Injector configured to be positioned within a reaction chamber of a substrate processing device

Abstract

To provide an injector configured for arrangement within a reaction chamber of a substrate processing apparatus to inject gas into the reaction chamber.SOLUTION: An injector may be elongated along a first axis and configured with an internal gas conduction channel extending along the first axis and provided with at least one gas entrance opening and at least one gas exit opening. The injector may have a width extending along a second axis perpendicular to the first axis substantially larger than a depth of the injector extending along a third axis perpendicular to the first and second axes. The wall of the injector may have a varying thickness.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an injector configured to be disposed within a reaction chamber of a substrate processing apparatus for injecting gas into the reaction chamber. The injector may be substantially elongated along a first axis and may be configured with an internal gas conduction channel extending along the first axis and having at least one gas inlet opening and at least one gas outlet opening. The injector has a width extending along a second axis perpendicular to the first axis, and the width may be substantially greater than a depth of the injector extending along a third axis perpendicular to the first and second axes. [Background technology]

[0002] A substrate processing apparatus, such as a vertical furnace, for processing substrates, e.g., semiconductor wafers, may include heating elements positioned around a bell-jar-shaped process tube, the upper end of which may be closed, e.g., by a dome-shaped structure, and the lower end of the process tube may be open.

[0003] The lower end may be partially closed by a flange. The interior bounded by the tube and the flange forms a reaction chamber in which the wafers to be handled may be processed. The flange may be provided with an entrance opening for inserting a wafer boat carrying the wafers into the reaction chamber. The wafer boat may be placed on a door that is vertically movably disposed and configured to close off the entrance opening in the flange.

[0004] The flange may support one or more injectors to provide gas to the reaction chamber. For this purpose, the injectors may be configured with internal gas conduction channels. In addition, a gas exhaust duct may be provided within the flange. This gas exhaust may be connected to a vacuum pump for pumping gas out of the reaction chamber. The gas provided by the injectors into the reaction chamber may be a reactive (process) gas for a deposition reaction on the wafer. This reactive gas may also deposit on other surfaces besides the wafer, for example, within the internal gas conduction channels. Layers created by these deposits may cause clogging and / or damage to the injectors. Summary of the Invention

[0005] Therefore, improved injectors may be needed.

[0006] In one embodiment, there may be provided an injector configured to be disposed within a reaction chamber of a substrate processing apparatus to inject gas into the reaction chamber, the injector being substantially elongated along a first axis and configured with an internal gas conduction channel extending along the first axis and provided with at least one gas inlet opening and at least one gas outlet opening, and the injector may have a width extending along a second axis perpendicular to the first axis, the width being substantially greater than a depth of the injector extending along a third axis perpendicular to the first and second axes, and a wall of the injector having a varying thickness.

[0007] The various embodiments of the present invention may be applied separately from one another or may be combined. Embodiments of the present invention will be further elucidated in the detailed description with reference to some examples shown in the drawings.

[0008] It will be appreciated that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of the illustrated embodiments of the present disclosure. [Brief explanation of the drawings]

[0009] [Figure 1] 1 shows a cross-sectional view of a vertical furnace tube including an injector. [Figure 2] 2 shows a schematic top view of the tube of FIG. 1. [Figure 3] 3 shows a cross section of an injector according to one embodiment for use in the vertical furnace of FIGS. 1 and 2. FIG. [Figure 4a] 2 shows a schematic diagram of an injector according to another embodiment for use in the vertical furnace of FIG. 1; [Figure 4b] 2 shows a schematic diagram of an injector according to another embodiment for use in the vertical furnace of FIG. 1; [Figure 4c] 2 shows a schematic diagram of an injector according to another embodiment for use in the vertical furnace of FIG. 1; [Figure 4d] 2 shows a schematic diagram of an injector according to another embodiment for use in the vertical furnace of FIG. 1; [Figure 4e] 2 shows a schematic diagram of an injector according to another embodiment for use in the vertical furnace of FIG. 1; [Figure 5] 4a-4e shown in a tube; DETAILED DESCRIPTION OF THE INVENTION

[0010] In this application, like or corresponding features are indicated by like or corresponding reference numerals. The description of various embodiments is not limited to the examples shown in the figures, and reference numerals used in the detailed description and claims are not intended to limit what is described to the examples shown in the figures.

[0011] 1 shows a cross-sectional view of a vertical furnace. The vertical furnace may include a process tube 12 that forms a reaction chamber and a heater H configured to heat the reaction chamber. A liner 2 may be provided along the process tube 12, and the liner 2 may include a substantially cylindrical wall bounded by a liner opening at its lower end and a dome-shaped upper closure 2d at its upper end.

