Apparatus and method for removal of oxides and carbon from a semiconductor film within a single processing chamber

Abstract

To provide a system and method for removing both carbon-based contaminants and oxygen-based contaminants from a semiconductor substrate within a single process chamber.SOLUTION: A system 100 includes a remote plasma unit 140 for performing a process in a reaction chamber 110 and a plurality of gas sources 160 to 190. A method for processing a semiconductor substrate 150 comprises: performing an oxide conversion step comprising flowing a first gas into a first remote plasma unit to form a first radical gas and flowing the first radical gas onto the substrate; performing an oxide sublimation step comprising a first heating step and a second heating step; and performing a carbon removal step on the substrate; wherein any of the steps is repeated as needed.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure generally relates to apparatuses and methods for manufacturing electronic devices. More particularly, the present disclosure relates to the removal of oxides and carbon in a semiconductor film formed within a processing chamber.

Background Art

[0002] Before manufacturing a semiconductor device, it is desirable that the surface of a wafer or substrate be cleaned. Contaminants on the substrate can adversely affect the mechanical and electrical properties of the semiconductor device to be formed. It is desirable to remove these contaminants before depositing a particular film on the substrate.

[0003] Contaminants present on a silicon or silicon germanium substrate can include carbon-based contaminants, such as carbonaceous contaminants and hydrocarbon contaminants. Other contaminants can include, for example, oxygen-based contaminants, such as native oxides. It is essential to remove these contaminants before an epitaxial process occurs.

[0004] Conventional methods for removing contaminants focus on removing one of either carbon-based or oxygen-based contaminants, but not both. This may, in part, be due to limitations on the apparatus of conventional methods. Therefore, systems and methods for removing both carbon-based and oxygen-based contaminants are desired.

Brief Description of the Drawings

[0005] These and other features, aspects, and advantages of the present invention disclosed herein are intended to be described and illustrated below with reference to the drawings of several embodiments, and are not intended to limit the present invention.

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Embodiments for Carrying Out the Invention

[0006] Although some embodiments and examples are disclosed below, it will be understood by those skilled in the art that the present invention extends beyond the specifically disclosed embodiments and / or uses of the present invention, as well as their obvious modifications and equivalents. Accordingly, it is intended that the scope of the present invention disclosed should not be limited by the specific disclosed embodiments described below.

[0007] Embodiments of the present invention relate to a system using a single process chamber having the ability to remove both carbon-based contaminants and oxygen-based contaminants. Embodiments have several advantages including (1) the incorporation of at least one remote plasma unit (RPU) having the ability to generate both hydrogen radicals and fluorine radicals, and (2) the combined use of hydrogen radicals and fluorine radicals in the process chamber, over conventional methods.

[0008] Embodiments of the present invention can be used to clean semiconductor substrates manufactured from at least one of the following materials, such as silicon, silicon germanium, or germanium. In one embodiment, the proportion of germanium in silicon germanium can vary from 10% to 90%. Also, embodiments of the present invention can be used to etch carbon layers, such as advanced patterning films (APF), photoresists, or other carbon contaminants including CHF x , SiC, or SiOC. Further, embodiments of the present invention can be used to clean the surfaces of dielectric materials, such as silicon oxide, silicon nitride, silicon oxynitride, silicon fluoride oxide, silicon carboxide, and silicon carboxynitride. Further, embodiments of the present invention can be applied to a patterned wafer surface.

[0009] FIG. 1 illustrates a system 100 according to at least one embodiment of the present invention. The system 100 can include a reaction chamber 110, a susceptor 120, a showerhead 130, a remote plasma unit 140, and a transfer path 145 between the remote plasma unit 140 and the reaction chamber 110. The substrate 150 is placed on the susceptor 120 for processing.

[0010] The reaction chamber 110 defines a space in which the substrate 150 is processed. To enable the use of different radicals in combination, the reaction chamber 110, susceptor 120, showerhead 130, and transfer path 145 may be coated with a material or may be made of a bulk ceramic material. The coating material can include at least one of anodized aluminum (Al2O3), aluminum oxide formed by atomic layer deposition (ALD), plasma spray Al2O3, bare aluminum parts with native aluminum oxide, yttrium oxide (Y2O3), yttrium-stabilized zirconia (YSZ), zirconium oxide (ZrO2), lanthanum zirconium oxide (LZO), yttrium aluminum garnet (YAG), yttrium oxyfluoride (YOF), a combination of the above materials, or the above substrate doped with another glassy phase material. In some cases, the coating material is made of two layers. For example, the first layer can be coated with anodized Al2O3 and the second layer can be coated with Al2O3 formed by ALD. The coating may be an amorphous phase, crystalline phase, or mixed phase. The bulk ceramic material can include aluminum oxide (Al2O3), zirconium oxide (ZrO2), yttrium oxide (Y2O3), or yttrium-stabilized zirconia (YSZ).

