TWI857037B - Heating device for substrate holder of CVD reactor - Google Patents

Abstract

The invention relates to a device (1) for heating a substrate holder of a CVD reactor (10). Three heating surfaces (2) of equal or different size are provided and are distributed around a center (Z). The heating surfaces (2) are formed by electrically conductive heating elements (3) extending in a zigzag manner in a plane to form side edges (4) arranged side by side. The essence is that the side edges (4) have side segments (5) extending parallel to boundaries (a, b, c) extending along the radial boundaries between two heating surfaces (2). The heating zone arrangement using this construction scheme is surrounded by a circular second heating arrangement.

Description

Heating device for substrate holder of CVD reactor

The present invention relates to a device for heating a substrate holder of a CVD reactor, comprising at least three heating elements which are preferably of the same structure, electrically conductive, arranged in the same plane, extending in a zigzag manner in the plane to form side edges side by side, respectively confined on a heating surface of preferably the same size and uniformly distributed around a center and separated by radial boundaries, respectively having a first connection point at the first end and a second connection point at the second end, and connected to a conductive distribution element via the first and second connection points.

The present invention also relates to a CVD reactor having such a heating element and a heating element for a heating device.

Such a device is described in WO 2006/060134 A2. The case describes a heating device having a plurality of conductive heating elements arranged in a plane. The heating elements form a radial outer region and a radial inner region. The inner region is surrounded by an arc-shaped outer heating element, in which a heating element having a plurality of arc-shaped sides extends. The sides are connected by 180 degree arc segments, so that they extend side by side in a plane.

Similar heating elements are also described in US 5,759,281, US 2016/0270150 A1 and DE 10 2013 113 049 A1.

WO 2004/089039 describes a heating device having a total of four heating surfaces separated by radial boundaries. Each of the four cake-shaped heating surfaces has a heating element having a radially outward connection point and a radially inward connection point, wherein the radially inward connection point is arranged near the center. The heating element extends between the connection points in a manner forming arcuate sides extending side by side.

The object of the present invention is to optimize a heating element of the same type used in or on a CVD reactor.

The solution of the present invention to achieve the above-mentioned purpose is the device given in the scope of the patent application.

First and in essence, the sides are formed by side segments extending parallel to the boundaries. At least the sides adjacent to the boundaries are preferably straight line extensions. Thus, two sides of different heating elements can be parallel to each other. Specifically, at least part of, preferably all of the sides are formed by side segments parallel to the boundaries. Wherein, each side can have two side segments. Specifically, the heating surfaces are of the same size and extend in a region around the center, so that each heating surface has two radial boundaries, for example, at an angle of 120 degrees, 90 degrees or 72 degrees to each other, and an arc boundary extending on a circular arc around the center. Thus, each heating surface is in the shape of a cake piece. At least the longest side segment of the side segments is parallel to the radial boundary of the extension of the straight lines. Two side segments parallel to each other are preferably connected by a 180-degree arc segment, wherein a gap extends between the side segments parallel to each other. The gap width of the gap increases in the area at the end of the gap, thereby forming a disc-shaped gap end face, for example. In addition, the two side segments forming a side can form a corner segment, in which the two side segments are at an angle of 120 degrees, 90 degrees or 72 degrees to each other. The inner side region can form a corner notch, so the gap is also increased here. Particularly advantageously, the heating elements are punched from a plate, such as graphite or metal plate, for example by laser cutting. The material of the plate is conductive and has a high temperature resistance. The heating device can be heated to above 2000°C by supplying electricity. Each heating element has a first connection point and a second connection point. The first connection point is connected to the shortest side of the sides. The second connection point is connected to the longest side of the sides of the heating element and connects the corresponding end of the heating element to a distribution element. The distribution elements can be arranged in the same plane and can be composed of plates, which are separated by isolation gaps. The plates are arranged in a parallel plane parallel to the heating elements. An isolation element may be provided between the heating element and the distribution element. The isolation elements may refer to plates, which are composed of ceramic material and arranged between the heating element and the distribution element. The isolating elements may also be formed by flanges, which are only arranged at certain mutually spaced positions between the heating element and the distribution element. In a modified version of the present invention, the three central heating elements, in particular, form a central heating zone, which is surrounded by a radially outer heating zone. The radially outer heating zone is preferably formed by a second heating element extending in an arc. The arc-shaped heating elements can form the circular arc boundaries of the heating surfaces. In addition, all the heating elements of the central heating zone are connected in parallel, and/or all the heating elements of the radially outer heating zone are connected in parallel. In addition, the one or more heating elements constituting the radially outer heating zone may have two sides respectively. The sides extend side by side, thereby forming a gap between two side sections connected by arc sections. The gap may also be widened in the end of the gap. The gap may be widened towards the end of the gap in the form of a larger area, wherein the larger area may have an edge, which extends in the shape of a circular arc, a triangle, a trapezoid or generally a polygon. According to another embodiment, a larger recess may also be provided in the region of the shortest side. In addition, the second heating elements may have overlapping sides. In this case, the sides have an overlapping shape. Therefore, the sides of the second heating element may extend in two planes. The planes may be staggered with the same plane in which the first heating elements are located. The inner heating element may, for example, be staggered towards the outer heating element below with respect to the upper side of the outer heating element by the material thickness of the outer heating element. The distribution elements and/or the isolation elements arranged between the distribution elements and the heating elements can form a carrier element that carries the heating elements. The heating elements can be connected to the carrier element only by the connection points. The heating elements can also be fixed to the carrier element by means of fixing elements, for example, made of ceramic material. The fixing element can have a head fixed to a rod with a smaller diameter. The rod can pass through the opening of the heating element and be fixed to the carrier element. In this case, the head is preferably placed on the upwardly pointing surface of the heating element. A plurality of such fixing elements can be provided, which can also be arranged in the area of the gap between two heating elements. As an advantageous solution, a straight-line gap is formed between the side sections of two adjacent boundaries of two different heating elements, which gap has a constant gap width over its entire extension. The gap preferably extends on a radial line (relative to the center) of the heating device. The gap is preferably only slightly larger than the gap between two sides belonging to a heating element. Preferably, all gaps have approximately the same gap width.

