CN117802577A - Semiconductor epitaxial growth apparatus - Google Patents

Abstract

The application provides a semiconductor epitaxial growth apparatus, comprising: the reaction chamber body and induction coil, wherein, induction coil sets up the periphery of reaction chamber body, induction coil has first end and second end along the flow direction of process gas, first end is close to the process gas entry, the second end is close to the process gas export, be provided with the substrate tray in the reaction chamber body, the substrate tray is used for bearing and rotatory substrate, wherein, along the flow direction of process gas, the pitch of the coil at the middle part of induction coil is greater than the pitch of the coil at the both ends of induction coil, the number of turns center of induction coil is different from the tray center of rotation of substrate tray. The semiconductor epitaxial growth equipment can improve the temperature uniformity of the surface of the substrate, and is beneficial to improving the quality of the film.

Description

Semiconductor epitaxial growth apparatus

Technical Field

The present application relates generally to the field of semiconductors, and more particularly, to a semiconductor epitaxial growth apparatus.

Background

In silicon-based integrated circuit fabrication, epitaxial processes are widely used. Silicon carbide (SiC) has shown great potential in power device materials due to its excellent physical properties. SiC has excellent electrical properties of high melting point, good thermal conductivity, difficult breakdown and the like, and is an optimal material for manufacturing high-frequency, high-power, high-temperature-resistant and radiation-resistant electronic devices. Epitaxy is a common and important chemical technique for preparing SiC films, where SiC epitaxy is the growth of one or more layers of SiC film on the surface of a substrate. The method for preparing the SiC epitaxial layer comprises the following steps: liquid phase epitaxy, molecular beam epitaxy, magnetron sputtering, sublimation epitaxy, chemical Vapor Deposition (CVD), and the like. Among them, the CVD method is the most widely used method for preparing SiC at present, and has advantages of high growth rate, easy control, mass production, and the like, compared with other methods.

CVD processes are processes in which a substrate (e.g., a wafer) is placed in a reaction chamber and a plurality of precursors are heated and introduced to chemically react the substrate surface to produce a thin film to be deposited. The process has high temperature requirement, and not only needs to reach 1650 ℃ high temperature, but also needs to keep the uniformity of the temperature of the substrate. The main heating modes at present are infrared heating and electromagnetic induction heating.

In the related art of the battery induction heating mode, the overall temperature of the substrate is not uniform, and thus, the epitaxial layer (i.e., deposited thin film) deposited on the upper surface of the substrate is not uniform, and the quality of the epitaxial layer is reduced.

Disclosure of Invention

The technical problem to be solved by the application is that the surface temperature of the substrate is uneven under a high-temperature epitaxial growth scene to influence the quality of the film.

To solve the above technical problem, the present application provides a semiconductor epitaxial growth apparatus, including: the reaction chamber body and induction coil, wherein, induction coil sets up the periphery of reaction chamber body, induction coil has first end and second end along the flow direction of process gas, first end is close to the process gas entry, the second end is close to the process gas export, be provided with the substrate tray in the reaction chamber body, the substrate tray is used for bearing and rotatory substrate, wherein, along the flow direction of process gas, the pitch of the coil at the middle part of induction coil is greater than the pitch of the coil at the both ends of induction coil, the number of turns center of induction coil is different from the tray center of rotation of substrate tray.

In an embodiment of the present application, the center of turns is closer to the process gas inlet than the center of rotation of the tray.

In one embodiment of the present application, the distance between the center of the turns and the center of rotation of the tray is in the range of 0.15-0.3 times the diameter of the substrate.

In an embodiment of the present application, the induction coil includes a first section, a second section, and a third section in sequence along the flow direction of the process gas, wherein the center of the turns and the center of rotation of the tray are both located in an area where the second section is located, the plurality of coils in the first section have equal first pitches, the plurality of coils in the second section have equal second pitches, the plurality of coils in the third section have equal third pitches, the second pitches are greater than the third pitches, and the third pitches are greater than the first pitches.

In an embodiment of the present application, the induction coil comprises a first coil set and a second coil set, wherein the first coil set comprises a coil located between the first end and a maximum pitch position, the second coil set comprises a coil located between the maximum pitch position and the second end, the pitch of the first coil set has a first increase from the first end to the maximum pitch position, the pitch of the second coil set has a first decrease from the maximum pitch position to the second end, and an absolute value of the first increase is greater than an absolute value of the first decrease.

In an embodiment of the present application, the first coil group includes at least two first coil segments, and the pitches of the at least two first coil segments gradually increase from the first end to the maximum pitch position.

In an embodiment of the present application, the second coil set includes at least two second coil segments, and the pitches of the at least two second coil segments gradually decrease from the maximum pitch position to the absolute value of the amplitude reduction and the absolute value of the amplitude reduction rate of the second end.

In an embodiment of the present application, the substrate is located in a substrate area, and the first coil section near the first end and the first coil section near the second end are located outside the first area, as viewed in the flow direction of the process gas, where the first area is an area with a length of 1.2-1.4 times the diameter of the substrate around the rotation center of the substrate.

