Patent Application
20230349066
This application claims the priority of Chinese Application No. 202011053337.0, filed on Sep. 29, 2020, the disclosures of which are incorporated in their entirety by reference herein.
The present disclosure relates to the field of semiconductor wafer technologies, and in particular to a heater in a Hot-Zone of a single crystal pulling apparatus and a single crystal pulling apparatus.
When pulling single crystal silicon ingot, it is necessary to use a single crystal pulling apparatus to melt polycrystalline silicon raw material in a specialized quartz crucible, and then use a seed to lead a growth of a single crystal silicon ingot. With continuous improvement of quality of semiconductor silicon wasfers, there are more stringent control requirements for crystal defects of crystal ingots due to the crystal pulling process. Internal structures of the single crystal pulling apparatus constitute the Hot-Zone. Structures and performance of the Hot-Zone directly affect the quality of the crystal ingot, and thus the design of the Hot-Zone is very important.
For one single crystal pulling apparatus, the design of heaters is one of kernels of design of the Hot-Zone. The heaters are divided into a main heater and a bottom heater. The main heater is also referred as a side-main heater, which is arranged around the outside of the crucible, and the bottom heater is arranged at a bottom of the crucible. The side-main heater is responsible for main heat output of the single crystal pulling apparatus, and plays an important role in a melting stage of polysilicon material and a later body growth stage of crystal ingots. Shape and size of a heating area of the side-main heater directly affect a temperature field of the single crystal pulling apparatus, which in turn affects the quality of the crystal ingot.
However, the heating area of the side-main heater in the Hot-Zone in the related art is very small, and then the heating is uneven. When the temperature field is kept constant, the power consumption will increase, which is not conducive to cost saving. Further, the side-main heater is usually a resistance heater, which heats up slowly, leads to need a long time to reach the set temperature, and takes a long time on melting stage of polysilicon material, thereby greatly increasing the time cost. Meanwhile, it is difficult for one resistance heater to ensure stability of the temperature field required by three phases including solid, liquid and gas of a molten silicon melt surface. The instability of the temperature field will lead to formation of local thermal shock, which is not conducive to defect-free growth of the crystal ingot.
In order to solve the foregoing technical problems, embodiments of the present disclosure provide a heater in a Hot-Zone of a single crystal pulling apparatus and a single crystal pulling apparatus, which have characteristics such as good heating effect, fast heating up, stable temperature in a hot-zone, which are conducive to defect-free growth of crystal ingots during a crystal growth process, thereby improving the yield of the crystal ingots.
The technical solutions provided in the embodiments of the present disclosure are as follows.
A heater in a Hot-Zone of a single crystal pulling apparatus, includes: a side-main heater; and an auxiliary heater; wherein each of the side-main heater and the auxiliary heater is a cylindrical structure with openings at two ends thereof; each of the side-main heater and the auxiliary heater includes a top open end and a bottom open end; the auxiliary heater is sleeved around the side-main heater, and the top open end of the auxiliary heater extends out of the top open end of the side-main heater.
Optionally, the auxiliary heater includes:
Optionally, the protective casing includes an inner casing and an outer casing that are fastened to each other; each of the inner casing and the outer casing is cylindrical; the inner casing covers and surrounds an outer peripheral side of the side-main heater; the outer casing is sleeved around the inner casing with a chamber defined between the outer casing and the inner casing; the inner casing includes a first inner side wall that cooperates with the outer casing to define the chamber; the electromagnetic induction coil is accommodated in the chamber; the electromagnetic induction coil is spirally wound around the first inner side wall from a top open end of the inner casing to a bottom open end of the inner casing; and two ends of the electromagnetic induction coil extend out of the protective casing, respectively.
Optionally, a stepped first edge is provided at the top open end of the inner casing; a stepped second edge is provided at an edge of a top open end of the outer casing; stepped structures of the first edge and the second edge overlap each other; a stepped third edge is provided at an edge of the bottom open end of the inner casing and a stepped fourth edge is provided at an edge of a bottom open end of the outer casing; and stepped structures of the third edge and the fourth edge overlap each other.
Optionally, the electromagnetic induction coil includes a plurality of spiral rings; a plurality of first supporters is provided on the first inner side wall of the inner casing, and one of the plurality of first supporters is arranged between two adjacent spiral rings.
