Heating device

Abstract

The utility model provides a heating device which is used for laser annealing equipment and comprises a control unit and a heating table, the heating table comprises a heating area, the shape and size of the heating area are matched with those of a heated wafer, the heating area is divided into a plurality of subareas, the subareas at least comprise a first subarea, the first subarea is located at the edge of the heating area, and the second subarea is located at the edge of the heating area. The control unit is electrically connected with the subareas and independently controls the temperatures of the subareas. According to the heating device, temperature compensation is performed on each subarea of the heating table, so that the problem of non-uniform heating of the wafer is solved, and the heating uniformity of the edge of the wafer is obviously improved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor manufacturing technology, and in particular to a heating device for laser annealing equipment. Background Art

[0002] Laser spike annealing equipment uses laser scanning to anneal the wafer surface. Uniform heating of the wafer during the annealing process is a critical parameter that directly impacts product yield. However, laser annealing equipment uses a uniform temperature control system on the heating stage, resulting in poor uniformity in wafer heating.

[0003] In addition, the heat dissipation area at the edge of the wafer is larger, which will lead to poor thermal activation at the edge of the wafer. When the laser scans the wafer, in order to avoid excessive thermal stress at the edge causing fragments, a certain distance of blank space will be left without laser annealing. This will also cause poor thermal activation at the edge of the wafer, increase the wafer square resistance, and lead to poor thermal uniformity at the edge of the wafer. Although optimization can be achieved by amplifying the laser scanning trajectory, there is still a situation where the thermal activation effect of doped atoms at the outer edge of the wafer is poor and the wafer square resistance increases.

[0004] Therefore, a device is needed to improve the problem of poor wafer heating uniformity in the prior art. Utility Model Content

[0005] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a device for solving the problem of poor heating uniformity at the edge of the wafer in the prior art.

[0006] An embodiment of the present application provides a heating device, including a control unit and a heating platform, wherein the heating platform includes a heating area, the shape and size of the heating area are adapted to the shape and size of the heated wafer, the heating area is divided into several partitions, the several partitions include at least a first partition, the first partition is located at the edge of the heating area, the control unit is electrically connected to the several partitions, respectively, and independently controls the temperature of the several partitions.

[0007] In some embodiments, the plurality of partitions further includes a second partition; the second partition is located inside the first partition, and the outer side of the second partition is connected to the inner side of the first partition.

[0008] In some embodiments, each of the partitions includes at least one electric heating element, and each of the electric heating elements is electrically connected to the control unit.

[0009] In some embodiments, the electric heating element of the second partition is concentric with the electric heating element of the first partition.

[0010] In some embodiments, the second partition is divided into several arc-shaped sub-partitions, each of the sub-partitions includes at least one electric heating element, and the control unit is connected to the electric heating element of each sub-partition to independently control the temperature of each sub-partition.

[0011] In some embodiments, the shape of the electric heating element of each sub-region matches the shape of the sub-region to which it belongs.

[0012] In some embodiments, the curvature of the sub-partition matches the laser scanning trajectory.

[0013] In some embodiments, the electric heating element is built into the heating platform.

[0014] In some embodiments, each of the partitions is respectively configured with a temperature sensor, and each of the temperature sensors is respectively electrically connected to the control unit.

[0015] In some embodiments, the temperature sensors are respectively configured in the central area of ​​the corresponding partitions.

[0016] As described above, the heating device of the present application has the following beneficial effects: the heating area of ​​the heating table in the heating device includes at least a first sub-area located at the edge of the heating area, and the temperature of the first sub-area is independently controlled, which significantly improves the heating uniformity at the edge of the wafer. Furthermore, the heating area also includes a second sub-area that is independently temperature-compensated and several sub-areas within the second sub-area. The temperature of each sub-area of ​​the heating table is controllable and adjustable, which improves the uniformity of the wafer heating and further improves the product yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The following figures describe in detail exemplary embodiments disclosed in this application. Like reference numerals denote similar structures throughout the several views of the drawings. Those skilled in the art will appreciate that these embodiments are non-limiting, exemplary embodiments, and that the drawings are provided for illustration and description purposes only and are not intended to limit the scope of this application. Other embodiments may also achieve the inventive intent of this application. It should be understood that the drawings are not drawn to scale.

