Wafer silicon wafer infrared heater

Abstract

A wafer silicon wafer infrared heater comprises a heating lamp holder, an installation groove cavity is formed in the heating lamp holder, the lower end of the installation groove cavity is a radiation outlet penetrating through the bottom of the heating lamp holder, and a plurality of infrared heating bulbs distributed in the installation groove cavity in a circumferential mode are installed in the installation groove cavity. The infrared ray generating parts of the plurality of infrared heating bulbs are combined to form a circular heating area corresponding to the radiation outlet; and the bottom of the heating lamp holder is provided with a mounting positioning ring and a fixing seat which are used for positioning and mounting the heating lamp holder on a shell of the heating device. According to the utility model, the circular heating area can completely coincide with the wafer in space, so that infrared radiation emitted by the infrared heating bulb acts on the wafer as much as possible, the heating efficiency of the wafer is ensured, and the energy waste of the heater is reduced at the same time; a mounting positioning ring and a fixing seat are arranged on the heating lamp holder, so that the mounting convenience of the heater is improved, and the purpose of improving the mounting efficiency of the heater is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of infrared heaters, in particular to an infrared heater for wafer silicon wafers. Background Art

[0002] In the semiconductor industry, infrared heaters are often used. Short-wave infrared rays are emitted by the infrared heaters to irradiate the wafers to achieve the effect of temperature rise.

[0003] For example, the heating infrared lamp tube structure and wafer heating device for the semiconductor industry disclosed in the Chinese patent with the patent number CN202222327076.8. This patent uses two layers of lamp tubes, namely the main heating lamp tubes and the auxiliary heating lamp tubes, as the infrared heaters for heating. Along the arrangement direction of the multiple main heating lamp tubes, the temperature control of the middle and the edges of the wafer along the arrangement direction can be realized by separately controlling the multiple main heating lamp tubes; along the extension direction of the main heating lamp tubes, at least part of the auxiliary heating lamp tubes are arranged at one end of the multiple main heating lamp tubes and corresponding to the edge positions of the wafer, so as to compensate the heating temperature of the edge positions of the wafer and realize uniform heating temperature of the edges and the middle of the wafer along the extension direction of the main heating lamp tubes.

[0004] However, since the wafer is circular, in order to ensure that the infrared lamp tubes can completely cover and heat the wafer, the length of the infrared ray generating part in the middle of the infrared lamp tubes is usually greater than the diameter of the wafer. At the same time, the arrangement distance between the first and the last infrared lamp tubes in a single row of infrared lamp tubes also needs to be greater than the diameter of the wafer. Under the influence of this structure, the infrared ray generating parts of most of the infrared lamp tubes do not completely coincide with the wafer in space, resulting in that the infrared radiation emitted by them cannot act well on the wafer, and the heat energy of the infrared lamp tubes cannot be efficiently absorbed by the wafer, and there is a problem of relatively large energy waste in some infrared lamp tubes, which affects the heating efficiency of the wafer. Summary of the Utility Model

[0005] In order to overcome the deficiencies of the prior art, the utility model provides an infrared heater for wafer silicon wafers.

[0006] The technical solution adopted by the utility model to solve its technical problems is as follows:

[0007] An infrared heater for wafer silicon wafers, comprising a heating lamp holder. An installation cavity is arranged in the heating lamp holder. The lower end of the installation cavity is a radiation outlet penetrating through the bottom of the heating lamp holder. A plurality of infrared heating bulbs are installed in the installation cavity and are distributed in a circumferential manner in the installation cavity. The infrared ray generating parts of the plurality of infrared heating bulbs are combined to form a circular heating area corresponding to the radiation outlet.

[0008] The bottom of the heating lamp holder is provided with an installation positioning ring for positioning and installing it on the housing of the heating device. The installation positioning ring includes a support ring part and a positioning ring part connected in sequence along the axial direction. The outer diameter of the support ring part is larger than that of the positioning ring part, and the support ring part is connected to the heating lamp holder;

[0009] The inner ring of the installation positioning ring is a radiation dispersion port corresponding to the radiation outlet axially, and the diameter of the radiation dispersion port gradually increases from top to bottom.