Optionally, the side-main heater includes:
Optionally, the heater body includes a plurality of U-shaped heating column units; the plurality of U-shaped heating column units are connected in sequence to form the first cylindrical structure; among two adjacent ones of the plurality of U-shaped heating column units, an opening of one U-shaped heating column unit is oriented towards a top open end of the first cylindrical structure, and an opening of the other U-shaped heating column unit is oriented towards a bottom open end of the first cylindrical structure, thereby enabling an outline of the heater body to be a serpentine curve structure.
Optionally, each of the plurality of U-shaped heating column units includes:
Optionally, the width of the vertical straight heating column in the circumferential direction of the first cylindrical structure is 15-20 mm; a cross-sectional area of the vertical straight heating column is 150-200 mm2; and a length of the vertical straight heating column from the top open end to the bottom open end of the first cylindrical structure is 320˜350 mm.
Optionally, a plurality of second supporters for supporting the heater body is provided on an inner side wall of the insulating protective cover; and, at least one of the plurality of second supporters is disposed in the gap between the two vertical straight heating columns of each of the plurality of U-shaped heating column units.
Optionally, the plurality of second supporters include a plurality of first support columns and a plurality of second support columns arranged alternately; the first support column is arranged in the gap between the two vertical straight heating columns of the U-shaped heating column unit whose opening is oriented towards the top open end of the heater body; and the second support column is arranged in the gap between the two vertical straight heating columns of the U-shaped heating column unit whose opening is oriented towards the bottom open end of the heater body.
Optionally, the insulating protective cover includes a first cover body and a second cover body;
Optionally, the insulating protective cover includes a first cover body and a second cover body;
Optionally, the heater body is further connected with at least a first electrode connector and a second electrode connector; the first electrode connector and the second electrode connector are located at opposite sides of the heater body, respectively; the insulating protective cover is provided with at least a first opening and a second opening; the first electrode connector extends through the first opening, and the second electrode connector extends through the second opening.
A single crystal pulling apparatus includes the foregoing heater in a Hot-Zone of the single crystal pulling apparatus.
The beneficial effects brought by the embodiments of the present disclosure are as follows.
The heater in the Hot-Zone of the single crystal pulling apparatus and the single crystal pulling apparatus provided in the embodiment of the present disclosure includes the side-main heater and the auxiliary heater. The auxiliary heater can play the following functions: melting raw material with a rapid heating, performing temperature compensation for thermal field generated by the side-main heater and maintaining the temperature field of the area in which solid, liquid and gas are included near the surface of silicon melt stable by cooperating with the side-main heater during the body growth stage of crystal ingots, which is conducive to defect-free growth of the crystal ingot. Furthermore, the auxiliary heater can provide heating power together with the side-main heater, which prolongs the service life of the heater. In addition, compared with a heater in a Hot-Zone of a single crystal pulling apparatus in the related art, the heater in the Hot-Zone of the single crystal pulling apparatus and the single crystal pulling apparatus provided in the embodiments of the present disclosure are configured to provide a larger heating area and a higher energy conversion rate, and are configured to be more energy-saving and cost-saving in case of providing the same temperature field as the related art. Further, the side-main heater and the auxiliary heater are configured to cooperate with each other so that they are applicable in a more expended scope and provide the accurate adjustment.
In order to make the objects, the technical solutions and the advantages of the present disclosure more apparent, the present disclosure will be described hereinafter in a clear and complete manner in conjunction with the drawings and embodiments. Obviously, the following embodiments are merely a part of, rather than all of, the embodiments of the present disclosure, and based on these embodiments, a person skilled in the art may obtain the other embodiments, which also fall within the scope of the present disclosure.
Unless otherwise defined, any technical or scientific terms used herein shall have the common meaning understood by a person of ordinary skills. Such words as “first” and “second” used in the present disclosure are merely used to differentiate different components rather than to represent any order, number or importance. Similarly, such words as “one” or “one of” are merely used to represent the existence of at least one member, rather than to limit the number thereof. Such words as “include” or “including” mean that an element or thing appearing before the word encompass elements or things recited after the word and their equivalents, but do not exclude other elements or things. Such words as “connect” or “connected to” may include electrical connection, direct or indirect, rather than being limited to physical or mechanical connection. Such words as “on/above”, “under/below”, “left” and “right” are merely used to represent relative position relationship, and when an absolute position of an object is changed, the relative position relationship will be changed too.