In an embodiment of the present application, in the induction coil, a maximum pitch position is located on a side of the rotation center of the tray near the second end in a gas flow direction.

In an embodiment of the present application, the induction coil has a constant pitch section located between the first coil section and the second coil section near the center of rotation of the tray.

In an embodiment of the present application, the end points of the constant pitch segments are symmetrical about the tray rotation center along the flow direction.

In an embodiment of the present application, a heating ring is disposed inside the reaction chamber, the heating ring is configured to generate heat inductively when the induction coil is energized, the heating ring has a first edge and a second edge along a flow direction of the process gas, the first edge is located inside the first end, the second edge is located inside the second end, the induction coil has a first length along the flow direction of the process gas, the heating ring has a second length along the flow direction of the process gas, and the first length is 1.3 times to 1.6 times the second length.

In one embodiment of the present application, the heating ring, the substrate, and the induction coil are all symmetric about the rotational center of the tray along the flow direction of the process gas.

According to the semiconductor epitaxial growth equipment, the screw pitch of the middle coil of the induction coil is larger than that of the coils at the two ends, so that the heat generation quantity near the process gas inlet and the process gas outlet is improved, the temperature of the substrate near the process gas inlet and the process gas outlet is correspondingly improved, and the overall temperature uniformity of the substrate is further improved. Meanwhile, the center of the number of turns of the induction coil is different from the tray rotation center of the substrate tray, so that the temperature gradient of the surface of the substrate is further reduced, the temperature uniformity of the surface of the substrate is improved, and the quality of the film is improved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the principles of the application. In the accompanying drawings:

fig. 1 is a schematic view of a semiconductor epitaxial apparatus according to an embodiment of the present application;

fig. 2 is a cross-sectional view of a semiconductor epitaxial apparatus according to an embodiment of the present application;

FIG. 3 is a cross-sectional view of FIG. 2 taken along the line A-A (the induction coil is further shown);

fig. 4 is a schematic view for showing a positional relationship between the center of turns of an induction coil and the center of rotation of a tray in the semiconductor epitaxial apparatus according to an embodiment of the present application;

fig. 5 is a schematic diagram showing a distribution manner of induction coils of a semiconductor epitaxial growth apparatus according to the first embodiment of the present application;

fig. 6 is a schematic diagram showing a distribution manner of induction coils of a semiconductor epitaxial growth apparatus according to a second embodiment of the present application;

fig. 7 is a schematic diagram showing a distribution pattern of induction coils of a semiconductor epitaxial growth apparatus according to a third embodiment of the present application.

Detailed Description

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are used in the description of the embodiments will be briefly described below. It is apparent that the drawings in the following description are only some examples or embodiments of the present application, and it is obvious to those skilled in the art that the present application may be applied to other similar situations according to the drawings without inventive effort. Unless otherwise apparent from the context of the language or otherwise specified, like reference numerals in the figures refer to like structures or operations.

As used herein, the terms "a," "an," "the," and/or "the" are not specific to the singular, but may include the plural, unless the context clearly dictates otherwise. In general, the terms "comprises" and "comprising" merely indicate that the steps and elements are explicitly identified, and they do not constitute an exclusive list, as other steps or elements may be included in a method or apparatus.

The relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present application unless it is specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective parts shown in the drawings are not drawn in actual scale for convenience of description. Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but should be considered part of the specification where appropriate. In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.

In the description of the present application, it should be understood that, where azimuth terms such as "front, rear, upper, lower, left, right", "transverse, vertical, horizontal", and "top, bottom", etc., indicate azimuth or positional relationships generally based on those shown in the drawings, only for convenience of description and simplification of the description, these azimuth terms do not indicate and imply that the apparatus or elements referred to must have a specific azimuth or be constructed and operated in a specific azimuth, and thus should not be construed as limiting the scope of protection of the present application; the orientation word "inner and outer" refers to inner and outer relative to the contour of the respective component itself.

Spatially relative terms, such as "above … …," "above … …," "upper surface at … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial location relative to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "above" or "over" other devices or structures would then be oriented "below" or "beneath" the other devices or structures. Thus, the exemplary term "above … …" may include both orientations of "above … …" and "below … …". The device may also be positioned in other different ways (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

In addition, the terms "first", "second", etc. are used to define the components, and are merely for convenience of distinguishing the corresponding components, and unless otherwise stated, the terms have no special meaning, and thus should not be construed as limiting the scope of the present application. Furthermore, although terms used in the present application are selected from publicly known and commonly used terms, some terms mentioned in the specification of the present application may be selected by the applicant at his or her discretion, the detailed meanings of which are described in relevant parts of the description herein. Furthermore, it is required that the present application be understood, not simply by the actual terms used but by the meaning of each term lying within.