[0018] in:

[0019] Figure 1 is a schematic diagram of a laser annealing device according to some embodiments of the present application;

[0020] Figure 2 yes Figure 1 Schematic diagram of the heating device shown in;

[0021] Figure 3 is a schematic diagram of the heating area according to the first embodiment of the present application;

[0022] Figure 4 This is a schematic diagram of the heating area according to the second embodiment of the present application;

[0023] Figure 5 This is a schematic diagram of the heating area according to the third embodiment of the present application;

[0024] Figure 6 yes Figure 5 The schematic diagram showing the comparison of the square resistance of the wafer before and after the heating area is adjusted in the first partition;

[0025] Figure 7 yes Figure 5 Schematic diagram showing a comparison of the sheet resistance of the wafer before and after the second and third partitions of the second partition are adjusted by the heating area;

[0026] Figure 8 is used Figure 5 The diagram shown is a comparison of wafer heating uniformity before and after the heating area modification. DETAILED DESCRIPTION

[0027] The following description provides specific application scenarios and requirements of the present application, with the purpose of enabling those skilled in the art to make and use the content of this application. Various local modifications to the disclosed embodiments will be apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of this application. Therefore, this application is not limited to the embodiments shown, but is intended to be of the widest scope consistent with the claims.

[0028] The present invention provides a heating device for use in laser annealing equipment, comprising a control unit and a heating stage. The heating stage includes a heating area whose shape and size are adapted to the shape and size of the heated wafer. The heating area is divided into several zones, including at least a first zone located at the edge of the heating area. The control unit is electrically connected to each of the zones and independently controls the temperature of each zone. The provision of the first zone significantly improves heating uniformity at the edge of the wafer.

[0029] Furthermore, the plurality of partitions includes a second partition. The second partition is located inside the first partition, and the outer side of the second partition is adjacent to the inner side of the first partition. The provision of the second partition further fine-tunes the heating of the center area of ​​the wafer, thereby improving the uniformity of heating in the center area of ​​the wafer.

[0030] By performing independent temperature compensation on each zone of the heating platform so that the temperature of each zone of the heating platform is consistent, the problem of uneven heating of the wafer can be solved and the overall heating uniformity of the wafer can be improved.

[0031] like Figure 1 and Figure 2 As shown, current laser annealing equipment includes a wafer transfer device 3, a preheating device 4, a cooling device 5, a chamber 6, a laser unit 7, and a control unit (not shown). A heating table 2 is located within chamber 6, which includes a motion system (not shown). A heating zone 21 is provided at the interface between the heating table 2 and the wafer 1. Wafer 1 is sealed within chamber 6. Laser unit 7 emits laser light 71, which irradiates the chamber 6. The laser spot 71 scans across wafer 1, entering from one edge of wafer 1 and exiting symmetrically from the other edge of wafer 1 in an upwardly convex arc. Upon contact with the surface of wafer 1, laser light 71 anneals the surface of wafer 1. Heating table 2 supports and drives wafer 1, allowing the laser spot 71 to scan across wafer 1, annealing the surface. The control unit is connected to the laser unit 7, heating table 2, and motion system, receiving data from the laser unit 7 and heating table 2 and controlling the temperature of the laser unit 7 and heating table 2's heating zones and the motion system.

[0032] In some embodiments, each partition includes at least one electric heating element (refer to Figures 3 to 5 ), each electric heating element is electrically connected to the control unit, and the temperature control of each partition is independent of each other. In some embodiments, the electric heating element can be a heating wire, and the heating platform 21 is a quartz piece.

[0033] In some embodiments, the electric heating element is built into the heating platform 2. The electric heating element is arranged in the heating area 21 of the heating platform 2, and the electric heating element and the heating platform 21 are arranged in an integrated manner.

[0034] In some embodiments, the heating area 21 includes at least a first partition 211. The first partition 211 is located at the edge of the heating area 21. When the laser scans the wafer, in order to avoid excessive thermal stress at the edge causing fragments, a certain distance will be left blank without laser annealing, which will also cause the thermal activation at the edge of the wafer to deteriorate. Although the laser scanning track can be magnified to scan the wafer 1, there is still a situation where the thermal activation effect of the doped atoms at the outer boundary of the wafer 1 is poor and the resistance of the wafer block becomes higher; on the other hand, a track edge that is too small will cause wafer fragments. Therefore, a first partition 211 is set, and the temperature of the first partition 211 is controlled by a control unit to perform temperature compensation on the edge of the wafer, which solves the problem of poor thermal activation at the edge of the wafer due to the large heat dissipation area at the edge of the wafer, and also solves the problem of poor heating uniformity at the edge of the wafer.

[0035] The technical solution of this application is described in detail below with reference to the embodiments and drawings.