FIG. 22 schematically shows a CVD reactor 10, wherein a gas inlet component 11 having a showerhead-like exhaust surface is arranged in a gastight housing, in particular made of high-quality steel, and the process gas fed into the gas inlet component 11 can flow into a process chamber 14 through a plurality of exhaust ports of the exhaust surface. The process gas in particular comprises a carrier gas (such as hydrogen), an organic metal component (in particular an organic metal compound of a group III element, such as trimethyl gallium or trimethyl indium), and a hydride of a group V element (such as ammonia, arsenic or phosphorus). The bottom of the process chamber 14 is formed by a substrate holder 12, which forms a plurality of carrier slots, each of which can accommodate a substrate 13, which is coated by the fed process gas. The substrate holder 12 is heated from bottom to top by the heating device 1, which is an infrared radiator.

1 to 21 show different embodiments of the heating device 1 of the present invention that can be used in a CVD reactor 10.

The heating device 1 of embodiments 1 to 3 first has the following common features:

The heating element 1 is a disc-shaped body with a multi-layer structure. On the side pointing upward, the body forming the heating device 1 has a plurality of heating elements 3, which are distributed on the heating surfaces 2 of the same size. Starting from the center Z of the heating element 1, there are three radial lines a, b, and c arranged at an angle of 120 to each other, which represent the imaginary radial boundaries of the three heating surfaces 2. The heating surface 2 is limited in the radial outward direction by three arc-shaped radially outward second heating elements 21. All heating elements 21 of the heating element 1 can be made of temperature-resistant materials. Specifically, the heating elements are made of metal or graphite.

Each heating surface 2 preferably has exactly one heating element 3 with a first end 3' and a second end 3". The first end 3' is connected to a plurality of distribution elements 15, 15', 16, 17 via a connection point 6. The second end 3'' of the heating element 3 has a second connection point 7, via which the second end is connected to another of the distribution elements 15 to 17. The second end 3'' is formed by an end of a side 4 of the heating element 3, wherein the heating element 3 has a plurality of side edges 4 arranged side by side. Two side edges 4 arranged side by side each have a side segment 5, the angle between the side segments being equal to the angle between the two radial boundaries a, b, c limiting the corresponding heating surface 2. The second connection point 7 is connected to the longest side section 5 adjacent to the radial boundaries a, b, c, which transitions to another side section 5 in a manner forming an angle in the corner section 9, and the other side section transitions to an arc section 8. The arc section 8 transitions to two side sections 5, which have the same structure and form a corner section 9 between them. The zigzag-shaped side 4 has the shortest side, which forms the first end 3' of the heating element.