Fig. 1 is a schematic view of a semiconductor epitaxial apparatus according to an embodiment of the present application. Referring to fig. 1, the semiconductor epitaxial apparatus includes a reaction chamber 11 and an induction coil 12. Wherein the induction coil 12 is arranged at the outer periphery of the reaction chamber 11. It will be understood that the reaction chamber 11 is a space surrounded by a plurality of hardware devices, the semiconductor epitaxial device further includes hardware devices for forming the reaction chamber 11, the induction coil 12 is surrounded on the periphery of the hardware devices, when the induction coil 12 is powered on 13, an induction magnetic field is formed inside the induction coil 12, so that the magnetic induction element located inside the induction magnetic field generates heat, and thereby the substrate and the process gas entering the reaction chamber 11 are heated.

The semiconductor epitaxial apparatus further comprises a process gas inlet 14 and a process gas outlet 15, and the reaction chamber 11 has an inlet side 141 and an outlet side 151, respectively. In fig. 1, the flow direction D of the process gas in the reaction chamber 11 is indicated by arrows. The induction coil 12 has a first end 121 and a second end 122 in the flow direction D, wherein the first end 121 is adjacent to the process gas inlet 14 and the second end 122 is adjacent to the process gas outlet 15. Accordingly, the induction coil 12 has a first length L1 in the flow direction D, i.e. the distance between the first end 121 to the second end 122.

In a typical case, the process gas enters the reaction chamber 11 from the process gas inlet 14 and flows out from the process gas outlet 15, and the direction of the line between the process gas inlet 14 and the process gas outlet 15 is the flow direction. In a specific implementation, the flow direction is horizontal when the semiconductor epitaxial device is disposed in the orientation shown in fig. 1. It should be understood that the flow direction herein being a horizontal direction means that the main flow direction of the process gas in the reaction chamber is a horizontal direction. The following description will take the flow direction as a horizontal direction as an example.

As shown in fig. 1, a substrate tray 16 is disposed inside the reaction chamber 11 for carrying a substrate. The shape, size and material of the substrate are not limited in this application. The present specification describes a substrate having a circular shape (herein, the substrate having a circular shape means that the substrate has a substantially circular shape) as an example. During processing, the substrate tray 16 may rotate the supported substrate, the substrate tray 16 having its tray center of rotation. It will be appreciated that when the substrate is circular, the centre of the substrate ideally coincides with the centre of rotation of the tray. For a substrate tray 16 for carrying a substrate, the center of rotation of the tray, i.e., the center of the substrate, for a substrate tray 16 for carrying multiple substrates, the center of rotation of the tray may be the geometric center of the entire substrate tray 16, or the junction of the axis of rotation and the substrate tray 16.

Referring to fig. 1, in the semiconductor epitaxial apparatus of the present application, the pitch of the coil located at the middle of the induction coil 12 is larger than the pitch of the coils located at both ends of the induction coil 12 in the flow direction D, and the center of the turns of the induction coil 12 is different from the center of the tray rotation of the substrate tray 16.

In a coil, the pitch refers to the distance that a point on the coil moves in the axial direction for one revolution of the coil, and is also generally understood to be the distance between adjacent turns of the coil. Further, in the present application, the center of the turns of the induction coil 12 refers to a position point in the induction coil 12 at which the turns of the coils on both sides are equal.

The induction coils typically disposed outside the housing are of equal pitch, i.e., the distance between adjacent coils from the first end 121 to the second end 122 is equal. In this equidistant pitch distribution, the center of the turns coincides with the center of the length of the induction coil 12 in the flow direction D. When the induction coil 12 is not of equal pitch, then the center of turns may not coincide with the center of length, and the center of turns may be to the left or right of the center of length, as the case may be.

In one embodiment, the first end 121 and the second end 122 of the induction coil 12 are symmetrically disposed about the tray rotation center (where symmetrical disposition means that the distances from the first end 121 and the second end 122 to the tray rotation center are equal in the flow direction D), and in this embodiment, the length center position of the induction coil 12 in the flow direction D is the tray rotation center.

In another embodiment, the first end 121 and the second end 122 of the induction coil 12 are not symmetrically disposed about the tray rotation center, in which embodiment the length center position of the induction coil 12 in the flow direction D is different from the tray rotation center.

In both of the foregoing embodiments, the coil center of the induction coil 12 is different from the tray rotation center.

The inventors of the present application have found during development that the substrate surface has a phenomenon of uneven temperature distribution when an epitaxial process is performed, particularly in a SiC high temperature process. This problem is explained below in connection with fig. 2 and 3.