Before describing in detail a heater in a Hot-Zone of a single crystal pulling apparatus and a single crystal pulling apparatus according to embodiments of the present disclosure, it is necessary to describe the related technology as follows.
A heating area of a side-main heater in a Hot-Zone in the related art is very small, and then the heating is uneven. When a temperature field is kept constant, the power consumption will increase, which is not conducive to cost saving. Further, the side-main heater is usually a resistance heater, which heats up slowly, leads to need a long time to reach the set temperature, and takes a long time on melting stage of polysilicon material, thereby greatly increasing the time cost. Meanwhile, it is difficult for one resistance heater to ensure stability of the temperature field required by three phases including solid, liquid and gas of a molten silicon melt surface. The instability of the temperature field will lead to formation of local thermal shock, which is not conducive to defect-free growth of the crystal ingot.
In view of the foregoing problems, embodiments of the present disclosure provide a heater in a Hot-Zone of a single crystal pulling apparatus and a single crystal pulling apparatus, which have characteristics such as good heating effect, fast heating up, stable temperature in a hot-zone, which are conducive to defect-free growth of crystal ingots during a crystal growth process, thereby improving the yield of the crystal ingots.
As shown in
The heater in the Hot-Zone of the single crystal pulling apparatus provided in the embodiment of the present disclosure includes the side-main heater 10 and the auxiliary heater 20. The auxiliary heater 20 can play the following functions: melting raw material with a rapid heating, performing temperature compensation for thermal field generated by the side-main heater 10 and maintaining the temperature field of the area in which solid, liquid and gas are included near the surface of silicon melt stable by cooperating with the side-main heater during the body growth stage of crystal ingots, which is conducive to defect-free growth of the crystal ingot. Furthermore, the auxiliary heater can provide heating power together with the side-main heater, which prolongs the service life of the heater. In addition, compared with a heater in a Hot-Zone of a single crystal pulling apparatus in the related art, the heater in the Hot-Zone of the single crystal pulling apparatus and the single crystal pulling apparatus provided in the embodiments of the present disclosure are configured to provide a larger heating area and a higher energy conversion rate, and are configured to be more energy-saving and cost-saving in case of providing the same temperature field as the related art. Further, the side-main heater and the auxiliary heater are configured to cooperate with each other so that they are applicable in a more expended scope and provide the accurate adjustment.
In some embodiments, as shown in
In the above embodiment, the auxiliary heater 20 adopts an electromagnetic induction heater, and the side-main heater 10 and the electromagnetic induction auxiliary heater 20 cooperate together to increase the adjustment range and adjustment accuracy of the heater. Compared with resistance heaters, the electromagnetic induction heater, due to its higher adjustment range and adjustment accuracy, can better maintain the temperature field of the area in which solid, liquid and gas are included near the surface of silicon melt stable.
Of course, it can be understood that, in practical applications, the auxiliary heater 20 may also adopt a resistance heater.
In addition, in some embodiments, as shown in
In the above embodiment, the two ends of the electromagnetic induction coil 22 are power supply terminals 25, respectively, which extend out of the protective casing 21 and are connected to an AC power source. According to the principle of electromagnetic induction heating, the electromagnetic induction coil 22 converts the generated induced electric energy into heat energy, and then transfers heat in form of thermal radiation to silicon material in a quartz crucible. The protective casing 21 serves the purpose of protecting the electromagnetic induction coil 22, preventing erosion of the electromagnetic induction coil 22 in the auxiliary heater 20 by an argon flow and deposition of SiO2 on the electromagnetic induction coil 22, thereby improving the service life of the auxiliary heater 20. Meanwhile, the auxiliary heater 20 also has a heat preservation effect, which reduces heat loss, so that more heat can be transferred to the inside of the crucible in the Hot-Zone, thereby improving an energy conversion efficiency of the heater.
In some embodiments, as shown in
In the above embodiment, the inner casing 23 and the outer casing 24 are overlapped with each other by the stepped structures provided at the edges of the openings, thereby realizing the mutual fastening between the two. In practical applications, specific structures of the inner casing 23 and the outer casing 24 are not limited to this.