[0011] System 100 can also include a first gas source 160, a second gas source 170, a third gas source 180, and a fourth gas source 190, all of which can supply gas to the remote plasma unit 140. The remote plasma unit 140 is, for example, MKS It can include the Paragon H* remote plasma unit of Instruments. The third gas source 180 can also be configured to supply gas directly into the reaction chamber 110 without passing through the remote plasma unit 140. The first gas source 160 can include a precursor gas source that generates fluoride radicals, such as NF3, CF4, C2F6, C4F6, C4F8, COF2, SF6, or WF6. The second gas source 170 can include a gas source that generates hydrogen radicals, such as H2, NH3, or H2O. The second gas source 170 can include gases that generate oxygen radicals, such as oxygen or ozone. The third gas source 180 can be an NH3 source. The fourth gas source 190 can be a gas source of an inert gas, such as argon, helium, nitrogen, or neon.

[0012] The remote plasma unit 140 generates radicals supplied from a gas source. Then, the generated radicals enter the reaction chamber 110 through the showerhead 130 and then flow onto the substrate 150. The remote plasma source can include a toroidal ICP source or a coil-type ICP source driven by different RF frequencies, such as 400 kHz, 2 MHz, 60 MHz, and 2.56 GHz microwave sources.

[0013] Figure 2 illustrates a system 200 according to at least one embodiment of the present invention. The system 200 can include a reaction chamber 210, a susceptor 220, a showerhead 230, a first remote plasma unit 240 dedicated to oxide removal by F*, a second remote plasma unit 245 dedicated to carbon removal by H*, a transport path 246 under the first remote plasma unit, and a transport path 247 under the second remote plasma unit. The substrate 250 is placed on the susceptor 220 for processing. The system 200 may also include a first gate valve 248 and a second gate valve 249.

[0014] The reaction chamber 210 defines a space in which the substrate 250 is processed. To enable the use of different radicals in combination, the reaction chamber 210, susceptor 220, and showerhead 230 may be coated with a material, such as anodized aluminum (Al2O3), aluminum oxide formed by atomic layer deposition (ALD), plasma sprayed Al2O3, bare aluminum parts with native aluminum oxide, yttrium oxide (Y2O3), yttrium-stabilized zirconium oxide (YSZ), zirconium oxide (ZrO2), lanthanum zirconium oxide (LZO), yttrium aluminum garnet (YAG), yttrium oxyfluoride (YOF), a combination of the above materials, or the substrate doped with other glassy phase materials, or may be a bulk ceramic material. In some cases, the coating material is made of two layers. For example, the first layer can be coated with anodized Al2O3 and the second layer can be coated with Al2O3 formed by ALD. The coating may be an amorphous phase, crystalline phase, or mixed phase. The bulk ceramic material can include aluminum oxide (Al2O3), zirconium oxide (ZrO2), yttrium oxide (Y2O3), or yttrium-stabilized zirconium oxide (YSZ). In addition to the above coatings and bulk materials suitable for different radicals, the material of the transport path 247 under the second remote plasma unit may include a bulk quartz material.

[0015] System 200 can also include a first gas source 260, a second gas source 270, a third gas source 280, and a fourth gas source 290, all of which can supply gas to the first remote plasma unit 240 and the second remote plasma unit 245. The first remote plasma unit 240 and the second remote plasma unit 245 can include toroidal ICP sources or coil ICP sources driven by different RF frequencies, such as 400 kHz, 2 MHz, 60 MHz, and 2.56 GHz microwave sources. The third gas source 280 can also be configured to supply gas directly into the reaction chamber 210 without passing through either the first remote plasma unit 240 or the second remote plasma unit 245. The first gas source 260 can include a precursor gas source that generates fluoride radicals, such as NF3, CF4, C2F6, C4F6, C4F8, COF2, SF6, or WF6. The second gas source 270 can include a gas source that generates hydrogen radicals, such as H2, NH3, or H2O. The second gas source 270 can include a gas that generates oxygen radicals, such as oxygen or ozone. The third gas source 280 can be an NH3 source. The fourth gas source 290 can be a gas source of an inert gas, such as argon, helium, nitrogen, or neon. The first remote plasma unit 240 (which may be dedicated to F* radicals) and the second remote plasma unit 245 (which may be dedicated to H* radicals) generate radicals provided from the gas source. The generated radicals enter the reaction chamber 210 through the showerhead 230 and then flow onto the substrate 250. Gate valves 248 and 249 can be disposed at the outlet of the RPU to prevent radicals generated by one remote plasma unit from flowing back into the second remote plasma.