A relatively narrow gap 18 extends between the parallel sides 5, which is larger in the area of the arc section 8 in a circular shape, thereby forming a larger gap end 19. A plurality of, preferably all, gaps 18 are parallel to the radial boundaries a, b, c. Therefore, each heating surface 2 has a plurality of side sections 5 that are parallel to each other and parallel to a radial boundary a, b, c.

A fixing element 27 is provided in the center Z, which is shown by way of example in FIG 4. The fixing element 27 overlaps the three tips of the corner sections 9 of the heating element 3 which are adjacent here.

A plurality of second heating elements 21 are provided, which also extend in the area where the first heating elements 3 are located. Each second heating element 21 arcuately surrounds an inner heating element 3. The radially outer second heating elements 21 have two side edges 22 extending side by side, wherein the two ends 21', 21" of the second heating element 21 or the side edges 22 are connected to the distribution elements 15, 15', 16, 17 via connection points 23, 24, respectively.

FIG. 2 or 4 shows the vertical structure of the heating device 1. The heating element 3 and the heating element 21 are at the top. The distribution elements 15, 15', 16, 17 are at the bottom, and together they form a circular plate separated by a number of gaps. Between the distribution elements 15, 15', 16, 17 and the heating elements 3, 21, there is an isolation element, which in the first embodiment is constructed as an isolation plate 25, which has an opening for the connection point to pass through.

FIG. 4 shows a connection point 7 which is connected to a distribution element 15 via a contact bushing 25 which can also function as a spacer bushing.

FIG4 also shows one of the fixing elements 27 used to connect the heating element 3 to the distribution element 15, 15', 16, 17. The fixing element 27 is an isolating body, such as a ceramic body, which has a head placed on the heating element 3, 21. The rod of the fixing element 27 passes through the isolating element and is fixed under the distribution element 16 by a split pin.

Fig. 5 shows an alternative construction scheme of the joint 24, through which the second heating element 21 is connected to the distribution element 15'. In this case, a spacer sleeve 26 is also provided between the heating element 21 and the distribution element 15', which can adopt a conductive scheme.

Figure 6 shows a fixing screw 28, which is located below the heating element 3 and is used to connect the isolation element (here the isolation plate 25) to the distribution element 16. The head of the fixing screw 28 is inserted into the recess. The nut tightened on the threaded rod of the fixing screw 28 is supported on the bottom side of the distribution element 15'.

The first connection point 6 and the second connection point 7 of the first heating element 3 are located in a radially outer region of the corresponding heating surface 2. The radial extension of the radially outer region in which the connection points 6, 7 are located is preferably smaller than the width of one of the side edges 5.

The bottom plane of the heating device 1 is composed of a total of five distribution elements 15, 15', 16, 17. One distribution element 16 extends in three 60-degree sections. Distribution elements 15, 15', 16, 17 extend between the three sections of the distribution element 16. In addition, the distribution elements have an external arc-shaped distribution element 17, which extends around the center Z in a range greater than 180 degrees. The distribution element 16 is a common distribution element, and a number of heating elements are connected to the distribution element. The internal heating elements 3 can be individually powered through the distribution elements 15, 15'. The radially external heating elements 21 can be individually powered through the radially external distribution element 17. However, according to a preferred embodiment, all internal heating elements 3 are connected in parallel and all external heating elements 21 are connected in parallel. However, the external heating elements and the internal heating elements 3, 21 can be powered separately from each other.

In the first embodiment shown in Figures 1 to 7 and in the second embodiment shown in Figures 8 to 13, the second heating element 21 extends side by side in the same plane in which the heating element 3 also extends. A narrow gap extends between the two sides 22 formed thereby.