In addition, in some embodiments, as shown in
In the foregoing solution, the electromagnetic induction coil 22 is spirally distributed inside the protective casing 21, and each spiral ring can be supported by the first supporter 26, thereby improving comprehensive mechanical properties of the electromagnetic induction coil 22.
Optionally, the first supporter 26 may be a support column, but the specific structure of the first supporter is not limited thereto.
In addition, a main heater in a Hot-Zone of a single crystal pulling apparatus in the related art is arranged at an outer peripheral side of a crucible, and is directly exposed to argon flows without a protective device. During the crystal pulling process, the argon flows will continuously erode an upper surface and an outer surface of the heater, which greatly reduces the service life of the main heater; and SiO2 (silicon dioxide) deposition occurs in corresponding positions, and the removal of SiO2 will also reduce the service life of the heater.
In order to solve the foregoing technical problems, in some embodiments of the present disclosure, as shown in
In the single-crystal-furnace Hot-Zone heater provided in the embodiment of the present disclosure, by covering the heater body 100 with the insulating protective cover 200, the insulating protective cover 200 can wrap and cover the top open end, the bottom open end and the outer peripheral side of the heater body 100, thereby preventing erosion of the heater body 100 by the argon flows and deposition of SiO2 on the heater body 100, and then improving the service life of the heater. Meanwhile, the cylindrical insulating protective cover 200 also has a heat preservation effect, which reduces heat loss of the heater body 100, so that more heat can be transferred to the inside of the crucible in the Hot-Zone, thereby improving an energy conversion efficiency of the heater.
In addition, in the related art, a conventional side-main heater 10 in a Hot-Zone of a single crystal pulling apparatus includes a sheet-like cylindrical structure, and the sheet-like cylindrical structure is provided with a plurality of slits to form a plurality of blades. Each blade has a large width. The heating power of the side-main heater 10 is related to a cross-sectional size of the blade. The relationship between the heating power of the side-main heater 10 and a cross-sectional area of the blade is as follows:
Where, P represents a power of the side-main heater 10; I represents a current; R represents resistance of a blade; ρ represents a resistivity of the blade; S represents a cross-sectional area of the blade; and L represents a length of the blade.
From formulas (I) and (II), it can be obtained:
It can be seen from the formula (III) that when S becomes larger, the heating power P decreases. Therefore, the larger the cross-sectional area of the blade, the smaller the resistance of the heater and the smaller the heating power of the heater. In this way, a heating area of the side-main heater 10 is small and then the heating is uneven. When the temperature field is kept constant, the power consumption will increase, which is not conducive to cost saving and control of oxygen content of a crystal ingot during the crystal pulling process, thereby affecting the overall quality of the crystal ingot.
In one embodiment of the present disclosure, as shown in
Optionally, each of the U-shaped heating column units includes:
In the above solution, the structure of the heater body 100 is improved in such a manner that the heater body 100 is designed as a first cylindrical structure formed by a plurality of U-shaped heating column units 100A connected end to end, and the heating columns in each U-shaped heating column unit 100A include two vertical straight heating columns 110 and one arc-shaped or linear transverse heating column 120. The heating column of such structure has a cross-sectional size smaller than a cross-sectional size of the blade of the blade structure in the side-main heater 10 in the related art. Comparing the gap A between the two vertical straight heating columns 110 with the slit between the blades in the side-main heater 10 in the related art, a size of the gap A is larger than the size of the slit. In this way, due to reduction of the cross-sectional area of the heating column, the resistance of the heater is increased and then the heating power of the heater is increased. As a result, the design of the annular U-shaped heating column units 100A ensures that the heating of the heater is more uniform, and the heating area of the side-main heater 10 is large, thereby reducing power consumption in case of keeping the temperature field constant, which is conducive to cost saving and control of oxygen content of a crystal ingot during the crystal pulling process, thereby improving the overall quality of the crystal ingot.
In addition, it should be noted that, in some embodiments of the present disclosure, the heating power may be further increased by increasing a length of a single vertical straight heating column 110.
In some embodiments, a width of the vertical straight heating column 110 in the circumferential direction of the first cylindrical structure is 15-20 mm, and a cross-sectional area of the vertical straight heating column is less than or equal to a cross-sectional area of the gap between two adjacent vertical straight heating columns. Further, the cross-sectional area of the vertical straight heating column is 150-200 mm2; and a length of the vertical straight heating column 110 from the top open end to the bottom open end of the first cylindrical structure is 320˜350 mm. It should be noted that, in practical applications, the specific structure of the side-main heater 10 may not be limited to this.