[0012] A flange 3 may be provided to at least partially close an opening of the process tube 12. A vertically movably disposed door 14 may be configured to close off a central entrance opening O in the flange 3 and may be configured to support a wafer boat B configured to hold substrates W. The door 14 may be provided with a pedestal R, which may be rotated to rotate the wafer boat B within the reaction chamber.

[0013] In the embodiment shown in Figure 1, the liner 2 may comprise a substantially cylindrical liner wall having an outer substantially cylindrical surface 2a and an inner substantially cylindrical surface 2b. The flange 3 may be configured to at least partially close the tube opening and a liner opening more precisely defined by the lower end surface 2c of the liner 2. The flange 3 may be an inlet opening O configured for inserting and removing a boat B configured to transport a substrate W into the reaction chamber I of the liner 2; a gas inlet 16 for providing a gas F, e.g., a process gas, to the reaction chamber I; and a gas exhaust duct 7 for removing gases from the reaction chamber I.

[0014] The substrate processing apparatus may have a vessel for containing the silicon precursor and may be operatively connected to an elongated injector 17 via a gas inlet 16. The injector 17 may be constructed and arranged to extend vertically along the substantially cylindrical wall of the liner 2 toward a higher second end and into the reaction chamber I. The injector may be supported by a flange 3 at a first lower end thereof and may include an injector opening for injecting gas into the reaction chamber I. One or more injectors 17 may be used to provide process gas to the reaction chamber I. One injector 17 is shown in FIG. 2.

[0015] A gas exhaust duct 7 for removing gases from the reaction chamber I may be constructed and positioned below the injector opening 18. In this manner, a downward flow F may be created within the reaction chamber of the liner 2. This downward flow F may carry reaction by-products and particulate contaminants from the substrate W, boat B, liner 2, and / or support flange 3 downward into the exhaust duct 7 and away from the processed substrate W.

[0016] A gas exhaust duct 7 may be provided below the liner opening in the liner 2 to remove gases from the reaction chamber I. This may be beneficial as a source of contamination in the reaction chamber may be formed by contact between the liner 2 and the flange 3. Again, the downward flow F may carry particles from the liner-flange interface downward to the exhaust, away from the treated substrate.

[0017] Gas exhaust openings 8 may be constructed and arranged between the liner 2 and the flange 3 to remove gas from the circumferential space between the liner 2 and the tube 12. In this way, the pressure in the circumferential space may be equalized to the pressure in the internal space I and may be lower than the ambient atmospheric pressure surrounding the tube 12 in a low-pressure vertical furnace. The vertical furnace may be provided with a pressure control system to remove gas from the reaction chamber.

[0018] In this way, the liner 2 can be made of a somewhat thinner and relatively weaker material, since it does not need to compensate for atmospheric pressure. This creates greater freedom in choosing the material for the liner 2. The thermal expansion of the material for the liner 2 can be chosen to match that of the material deposited on the substrate in the reaction chamber. The latter has the advantage that the expansion of the liner and the expansion of the material also deposited on the liner can be the same. This minimizes the risk of the deposited material falling off as a result of temperature changes in the liner 2.

[0019] The tube 12 may be made of a material that is somewhat thick and has a relatively high compressive strength, since atmospheric pressure may need to be compensated for the low pressure inside the tube. For example, the low-pressure process tube 12 may be made of quartz that is 5-8 mm thick, preferably approximately 6 mm thick. Quartz has a tensile strength of 0.59×10 -6 K -1 The deposited material has a very low coefficient of thermal expansion (CTE) of 0.05% (see Table 1), which makes it easier to accommodate thermal variations in the device. The CTE of the deposited material is higher (e.g., CTE of Si3N4 = 3 × 10 -6 K -1 , CTE of Si = 2.3 × 10 -6 K -1 ), but the difference may be relatively small. When a film builds up on a quartz tube, it may adhere even when the tube undergoes many large thermal cycles, but the risk of contamination may be increased.

[0020] The liner 2 may avoid any deposition on the inside of the tube 2 and may therefore reduce the risk of deposition on the tube 12 falling off. The tube may therefore be made from quartz.