[0016] (It may be dedicated to F* radicals) The first remote plasma unit 240 and (it may be dedicated to H* radicals) the second remote plasma unit 245 generate radicals provided from the gas source. Then, the generated radicals enter the reaction chamber 210 through the showerhead 230 and then flow onto the substrate 250. In order to prevent the radicals generated by one remote plasma unit from flowing back into the second remote plasma, gate valves 248 and 249 can be arranged at the outlet of the RPU.

[0017] Figure 3A illustrates a method according to at least one embodiment of the present invention. This method includes an oxide conversion step 300, an oxide sublimation step 400, and a carbon removal step 500. Any one of these steps, or any combination of these steps, can be repeated as necessary. The entire method can be repeated by a repetition cycle 600.

[0018] Figure 3B illustrates a method according to at least one embodiment of the present invention. This method includes a carbon removal step 500, an oxide conversion step 300, and an oxide sublimation step 400. Any one of these steps, or any combination of these steps, can be repeated as necessary. The entire method can be repeated by a repetition cycle 600. The method of Figure 3B is different from that of Figure 3A in that the carbon removal step 500 is before the oxide conversion step 300.

[0019] Figure 3C illustrates a method according to at least one embodiment of the present invention. This method includes a carbon removal step 500, an oxide conversion step 300, an oxide sublimation step 400, and a carbon removal step 500. Any one of these steps, or any combination of these steps, can be repeated as necessary. The entire method can be repeated by a repetition cycle 600. The method of Figure 3C is different from that of Figure 3B in that an additional carbon removal step 500 is after the oxide sublimation step 400.

[0020] The oxide conversion process 300 according to at least one embodiment of the present invention is illustrated in FIG. 4. The oxide conversion process 300 can include a step 310 of flowing a gas precursor into a remote plasma unit and a step 320 of flowing the generated radicals and additional precursors onto a substrate. According to at least one embodiment of the present invention, step 310 can include flowing argon, hydrogen, and NF3 into the remote plasma unit. The flow rate of argon can be in the range of 0.01 to 20 slm, 0.1 to 10 slm, or 1 to 8 slm. The flow rate of hydrogen can be in the range of 10 sccm to 1500 slm, 25 to 1200 slm, or 50 sccm to 1000 slm. NF3 can flow for a specific time in the range of 0.1 to 120 seconds, 1 to 100 seconds, or 5 to 80 seconds while the plasma is generated in the remote plasma device. Step 310 can include heating the reaction chamber 210 to a temperature between 5 and 120 °C, 5 and 80 °C, or 5 and 60 °C.

[0021] As a result of step 310, a gas of fluorine radicals is generated in the remote plasma unit. The fluorine radicals exit the remote plasma unit and can combine with any additional precursor gas on the substrate disposed in the reaction chamber in step 320. Any additional precursor gas can include ammonia flowing at a flow rate in the range of 10 sccm to 1500 slm, 25 to 1200 slm, or 50 sccm to 1000 slm. Step 320 can include heating the reaction chamber 210 to a temperature between 5 and 120 °C, 5 and 80 °C, or 5 and 60 °C. The oxide conversion process 300 can result in a chemical reaction with the oxide on the silicon germanium substrate having the oxide as follows. NH4F (g) +SiGeO x(s) →(NH4)2SiF 6(s) +(NH4)2Ge F 6(s) +H2O (g) As a result of the oxide conversion step 300, the oxide can be converted on the substrate into a solid ammonium hexafluorosilicate compound and a solid ammonium hexafluorogermanate compound.

[0022] The oxide sublimation step 400 according to at least one embodiment of the present invention is illustrated in FIG. 5. The oxide sublimation step 400 includes the first heating step 410 or the second heating step 420, or both. The first heating step 410 can include heating the substrate to a temperature above 125°C, above 100°C, or above 90°C. As a result of the first step 410, the solid ammonium hexafluorosilicate compound can be sublimated according to the following reaction. (NH4)2SiF 6(s) →NH 3(g) +HF (g) +SiF 4(g) Thereafter, the gaseous product can be removed from the reaction chamber.