[0036] Example 1

[0037] like Figure 3 Shown and combined Figure 1 and Figure 2 , Figure 3 According to the heating area 21 shown in some embodiments of the present application, in some embodiments, the several partitions of the heating area 21 further include a second partition 212. The second partition 212 is located inside the first partition 211, and the outer side of the second partition 212 is connected to the inner side of the first partition 211. The first partition 211 and the second partition 212 are respectively provided with one or more electric heating elements, and the electric heating elements are circular. Specifically, the electric heating element 2110 of the first partition 211 is configured as a circle, and the electric heating element 2120 of the second partition 212 is a concentric circle with the electric heating element 2110 of the first partition. The control unit controls the temperature of the first partition 211 and the second partition 212 respectively, so that the temperature of the first partition 211 and the second partition 212 are consistent. The heating area 21 solves the problem of poor heating uniformity at the edge of the wafer, but the spot scanning trajectory of the laser 71 is different from the layout of the electric heating element 2120 in the second partition 212 of the heating table 21, which still affects the heating uniformity effect of the wafer.

[0038] Example 2

[0039] Figure 4 This is based on the heating region 21' shown in some embodiments of the present application. In some embodiments, the electric heating element 2120' of the second subarea 212' of the heating region 21' is arc-shaped. The second subarea 212' is located inside the first subarea 211' and is connected to the first subarea 211'. A control unit controls the temperature of the first subarea 211' and the second subarea 212' respectively. The scanning trajectory of the laser spot 71 matches the arc curvature of the electric heating element 2120' of the second subarea 212'. Compared with the heating region 21 of the first embodiment, the heating region 21' improves the uniformity of heating across the wafer.

[0040] Example 3

[0041] Figure 5 According to some embodiments of the present application, the heating area 21", the second sub-area 212", is divided into several arc-shaped sub-areas, each of which includes at least one electric heating element. The control unit is connected to the electric heating element of each sub-area to independently control the temperature of each sub-area. In some embodiments, the shape of the electric heating element of each sub-area matches the shape of the sub-area to which it belongs. It should be noted that the electric heating elements of each area and sub-area are made of the same material and may differ only in length or curvature.

[0042] In some embodiments, the heating area 21" is divided into a first partition 211" and a second partition 212". The second partition 212" is divided into three sub-partitions, namely the first partition 2121", the second partition 2122" and the third partition 2123". The first partition 211" is a circular ring, and the first partition 2121", the second partition 2122" and the third partition 2123" of the second partition 212" are arc-shaped. In some embodiments, the arc curvature of each sub-partition matches the laser scanning trajectory. The second partition 212" is located inside the first partition 211". The control unit independently controls the temperatures of the first partition 211", the first partition 2121", the second partition 2122" and the third partition 2123", so that the temperatures of the first partition 211", the first partition 2121", the second partition 2122" and the third partition 2123" are consistent. Compared with the heating area 21 ′ of the second embodiment, the heating area 21 ″ includes the features of the heating area 21 ′ and further subdivides the second subarea 212 ″, thereby further improving the heating uniformity of the wafer.

[0043] In some embodiments, the arc curvature of the electric heating element matches the laser scanning trajectory. The laser spot scanning trajectory of laser 71 is consistent with the layout of the arc-shaped electric heating elements in the first sub-area 2121″, the second sub-area 2122″, and the third sub-area 2123″ of the second sub-area 212″. In some embodiments, taking a 12-inch wafer as an example, the arc curvature radius ranges from 250 mm to 350 mm. The arc curvature of the electric heating elements in the first sub-area 2121″, the second sub-area 2122″, and the third sub-area 2123″ of the second sub-area 212″ matches the laser scanning trajectory.

[0044] In some embodiments, a plurality of subareas are respectively configured with temperature sensors 8, and each temperature sensor 8 is electrically connected to a control unit. In some embodiments, the temperature sensors 8 are respectively configured in the central area of ​​the corresponding subarea. The central area is the center of the plurality of electric heating elements distributed in each subarea.

[0045] Specifically, taking a 12-inch wafer as an example, the first partition 211", the first partition 2121", the second partition 2122" and the third partition 2123" are respectively configured with temperature sensors 8, and the entire heating area 21" includes 14 heating wires, among which the first partition 211" is provided with two heating wires, the first partition 2121" is provided with two heating wires, the second partition 2122" is provided with seven heating wires, and the third partition 2123" is provided with three heating wires. Specifically, the first partition 211" is provided with a first heating wire 21101" and a second heating wire 21102", and the first heating wire 21101" and the second heating wire 21102" form two circles with diameters of 300 mm and 280 mm respectively. The distance D between the adjacent heating wires between the first partition 211” and the first partition 2121” is 30 mm; the spacing between the heating wires in the first partition 2121”, the second partition 2122” and the third partition 2123” is 20 mm respectively. The curvature radius of the heating wire is 300 mm. It should be noted that the distance, curvature radius and number of heating wires in the first partition 2121”, the second partition 2122” and the third partition 2123” are only examples and can be adjusted according to the size of wafers of different sizes and the area where they are located, and need to match the scanning trajectory of the laser spot.