[0021] Silicon carbide liner 2 (SiC CTE = 4 × 10 -6 K -1) may provide an even better match in CTE between the deposited film and the liner, resulting in a greater cumulative thickness before removal of the deposited film from the liner may be required. The CTE mismatch leads to cracking and flaking of the deposited film and a correspondingly high particle count. This is undesirable and may be mitigated by using a SiC liner 2. The same mechanism may also operate for the injector 17. However, in the case of the injector 17, deposition of too much material with a different thermal expansion may cause the injector to fail. Therefore, it may be advantageous to fabricate the injector 17 from silicon carbide or silicon.

[0022] [Table 1]

[0023] Whether a material is suitable for the liner 2 and / or the injector 17 may depend on the material being deposited. Therefore, it may be advantageous to use a material for the liner 2 and / or the injector 17 that has substantially the same thermal expansion as the deposited material. Therefore, it may be advantageous to use a material for the liner 2 and / or the injector 17 that has a relatively higher thermal expansion than quartz. For example, silicon carbide (SIC) may be used. The silicon carbide liner may be 4-6 mm thick, preferably 5 mm thick, since it does not need to be compensated for atmospheric pressure. Pressure compensation may be provided by the tube.

[0024] Approximately 4×10 -6 K -1 ~6×10 -6 K -1 For systems depositing metal and metal compound materials (such as TaN, HfO2, and TaO5) with a CTE of about 4×10, the liner and injector materials preferably have a CTE of about 4×10. -6 K -1 ~9×10 -6 K -1and may have a CTE of, for example, silicon carbide.

[0025] For deposition of materials with even higher CTEs, liner and / or injector materials may be selected, for example, as shown in Table 2.

[0026] [Table 2]

[0027] A purge gas inlet 19 may be provided within tube 12 to provide purge gas P to the circumferential space S between the outer surface of liner 2b and process tube 12. The purge gas inlet comprises a purge gas injector 20 that extends vertically along the outer surface of the cylindrical wall of liner 2 from flange 3 toward the top end of the liner. The purge gas P into circumferential space S may create a flow within gas exhaust openings 8 that may counteract diffusion of process gas from exhaust tube 7 into circumferential space S, as shown by the arrows.

[0028] The flange 3 may have an upper surface. The liner 2 may be supported by support members 4 connected to the outer cylindrical surface of the liner wall 2 a and each may have a downwardly oriented support surface. The liner may also be supported directly on the upper surface of the flange 3 at the liner's lower surface 2 c, while allowing for gas vent openings 8 between the upper surface and the liner 2.

[0029] The support surfaces of the support members 4 may be positioned radially outward from the inner cylindrical surface 2b of the liner 2. In this embodiment, the support surfaces of the support members 4 may also be positioned radially outward from the outer cylindrical surface 2a of the liner 2 to which they are attached. The downwardly oriented support surfaces of the support members 4 may contact the upper surface of the flange 3 and support the liner 2, while allowing for gas vent openings 8 between the upper surface and the liner 2.

[0030] The support flange 3 of the closure may include gas exhaust openings 8 for removing gases from the reaction chamber of the liner 2 and from the annular space between the liner 2 and the low-pressure tube 12. At least some of the gas exhaust openings 8 may be located between the top surface of the flange 3 and the liner 2. At least some of the gas exhaust openings 8 may be located near the liner openings. The gas exhaust openings 8 may be fluidly connected to a pump via an exhaust duct 7 for drawing gases from the reaction chamber and from the annular space between the process tube 12 and the liner 2.

[0031] Figure 2 is a schematic top view of the tube of Figure 1. The figure shows a liner 2 having a cylindrical wall defining an inner substantially cylindrical surface 2b and an outer substantially cylindrical surface 2a, which form an opening 13 for inserting a boat configured to carry a substrate.

[0032] In this embodiment, the liner 2 has three support members 4 evenly spaced around the circumference of the outer cylindrical surface 2a of the liner 2. The flange may be provided with locating projections 5 extending upward from the upper surface 3a of the flange. The locating projections 5 may engage the support members 4 on their tangential end faces. As a result, the locating projections 5 provide a centering function for the liner 2 relative to the support flange 3.

[0033] The liner 2 and notch that form the support member 4 may be fabricated from quartz, silicon, or silicon carbide. The liner 2 that bounds the reaction chamber may have a bulge 2e extending radially outward to accommodate an injector 17 or a temperature measurement system within the reaction chamber.

[0034] 3 shows a schematic cross-section of an injector 17 according to one embodiment for use in the vertical furnace of FIGS. 1 and 2. The injector 17 may be configured for placement within a reactor of the vertical furnace to inject gas into the reaction chamber I. The injector 17 may be configured with an internal gas conduction channel 20 for conveying the gas. The injector 17 may be substantially elongated along a first axis, and the internal gas conduction channel 20 may extend along the first axis.