[0010] In the present utility model, at least two fixing seats are provided on the outer side of the heating lamp holder.

[0011] In the present utility model, a cooling passage for accessing a cooling medium to cool the heater is provided in the heating lamp holder, and the cooling passage is at least arranged to surround the outer periphery of the installation cavity.

[0012] In the present utility model, the heating lamp holder includes a lamp holder main body. The support ring part is installed at the bottom of the lamp holder main body. The installation cavity is arranged on the lamp holder main body. An intermediate convex part is provided at the middle position of the lamp holder main body. The cooling passage includes a peripheral passage arranged on the lamp holder main body and an intermediate passage arranged in the intermediate convex part. The peripheral passage surrounds the outer periphery of the installation cavity, and the intermediate passage communicates with the peripheral passage.

[0013] In the present utility model, both the peripheral passage and the intermediate passage penetrate through the top of the lamp holder main body. The heating lamp holder further includes a lamp holder cover plate. The lamp holder cover plate is installed on the top of the lamp holder main body and closes the openings of the peripheral passage and the intermediate passage.

[0014] In the present utility model, the cooling passage further includes a first connection port, a second connection port, a first passage and a second passage arranged on the lamp holder cover plate;

[0015] Wherein, the first connection port extends along the axial direction of the lamp holder cover plate and communicates with the intermediate passage;

[0016] The second connection port extends along the axial direction of the lamp holder cover plate and communicates with one end of the first passage. The other end of the first passage extends along the radial direction of the lamp holder cover plate and communicates with the peripheral passage;

[0017] One end of the second passage is provided with a communicating connection port. One end of the communicating connection port communicates with one end of the second passage, and the other end extends along the axial direction of the lamp holder cover plate and communicates with the intermediate passage; the other end of the second passage communicates with the peripheral passage.

[0018] In the present utility model, a flow-around convex part for changing the direction of the cooling medium in the intermediate passage is provided at the central position of the intermediate passage.

[0019] In the present utility model, a pipe connection seat is installed at one end of the lamp socket cover plate facing away from the lamp socket body, and the pipe connection seat is provided with a first screw hole corresponding to the first connection port and a second screw hole corresponding to the second connection port.

[0020] In the present utility model, a plurality of connection lamp sockets are provided on one side of the lamp socket cover plate facing away from the lamp socket body. The lamp socket cover plate is provided with a plurality of cover plate avoidance holes axially penetrating through both ends thereof. One end of the lamp socket body facing the lamp socket cover plate is provided with a plurality of connection avoidance holes axially penetrating through and communicating with the installation cavity. Each of the cover plate avoidance holes corresponds to one of the connection avoidance holes and forms an avoidance channel. Each of the avoidance channels corresponds to one of the connection lamp sockets and an infrared heating bulb respectively. The lamp pins of the infrared heating bulb penetrate into the avoidance channel and are electrically connected to the connection lamp socket.

[0021] In the present utility model, a plurality of bulb locking holes are provided on the outer peripheral surface of the lamp socket cover plate. Each of the bulb locking holes corresponds to and communicates with one of the cover plate avoidance holes, and a locking screw for pressing against the infrared heating bulb is screwed in the bulb locking hole.

[0022] Advantages of the present utility model:

[0023] 1. In the present utility model, a plurality of the infrared heating bulbs are circumferentially distributed in the installation cavity, and the infrared ray generating parts of the plurality of infrared heating bulbs are combined to form a circular heating area corresponding to the radiation outlet. The circular heating area can completely coincide with the wafer in space, enabling the infrared radiation emitted by the infrared heating bulbs to act on the wafer as much as possible, ensuring the heating efficiency of the wafer and reducing the waste of heater energy at the same time;

[0024] 2. The heating lamp socket is provided with an installation positioning ring and a fixing seat, improving the installation convenience of the heater and achieving the purpose of improving the installation efficiency of the heater;

[0025] 3. The heater is connected to a cooling medium through a cooling passage to reduce the temperature of the heater, so as to ensure the working stability of the heater. Description of the Drawings

[0026] The following further describes the present utility model in conjunction with the drawings and embodiments:

[0027] Figure 1 is the three-dimensional view of this embodiment Figure 1 ;

[0028] Figure 2 is the cross-sectional view of this embodiment

[0029] Figure 3 is the installation schematic diagram of the pipe connection seat;

[0030] Figure 4 is the three-dimensional view Figure 2 ;

[0031] Figure 5 is the exploded view between the lamp socket cover plate and the lamp socket main body;

[0032] Figure 6 is the combined top view of the lamp socket cover plate and the lamp socket main body;

[0033] Figure 7 is Figure 6 the sectional view taken along A-A in

[0034] Figure 8 is Figure 6 the sectional view taken along B-B in Detailed implementation manners

[0035] To make the objectives, technical solutions and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model.