The second embodiment shown in FIGS. 8 to 13 is characterized in that it has an isolating body with an alternative design. As an alternative to the isolating plate 25 used in the first embodiment, the isolating body here consists of flanges 29, 30 with a square shape. These flanges 29, 30 extend between the distribution elements 15, 15', 16, 17 and the heating elements 3, 21. The isolating bodies 29, 30 have studs on their upper surface, which can be snapped into the gap between the adjacent sides 4 or 22. Like the spacing elements 33 that keep the distribution elements 15, 15', 16, 17 at a distance, the isolating bodies 29, 30 can also be made of ceramic material.

Another difference of the second embodiment from the first embodiment is the corner notch 20. In particular, the side segment 5 adjacent to the radial boundaries a, b, c of the longest side 4 has a corner segment 9, which has a groove on the inside of the corner. The groove has a straight-running edge and widens the gap 18 between two side segments extending side by side in the corner segment 9.

The third embodiment shown in Figures 14 to 21 of the present invention has an isolator corresponding to the isolator of the second embodiment, so reference can be made to the relevant description. In the third embodiment, the side edges 22 of the second heating element 21 are not in the same plane, but in planes that are staggered from each other. In addition, the plane in which the heating element 3 is located is also staggered from the plane of the side edges 22.

The sides 22 of the second heating element 21 are arranged one above the other in a superimposed manner. Here too, a spacer sleeve is provided in the contact area to keep the two sides 22 at a certain distance from each other. The connection point 23 shown in FIG. 2 shows that it also keeps the lowermost side 22 at a certain distance from the distribution element 17. There is a connection point 23, 24 respectively connecting the two sides 22 of the second heating element 21 together. The spacer sleeves can adopt a conductive solution or an electrically insulating solution.

In this embodiment, the contact strip 32 extends in a hook shape. A substantially triangular corner notch 20' is formed between the radially outer side and the contact strip 32. The contact strip 32 is located to some extent between the two sides of the heating element 3. The arc-shaped section of the heating element 3 located in the radially outer region encloses a substantially trapezoidal free space, which forms the gap end 19.

FIG18 shows a contact bar 31 that connects the connection point 23 to the distribution element 16. The connection point 23 is arranged vertically above the distribution element 17, but is not connected to the distribution element 17. Specifically, the contact bar 31 spans the gap between the distribution element 17 and the adjacent distribution element 16, and the contact bar 31 is connected to the adjacent distribution element. The contact bar 31 has a Z shape.

FIG. 19 shows another Z-shaped contact strip 32, which connects the connection point 6 of the first heating element 3, which is higher than the distribution element 16, to another distribution element 15', wherein the contact strip 32 here also spans the gap between the two distribution elements 16 and 15'. The contact strips 31, 32 can be connected to the distribution elements assigned to them by screws not shown.

The aforementioned embodiments are used to illustrate the inventions included in the present application as a whole, which at least independently constitute improvements over the prior art through the following feature combinations, wherein two, several or all of these feature combinations may also be combined with each other, namely:

A device is characterized in that the sides 4 are composed of side segments 5 extending parallel to the boundaries a, b, c.

A device is characterized in that each side 4 has two side sections 5, which are respectively parallel to one of the boundary lines a, b, c that are at an angular distance from each other.

A device is characterized in that the first and second connection points 6, 7 are located in the radially outermost area of the heating surface 2 and/or the radially outermost area of the heating surface 2 has two superimposed elements.

A device is characterized in that two parallel side sections 5 extending side by side are connected through a 180 degree arc section 8 of the heating element 3.

A device is characterized in that the side segments 5 extend between an arc segment 8 and a corner segment 9 respectively.

A device is characterized in that the heating elements 3 are punched out of a flat blank, in particular from graphite or metal.

A device is characterized in that the first connection point 6 is assigned to the shortest side of the sides 4, the second connection point 7 is assigned to the longest side of the sides 4, and the longest side has two side sections 5 of equal length.

A device characterized by a gap 18 between two mutually parallel side sections 5, wherein the gap 18 widens in the region of the arc-shaped section 8 to a gap end 19 of larger area, wherein the area thus formed has an edge which extends in the shape of a circular arc, a polygon, in particular a triangle or a trapezoid.

A device is characterized in that the corner section 9 of two V-shaped abutting side sections 5 has a corner notch 20 on the inner side of the corner, wherein in particular, the corner notch 20 is only arranged on the longest side of the side sections 4.