In addition, in the embodiments provided in the present disclosure, as shown in
With the above solution, since the heater body 100 adopts the U-shaped heating column units 100A, the gap A between the adjacent vertical straight heating columns 110 is large and its mechanical properties may be weakened. In order to improve impact resistance of the heater body 100 to improve its comprehensive mechanical properties, in the above solution, by providing the second supporters 300 on the insulating protective cover 200, at least one of the second supporters 300 is disposed in the gap A between the two vertical straight heating columns 110 of each U-shaped heating column unit 100A, thereby supporting and protecting the heater body 100, so that the heater in the Hot-Zone of the single crystal pulling apparatus has a better impact resistance and improved comprehensive mechanical performance.
In some embodiments provided in the present disclosure, as shown in
In the above embodiment, the second supporter 300 is a columnar structure, i.e., a support column, disposed in the gap A between the two vertical straight heating columns 110 of the U-shaped heating column unit 100A. In other embodiments, the second supporter 300 is not limited to a support column, and may adopt other structures, such as a support block.
In addition, in some embodiments of the present disclosure, as shown in
In the above embodiment, the insulating protective cover 200 is composed of upper and lower cover bodies, namely, the first cover body 210 and the second cover body 220. Such structure is convenient for fastening the cover bodies to the heater body 100. Further, the first support columns 310 and the second support columns 320 are respectively provided on the two cover bodies, serve as the framework of the heater body 100, and play a role of supporting and protecting the heater body 100.
In other embodiments of the present disclosure, the insulating protective cover 200 includes a first cover body 210 and a second cover body 220. The first cover body 210 includes: an annular bottom shielding plate 221, where the bottom shielding plate 221 shields the bottom open end of the heater body 100; and, a side shielding plate 212, where the side shielding plate 212 surrounds the outer peripheral side of the heater body 100 and fixedly connected with the bottom shielding plate 221. The plurality of second support columns 320 are evenly distributed along a circumferential direction of the bottom shielding plate 221, and are fixed on an inner side wall of the side shielding plate 212. The second cover body 220 includes: an annular top shielding plate 211, where the top shielding plate 211 shields the top open end of the heater body 100. The plurality of first support columns 310 are evenly distributed along a circumferential direction of the top shielding plate 211. The plurality of first support columns 310 are fixed on the top shielding plate 211.
The plurality of first support columns 310 are inserted into the side shielding plate 212 to fasten the first cover body 210 to the second cover body 220.
It should be noted that the above is only an exemplary embodiment of the insulating protective cover 200, and in practical applications, the specific structure of the insulating protective cover 200 is not limited.
In addition, it should be noted that, the insulating protective cover 200 may be made of high-temperature-resistant and corrosion-resistant insulating materials, for example, semiconductor ceramic materials.
In addition, the length of the vertical straight heating column from the top open end to the bottom open end of the first cylindrical structure is equal to a length of the first support column on the first cover or a length of the second support column on the second cover.
In addition, as shown in
In the above embodiment, the first electrode connector 410 and the second electrode connector 420 are respectively provided on the heater body 100 for connecting with electrodes of the heater body 100.
It should be noted that, in some embodiments, the heater body 100 is provided with at least two electrode connectors, but in practical applications, the number of electrode connectors on the heater body 100 is not limited to two. For example, there may be three electrode connectors, that is, the connectors on the heater body 100 may be a three-phase electrical connector.
In addition, one embodiment of the present disclosure further provides a single crystal pulling apparatus, which includes the heater in the Hot-Zone of the single crystal pulling apparatus provided in the embodiment of the present disclosure. Obviously, the single crystal pulling apparatus provided in the embodiment of the present disclosure can also bring about the beneficial effects brought by the heater in the Hot-Zone of the single crystal pulling apparatus provided in the embodiment of the present disclosure, which is not repeated here.
The following points need to be noted:
The above are only specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited thereto, and the protection scope of the present disclosure should be subject to the protection scope of the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202011053337.0 | Sep 2020 | CN | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2021/120451 | 9/24/2021 | WO |
