Reaction chamber and epitaxial reactor with coating system

Abstract

The reaction chamber (100) is disposed within its cavity (101) and comprises a coating system (90) comprising at least one lower coating element (120) mounted on a lower wall of the cavity and an upper coating element (130) mounted on the lower coating element (120), the lower coating element (120) and the upper coating element (130) defining an insulating interior space for accommodating at least one substrate and creating four walls surrounding this interior space and spaced apart from the cavity walls, the walls of the chamber (100) typically being made from quartz and the coating system (90) typically being made from quartz.

Description

Technical Field

[0001] The present invention relates to a reaction chamber and related reactors for an epitaxial reactor having a "covering system". The (non-contact) "covering system" of the chamber wall is inside the cavity of the reaction chamber and serves to define an insulated space.

Background Art

[0002] The applicant is the owner of an international patent application published under number WO2010119430 in connection with a reaction chamber for an epitaxial reactor having a covering system. The reaction chamber comprises a box-shaped cavity surrounded by four walls, where the reaction and deposition process of semiconductor material onto a substrate takes place, and the substrate is placed on a rotating susceptor disk. The reaction chamber comprises a covering system disposed within the cavity and defining an internal space and an external space within the cavity. The covering system consists of three elements, namely a first pair of opposing walls and an upper and a second pair of opposing walls, which form an inverted "U" - shaped slab resting on the lower wall of the reaction chamber.

[0003] The term "opposing wall" in this patent application means a wall that is located at a certain distance from and not in contact with a reference wall, with an empty cavity existing therebetween - generally, the reactor has gas within the cavity, and in particular, during the reaction and deposition process, gas, in particular process gas or inert gas, is made to exist within the cavity depending on the location and embodiment.

[0004] The solution according to WO2010119430 is hereby incorporated by reference in its entirety. While it is a simple and effective solution, it forms an "internally partial covering" of the reaction chamber since the lower opposing wall is not provided.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The general objective of this invention is to improve upon the prior art.

[0006] In particular, the objectives identified were to improve the "chemical" insulation of the internal space, and / or the "thermal" insulation of the internal space, and / or fouling of the inner surface of the reaction chamber walls (in the sense of reducing it), and / or the possibility of local temperature control in the lower region of the reaction chamber.

[0007] It should be noted that this internal space of the reaction chamber cavity includes a susceptor disk and is adapted to also include a substrate on which the semiconductor material is epitaxially deposited during the epitaxial growth process.

[0008] As is well known, there is interest in the high thickness uniformity and high quality of semiconductor material layers deposited on substrates. [Means for solving the problem]

[0009] This general objective, and at least these objectives, are achieved by the appended claims which form an integral part of this specification.

[0010] The present invention will become more readily apparent from the following detailed description, which should be considered in conjunction with the accompanying drawings. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 shows a first schematic and simplified (not to scale) cross-sectional view (in the longitudinal direction) of a first embodiment of the reaction chamber according to the present invention, the figure being subdivided into three figures: Figure A shows only the chamber, Figure B shows only the components of the coating system, and Figure C shows the chamber containing the coating system. [Figure 2] Figure 2 shows a second schematic and simplified cross-section (not to scale) of the embodiment shown in Figure 1. [Figure 3]Figure 3 shows a first schematic and simplified horizontal section (not to scale) of the first elevation view of the embodiment in Figure 1. [Figure 4] Figure 4 shows a second schematic and simplified horizontal section (not to scale) in the second elevation of the embodiment of Figure 1. [Figure 5] Figure 5 shows a third schematic and simplified horizontal section (not to scale) of the third elevation in the embodiment of Figure 1. [Figure 6] Figure 6 shows a fourth schematic and simplified horizontal cross-section (not to scale) of the embodiment shown in Figure 1. [Figure 7] Figure 7 shows a fifth schematic and simplified horizontal cross-section (unspecified scale) at the fifth height of the embodiment in Figure 1. [Figure 8] Figure 8 shows a schematic and simplified horizontal cross-section (not to scale) of the sixth embodiment of Figure 1. [Figure 9] Figure 9 shows an exploded perspective view of a second embodiment of the reaction chamber according to the present invention (which differs slightly from the first embodiment). [Figure 10] Figure 10 shows a schematic partial cross-sectional side view of the embodiment shown in Figure 9, combined with a tank. [Modes for carrying out the invention]