[0046] In some embodiments, a temperature sensor 8 is added in the middle of each partition to monitor the temperature of the partition. Figure 5 The heating area 21" includes four temperature sensors 8. Temperature compensation is performed based on the temperature measured by the temperature sensor 8. Figure 5 Combine Figure 2 Below wafer 1 is the heating zone of heating stage 2, which heats and maintains wafer 1 at a constant temperature. Laser 71 scans and heats the top surface of wafer 1. If laser 71 heats unevenly, the control unit adjusts the temperature of each zone's heating wire, causing heating stage 2 to compensate for heating in the corresponding area of ​​wafer 1. Specifically, the temperature of the heating wire is increased (for example, by 10°C, 15°C, 20°C, etc.), and then the sheet resistance is measured. The decrease in sheet resistance compared to the pre-temperature increase is calculated, and a corresponding relationship is established. This relationship allows for a linear relationship between temperature and sheet resistance. Increasing the heating wire temperature decreases the sheet resistance, while decreasing it increases it. Therefore, to adjust an area with high sheet resistance, the heating wire temperature in that area should be increased to lower the sheet resistance. To adjust an area with low sheet resistance, the heating wire temperature in that area should be decreased to increase the sheet resistance. This adjustment improves temperature uniformity across the entire wafer.

[0047] The scanning trajectory of the laser spot 71 matches the arc curvature of the electric heating element 2120" in the second partition 212". The scanning trajectory of the laser spot 71 also matches the distance between the electric heating elements 2120" in each sub-partition of the second partition 212". Compared with the heating area 21' of the second embodiment, the heating area 21" of the third embodiment further improves the uniformity of heating of the wafer.

[0048] refer to Figure 6 The schematic diagram of the comparison of the sheet resistance of the first area 211" before and after temperature adjustment is shown in FIG. (a) is before temperature adjustment, and (b) is after temperature adjustment. Figure 5 The temperature adjustment steps of the first area 211" of the laser annealing equipment heating stage 2 are exemplified as follows:

[0049] 1. First test the sheet resistance map of wafer 1 after annealing, and locate the partition that needs to adjust the temperature according to the sheet resistance distribution, such as Figure 6 As shown, the sheet resistance on the wafer corresponding to the outermost first region 211 ″ is significantly higher, and can be located in the first region 211 ″;

[0050] 2. Calculate the required temperature increase T°C based on the corresponding relationship between temperature and sheet resistance, and adjust the temperature of the first region 211″;

[0051] 3. After adjustment, laser anneal the wafer 1 and continue to perform fine-tuning according to steps 1 and 2 until the optimal result is achieved.

[0052] refer to Figure 7 The schematic diagram of the comparison of the block resistance of the second partition 2122" and the third partition 2123" before and after temperature adjustment is shown in FIG. (c) is before temperature adjustment, and (d) is after temperature adjustment. Figure 5 The temperature regulation principle of the second sub-area 2122" and the third sub-area 2123" of the second sub-area 212" of the laser annealing equipment heating area is as follows: the higher the wafer temperature, the lower the band gap of the semiconductor, the lower the energy of the photons required for intrinsic absorption, and the higher the absorption of laser energy, and vice versa. Specifically, Figure 7As shown, before temperature adjustment, the block resistance on the wafer corresponding to the third partition 2123" is relatively high. The temperature of the third partition 2123" can be increased to improve the wafer's absorption rate of laser energy and reduce the block resistance on the wafer corresponding to the third partition 2123". On the other hand, the block resistance on the wafer corresponding to the second partition 2122" is relatively low. At the same time, the temperature of the second partition 2123" can be reduced to increase the block resistance on the wafer corresponding to the second partition 2122". It can be seen that after the partition temperature adjustment, the uniformity of the block resistance on the wafers corresponding to the second partition 2122" and the third partition 2123" is improved. Similarly, the temperature of the first partition 2121" can be further adjusted, which will not be repeated here.

[0053] like Figure 8 As shown in the figure, the comparison shows that the uniformity of wafer heating after using the heating device of the present application is greatly improved compared with that before use. Therefore, using the heating device of the present application, the uniformity of wafer heating can be improved by adjusting the temperature of each zone of the heating area of ​​the heating table.