[0036] It should be noted that if there are directional indications (such as up, down, left, right, front, back, top, bottom, inside, outside, vertical, horizontal, longitudinal, counterclockwise, clockwise, circumferential, radial, axial...) involved in the embodiments of the present utility model, then the directional indications are only used to explain the relative positional relationship and movement conditions between components in a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0037] In addition, if there are descriptions involving "first" or "second" etc. in the embodiments of the present utility model, then the descriptions of "first" or "second" etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present utility model.

[0038] Refer to Figures 1 - 8, A wafer silicon infrared heater, comprising a heating lamp holder 10, wherein an installation cavity 20 is arranged in the heating lamp holder 10, the lower end of the installation cavity 20 is a radiation outlet penetrating through the bottom of the heating lamp holder 10, and a plurality of infrared heating bulbs 30 distributed circumferentially in the installation cavity 20 are installed in the installation cavity 20. The infrared ray generating parts of the plurality of infrared heating bulbs 30 are combined to form a circular heating area corresponding to the radiation outlet, and the outer diameter of the circular heating area is configured to be less than or equal to the outer diameter of the wafer;

[0039] Further, an installation positioning ring 1 for positioning and installing it on the housing of the heating device is arranged at the bottom of the heating lamp holder 10. The installation positioning ring 1 includes a support ring part 11 and a positioning ring part 12 connected in sequence along the axial direction. The outer diameter of the support ring part 11 is larger than the outer diameter of the positioning ring part 12, and the support ring part 11 is connected to the heating lamp holder 10; during installation, the positioning ring part 12 is inserted and fitted into a positioning round hole on the housing of the heating device, so as to realize the positioning of the heating lamp holder 10 on the housing of the heating device. In addition, when necessary, positioning connection screw holes for cooperating with screws to fix the installation positioning ring 1 on the housing of the heating device are arranged on the support ring part 11 or the positioning ring part 12. After the positioning ring part 12 is inserted and fitted into the positioning round hole, the installation positioning ring 1 is fixed on the housing of the heating device by using screws.

[0040] Still further, the inner ring of the installation positioning ring 1 is a radiation dispersion port 13 axially corresponding to the radiation outlet. The radiation dispersion port 13 sequentially penetrates through the support ring part 11 and the positioning ring part 12 along the axial direction. The radiation dispersion port 13 is in a horn shape, and the diameter of the radiation dispersion port 13 gradually increases from top to bottom. Through the structural design of the radiation dispersion port 13, it is beneficial to the divergence of the infrared radiation emitted by the infrared heating bulbs 30 to the outer circle position of the wafer, thereby ensuring the heating efficiency of the outer circle of the wafer. In addition, a reflecting surface for reflecting infrared radiation is arranged on the wall of the installation cavity 20 or / and on the wall of the radiation dispersion port 13, so that the infrared radiation can better act on the wafer.

[0041] In this embodiment, by arranging a plurality of the infrared heating bulbs 30 circumferentially in the installation cavity 20, the infrared ray generating parts of the plurality of infrared heating bulbs 30 are combined to form a circular heating area corresponding to the radiation outlet. The circular heating area can completely coincide with the wafer in space, enabling the infrared radiation emitted by the infrared heating bulbs 30 to act on the wafer as much as possible, ensuring the heating efficiency of the wafer and reducing the waste of the energy of the heater at the same time.

