution of wafer 2 after annealing is different from that of Figure 1 There is a significant improvement, and the resistance distribution of wafer 2 after annealing is more uniform.

[0124] It should be noted that during the process of closing the furnace chamber for annealing, the sensor is still collecting signals in real time and transmitting the signals to the control module. The control module can accurately control the end time of annealing based on the number of wafer rotations set for annealing and the signal fed back by the sensor, and after the annealing is completed, the wafer 2 is rotated back to the initial position, so that the wafer can be placed in the furnace chamber at the same angle and taken out of the furnace chamber at the same angle during the annealing process.

[0125] Specifically, a plurality of evenly distributed positioning holes 31 are arranged on the turntable 3, and sensors are used to collect signals of the positioning holes 31 and transmit them to the control module. The control module controls the turntable 3 to stop rotating based on the signals of the positioning holes Ai received by the sensors, and identifies the positions of the positioning holes Ai at the same time. When the positioning holes Ai are in the middle process, the turntable 3 stops rotating and waits for a preset time, and the preset time is the sum of the time for the transfer arm 11 to take and place the wafer 2, thereby reducing the heat difference at various parts of the wafer 2, making the wafer 2 more evenly heated during the preheating process, avoiding the phenomenon of unilateral offset in the resistance distribution of the wafer 2 after annealing, and making the resistance distribution of the annealed wafer 2 more uniform.

[0126] Specifically, by performing preheating operations based on the positioning hole 31 signal, the heat difference during the annealing process of the wafer 2 is reduced, the product yield is improved, the uniformity and consistency of the entire heating of the product are improved, and more precise control of the product resistance and film thickness is achieved.

[0127] Specifically, through the combination of the positioning hole 31, the sensor and the control module, the number of revolutions of the wafer 2 and the position of the wafer 2 can be accurately controlled through a simple structure, and at the same time, the wafer 2 can be placed in and taken out at the same angle, thereby solving the problem of random angles of the wafer 2 taken out of the annealing furnace and providing convenience for subsequent processes.

[0128] The wafer annealing method of the present embodiment adopts the wafer annealing furnace in the first embodiment. During the preheating process of the wafer 2 before annealing, the initial position of the wafer 2 is determined based on the positioning hole 31 on the turntable 3. At the same time, after the turntable 3 rotates, the control module stops the rotation of the turntable 3, waits for the placement of the wafer 2 and the length of time for taking out the wafer 2, and continues to rotate the turntable 3 each time it receives a signal from the positioning hole 31, thereby reducing the difference in heat exposure of some areas of the wafer 2 caused by the tilt of the liner 12 during the process of taking and placing the wafer 2, so that the wafer 2 is heated more during the annealing process. The annealing furnace has a uniform structure, which avoids the phenomenon of unilateral deviation of the resistance distribution of the wafer 2 after annealing, makes the resistance distribution of the annealed wafer 2 more uniform, improves the yield of the product, improves the uniformity and consistency of the entire heating of the product, and realizes more precise control over the product resistance and film thickness; the number of revolutions of the wafer 2 and the position of the wafer 2 can be accurately controlled through a simple structure, and at the same time, the angles of the wafer 2 in and out of the furnace cavity of the wafer annealing furnace are the same, which solves the problem of random angles of the wafer taken out of the annealing furnace and provides convenience for subsequent processes.

[0129] In summary, the wafer annealing furnace and the wafer annealing method of the present invention improve the structure of the wafer annealing furnace, set n positioning holes whose trajectories rotating around the rotating axis at least partially overlap on the periphery of the wafer placement area of ​​the turntable, and set a sensor for collecting positioning hole signals below the overlapping area of ​​the positioning hole trajectories. The control module of the wafer annealing furnace controls the wafer annealing based on the signal collected by the sensor. In the preheating process before the wafer annealing, the control module places the wafer into the furnace chamber of the wafer annealing furnace after receiving the initial positioning hole signal and rotates for preheating. In the middle of the preheating process, the control module controls the turntable to stop rotating after receiving the positioning hole signal. The preset dwell time and the rotating table are operated for the first time, and then the heating process of the lining in a tilted state is carried out at multiple angles of the wafer during the preheating process of the entire wafer, which reduces the difference in heating of each area during the wafer annealing process, makes the wafer more evenly heated during the annealing process, improves the yield of the product, improves the uniformity and consistency of the entire heating of the product, realizes more precise control of the product resistance and film thickness, and avoids the phenomenon of biased resistance distribution of the wafer after annealing; through simple structural improvements, the wafers are placed in the wafer annealing furnace at the same angle and taken out of the wafer annealing furnace at the same angle, which provides convenience for subsequent process. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has a high industrial utilization value.