[0035] The injector 17 may have a width extending along a second axis X perpendicular to the first axis that is substantially greater than a depth of the injector extending along a third axis Y perpendicular to the first and second axes. The wall 22 of the injector 17 may have a varying thickness. The wall 22 of the injector 17 may have a varying thickness along the second axis X. The varying thickness of the wall 22 may vary between 10 and 60%. For example, 40% is 2.5 to 3.5 mm, as shown.

[0036] The internal gas conduction channel 20 of the injector 17 may have a substantially elliptical cross section. The internal gas conduction channel 20 may extend along a width in a second axis X substantially greater than it extends along a depth in a third axis Y. The substantially elliptical cross section may be constructed from multiple circles with fixed radii to accommodate drilling and milling. Rounded corners also avoid stress and contamination accumulation at the corners. The radius of the circles may be 1 to 10 mm, for example, a circle having a radius of 5 mm. The horizontal internal cross-sectional area of ​​the internal gas conduction channel 20 inside the injector 17 may be 100 to 1500 mm. 2 It may be 200 to 500 mm 2 It is preferable that the thickness is 250 to 350 mm. 2 It is most preferable that:

[0037] The substantially elliptical gas conduction channel 20 may be partially pinched off in the middle. Pinched off here means that the internal gas conduction channel 20 has a smaller depth in the third direction. The middle refers to the middle relative to the width of the injector 17 in the second direction X. The pinch may be achieved by a wall 22 having a varying thickness. For example, the gas conduction channel 20 is pinched off by a wall 22 having an increased thickness in the middle of its width.

[0038] The substantially elliptical gas conduction channel 20 may be partially sandwiched in the second direction by a bulbous portion 24 that thickens the wall 22 and extends into the gas conduction channel 20, constricting the gas conduction channel 20. The surface of the bulbous portion 24 may partially follow the circle of the bulbous portion. The circle of the bulbous portion may have a constant radius relative to an axis parallel to the first axis. The radius may be between 10 and 50 mm, preferably between 15 and 30 mm, and may be 23 mm as shown.

[0039] The wall 22 of the injector 17 may have a thickness that varies along the third axis Y. The thickness that varies along the third axis Y may be a relatively small variation of around 7 mm.

[0040] The wall 22 of the injector 17 may have a varying thickness around its circumference along the second axis X and the third axis Y. The varying thickness of the wall 22 may vary between 4 and 60%.

[0041] The wall 22 of the injector 17 may have a thickness that varies along the majority of the first axis, in this manner adding strength where needed.

[0042] The gas outlet opening 25 may have a radius of 3 to 15 mm, preferably 4 to 10 mm, and most preferably 5 to 9 mm (eg 8 mm).

[0043] 4a-4e schematically illustrate injectors 17a, 17b, and 17c according to another embodiment for use in the vertical furnace of FIGS. 1 and 5. Each of the injectors 17a, 17b, and 17c of FIGS. 4a-4e may be specifically configured to provide process gas at a particular height within the reaction chamber I. Accordingly, the injectors 17a, 17b, and 17c of FIGS. 4a-4e may be optimized to work together, as shown in FIG. 5. Alternatively, each injector 17 may be used alone, as shown in FIG. 2. The injectors 17a, 17b, and 17c may be substantially elongated along the first axis Z.

[0044] The injectors 17a, 17b, 17c may be configured with internal gas conduction channels 20 for transporting process gases. The internal gas conduction channels 20 may extend along the first axis Z. The internal gas conduction channels 20 of the injectors 17a, 17b, 17c may have a substantially elliptical cross-section.

[0045] The internal gas conduction channel 20 may extend along the second axis X by 10 to 50 mm, preferably by 20 to 30 mm (e.g., about 25 mm). The internal gas conduction channel 20 may extend substantially further along the second axis X than it extends along the third axis Y. The internal gas conduction channel 20 may extend along the third axis Y by 8 to 30 mm, preferably by 10 to 20 mm (e.g., about 12 mm).

[0046] The substantially elliptical cross section may be constructed from a circle having a radius of 1-10 mm, for example a circle having a radius of 5 mm, which avoids straight corners in the gas conducting channel 20, since the corners will have a minimum rounding of 1-10 mm (for example 5 mm).