A device, characterized in that the heating elements 3, in particular three, form a central heating zone, which is surrounded by a radial outer heating zone, which has a number of arc-shaped extending second heating elements 21.

A device, characterized in that the arc-shaped extending heating elements 21 form the azimuth boundaries of the arcs of the heating surfaces 2.

A device is characterized in that the heating elements 3 of the heating surfaces 2 are located in the same plane and/or the second heating elements 21 are arranged in the same plane or staggered with respect to each other.

A device is characterized in that the second heating element 21 has two arc-shaped sides 22, which extend side by side in a plane or are arranged one above the other in an overlapping manner.

A device characterized in that isolation elements 25, 29, 30 are arranged between the heating elements 3, 21 and the distribution elements 15, 15', 16, 17, and/or the heating elements 2 of the central heating zone are connected in parallel, and/or the second heating elements 21 of the radially outer heating zone are connected in parallel.

A CVD reactor has a gas inlet component 11 and a substrate holder 12 for accommodating a substrate 13, wherein the substrate holder can be heated by a heating device 1, wherein the heating device 1 adopts the construction scheme of any one of the aforementioned claims.

All disclosed features (as individual features or in combination of features) are essential to the invention. Therefore, the disclosure of this application also includes all the contents disclosed in the relevant/attached priority files (copies of prior applications), and the features described in such files are also included in the scope of the patent application of this application. The dependent items describe the features of the invention as an improvement over the prior art by their features (even if they do not contain the features of the relevant claim items), and their main purpose is to make divisional applications based on such claim items. The invention given in each claim item may further have one or more of the features given in the preceding description, especially those indicated by symbols and/or given in the symbol description. The present invention also relates to the following design forms: individual features described in the above description are not realized, especially features that are not necessary for a specific use or can be replaced by other components with the same technical effect.

1: heating device, device 2: heating surface 3: heating element 3': first end 3'': second end 4: side 5: side section 6: connection point 7: connection point 8: arc section 9: corner section 10: CVD reactor 11: gas inlet component 12: substrate holder 13: substrate 14: process chamber 15: power distribution element 15': power distribution element 16: power distribution element 17: power distribution element 18: gap 19: gap end of gap 20: corner notch 20': corner notch 21: heating element 21': first end 21'': second end 22: side 23: connection point 24: connection point 25: isolation element, isolation plate 26: spacer sleeve 27: fixing element 28: fixing screw 29: isolation element 30: isolation element 31: contact strip 32: contact strip 33: spacer element a: boundary b: boundary c: boundary Z: center

The following is an explanation of the embodiments of the present invention with reference to the accompanying drawings. Among them: Figure 1 is a perspective view of the heating device 1 of the first embodiment, Figure 2 is a view corresponding to Figure 1, but is cut open to show the vertical structure of the heating device 1, Figure 3 is a top view of the heating device 1 showing radial boundaries a, b, and c, Figure 4 is a cross-sectional view according to line IV-IV in Figure 3, Figure 5 is a cross-sectional view according to line V-V in Figure 3, Figure 6 is a cross-sectional view according to line VI-VI in Figure 3, Figure 7 is an exploded view of the main components of the heating device 1, Figure 8 is a view corresponding to Figure 1 of the second embodiment of the present invention, Figure 9 is a view corresponding to Figure 8, but is cut open to show the vertical structure of the heating device 1, Figure 10 is a top view of the heating device, Figure 11 is a perspective view of the isolator 29, Figure 12 is a perspective view of the isolator 30, Figure 13 is an exploded view of the second embodiment, Figure 14 is a view corresponding to Figure 1, including the cover edge of the third embodiment, Figure 15 is a partial XV in Figure 14, Figure 16 is a partial XVI in Figure 14, Figure 17 is a top view of the heating device 1, Figure 18 is a cross-sectional view according to the line XVIII-XVIII in Figure 17, Figure 19 is a cross-sectional view according to the line XIX-XIX in Figure 17, Figure 20 is a cross-sectional view according to the line XX-XX in Figure 17, Figure 21 is an exploded view of the third embodiment, and Figure 22 is a schematic diagram of an application example of the heating device 1 in the CVD reactor 10.