[0042] As a preferred embodiment, at least two fixing seats 2 are provided on the outer side of the heating lamp socket 10. The fixing seats 2 can be used as handles, enabling convenient lifting of the heater by the staff. Additionally, when a heater positioning groove adapted to the fixing seat 2 is provided on the housing of the heating device, the fixing seat 2 can be inserted into the heater positioning groove from top to bottom to prevent circumferential rotation of the heater and ensure the installation quality of the heater, which is particularly suitable for heating devices where the heater is only installed on the top of the housing of the top heating device.

[0043] As a preferred embodiment, since the infrared heating bulb 30 causes the temperature of the heating lamp socket 10 to rise during operation, affecting the working stability of the heater. To solve this technical problem, a cooling passage for accessing a cooling medium to cool the heater is provided in the heating lamp socket 10. The cooling passage is at least arranged to surround the outer periphery of the installation cavity 20. By accessing the cooling medium through the cooling passage, the temperature of the heater is reduced to ensure the working stability of the heater. The cooling medium is preferably a coolant and secondarily a cooling gas.

[0044] As a preferred embodiment, the heating lamp socket 10 includes a lamp socket main body 3. The support ring portion 11 is installed at the bottom of the lamp socket main body 3. The installation cavity 20 is provided on the lamp socket main body 3. An intermediate convex portion 31 is provided at the middle position of the installation cavity 20 on the lamp socket main body 3. The cooling passage includes a peripheral passage 100 provided on the lamp socket main body 3 and an intermediate passage 200 provided in the intermediate convex portion 31. The peripheral passage 100 surrounds the outer periphery of the installation cavity 20, and the intermediate passage 200 communicates with the peripheral passage 100.

[0045] As a preferred embodiment, for the convenience of processing the peripheral passage 100 and the intermediate passage 200, both the peripheral passage 100 and the intermediate passage 200 penetrate through the top of the lamp socket main body 3. The heating lamp socket 10 further includes a lamp socket cover plate 4. The lamp socket cover plate 4 is installed on the top of the lamp socket main body 3 and closes the openings of the peripheral passage 100 and the intermediate passage 200. Additionally, a first sealing ring 51 and a second sealing ring 52 are provided between the lamp socket cover plate 4 and the lamp socket main body 3. Among them, there are two first sealing rings 51 corresponding to the inner circle and the outer circle at the upper end of the peripheral passage 100 respectively. The first sealing ring 51 is used to prevent the cooling medium in the peripheral passage 100 from leaking from the opening at the top of the peripheral passage 100. The second sealing ring 52 surrounds the outer circle at the upper end of the intermediate passage 200. The second sealing ring 52 is used to prevent the cooling medium in the intermediate passage 200 from leaking from the opening at the top of the intermediate passage 200.

[0046] As a preferred embodiment, the cooling passage further includes a first connection port 300, a second connection port 400, a first passage 500, and a second passage 600 provided on the lamp socket cover plate 4; wherein, the first connection port 300 extends axially along the lamp socket cover plate 4 and communicates with the intermediate passage 200; the second connection port 400 extends axially along the lamp socket cover plate 4 and communicates with one end of the first passage 500, and the other end of the first passage 500 extends radially along the lamp socket cover plate 4 and communicates with the peripheral passage 100; one end of the second passage 600 is provided with a communication connection port 700, one end of the communication connection port 700 communicates with one end of the second passage 600, and the other end extends axially along the lamp socket cover plate 4 and communicates with the intermediate passage 200; the other end of the second passage 600 communicates with the peripheral passage 100.

[0047] Preferably, the cooling medium enters from the first connection port 300, then sequentially passes through the intermediate passage 200, the communication connection port 700, the second passage 600, the peripheral passage 100, and the first passage 500, and then flows out from the second connection port 400, thereby realizing the cooling of the heater. In other embodiments, the cooling medium enters from the second connection port 400 and then flows out from the first connection port 300, which can also achieve the purpose of cooling the heater.

[0048] As a preferred embodiment, a flow-around convex portion 33 for changing the direction of the cooling medium in the intermediate passage 200 is provided at the central position of the intermediate passage 200. The circumferential surface of the flow-around convex portion 33 is provided with a first concave portion 34 corresponding to the first connection port 300 and a second concave portion 35 corresponding to the communication connection port 700. By the above structure, the flow direction of the cooling medium in the intermediate passage 200 is changed, so that the cooling medium can exchange heat with the heater in the intermediate passage 200 as much as possible, which is beneficial to the cooling medium to take away the heat at the middle position of the heater.