[0047] The horizontal inner cross-sectional area of ​​the internal gas conduction channel 20 inside the injector 17 is 100 to 1500 mm 2 It may be 200 to 500 mm 2 It is preferable that the thickness is 250 to 350 mm. 2It is most preferable that:

[0048] The substantially elliptical shaped gas conduction channel 20 may be partially pinched off in the middle, where pinched off means that the internal gas conduction channel 20 is smaller in the third direction Y. The middle refers to the middle relative to the width of the injectors 17a, 17b, 17c in the second direction X. The pinch may be achieved by a wall 22 having an increased thickness in the middle.

[0049] The substantially elliptical gas conduction channel 20 may be partially constricted in the second direction by a bulbous portion 24 provided in the wall 22 and extending into the gas conduction channel 20. The surface of the bulbous portion 24 may partially trace a circle. The circle may have a constant radius relative to an axis parallel to the first axis. The radius may be between 10 and 50 mm, preferably between 15 and 30 mm, and may be 23 mm as shown.

[0050] The injectors 17a, 17b, 17c may have a width extending along a second axis X perpendicular to the first axis that is substantially greater than a depth of the injector extending along a third axis Y perpendicular to the first and second axes, as shown in Figure 4c. The walls 22 of the injectors 17a, 17b, 17c may have a varying thickness.

[0051] The walls 22 of the injectors 17a, 17b, 17c may have a thickness that varies along the third axis Y. The walls 22 of the injectors 17a, 17b, 17c may have a thickness that varies along the second axis X and the third axis Y over their circumference. The walls 22 of the injectors 17a, 17b, 17c may have a thickness that varies along a majority of the first axis X.

[0052] Injectors 17a, 17b may be referred to as multi-hole injectors and have multiple gas exit holes 25 along their length at first end 21 and opposing second end 23, as shown in Figures 4a and 4b. Gas exit openings 25 may have a radius of 3 to 15 mm, preferably 4 to 10 mm, and most preferably 5 to 9 mm (e.g., 6 mm). The longer injector 17a of the multiple injectors 17a, 17b, and 17c may have multiple gas exit holes 25 as shown in Figure 4a and may extend internally, near the upper closure portion 2d of the closure liner 2 (Figures 1 and 5). The shorter injector 17b of the multiple injectors 17a, 17b, and 17c may have multiple gas exit holes 25 as shown in Figure 4b and may extend to the middle of the boat B.

[0053] The size of the gas conduction channel 20 may be smaller at the first end 21 where the injectors 17a, 17b, 17c may connect to the gas inlet 16 near the flange 3. Because the temperature is lower near the first end 21, the process gas accumulates less near the first end 21 in the internal channel 20.

[0054] The depth of the injectors 17a, 17b, 17c in the third direction Y may decrease towards the second end 23. In the interior I, the injectors extending close to the upper closure portion 2d of the closure liner 2 may have a shape with a radial dimension that decreases closer to the upper closure portion in FIG.

[0055] 4a-4e may each be specifically configured to provide process gas at a particular height within reaction chamber I. Accordingly, at least one of injectors 17a, 17b, 17c may have a different length.

[0056] The longer injectors 17a, 17c of the plurality of injectors 17, as shown in Figures 4a and 4e, may extend within the interior 1 to near the upper closure portion 2d of the closure liner 2, as shown in Figures 1 and 5. The longer injector 17c of the plurality of injectors 17a, 17b, 17c may have a single gas outlet hole 25 at its second end 23, as shown in Figure 4d. This injector may be referred to as a dump injector 17c, which is closed along its elongated length and has only a single process gas outlet at its second end 23. Figure 4e illustrates a cross-section of this dump injector, which has the same characteristics as described in connection with Figure 4c above, except for the absence of the side gas outlet hole 25.

[0057] The single gas exit hole 25 at the second end 23 of the dump injector may have the same characteristics as described in connection with Figure 4c above. The single gas exit hole 25 of the dump injector may have a diameter of 100 to 1500 mm. 2 It may be 200 to 500 mm 2 It is preferable that the thickness is 250 to 350 mm. 2 Therefore, the injectors 17a, 17b, 17c of Figures 4a to 4e may be optimised to work together as shown in Figure 5.

[0058] FIG. 5 illustrates how the injectors 17a, 17b, and 17c of FIGS. 4a-4e can be arranged within the tube 2. The injectors 17a and 17b may be multi-hole injectors with a series of outlet openings 25 extending elongately along the injectors 17a and 17b to transport gas from the conduction channel into the reaction chamber I (see FIGS. 4a and 4b). The shorter injector 17b and / or the longer injector 17a of the multiple injectors 17a, 17b, and 17c may have multiple gas outlet holes 25. The outlet openings 25 may be substantially rounded. The series of outlet openings 25 may be aligned along a line across the surface of the multi-hole injectors 17a and 17b.