Fig. 2 is a cross-sectional view of a semiconductor epitaxial apparatus according to an embodiment of the present application, in which an induction coil is not shown, and fig. 3 is a cross-sectional view of fig. 2 along AA. In conjunction with fig. 2 and 3, in some embodiments, the semiconductor epitaxial apparatus further comprises an upper heating ring 21, a lower heating ring 22, both of which may be embodied as graphite heating rings. The substrate tray 16 may be embodied as an air-float tray and the substrates 24 are disposed on an upper surface of the substrate tray 16. The front and rear ends of the reaction cavity 11 further comprise a front heat-insulating member 23 and a rear heat-insulating member 24, the upper and lower parts of the reaction cavity 11 further comprise an upper heat-insulating member 25 and a lower heat-insulating member 26, and the four parts can be embodied as heat-insulating graphite felt. As shown in fig. 3, the upper heating ring 21 and the lower heating ring 22 are both semicircular in cross section, and a cylindrical member having a circular cross section can be enclosed by combining the semicircular upper heat insulating member 25 and the semicircular lower heat insulating member 26. The induction coil 12 is shown in fig. 3, and it is apparent that the induction coil 12 does not contact the upper and lower insulation members 25, 26.

Further, referring to fig. 1, a cooling liquid jacket 17 is further provided at the outer circumference of the reaction chamber 11, and the cooling liquid jacket 17 may be sleeved at the outer circumferences of the upper and lower heat insulating members 25 and 26, and has a cooling liquid inlet 18 and a cooling liquid outlet 19 for cooling the reaction chamber 11. The induction coil 12 is further provided outside the cooling liquid jacket 17. The cooling liquid jacket 17 may be embodied as a quartz jacket, the cooling liquid being embodied as water.

Referring to fig. 1 to 3, an alternating current flows to generate an alternating induction magnetic field in the induction coil 12, thereby generating a varying magnetic field in the upper and lower heating rings 21 and 22, so that free electrons in the upper and lower heating rings 21 and 22 form eddy currents, thereby inducing heat generation in both the upper and lower heating rings 21 and 22, and generating an induction heat source. Typically, the induction coil 12 is mounted coaxially with the reaction chamber 11, and the midpoints of the induction coil 12, the substrate tray 16, and the heating rings (including the upper heating ring 21 and the lower heating ring 22) are located on the same vertical line (the aforementioned vertical line is a line extending in the up-down direction with reference to fig. 2) in the flow direction D. In some embodiments, the substrate tray 16 is a graphite tray that can also inductively generate heat.

The inventors of the present application conducted a thermal equilibrium analysis of the reaction chamber 11 and found that the heat of the upper heating ring 21, the lower heating ring 22 and the substrate tray 16 was taken away mainly by three ways:

(1) The process gas enters the reaction cavity 11 and is heated and then flows out to take away part of heat;

(2) Heat is taken away by the cooling liquid through heat conduction, heat convection and heat radiation of the thermal insulation graphite felt to the cooling liquid jacket 17;

(3) Radiating from the reaction chamber 11 to the outside.

Wherein the flow of process gases inside the reaction chamber 11 has a relatively large influence on the temperature field. The inventors found that the temperature difference between the inlet side 141 and the outlet side 151 is relatively large during the process gas is continuously heated in the reaction chamber 11. The main reason is that, in order to dilute the C source gas and Si source gas during SiC epitaxy, carrier gas (e.g., H ₂ ) Large duty ratio, large flow velocity and short residence time. The process gas may carry away some of the heat from the surfaces of the heating ring, substrate tray 16, and substrate 24, and since the temperature difference between the heating ring, substrate, and tray and process gas near the inlet side 141 is greater than the temperature difference between the heating ring, substrate, and tray and process gas at the outlet side 151, the inlet side process gas carries away more heat, resulting in a lower temperature of the substrate near the inlet side.

Aiming at the substrate surface temperature difference caused by uneven temperature fields in the reaction cavity, the semiconductor epitaxial growth equipment is provided, and the distribution of a magnetic field is changed by arranging the induction coil 12 with a large middle pitch and small middle two ends, so that the heat generated by the upper heating ring and the lower heating ring at the two ends is increased, and the heat in the middle is reduced; meanwhile, the circle centers of the induction coils 12 are different from the rotation center of the tray, and the distribution of the temperature field can be changed according to actual conditions, so that the temperature of the substrate is uniform, and the film forming quality is improved.

In some embodiments, the center of the turns is closer to the process gas inlet 14 than the center of rotation of the tray. As shown in fig. 4, C1 represents the center of rotation of the tray, C2 represents the center of the turns, and the left side in the figure is the process gas inlet 14 side, and the right side is the process gas outlet 15 side. The foregoing arrangement allows more heat to be generated in the environment of the substrate near the inlet side 141, and the temperature of that portion of the substrate is compensated for, thereby reducing the temperature differential between the substrate near the inlet side 141 and other areas of the substrate.

As shown in fig. 4, in some embodiments, the distance d1 between the center of turns C2 and the center of rotation C1 of the tray ranges from 0.15 to 0.3 times the diameter of the substrate. For example, when the substrate diameter is 200mm, d1 ranges from 30 to 60mm.

In some embodiments, the inner diameter of the induction coil 12 is 1.8-2.2 times the diameter of the substrate, which is reduced by about 5% -10% compared to the original design, which can increase the magnetic field strength inside the coil and facilitate the improvement of the heat generation efficiency of the heating ring.