[0049] As a preferred embodiment, a pipe connection seat 6 is installed on the end of the lamp socket cover plate 4 facing away from the lamp socket body 3. The pipe connection seat 6 is provided with a first screw hole 61 corresponding to the first connection port 300 and a second screw hole 62 corresponding to the second connection port 400. The threaded joints of the two cooling pipes are respectively threadedly fitted in the first screw hole 61 and the second screw hole 62, so that the cooling medium can flow into the cooling passage to take away heat and then flow out. In addition, a mating positioning groove 41 is provided on the lamp socket cover plate 4, and the pipe connection seat 6 is positioned and installed in the mating positioning groove 41, thereby improving the installation quality of the pipe connection seat 6 on the lamp socket cover plate 4.

[0050] As a preferred embodiment, a plurality of electric connection lamp sockets 7 are provided on the side of the lamp socket cover plate 4 facing away from the lamp socket body 3. A plurality of cover plate avoidance holes 42 that axially penetrate through both ends thereof are provided on the lamp socket cover plate 4. A plurality of connection avoidance holes 32 that axially penetrate through and communicate with the installation cavity 20 are provided at one end of the lamp socket body 3 facing the lamp socket cover plate 4. Each of the cover plate avoidance holes 42 corresponds to one of the connection avoidance holes 32 to form an avoidance channel. Each of the avoidance channels corresponds to one of the electric connection lamp sockets 7 and the infrared heating bulb 30. The lamp pins of the infrared heating bulb 30 penetrate into the avoidance channel and are electrically connected to the electric connection lamp socket 7.

[0051] As a preferred embodiment, a plurality of bulb locking holes 43 are provided on the outer peripheral surface of the lamp socket cover plate 4. Each of the bulb locking holes 43 corresponds to and communicates with one of the cover plate avoidance holes 42. A locking screw 40 for pressing against the infrared heating bulb 30 is screwed in the bulb locking hole 43.

[0052] As a preferred embodiment, an insulating protective shell 8 is provided on the top end of the lamp socket cover plate 4. The insulating protective shell 8 surrounds the electric connection lamp socket 7 and the pipe connection seat 6. A notch for the cooling pipe to enter the insulating protective shell 8 is provided at the top of the insulating protective shell 8. The insulating protective shell 8 can protect the electric connection lamp socket 7, the pipe connection seat 6, etc., and reduce the risk of damage to the electric connection lamp socket 7 and the pipe connection seat 6.

[0053] As a preferred embodiment, a connection shell 9 is further provided on the top edge of the lamp socket cover plate 4. The interior of the connection shell 9 communicates with the interior of the insulating protective shell 8. A wire passing port is provided on the connection shell 9 for the wire connecting the heater to sequentially pass through the interior of the connection shell 9 and the interior of the insulating protective shell 8 and then be electrically connected to the power connection end of the electric connection lamp socket 7.

[0054] The above are only the preferred embodiments of the present invention. As long as the technical solutions that achieve the purpose of the present invention by basically the same means fall within the protection scope of the present invention.

Claims

1. A silicon wafer infrared heater, comprising a heating lamp holder (10), wherein the heating lamp holder (10) is provided with a mounting groove (20), wherein the lower end of the mounting groove (20) is a radiation outlet penetrating the bottom of the heating lamp holder (10), and wherein: A plurality of infrared heating bulbs (30) are installed in the installation cavity (20) and are distributed in a circular pattern in the installation cavity (20); the infrared generating parts of the plurality of infrared heating bulbs (30) are combined to form a circular heating area corresponding to the radiation outlet; The bottom of the heating lamp holder (10) is provided with a mounting and positioning ring (1) for positioning the heating lamp holder on the housing of the heating device, the mounting and positioning ring (1) comprising a supporting ring portion (11) and a positioning ring portion (12) connected in sequence along the axial direction, the outer diameter of the supporting ring portion (11) being larger than the outer diameter of the positioning ring portion (12), and the supporting ring portion (11) being connected to the heating lamp holder (10); The inner ring of the mounting positioning ring (1) is a radiation dispersion opening (13) corresponding to the axial direction of the radiation outlet, and the diameter of the radiation dispersion opening (13) gradually increases from top to bottom.