[0059] The outlet openings 25 may be configured to inject gas in at least two different directions substantially perpendicular to the elongated direction of the multi-hole injector 17 to improve mixing of the process gas within the reaction chamber 1. The series of openings 25 may therefore be aligned along at least two lines across the surface of the injector 17. A first line with openings may be shown in FIGS. 4a and 4b, and a similar second line with openings 25 may be configured on the other side of the injector 17, as shown in FIG. 5. The series of openings 25 along the first line may be configured to inject gas in a first direction, and the series of openings 25 along the second line may be configured to inject gas in a second direction. The first and second directions may be at angles of 30 to 180 degrees from each other.

[0060] The outlet openings 25 may be provided in pairs at the same height as shown in Figure 5. Alternatively, the outlet openings 25 may be provided in pairs at unequal heights to improve the strength of the injector 17. The two outlet openings may inject gas in two directions, for example under an angle of about 90 degrees, to improve radial uniformity.

[0061] The distance between openings 25 in the series of openings may be constant from the first end 21 to the second end 23 of the multi-hole injector 17 in Figures 4a and 4b. Advantageously, each outlet opening 25 may have a substantially equal flow of process gas therethrough.

[0062] The distance between the outlet openings 25 in the series of outlet openings may also be designed to decrease when moving from the first end 21 to the second end 23 of the multi-hole injector 17. The latter may be beneficial to compensate for pressure losses when the process gas is transported from the first end 21 to the second end 23.

[0063] The area of ​​the outlet opening for multi-hole injectors is 1 to 200 mm 2 It may be 7 to 100 mm 2 It is preferable that the thickness is 13 to 80 mm. 2 It is more preferable that the number of outlet openings 25 is 2 to 40, preferably 3 to 30, and more preferably 5 to 15. Larger openings may have the advantage that it takes longer for the openings to become clogged with a sediment layer within the openings.

[0064] The longer injector 17c of the multiple injectors 17a, 17b, 17c may have a single gas outlet hole at its second end, as shown in Figure 4d. This injector 17c may be referred to as a dump injector 17c, which is closed along its elongated length and has only one single process gas outlet at its second end near the top closure 2d of the liner. The single gas outlet hole at the second end of the dump injector may have the same characteristics as those described in connection with Figures 4d and 4e above.

[0065] The exit opening 25 of the gas injector 17 may be configured to reduce clogging of the opening. The exit opening may have a concave shape from the inside to the outside. A concave shape with the surface area of ​​the opening on the inside surface of the injector greater than the surface area of ​​the exit opening 25 on the outside of the injector may reduce clogging. The larger the area on the inside, the greater the pressure, and therefore the deposition, allowing for more deposition on the inside. The pressure is lower on the outside, and therefore the deposition is slower, and a smaller area may collect the same deposition as a larger diameter on the inside.

[0066] Since reaction rates typically increase with increasing pressure, reducing the pressure at the injector can result in a decrease in the reaction rate within injector 17. An additional benefit of lower pressure inside the injector is that the gas volume through the injector expands at lower pressure, and for a constant source gas flow, the residence time of the source gas inside the injector is correspondingly shorter. The combination of both may reduce source gas decomposition, which may also reduce deposition within the injector.

[0067] Process gases injected into reaction chamber I through injectors 17, which may deposit layers on wafers W in wafer boat B, may also deposit on the internal gas conduction channels or on the outer surfaces of injectors 17. This deposition may cause tensile or compressive stresses in injectors 17. This stress may cause breakage in injectors 17, which may result in downtime of the vertical furnace and / or damage to wafers W. Therefore, less deposition in injectors may extend the life of injectors 17 and make the vertical furnace more economical.

[0068] Temperature changes in the injector 17 can further increase these stresses. To mitigate stresses, the injector may be made from a material that can have the thermal expansion coefficient of the material deposited with the process gas. For example, the gas injector may be made from silicon nitride if the process gas deposits silicon nitride, or silicon if the process gas deposits silicon, or silicon oxide if the process gas deposits silicon oxide. Thus, the thermal expansion of the deposited layers in the injector may better match that of the injector, reducing the likelihood of the gas injector breaking during temperature changes.

[0069] Silicon carbide may also be a suitable material for the injector 17. Silicon carbide has a thermal expansion that may match many deposited materials.

[0070] The disadvantage of low pressure inside the injector is that the conduction of the injector is significantly reduced, which will lead to poor distribution of the source gas flow across the opening pattern over the length of the injector, with most of the source gas exiting through the holes near the inlet end of the injector.