[0012] As can be easily understood, there are various ways to actually carry out the present invention, and the present invention is defined in its main advantageous embodiment in the appended claims and is not limited by the following detailed description or by the appended drawings which refer to two slightly different embodiments.

[0013] It is noted that the technical features described below with respect to specific embodiments are strictly linked and therefore should not be considered to be interconnected.

[0014] Referring to FIGS. 1 to 8, the reaction chamber 100 for an epitaxial reactor according to the present invention comprises, for example as shown in FIG. 1C, a chamber 80 and a coating system 90 combined with each other. FIG. 1A shows only the chamber 80, and FIG. 1B shows only the coating system 90. The chamber 80 is provided with a box-shaped cavity 101.

[0015] The dimensions of the figures from FIG. 3 to FIG. 8 will be clarified later.

[0016] The cavity 101 is surrounded by at least four walls of the chamber 80, namely, a lower wall 105, a first side wall 106 (left side), an upper wall 107, and a second side wall 108 (right side). According to this embodiment, since the reaction gas enters the exhaust gas outlet at the front and exits at the back of the chamber 80, it has no front or back surface. These are, in particular, substantially four flat slabs, made of, for example, transparent quartz, joined to each other at their longitudinal edges, and the structure of the chamber may be more complex as can be seen below, for example, having flanges on the front and / or rear and / or reinforcing ribs and / or small outer partitions.

[0017] In the cavity 101, the reaction and deposition process of the semiconductor material on the substrate takes place. More precisely, according to the present invention, such a process occurs only in the "internal space" of the cavity.

[0018] The reaction chamber 100 comprises a "coating system" 90 disposed entirely within the cavity 101. The "coating system" of the chamber walls does not contact them (except for a small, low lower support element) but serves to define the "internal space".

[0019] The coating system 90 comprises at least a lower coating element 120 placed directly or indirectly on the lower wall 105 of the cavity 101, an upper coating element 130 placed directly or indirectly on the lower coating element 120, and has.

[0020] The lower covering element 120 and the upper covering element 130 define an "inner space" 102 included in the cavity 101 and an "outer space" 103 included in the cavity 101, and form at least four walls 127, 136, 137, 138 surrounding the inner space 102.

[0021] These four walls 127, 136, 137, 138 of the inner space 102 are separated from the corresponding four walls 105, 106, 107, 108 of the cavity 101 by a free space, and depending on the position and embodiment, a gas, particularly a process gas or an inert gas, can be present, and thus, they can be considered as opposing walls, and the considerations regarding the front and rear parts made above for the cavity walls are also applicable to the walls of the inner space. In addition to the empty space, there can be possible support elements of the coating system (see, for example, elements 112 and 122 in FIG. 1) that contribute to achieving the distance.

[0022] The inner space 102 is adapted to accommodate at least one or more substrates that receive the deposition of a semiconductor material, and the substrates are (directly or indirectly) placed on a susceptor 150, particularly on a susceptor disk 152 (see, for example, FIG. 2), and typically, the susceptor is always adapted to remain within the reaction chamber, that is, during the reaction process and the deposition process, as well as both before and after such processes.

[0023] The coating system according to the present invention may be configured to accommodate at least the disk of the substrate support susceptor. Such a disk is made of graphite and is adapted to be heated by induction. The disk heating system is not shown in the figure, and this advantageously consists of at least one flat inductor arranged close to the disk outside the chamber (for example, under the lower wall). Referring to FIG. 10, for example, the inductor can be within a cavity 301 that is appropriately electrically insulated from water. Advantageously, the heating system of the reaction chamber according to the present invention is induction type, but the use of a lamp (for example, above the upper wall) is not excluded.