Fig. 5 is a schematic diagram showing a distribution manner of induction coils of a semiconductor epitaxial growth apparatus according to the first embodiment of the present application. Referring to fig. 5, the horizontal axis is the coil length and the vertical axis is the pitch. Wherein the position points are represented by circles comprising a first end 121, a second end 122 of the induction coil 12, a tray rotation center C1 and a turn center C2, wherein the tray rotation center C1 is located on the longitudinal axis, the origin of coordinates being represented for representing the position of the tray rotation center C1 in the flow direction D.

As shown in fig. 5, the induction coil 12 has a maximum pitch position Cmax.

In the present application, when the plurality of pitches are each the maximum pitch, the maximum pitch position Cmax is the midpoint of the number of coils having the maximum pitch in the flow direction D of the process gas. When the maximum pitch is unique, the maximum pitch position Cmax is the midpoint of the adjacent two coils with the maximum pitch in the flow direction D. It will be appreciated that when the pitch between two adjacent coils having the greatest pitch is graded, the maximum pitch position Cmax is the midpoint in the flow direction D at the position of the two adjacent coils being the greatest pitch apart.

In the first embodiment shown in fig. 5, the induction coil 12 includes a first coil group G1 and a second coil group G2, wherein the first coil group G1 includes a coil located between the first end 121 and the maximum pitch position Cmax, the second coil group G2 includes a coil located between the maximum pitch position Cmax and the second end 122, the pitch of the first coil group G1 has a first increase from the first end 121 to the maximum pitch position Cmax, and the pitch of the second coil group G2 has a first decrease from the maximum pitch position Cmax to the second end 122, and an absolute value of the first increase is larger than an absolute value of the first decrease.

The first coil group G1 includes at least two first coil segments, and the pitches of the at least two first coil segments gradually increase from the first end 121 to the maximum pitch position Cmax.

Specifically, referring to fig. 5, in the first embodiment, the first coil group G1 includes two first coil sections 611a, 611b, and the first coil section 611a and the first coil section 611b are straight lines having different slopes with a inflection point 621 therebetween. The slope of the first coil segment 611a is smaller than the slope of the first coil segment 611b, that is, the rate of increase of the pitch of the induction coil 12 corresponding to the first coil segment 611a is smaller than the rate of increase of the pitch of the induction coil 12 corresponding to the first coil segment 611b, and at the same time, the length of the first coil segment 611a in the longitudinal direction (i.e., up-down direction in fig. 5) is smaller than the length of the first coil segment 611b in the longitudinal direction, that is, the rate of increase of the pitch of the induction coil 12 corresponding to the first coil segment 611a is smaller than the rate of increase of the pitch of the induction coil 12 corresponding to the first coil segment 611 b.

In some embodiments, more first coil segments may be included in the first coil group G1.

The illustration in fig. 5 is merely an example, and in other embodiments, the first coil segment 611a and the first coil segment 611b may be non-linear curves, rather than straight lines.

The second coil group G2 includes at least two second coil segments, and the pitches of the at least two second coil segments gradually decrease from the maximum pitch position Cmax to the second end 122.

Referring to fig. 5, in the first embodiment, the second coil group G2 includes two second coil segments 612a, 612b, wherein the second coil segment 612a is closer to the second end 122. The second coil segment 612a and the second coil segment 612b are straight lines having different slopes with a inflection point 622 therebetween. The absolute value of the slope of the second coil section 612a is smaller than the absolute value of the slope of the second coil section 612b, that is, the absolute value of the rate of decrease in the pitch of the induction coil 12 corresponding to the second coil section 612a is smaller than the absolute value of the rate of increase in the pitch of the second coil section 612b, and at the same time, the length of the second coil section 612a in the longitudinal direction is smaller than the length of the second coil section 612b in the longitudinal direction, that is, the rate of decrease in the pitch of the second coil section 612a is smaller than the rate of decrease in the pitch of the second coil section 612 b.

In some embodiments, more second coil segments may be included in the second coil group G2.

The illustration in fig. 5 is merely an example, and in other embodiments, the second coil segment 612a and the second coil segment 612b may be non-linear curves, rather than straight lines.

As shown in fig. 5, the maximum pitch position Cmax is located on the right side of the tray rotation center C1, and the distance between the maximum pitch position Cmax and the tray rotation center C1 is in the range of 0.025-0.1 times the substrate diameter. For example, when the substrate diameter is 200mm, the distance is in the range of 5mm to 20mm.

The substrate is located in a substrate zone W, and the first coil segment 611a near the first end 121 and the first second coil segment 612a near the second end 122 are located outside the first zone Z1, as viewed in the flow direction D of the process gas, the first zone Z1 being centered on the substrate rotation center C1 and having a length of 1.2 to 1.4 times the substrate diameter.