[0071] To facilitate the flow of process gases inside the injector along its length, the injector may be provided with an internal gas conduction channel having a large internal cross section. To enable an injector according to the present invention to be accommodated inside a reaction chamber, the tangential size of the injector 17 may be larger than its radial size, and the liner 2 may be provided with an outwardly extending bulge to accommodate the injector.

[0072] In one embodiment, the two source gases that provide the two components of the two-component film are mixed in the gas supply system before entering the injectors. This is the simplest way to ensure a uniform composition of the injected gases along the length of the boat. However, this is not required. Alternatively, the two different source gases can be injected through separate injectors and mixed in the reaction chamber after injection.

[0073] The use of two injector branches allows for some adjustment. If gases of substantially the same composition are supplied to both parts of the injector via separate source gas supplies, the flows supplied to the different injector branches can be chosen differently to fine-tune the deposition rate uniformity across the boat. It is also possible to supply gases of different compositions to the two lines of the injector to fine-tune the composition of the two-component film across the boat. However, best results may be achieved when the composition of the injected gas is the same in both injector lines.

[0074] Because the injector 17 may be supported by the flange 3 at its first end 21, the injector 17 may wobble slightly at its second end 23 because it is a very long and thin structure, as shown in Figure 1. Therefore, it is desirable or necessary to design the liner 2, the injector 17, and the wafer boat B so that there is sufficient space between the three.

[0075] The outer sidewall of injector 17 may be tapered toward injector second end 23 over at least 10%, preferably 30%, more preferably 50%, and even more preferably 100% of the injector's length. By tapering injector 17 at second end 23, injector 17 may occupy less space within the tightest toleranced small space between liner 2 and the wafer boat within reaction chamber I near its second end 23. Thus, tolerances within which injector 17 with a tapered second end 23 may be positioned may be slightly relaxed.

[0076] Therefore, the injector 17 extending internally near the upper closure of the closure liner may have a shape with a radial dimension that decreases as it approaches the upper closure. Also, in vertical furnaces where a liner 2 is not used, an injector 17 having a tapered shape at the second end 23 may be useful to relax the tolerances for positioning the injector between the tube and the boat.

[0077] The injector 17 may have multiple branches (e.g., two branches), each with a separate gas supply conduit connection. One branch may inject process gas into the lower part of the reaction chamber, and the other branch may inject process gas into the upper part of the reaction chamber. The branches may be connected by a connector. However, it is not essential to the invention for the injector to have more than two injector branches. The branches may be partially tapered at their second ends.

[0078] The injector 17 may be made of a ceramic. The ceramic may be selected from silicon carbide (SiC), silicon oxide (SiOx), silicon, or aluminum oxide (AlOx). The injector may be manufactured in a process in which the injector is first formed and then fired to harden the ceramic.

[0079] Preceramic polymers may be used as precursors that may form ceramic products through pyrolysis at temperatures ranging from 1000 to 1100°C. Precursor materials for obtaining silicon carbide in this manner may include polycarbosilane, poly(methylsilane), and polysilazanes. Silicon carbide materials obtained through pyrolysis of preceramic polymers are sometimes known as polymer-derived ceramics or PDCs.

[0080] Pyrolysis of preceramic polymers is most often carried out at relatively low temperatures under an inert atmosphere. This pyrolysis method is advantageous because the polymer can be formed into a variety of shapes before pyrolysis to ceramic silicon carbide. Prior to pyrolysis, the material is very soft and therefore easier to mold into shapes.

[0081] The injector 17 may have a bottom portion connected to a top portion, which may be slightly tapered, and terminate at a second end 23. The bottom portion begins at the first end 21, may be 30-40 cm long, and may be substantially straight.

[0082] The bottom part may be provided with a connecting pipe 27 (see Figures 4a, 4b). The connecting pipe 27 may be fitted into a hole in the flange 3 (in Figure 1) to position and hold the injector 17. Such a construction on the first end 21 of the injector may be advantageous when the injector is heated, as it allows the injector 17 to expand. A disadvantage is that it may allow some wobbling of the injector 17, especially at the second end 23.

[0083] The second end 23 may be tapered to increase the resistance of the injector 17 to shaking. The upper portion may have a cross-sectional area at the second end 23 that is 1 to 80%, preferably 3 to 40%, and most preferably 4 to 20% less than the cross-sectional area at the first end. The upper portion may have a wall thickness at the second end that is 2 to 50%, preferably 5 to 30%, and most preferably 10 to 20% less than the wall thickness at the first end 21.