[0024] The internal space 102 is isolated from the external space 103 by constant and uniform contact between element 120 and element 130.

[0025] From the set of Figures 1C and 2, it can be seen that the upper surface of the susceptor disk 152 is aligned with the upper surface of the wall 127 made by element 120, and in particular, these surfaces are also aligned with the upper surface of any substrate W supported by the susceptor disk 152 within a particular recess.

[0026] Advantageously, the cavity walls are made entirely of quartz, and the coating system is made entirely of quartz, and the quartz may be of different types depending on the location. Therefore, the cavity walls and coating system do not actively contribute to the heating of the cavity, in particular its "internal space" and the substrate; in other words, the reaction chamber according to the present invention is not of the high-temperature wall type. In the embodiments shown in the figures (particularly the embodiments in Figures 2 to 10), the only element that actively contributes to the heating of the cavity, in particular its "internal space" and the substrate is the susceptor, in particular its rotating disk.

[0027] Typically and preferably, the covering system 90 is placed directly on the lower wall 105 of the cavity 101 and further comprises a base covering element 110 that functions as a further (indirect) closing element of the internal space 102, in which case the lower covering element 120 is placed directly or indirectly on the base covering element 110.

[0028] The covering element 130 may be schematically represented as an inverted "U" shaped slab (see, for example, Figure 1B). The covering element 120 may be schematically represented as an inverted "U" shaped slab (see, for example, Figure 1B). The covering element 110 may be schematically represented as a flat slab (see, for example, Figure 1B), except for the "feet" described below.

[0029] Typically and preferably, the base covering element 110 rests directly on the lower wall 105 of the cavity 101 via only the support element 112. In Figure 8, eight support elements, known as "feet," are shown as an example, four for the first part and four for the second part, but their number may differ, i.e., it may be fewer, for example, ranging from a minimum of 3 to a maximum of 30. The support elements are typically small, for example, each being 3 mm 2 ~300mm 2 It may have a support area. The support elements are typically low, and may be, for example, 0.5 mm to 5.0 mm in height.

[0030] The base covering element 110 is essentially in the form of a flat rectangular slab 117.

[0031] The base covering element 110 is made of transparent quartz.

[0032] The base covering element 110 consists of two mechanically coupled parts (substantially equal to each other), with the first part of the two parts located upstream and the second part located downstream, taking into account the flow direction of the reaction gas. This can be seen particularly in Figure 9.

[0033] The base covering element 110 has a (small) central hole 114 that fits into the passage of the rotating shaft 154 of the substrate support susceptor 150, with the diameter of the hole and the diameter of the shaft being slightly different (e.g., 2-20 mm). In particular, the two parts of the slab each define half of the hole by their mechanically joined edges.

[0034] The upper covering element 130 is in the form of a flat rectangular slab 137, preferably having two shoulders 132 on two opposing longitudinal edges of the flat slab. The element 130 can be said to be in the form of an inverted "U" shaped slab. The two shoulders 132 form two side walls 136 and 138 of the interior space 102, and the slab 137 forms the upper wall of the interior space 102.

[0035] The upper covering element 130 is made of transparent quartz.

[0036] The upper covering element 130 consists of a single component.

[0037] The lower covering element 120 is preferably in the form of a rectangular flat slab 127 having shoulders corresponding to at least some edges of the flat slab, for example, longitudinal shoulders 122 and / or transverse shoulders 123, in particular having shoulders 122 on two opposing longitudinal edges of the flat slab (see, for example, Figures 1B and 1C). The element 120 can also be said to have the shape of an inverted "U" shaped slab. The slab 127 forms the lower wall of the interior space 102.

[0038] The lower covering element 120 is made from opaque quartz.