As shown in fig. 5, the substrate area W in which the substrate is located is indicated by a double-headed arrow labeled W, the length of which may be indicative of the substrate diameter. The first zone Z1 is symmetrical about C1, the length in the flow direction D being 1.2 to 1.4 times the diameter of the substrate, i.e. the first zone Z1 should completely cover the substrate and be arranged beyond the substrate. Both the first coil segment 611a and the second coil segment 612a are located outside the first zone Z1, the pitch increase of the first coil segment 611a being relatively minimal in the first coil group G1, and the pitch decrease of the second coil segment 612a being relatively minimal in the second coil group G2. According to the design, the coil pitch at the port is smaller, so that the heat at the port is higher, the temperature of the process gas is favorably increased, and the temperature difference of the surface of the substrate is reduced.

The heat received by the substrate is analyzed in conjunction with the following formula.

In formula (1), q corresponds to the amount of heat received by the substrate, T represents the substrate surface temperature, x represents the horizontal axis distance, and k is the heat transfer coefficient.

Equation (1) shows that the smaller the gradient of the substrate surface temperature T on the horizontal axis x, i.e., the more uniform the substrate surface temperature T, the less the amount of heat q received by the substrate decreases. Thus, by increasing the pitch of the coil in the middle of the induction coil 12, the amount of heat generated by this partial region is reduced, thereby reducing the temperature differential across the substrate surface and making the temperature across the substrate surface more uniform. Further, by reducing the pitch of the coils at both ends, the temperature of the process gas at both ends is increased, reducing the temperature difference of the process gas across the flow path, further reducing the temperature difference across the substrate surface, and making the deposited film more uniform.

The heating ring is configured to inductively generate heat when the induction coil 12 is energized, the heating ring having a first edge and a second edge along the flow direction D of the process gas, the first edge being located inside the first end and the second edge being located inside the second end, the induction coil 12 having a first length L1 along the flow direction D of the process gas, the heating ring having a second length L2 along the flow direction D of the process gas, the first length L1 being 1.3-1.6 times the second length L2.

The inventors have found that because the induction coil 12 has a finite number of turns, the magnetic field strength is relatively uniform in the middle region, but varies greatly as fast as the two side ports. Thus, the heating ring heats relatively uniformly in the middle, but relatively less near the two ports. The low heating amount at the inlet side can lead to lower temperature of the process gas, thereby increasing the temperature gradient of the SiC epitaxial layer; the amount of heating on the outlet side decreases and the temperature gradient increases. In response to this problem, the present application addresses the design described in the foregoing for the edge and length of the heating ring.

To more clearly illustrate the positional relationship of the heating ring to the induction coil 12, a first edge 521, a second edge 522, and a distance therebetween representing a second length L2 of the heating ring, and a distance between the first end 121 and the second end 122 representing a first length L1 of the induction coil 12 are shown in connection with fig. 5. Obviously, the second length L2 is smaller than the first length L1 of the induction coil 12.

In order to have a more uniform magnetic field in the region of the heating ring, both edges of the heating ring are retracted inwardly with respect to both ends of the induction coil 12, that is, the heating ring is entirely located in the region of relatively uniform magnetic field intensity, so that uniformity of heat generated by the heating ring in the flow direction D can be further improved, and uniformity of the substrate surface temperature can be further improved.

In some embodiments, the heating ring, the substrate, and the induction coil 12 in the semiconductor epitaxial growth apparatus of the present application are all symmetrically disposed about the tray rotation center C1 along the flow direction D of the process gas. The sense of symmetry of the induction coil 12 with respect to C1 is: the distance from the first end 121 to C1 is equal to the distance from the second section 122 to C1.

In some embodiments, the induction coil 12 may not be symmetrical about C1. For example, the first end 121 is a distance d10 from C1, the second end 122 is a distance d20 from C1, d10 is greater than d20, and the difference between d10 and d20 is set to be less than 0.2 times the diameter of the substrate. For example, when the induction coil 12 is initially symmetrical about C1, the induction coil 12 is moved forward by, for example, 40mm, i.e., toward the process gas inlet 14, and the coil is then adjusted so that the coil center C2 is moved rearward by, for example, 5mm, and C2 is still located on the left side of C1, the same effect as in the previous embodiment can be obtained as well as a uniform substrate surface temperature.

Fig. 6 is a schematic diagram showing a distribution pattern of induction coils of a semiconductor epitaxial growth apparatus according to a second embodiment of the present application. The following description will be made with respect to a portion of the second embodiment that is different from the first embodiment.

As shown in fig. 6, a middle coil section 613 is further included on the right side of the first coil section 611b, and the middle coil section 613 is located at both the first coil group G1 and the second coil group G2. In some embodiments, the intermediate coil section 613 of this second embodiment includes a number of turns, and the turns are equidistant from the pitch and equal to the maximum pitch. In the embodiment shown in fig. 6, the maximum pitch position Cmax, i.e. the midpoint of the intermediate coil section 613, corresponds to the tray rotation center C1 (i.e. Cmax is located at the tray rotation center C1 as seen in fig. 6).