2. The silicon wafer infrared heater according to claim 1, characterized in that: At least two fixing seats (2) are provided on the outer side of the heating lamp holder (10).

3. The silicon wafer infrared heater according to claim 1, characterized in that: The heating lamp holder (10) is provided with a cooling passage for receiving a cooling medium to cool the heater, and the cooling passage is at least arranged around the outer circumference of the mounting groove cavity (20).

4. The silicon wafer infrared heater according to claim 3, characterized in that: The heating lamp holder (10) comprises a lamp holder body (3), the support ring (11) is mounted on the bottom of the lamp holder body (3), the mounting groove (20) is arranged on the lamp holder body (3), the lamp holder body (3) is provided with a middle convex portion (31) located in the middle of the mounting groove (20), the cooling passage comprises a peripheral channel (100) arranged on the lamp holder body (3) and a middle channel (200) arranged in the middle convex portion (31), the peripheral channel (100) surrounds the outer periphery of the mounting groove (20), and the middle channel (200) is connected to the peripheral channel (100).

5. The silicon wafer infrared heater according to claim 4, characterized in that: The peripheral channel (100) and the middle channel (200) both pass through the top of the lamp holder body (3); the heating lamp holder (10) further comprises a lamp holder cover plate (4); the lamp holder cover plate (4) is mounted on the top of the lamp holder body (3) and closes the openings of the peripheral channel (100) and the middle channel (200).

6. The silicon wafer infrared heater according to claim 5, characterized in that: The cooling passage further comprises a first connection port (300), a second connection port (400), a first channel (500) and a second channel (600) which are arranged on the lamp holder cover plate (4); Wherein, the first connection port (300) extends axially along the lamp holder cover plate (4) and communicates with the middle channel (200); The second connection port (400) extends axially along the lamp holder cover plate (4) and is connected to one end of the first channel (500), and the other end of the first channel (500) extends radially along the lamp holder cover plate (4) and is connected to the peripheral channel (100); A connecting port (700) is provided at one end of the second channel (600); one end of the connecting port (700) is connected to one end of the second channel (600), and the other end extends along the axial direction of the lamp holder cover plate (4) and is connected to the middle channel (200); the other end of the second channel (600) is connected to the peripheral channel (100).

7. The silicon wafer infrared heater according to claim 6, characterized in that: A flow convex portion (33) for changing the direction of the cooling medium in the middle channel (200) is provided at the center of the middle channel (200).

8. The silicon wafer infrared heater according to claim 6, characterized in that: A pipe connection seat (6) is mounted on one end of the lamp holder cover plate (4) facing away from the lamp holder body (3), and the pipe connection seat (6) is provided with a first screw hole (61) corresponding to the first connection port (300) and a second screw hole (62) corresponding to the second connection port (400).

9. The silicon wafer infrared heater according to claim 5, characterized in that: A plurality of electrical lamp sockets (7) are provided on the side of the lamp socket cover plate (4) facing away from the lamp socket body (3); a plurality of cover plate avoidance holes (42) are provided on the lamp socket cover plate (4) and extend axially through both ends thereof; a plurality of connection avoidance holes (32) are provided on the end of the lamp socket body (3) facing the lamp socket cover plate (4) and extend axially through the connecting groove cavity (20); each of the cover plate avoidance holes (42) corresponds to one of the connection avoidance holes (32) and forms an avoidance channel; each of the avoidance channels corresponds to one of the electrical lamp sockets (7) and the infrared heating bulb (30); the lamp pin of the infrared heating bulb (30) penetrates into the avoidance channel and is electrically connected to the electrical lamp socket (7).

10. The silicon wafer infrared heater according to claim 9, characterized in that: A plurality of bulb locking holes (43) are provided on the outer peripheral surface of the lamp holder cover plate (4), each bulb locking hole (43) correspondingly communicates with one of the cover plate avoidance holes (42), and a locking screw (40) for tightening the infrared heating bulb (30) is matched with an inner screw of the bulb locking hole (43).

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