[0039] The lower covering element 120 consists of two mechanically coupled parts (substantially equal to each other), with the first part of the two parts located upstream and the second part located downstream, taking into account the flow direction of the reaction gas. This can be seen particularly in Figure 9.

[0040] As shown in Figure 1C, the shoulder portion 132 of element 130 is placed directly on the shoulder portion 122 of element 120, particularly the outer region, and the slab 127 is placed on the inner region of the shoulder portion 122.

[0041] The lower covering element 120, in particular the flat slab 127, has a (large) central hole 124 fitted to receive the disk 152 of the substrate support susceptor 150, the diameter of which the hole and the diameter of which the disk differ slightly (e.g., 2 to 20 mm), and the associated gap is traversed by a small flow of reaction gas exiting space 102 and entering the space between wall 127 and wall 117. This can be seen in particular in Figures 4 and 5.

[0042] The bottom covering element 120 has a width that is slightly larger than the diameter of the central hole 124 (for example, 2 to 20 mm).

[0043] The lower covering element 120 has longitudinal shoulders 122 on two opposing longitudinal edges of the flat slab and / or transverse shoulders 123 on the central hole 124 (see, for example, Figures 6 and 7). Since the shoulders 123 are not joined to the shoulders 122 (there is a gap between them), there is no dead space for gas circulation, which facilitates the manufacture of the element 120, especially the welding of its components.

[0044] The lower wall 105 of the chamber 80 has a (small) hole 109 fitted for the rotation shaft 154 of the substrate support susceptor 150 to pass through, with the diameter of the hole and the diameter of the shaft being slightly different (e.g., 2 to 20 mm).

[0045] For example, it is advantageous to inject a hydrogen gas stream into the reaction chamber from the rotating shaft 154 of the susceptor 150 to place the areas of holes 109 and 114 under a slight overpressure, thereby preventing the reaction gas from leaking out of the cavity 101, particularly from spaces 102 and 103, and from the space between walls 127 and 117.

[0046] From Figures 5, 6, and 7, it can be seen that, according to this embodiment, the shoulder portion 122 of the element 120 is slightly thinner in its intermediate region, particularly in the cross-section passing through the center of the hole 124. In this example, the point of maximum thinning is where the upstream and downstream portions meet. By comparing Figure 1C and Figure 2, the differences in the cross-section of the shoulder portion 122 can also be seen.

[0047] From the diagram of this first embodiment, it is clear that the space 102 is very well insulated, except for a small gap (e.g., 2-20 mm) between the shaft 154 and the periphery of the hole 114 in the wall 117.

[0048] According to the first embodiment, the elements of the reaction chamber may have the following dimensions, for illustrative and non-limiting purposes: Lengths of elements 106 and 108 in Figure 1A (i.e., height of room 80): 75 mm, Lengths of elements 105 and 107 in Figure 1A (i.e., width of chamber 80): 800 mm, Thickness of elements 105-108 in Figure 1A: 8 mm, Length of element 132 in Figure 1B: 50 mm, Length of element 137 in Figure 1B: 780 mm, Thickness of elements 132 and 137 in Figure 1B: 3 mm, Length of element 122 in Figure 1B: 20 ​​mm, Length of element 127 in Figure 1B: 780 mm, Thickness of element 122 in Figure 1B: 40 mm, Thickness of element 127 in Figure 1B: 3 mm, Length of element 117 in Figure 1B: 780 mm, Thickness of element 117 in Figure 1B: 3 mm. Lengths of elements 106 and 108 in Figure 4 (i.e., length of chamber 80): 1100 mm, Diameter of element 152: 720mm, Hole diameter 124:740mm.