In some variant embodiments based on embodiment two, the maximum pitch position Cmax, i.e. the midpoint of the intermediate coil section 613, may be located to the right of the centre of rotation C1 of the pallet.

Fig. 7 is a schematic diagram showing a distribution pattern of induction coils of a semiconductor epitaxial growth apparatus according to a third embodiment of the present application. As follows, only the differences between the third embodiment and the first embodiment will be described.

In the third embodiment, the induction coil 12 includes a first segment 711, a second segment 712, and a third segment 713 in this order along the flow direction of the process gas, wherein the center of turns C2 and the center of rotation C1 of the tray are located in the region where the second segment 712 is located, the number of coils in the first segment 711 have equal first pitches, the number of coils in the second segment 712 have equal second pitches, the number of coils in the third segment 713 have equal third pitches, the second pitches are larger than the third pitches, and the third pitches are larger than the first pitches. Referring to fig. 7, in the third embodiment, the absolute value of the difference between the second pitch and the first pitch is larger than the absolute value of the difference between the second pitch and the third pitch. This arrangement may result in a higher heat generation of the heating ring near the first end 121 than the heating ring near the second end 122, which in turn results in a higher heat generation of the process gas near the first end 121 than the process gas near the second end 122.

As shown in fig. 7, the pitch of the first segment 711 to the second segment 712 increases abruptly, with a turning point 714 in between, and the pitch of the second segment 712 to the third segment 713 decreases abruptly, with a turning point 715 in between. In practice, a transition of 1-2 turns may be included from the first segment 711 to the second segment 712, and a transition of 1-2 turns may be included from the second segment 712 to the third segment 713.

The pitch of the induction coil 12 of the present application has the characteristics of small ends and large middle. In the third embodiment, since the pitches of the coils in the second segment 712 are all the second pitches, the maximum pitch is the second pitch. In the embodiment shown in fig. 7, cmax corresponds to the midpoint of the second segment 712, i.e., cmax coincides with C1. The induction coil 12 in the third embodiment also includes a first coil group G1 and a second coil group G2, which are separated by a longitudinal axis. In this embodiment, the average pitch of the coils on the left side of C1 is smaller and the average pitch of the coils on the right side of C1 is larger as a whole, so that the temperature of the substrate on the left side of the corresponding C1 is compensated.

The first, second and third embodiments provide 3 different coil pitch distribution examples, and on this basis, those skilled in the art can design other pitch distribution forms, which are all within the scope of the present application.

While the basic concepts have been described above, it will be apparent to those skilled in the art that the foregoing application disclosure is by way of example only and is not intended to be limiting. Although not explicitly described herein, various modifications, improvements, and adaptations of the present application may occur to one skilled in the art. Such modifications, improvements, and modifications are intended to be suggested within this application, and are therefore within the spirit and scope of the exemplary embodiments of this application.

Meanwhile, the present application uses specific words to describe embodiments of the present application. Reference to "one embodiment," "an embodiment," and/or "some embodiments" means that a particular feature, structure, or characteristic is associated with at least one embodiment of the present application. Thus, it should be emphasized and should be appreciated that two or more references to "an embodiment" or "one embodiment" or "an alternative embodiment" in various positions in this specification are not necessarily referring to the same embodiment. Furthermore, certain features, structures, or characteristics of one or more embodiments of the present application may be combined as suitable.

Some aspects of the present application may be performed entirely by hardware, entirely by software (including firmware, resident software, micro-code, etc.) or by a combination of hardware and software. The above hardware or software may be referred to as a "data block," module, "" engine, "" unit, "" component, "or" system. The processor may be one or more Application Specific Integrated Circuits (ASICs), digital Signal Processors (DSPs), digital signal processing devices (DAPDs), programmable Logic Devices (PLDs), field Programmable Gate Arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, or a combination thereof. Furthermore, aspects of the present application may take the form of a computer product, comprising computer-readable program code, embodied in one or more computer-readable media. For example, computer-readable media can include, but are not limited to, magnetic storage devices (e.g., hard disk, floppy disk, tape … …), optical disk (e.g., compact disk CD, digital versatile disk DVD … …), smart card, and flash memory devices (e.g., card, stick, key drive … …).

The computer readable medium may comprise a propagated data signal with the computer program code embodied therein, for example, on a baseband or as part of a carrier wave. The propagated signal may take on a variety of forms, including electro-magnetic, optical, etc., or any suitable combination thereof. A computer readable medium can be any computer readable medium that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. Program code located on a computer readable medium may be propagated through any suitable medium, including radio, cable, fiber optic cable, radio frequency signals, or the like, or a combination of any of the foregoing.

Likewise, it should be noted that in order to simplify the presentation disclosed herein and thereby aid in understanding one or more inventive embodiments, various features are sometimes grouped together in a single embodiment, figure, or description thereof. This method of disclosure, however, is not intended to imply that more features than are presented in the claims are required for the subject application. Indeed, less than all of the features of a single embodiment disclosed above.