[0054] The potential beneficial effects of the embodiments of the present application include, but are not limited to: The heating device of the present application adjusts the temperature of each zone of the heating platform through temperature compensation to adjust the uniformity of heating across the entire wafer. This includes at least zoned temperature control for the wafer edge, which is matched to the laser scanning trajectory, making the temperature of each zone of the heating platform controllable and adjustable, thereby improving the uniformity of wafer heating and further improving product yield.

[0055] It should be noted that different embodiments may produce different beneficial effects. In different embodiments, the beneficial effects that may be produced may be any one or a combination of the above, or any other possible beneficial effects.

[0056] The basic concepts have been described above. It will be apparent to those skilled in the art that the detailed disclosure above is merely illustrative and does not limit this specification. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and revisions to this application. Such modifications, improvements, and revisions are suggested in this specification and remain within the spirit and scope of the exemplary embodiments of this application.

[0057] It should be noted that, in the description of this application, unless otherwise expressly specified or limited, the terms "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections, electrical connections; rotational connections, or sliding connections; direct connections, or indirect connections through an intermediate medium; and can refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application in light of specific circumstances.

[0058] In addition, when terms such as "first", "second", and "third" are used in the specification of this application to describe various features, these terms are only used to distinguish these features and cannot be understood as indicating or implying the relationship between the features, the relative importance, or implicitly indicating the number of features indicated.

[0059] In addition, this specification describes exemplary embodiments by reference to idealized exemplary cross-sectional views and / or plan views and / or perspective views. Therefore, differences from the illustrated shapes due to, for example, manufacturing techniques and / or tolerances are foreseeable. Therefore, the exemplary embodiments should not be interpreted as limited to the shapes of the regions shown herein, but should include deviations in shapes due to, for example, manufacturing. Therefore, the regions shown in the figures are schematic in nature, and their shapes are not intended to illustrate the actual shapes of the regions of the device nor to limit the scope of the exemplary embodiments.

[0060] At the same time, this application uses specific terms to describe the embodiments of this specification. For example, "one embodiment," "an embodiment," and / or "some embodiments" refer to a certain feature, structure, or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment," "an embodiment," or "an alternative embodiment" mentioned twice or multiple times in different locations in this application does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the present application may be appropriately combined.

[0061] Similarly, it should be noted that, in order to simplify the presentation of this application and thus facilitate understanding of one or more embodiments of the invention, the foregoing descriptions of the embodiments of this application sometimes combine multiple features into a single embodiment, figure, or description thereof. However, this disclosure method does not mean that the subject matter of this application requires more features than those recited in the claims. In fact, an embodiment may have fewer features than all of the features of a single embodiment disclosed above.

[0062] Finally, it should be understood that the embodiments described in this application are merely illustrative of the principles of the embodiments of this application. Other variations may also fall within the scope of this application. Therefore, by way of example and not limitation, alternative configurations of the embodiments of this application may be considered consistent with the teachings of this application. Accordingly, the embodiments of this application are not limited to the embodiments explicitly introduced and described in this application.

Claims

1. A heating device for laser annealing equipment, characterized in that: The system comprises a control unit and a heating platform, wherein the heating platform comprises a heating area, the shape and size of the heating area being adapted to the shape and size of the heated wafer, the heating area being divided into a plurality of partitions, the plurality of partitions comprising at least a first partition, the first partition being located at the edge of the heating area, the control unit being electrically connected to the plurality of partitions respectively, and independently controlling the temperatures of the plurality of partitions respectively.

2. The heating device according to claim 1, characterized in that The plurality of partitions further includes a second partition; the second partition is located inside the first partition, and the outer side of the second partition is connected to the inner side of the first partition.

3. The heating device according to claim 2, characterized in that Each of the partitions includes at least one electric heating element, and each of the electric heating elements is electrically connected to the control unit.

4. The heating device according to claim 3, characterized in that The electric heating element in the second partition is concentric with the electric heating element in the first partition.

5. The heating device according to claim 3, characterized in that The second partition includes a plurality of arc-shaped sub-partitions, each of which includes at least one electric heating element. The control unit is connected to the electric heating element of each sub-partition to independently control the temperature of each sub-partition.

6. The heating device according to claim 5, characterized in that The shape of the electric heating element of each sub-region matches the shape of the sub-region to which it belongs.

7. The heating device according to claim 6, characterized in that The curvature of the sub-partition matches the laser scanning trajectory.

8. The heating device according to claim 3, characterized in that The electric heating element is built into the heating platform.

9. The heating device according to claim 1, characterized in that Each of the partitions is respectively configured with a temperature sensor, and each of the temperature sensors is respectively electrically connected to the control unit.

10. The heating device according to claim 9, characterized in that The temperature sensors are respectively arranged in the central areas of the corresponding partitions.

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