[0049] Referring to Figures 3 to 8, it should be clearly stated that the first height (i.e., the height in Figure 3) corresponds to a plane slightly higher than the top surface of wall 137, the second height (i.e., the height in Figure 4) corresponds to an intermediate plane between wall 137 and wall 127, the third height (i.e., the height in Figure 5) corresponds to a plane passing through wall 127, the fourth height (i.e., the height in Figure 6) corresponds to a plane slightly lower than the bottom surface of wall 127, the fifth height (i.e., the height in Figure 7) corresponds to a plane slightly higher than the top surface of wall 117, and the sixth height (i.e., the height in Figure 8) corresponds to a plane passing through wall 117. Note that in these figures, section hatching has been omitted for visual clarity.

[0050] Figures 9 and 10 show a second embodiment 200 of the reaction chamber according to the present invention.

[0051] This second embodiment differs from the first embodiment only in the chamber; in fact, chamber 280 is somewhat different from chamber 80.

[0052] Chamber 280 includes a box-shaped element 281 made of quartz that precisely corresponds to the quartz in chamber 80.

[0053] The box-shaped element 281 may be identical (or similar) to the system 90 of the first embodiment, and includes a box-shaped cavity in which the covering system is housed, with components 110, 120, and 130 of the covering system being shown with the same reference numbers as the components of system 90 in Figure 9.

[0054] Chamber 280 has two flanges 282 and 283 at the longitudinal ends of element 281. The two flanges each have an opening for reaction gases entering the chamber cavity and exhaust gases exiting the chamber cavity.

[0055] In this second embodiment, the elements of the covering system extend at least partially into the flange openings, but do not protrude from these openings.

[0056] Chamber 280 has two partitions 286 and 287 on its upper outer surface, the function of which is described below. These extend laterally with respect to the longitudinal direction of chamber 280 and have a curved shape, which substantially reflects the shape of the susceptor disk in the internal space defined by the covering system.

[0057] Chamber 280 has a transparent window (e.g., 10-20 mm wide) on its upper wall that is adapted for measuring the temperature of the susceptor or substrate.

[0058] Figure 10 shows a tank 300 with a cavity 301 adapted so that the chamber 280 is filled with water (preferably desalted) during the operation of the reactor or equivalent liquid.

[0059] Chamber 280 is mounted to tank 300 such that the inner surface of the chamber faces the cavity 301 of tank 300, and in particular, flanges 282 and 283 are on the outside of tank 300 and substantially adjacent to the vertical wall of tank 300.

[0060] As schematically shown in Figure 10, during use, the water level in the cavity 301 is such that it slightly touches the lower surface of the chamber 280, and a small amount, for example 1-10 mm, is above it for cooling. Typically, such water is circulated and cooled.

[0061] On the lower surface of chamber 280, cooling is achieved partly by a gas flow (typically an air flow) and partly by a liquid flow (typically preferably a flow of demineralized water).

[0062] The liquid flow occurs between two partitions 286 and 287 and eventually reaches the cavity 301 of tank 300, which cascades downward from the edge of the upper wall of chamber 280, as schematically shown by the arrow in Figure 10. The gas flow occurs elsewhere.

[0063] Although not shown in Figure 10, an inductor (properly electrically insulated) is placed within the cavity 301 to heat at least one susceptor disk located within the internal space defined by the covering system by electromagnetic induction; see, for example, Patent Document WO2018083582.

[0064] From the above, it is understood that the reaction chamber according to the present invention can be applied in particular to an epitaxial reactor for growing silicon on a silicon substrate.

[0065] One or more technical features of the present invention can be advantageously combined with one or more technical features of prior inventions of the same applicant, for example, those described and shown in international patent applications WO2016001863, WO2017137872, WO2017163168, WO2018065852 and WO2018083582, which are incorporated herein by reference.

[0066] In a further aspect, the present invention more precisely relates to an inner coating element for a reaction chamber, i.e., referring to the coating system 90 shown in Figure 1, for example, the components constituting the coating system, the coating elements are referred to as 110, 120, and 130. Advantageously, each of these elements may be made entirely of quartz. Advantageously, each of these elements may have its own configuration (in Figure 1, there are three different configurations and three different sizes) which is particularly adapted to form a coating system when these components are assembled and fitted together.