In some embodiments, numbers describing the components, number of attributes are used, it being understood that such numbers being used in the description of embodiments are modified in some examples by the modifier "about," approximately, "or" substantially. Unless otherwise indicated, "about," "approximately," or "substantially" indicate that the number allows for a 20% variation. Accordingly, in some embodiments, the numerical parameters employed in this application are approximations that may vary depending upon the desired properties sought for the individual embodiment. In some embodiments, the numerical parameters should take into account the specified significant digits and employ a method for preserving the general number of digits. Although the numerical ranges and parameters set forth herein are approximations that may be employed in some embodiments to confirm the breadth of the range, in particular embodiments, the setting of such numerical values is as precise as possible.

While the present application has been described with reference to the present specific embodiments, those of ordinary skill in the art will recognize that the above embodiments are for illustrative purposes only, and that various equivalent changes or substitutions can be made without departing from the spirit of the present application, and therefore, all changes and modifications to the embodiments described above are intended to be within the scope of the claims of the present application.

Claims (13)

1. A semiconductor epitaxial growth apparatus, comprising: the reaction chamber body and induction coil, wherein, induction coil sets up the periphery of reaction chamber body, induction coil has first end and second end along the flow direction of process gas, first end is close to the process gas entry, the second end is close to the process gas export, be provided with the substrate tray in the reaction chamber body, the substrate tray is used for bearing and rotatory substrate, wherein, along the flow direction of process gas, the pitch of the coil at the middle part of induction coil is greater than the pitch of the coil at the both ends of induction coil, the number of turns center of induction coil is different from the tray center of rotation of substrate tray.

2. The semiconductor epitaxial growth apparatus of claim 1, wherein the center of turns is closer to the process gas inlet than the center of rotation of the tray.

3. The semiconductor epitaxial growth apparatus of claim 2, wherein a distance between the center of the turns and the center of rotation of the tray is in the range of 0.15-0.3 times a diameter of the substrate.

4. The semiconductor epitaxial growth apparatus of claim 2, wherein the induction coil comprises a first segment, a second segment, and a third segment in sequence along the flow direction of the process gas, wherein the center of turns and the center of rotation of the tray are both located in an area where the second segment is located, wherein the number of coils in the first segment have equal first pitches, wherein the number of coils in the second segment have equal second pitches, wherein the number of coils in the third segment have equal third pitches, wherein the second pitches are greater than the third pitches, and wherein the third pitches are greater than the first pitches.

5. The semiconductor epitaxial growth apparatus of claim 2, wherein the induction coil comprises a first coil set and a second coil set, wherein the first coil set comprises a coil located between the first end and a maximum pitch location, the second coil set comprises a coil located between the maximum pitch location and the second end, the pitch of the first coil set has a first increase from the first end to the maximum pitch location, the pitch of the second coil set has a first decrease from the maximum pitch location to the second end, and an absolute value of the first increase is greater than an absolute value of the first decrease.

6. The semiconductor epitaxial growth apparatus of claim 5, wherein the first coil group comprises at least two first coil segments having pitches that increase gradually from the first end to the maximum pitch position.

7. The semiconductor epitaxial growth apparatus of claim 6, wherein the second coil set comprises at least two second coil segments having pitches that decrease gradually from a maximum pitch position to an absolute value of a decrease in amplitude and an absolute value of a decrease in amplitude rate at the second end.

8. The semiconductor epitaxial growth apparatus of claim 7, wherein the substrate is located in a substrate region, a first one of the first coil segments near the first end and a first one of the second coil segments near the second end being located outside of a first region, as viewed in a flow direction of the process gas, the first region being a region having a length of 1.2 to 1.4 times a diameter of the substrate centered on a center of rotation of the substrate.

9. The semiconductor epitaxial growth apparatus of claim 8, wherein in the induction coil, a maximum pitch position is located on a side of the center of rotation of the tray near the second end in a gas flow direction.

10. The semiconductor epitaxial growth apparatus of claim 8, wherein the induction coil has a constant pitch section located between the first coil section and the second coil section near the center of rotation of the tray.

11. The semiconductor epitaxial growth apparatus of claim 10, wherein the endpoints of the constant pitch segments are symmetrical about the tray center of rotation along the flow direction.

12. The semiconductor epitaxial growth apparatus of claim 1, wherein a heating ring is disposed inside the reaction chamber, the heating ring configured to inductively generate heat when the induction coil is energized, the heating ring having a first edge and a second edge along a flow direction of the process gas, the first edge being located inside the first end, the second edge being located inside the second end, the induction coil having a first length along the flow direction of the process gas, the heating ring having a second length along the flow direction of the process gas, the first length being 1.3-1.6 times the second length.

13. The semiconductor epitaxial growth apparatus of claim 12, wherein the heating ring, the substrate, and the induction coil are symmetrical about the rotational center of the tray along the flow direction of the process gas.