[0084] The injector 17 may have a cross-sectional area at the second end that is 1 to 80%, preferably 3 to 40%, and most preferably 4 to 20% less than the cross-sectional area at the first end. The injector may have a wall thickness at the second end 23 that is 2 to 50%, preferably 5 to 30%, and most preferably 10 to 20% less than the wall thickness at the first end 21.

[0085] While specific embodiments have been described above, it will be understood that the invention may be practiced otherwise than as described. The above description is intended to be illustrative and not limiting. Thus, it will be apparent to those skilled in the art that modifications may be made to the invention as described without departing from the scope of the appended claims. The various embodiments may be applied in combination or independently of one another.

Claims

1. 1. An injector configured to be positioned within a reaction chamber of a substrate processing apparatus to inject gas into the reaction chamber, the injector being substantially elongated along a first axis, the injector being configured with an internal gas conduction channel extending along the first axis, the injector being provided with at least one gas inlet opening and at least one gas outlet opening, the injector having a width along a second axis perpendicular to the first axis, the width being substantially greater than a depth of the injector along a third axis perpendicular to the first and second axes, the injector having a varying wall thickness; the internal gas conduction channel has a substantially elliptical cross section such that the internal gas conduction channel extends substantially further along the second axis than along the third axis, the substantially elliptical cross section being partially constricted midway along the second axis by the increased wall thickness.

2. 2. The injector of claim 1, wherein the injector wall thickness varies along the second axis.

3. 10. The injector of claim 1, wherein the injector wall thickness varies along the third axis.

4. 2. The injector of claim 1, wherein the thickness of the injector wall varies around the circumference of the wall along the second axis and the third axis.

5. 2. The injector of claim 1, wherein the injector wall thickness varies along a majority of the first axis.

6. 2. The injector of claim 1, wherein the substantially elliptical cross section is partially constricted in the middle in the direction of the second axis by a bulbous portion provided in the wall and extending into the internal gas conducting channel.

7. 7. The injector of claim 6, wherein the surface of the bulb partially traces out a circle having a constant radius relative to an axis parallel to the first axis.

8. 10. The injector of claim 1, wherein the injector has one gas inlet opening at a first end of the injector.

9. 9. The injector of claim 8, wherein the injector has a single gas exit opening at a second end opposite the first end.

10. 9. The injector of claim 8, wherein the injector has a plurality of gas exit holes along its length at a second end opposite the first end.

11. 2. The injector of claim 1, wherein the depth of the injector in the direction of the third axis decreases toward the second end.

12. The horizontal inner cross-sectional area of ​​the internal gas conduction channel inside the injector is 100 mm ２ ~1500mm ２ 2. The injector of claim 1, wherein:

13. A substrate processing apparatus, Tube and a closure liner configured to extend inside the tube; an injector for providing gas to the interior of the tube; a gas exhaust duct for removing gas from the interior; 10. A substrate processing apparatus, comprising: a closure liner having a substantially cylindrical wall bounded by a liner opening at a lower end and a top closure portion at an upper end, the closure liner being substantially closed to gas above the liner opening; and the injector being the injector of claim 1.

14. The substrate processing equipment of claim 13 , wherein the substrate processing equipment comprises a plurality of injectors, at least one of the plurality of injectors having a different length.

15. The substrate processing apparatus of claim 14 , wherein the longest injector of the plurality of injectors extends inwardly to close the top closure portion of the closure liner.

16. The substrate processing apparatus of claim 14 , wherein the longest injector of the plurality of injectors has a single gas outlet hole.

17. The substrate processing apparatus of claim 14 , wherein the longest injector of the plurality of injectors has a plurality of gas outlet holes.

18. The substrate processing apparatus of claim 14 , wherein the shortest injector of the plurality of injectors has a plurality of gas outlet holes.

19. 14. The substrate processing apparatus of claim 13, wherein the closure liner is substantially cylindrical and the horizontal internal cross-sectional area of ​​the internal gas conduction channel within the injector has a shape such that the tangential dimension of the periphery of the substantially cylindrical liner is greater than the radial dimension.

20. 20. The substrate processing apparatus of claim 19, wherein the injector extends internally to near an upper closure portion of the closure liner, the injector having a shape that decreases in radial dimension as it approaches the upper closure portion.

21. 14. The substrate processing apparatus of claim 13, wherein the closure liner is supported on a flange, and a gas exhaust opening is provided between the closure liner and the flange for removing the gas from a circumferential space between the closure liner and the tube to the gas exhaust duct.

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