Claims

1. A reaction chamber (100) for an epitaxial reactor, The chamber (100) comprises a cavity (101) in which reaction and deposition processes of semiconductor material on a substrate occur, The cavity (101) is provided with a covering system (90) located within it. The cavity (101) is surrounded by four walls (105, 106, 107, 108), The aforementioned covering system (90) is The lower covering element (120) rests on the lower wall (105) of the cavity (101), The upper covering element (130) is placed on the lower covering element (120), The lower covering element (120) and the upper covering element (130) define the internal space (102) and the external space (103) contained within the cavity (101), and form four walls (127, 136, 137, 138) surrounding the internal space (102). The walls (127, 136, 137, 138) of the internal space (102) are separated from the walls (105, 106, 107, 108) of the cavity (101) by the empty space. The internal space (102) is adapted to accommodate at least one substrate that will receive a semiconductor material deposition. The internal space (102) is isolated from the external space (103). Reaction chamber (100).

2. The walls (105, 106, 107, 108) of the chamber (100) are entirely made of quartz, and The coating system (90) is entirely made of quartz. The reaction chamber (100) according to claim 1.

3. The coating system (90) is at least one rotating part of the substrate support susceptor (150) The reaction chamber (100) according to claim 2, configured to accommodate a sk (152), wherein the rotating disk (152) is made of graphite and adapted to be heated by induction.

4. The reaction chamber (100) according to claim 1, wherein the coating system (90) further comprises a base coating element (110) that is placed directly on the lower wall (105) of the cavity (101), and the lower coating element (120) is placed on the base coating element (110).

5. The reaction chamber (100) according to claim 4, wherein the base covering element (110) is placed directly on the lower wall (105) of the cavity (101) by only the feet (112).

6. The reaction chamber (100) according to claim 4, wherein the base covering element (110) is in the form of a flat rectangular slab (117).

7. The reaction chamber (100) according to claim 4, wherein the base covering element (110) is made of transparent quartz.

8. The base covering element (110) consists of two parts that are mechanically connected to each other. Of the two components, the first component is located upstream, and the second component is located downstream with respect to the reaction gas flow direction. The reaction chamber (100) according to claim 4.

9. The base covering element (110) has a central hole (114) that fits into the passage of the rotating shaft (154) of the substrate support susceptor (150). The reaction chamber (100) according to claim 4.

10. The upper covering element (130) is in the form of a flat rectangular slab having two shoulder portions (132) on two opposing edges of the flat slab. The reaction chamber (100) according to claim 1.

11. The reaction chamber (100) according to claim 10, wherein the upper covering element (130) is made of transparent quartz.

12. The reaction chamber (100) according to claim 10, wherein the upper covering element (130) is made of a single component.

13. The lower covering element (120) is in the form of a flat rectangular slab having shoulders (122, 123) corresponding to at least some edges of the flat slab. The reaction chamber (100) according to claim 1.

14. The reaction chamber (100) according to claim 13, wherein the lower covering element (120) is made of opaque quartz.

15. The lower covering element (120) consists of two parts that are mechanically connected to each other. Of the two components, the first component is located upstream, and the second component is located downstream, taking into consideration the flow direction of the reaction gas. The reaction chamber (100) according to claim 13.

16. The lower covering element (120) has a central hole (124) configured to receive the disk (152) of the substrate support susceptor (150), as described in claim 13. Ba (100).

17. The lower covering element (120) has at least one shoulder portion (122) on two opposing edges of the flat slab, or a shoulder portion (123) on the central hole (124). The reaction chamber (100) according to claim 16.

18. An inner covering element (110, 120, 130) for a reaction chamber of an epitaxial reactor, configured to be a component of a reaction chamber covering system (90) according to any one of claims 1 to 17.

19. The inner covering element (110, 120, 130) according to claim 18, wherein the entire element is made of quartz.

20. An epitaxial reactor comprising at least one reaction chamber as described in any one of claims 1 to 17.

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