1: Heating device, device

2: Heating noodles

3: Heating element

3': First end

3": Second end

4: Side

5: Side section

6: Connection point

7: Connection point

8: Arc section

9: Corner section

18: Gap

19: End of gap

21: Heating element

21': First end

21": Second end

22: Side

23: Connection point

24: Connection point

Z: Center

a:Boundary

b:Boundary

c:Boundary

Claims (16)

A device (1) for heating a substrate holder of a CVD reactor (10), the device having at least three heating surfaces (2) of the same or different sizes, uniformly distributed around a center (Z) and separated by radial boundaries (a, b, c), each of the heating surfaces (2) having a conductive heating element (3) extending in a zigzag manner in a plane to form side edges (4) side by side, wherein each of the heating elements (3) is provided at a first end (3 ') has a first connection point (6) on the first end and a second connection point (7) on the second end (3"), the first and second connection points (6, 7) are connected to the conductive distribution elements (15, 15', 16), and are characterized in that the side edges (4) are connected to each other through a 180-degree arc segment, and each is composed of two side edge segments (5) extending parallel to the radial boundaries (a, b, c) and forming an angle with each other. A device for heating a substrate holder of a CVD reactor (10), the device having a heating surface (2) limited by radial boundaries (a, b, c) and in the form of conductive, meandering heating elements (3), the heating elements (3) extending in a plane and forming side edges (4) side by side, wherein the heating elements (3) each have a first connection point (6) at a first end (3') and a second connection point (7) at a second end (3"), characterized in that the side edges (4) are each composed of two longest side segments (5) extending parallel to the radial boundaries (a, b, c) and at an angle to each other. A device as claimed in claim 2, wherein each side (4) has two side segments (5), each of which is parallel to one of the equal radial boundaries (a, b, c) at an angular distance from each other. A device as claimed in claim 1, wherein the first and second connection points (6, 7) are located in the radially outermost region of the heating surface (2), and/or the radially outermost region of the heating surface (2) has two superimposed elements. A device as claimed in claim 1, wherein two parallel side sections (5) extending side by side are connected through a 180-degree arc section (8) of the heating element (3). A device as claimed in claim 1, wherein the side segments (5) extend between an arc segment (8) and a corner segment (9) respectively. A device as claimed in claim 1, wherein the heating elements (3) are punched from a flat blank comprising graphite or a metal part. A device as claimed in claim 1, wherein the first connection point (6) is assigned to the shortest side of the sides (4), and the second connection point (7) is assigned to the longest side of the sides (4), and the longest side has two side segments (5) of equal length. A device as claimed in claim 1, wherein a gap (18) is provided between two mutually parallel side segments (5), wherein the gap (18) widens in the region of the arc segment (8) to a gap end (19) of a larger area, wherein the area thus formed has edges extending in the shape of a circular arc, a polygon including a triangle or a trapezoid. A device as claimed in claim 6, wherein the corner section (9) of the two V-shaped abutting side sections (5) has a corner notch (20) on the inner side of the corner, wherein the corner notch (20) is only provided on the longest side among the side sections (4). The device of claim 1, wherein the number of the heating elements (3) is 3 and forms a central heating zone, the central heating zone is surrounded by a radial outer heating zone, and the outer heating zone has a plurality of arc-shaped extending second heating elements (21). A device as claimed in claim 11, wherein the arc-shaped extending second heating elements (21) form the arc-shaped azimuth boundaries of the heating surfaces (2). A device as claimed in claim 11, wherein the heating elements (3) of the heating surfaces (2) are in the same plane, and/or the second heating elements (21) are arranged in the same plane or staggered with each other. As in claim 11, the second heating element (21) has two arcuate sides (22), and the arcuate sides extend side by side or are arranged in an overlapping manner up and down in a plane. The device of claim 11, wherein an isolation element (25, 29, 30) is arranged between the heating elements (3, 21) and the distribution elements (15, 15', 16, 17), and/or the heating elements (3) of the central heating zone are connected in parallel, and/or the second heating elements (21) of the radially outer heating zone are connected in parallel. A CVD reactor has a gas inlet component (11) and a substrate holder (12) for accommodating a substrate (13). The substrate holder can be heated by a heating device (1). The characteristic of the reactor is that the heating device (1) is designed using the construction scheme described in claim 1.