[0130] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A wafer annealing furnace, characterized in that: include: The annealing furnace body comprises a turntable rotating around a rotation axis and a control module, wherein n positioning holes are arranged at the periphery of a wafer placement area of ​​the turntable, and the trajectories of the rotation around the rotation axis at least partially overlap and are evenly distributed, and the positioning holes penetrate the turntable, wherein n≥3; The sensor is fixed below the overlapping area of ​​the rotation tracks of the positioning holes, and the control module receives and processes the signals collected by the sensor in real time.

2. The wafer annealing furnace according to claim 1, characterized in that: The length of the arc area formed by one positioning hole swept by the sensing area of ​​the sensor is different from the length of the arc area formed by other positioning holes; or the length of the arc area formed by different positioning holes swept by the sensing area of ​​the sensor is different.

3. The wafer annealing furnace according to claim 1, characterized in that: The turntable is also provided with a reference hole, which is located at the periphery of the wafer placement area and passes through the turntable. At least one sensor is fixed directly below the trajectory of the reference hole rotating around the rotation axis.

4. The wafer annealing furnace according to claim 3, characterized in that: The reference hole is collinear with the rotating shaft and an adjacent positioning hole, and the reference hole is spaced apart from the positioning hole adjacent to the reference hole by a preset distance.

5. The wafer annealing furnace according to claim 3, characterized in that: The trajectory of the reference hole rotating around the rotation axis is spaced apart by a preset distance from the trajectory of the positioning hole rotating around the rotation axis, and the straight line where the positioning hole adjacent to the reference hole and the rotation axis are located intersects with the straight line where the reference hole and the rotation axis are located.

6. The wafer annealing furnace according to claim 1, characterized in that: The size of the sensor sensing area is not greater than the size of the minimum overlapping area that overlaps with each of the positioning holes in the overlapping portion of the rotation tracks of each of the positioning holes.

7. The wafer annealing furnace according to claim 1, characterized in that: The sensor includes a combination of one or more of a photoresistor, a photoinductor, a photocapacitor, a photosensitive field transistor, and a photosensitive circuit.

8. A wafer annealing method, characterized in that: The following steps are involved: A wafer annealing furnace and a wafer according to any one of claims 1 to 7 are provided, wherein the locating holes A1 are located directly above the sensor from one of the locating holes along the rotation direction set by the turntable, wherein 1≤i≤n. The control module receives a signal indicating that the sensor is located directly below the positioning hole A1, and sequentially controls the turntable to stop rotating, opens the furnace chamber of the annealing furnace, and the transfer arm to place the wafer in the wafer placement area and the turntable to rotate along the set direction; After the turntable starts to rotate, each time the control module receives a signal that the positioning hole Ai rotates to the position directly below the sensor, it sequentially controls the turntable to stop rotating, wait for a preset time, and continue rotating; Until the control module receives the signal that the positioning hole A1 moves to the position directly below the sensor for a predetermined number of times, the furnace chamber is controlled to be closed and the annealing process is performed.

9. The wafer annealing method according to claim 8, characterized in that: The preset time is the sum of the time taken by the transfer arm to place the wafer and the time taken to take out the wafer, and during the preset time when the turntable stops rotating, the wafer is located in the wafer placement area and remains stationary.

10. The wafer annealing method according to claim 8, characterized in that: During the preset time when the turntable stops rotating, the control module further controls the transfer arm to take out the wafer and put the taken out wafer back into the wafer placement area.

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