[0023] The second heating step 420 can include heating the substrate to a temperature higher than that of the first heating step 410. The temperature can be above 275°C, above 250°C, or above 225°C. To reach the high operating temperature, the high-temperature showerhead can be designed to be heated to a maximum of 250°C to 300°C without heating the reaction chamber. As a result of the second step 420, the solid ammonium hexafluorogermanate compound can be sublimated according to the following reaction. (NH4)2GeF 6(s) →NH 3(g) +HF (g) +GeF 4(g) Thereafter, the gaseous product can be removed from the reaction chamber.

[0024] A carbon removal process 500 according to at least one embodiment of the present invention is illustrated in FIG. 6. The carbon removal process 500 can include a step 510 of flowing a hydrogen precursor and other gas precursors into a remote plasma unit, and a step 520 of flowing the generated radicals and any additional precursors onto a substrate. The first heating step 510 can include flowing argon, hydrogen, and ammonia into the remote plasma unit. The gas can be flowed for a time in the range of 0.1 to 180 seconds, 1 to 120 seconds, or 10 to 90 seconds. As a result, hydrogen radicals are generated in the remote plasma unit.

[0025] In step 520, the generated hydrogen radicals are reacted with carbon-based contaminants in the substrate. This step can occur at a temperature of 25°C to 500°C, 75°C to 400°C, or 150°C to 300°C. A higher temperature showerhead can heat the substrate and result in effective removal of carbon. As a result of step 520, carbon can be removed according to the following reaction. C (s) +H* (g) →C x H y(g) Other reactions can involve carbon with oxygen radicals. Thereafter, the gaseous products can be removed from the reaction chamber.

[0026] The specific embodiments shown and described are illustrative of the invention and its best mode and are not intended to limit the scope of the aspects and embodiments in any way. Indeed, for the sake of brevity, conventional manufacturing, related, preparatory, and other functional aspects of the systems may not be described in detail. Further, the connecting lines shown in the various figures are intended to represent exemplary functional relationships and / or physical couplings between the various elements. Many alternative or additional functional relationships or physical connections may exist in the actual system and / or may not exist in some embodiments.

[0027] The configurations and / or methods described herein are exemplary in nature and these specific embodiments or examples are subject to many variations and should not be considered in a limiting sense. It should be understood that the specific routines or methods described herein can represent one or more of any number of processing methods. Accordingly, the various operations illustrated may be performed in the sequence illustrated, in other sequences, or in some cases, may be omitted.

[0028] The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various processes, systems, and configurations, as well as other features, functions, operations, and / or characteristics disclosed herein, and any and all equivalents thereof.

Claims

1. An apparatus for processing a semiconductor substrate, comprising: a reaction chamber; a susceptor configured to support the substrate; a first gas source for supplying a first gas; a second gas source for supplying a second gas; a first remote plasma unit configured to receive the first gas and generate a first radical gas, wherein the first remote plasma unit is also configured to receive the second gas and generate a second radical gas; a second remote plasma unit configured to receive the second gas and generate the second radical gas, wherein the second remote plasma unit is also configured to receive the first gas and generate the first radical gas; a first gate valve disposed at an outlet of the first remote plasma unit and a second gate valve disposed at an outlet of the second remote plasma unit; a gas distribution device configured to flow the first radical gas and the second radical gas onto the substrate; a transport path connecting the first remote plasma unit to the gas distribution device, through which the first radical gas passes over the substrate via the gas distribution device; wherein The gas distribution device, the reaction chamber, the transfer path, and the susceptor are coated with a first layer and a second layer, the first layer is disposed under the second layer, and at least one of the first layer and the second layer is anodized aluminum (Al ２ O ３ ), aluminum oxide formed by atomic layer deposition (ALD), plasma spray Al ２ O ３ , natural aluminum oxide, yttrium oxide (Y ２ O ３ ), zirconium oxide (ZrO ２ ), lanthanum zirconium oxide (LZO), yttrium aluminum garnet (YAG), yttrium oxyfluoride (YOF), aluminum oxide (Al ２ O ３ ), or yttria-stabilized zirconia (YSZ), and includes a material selected from the group consisting of: the first radical gas contains fluorine radicals, and the second radical gas contains hydrogen radicals.

2. The first gas is NF ３ , CF ４ , C ２ F ６ , C ４ F ６ , C ４ F ８ , COF ２ , SF ６ , or WF ６ The apparatus according to claim 1, comprising at least one of them.

3. The second gas is H ２ , NH ３ , H ２ O, O ２ , or O ３ The apparatus according to claim 1, comprising at least one of them.

4. A third gas source for supplying a third gas, wherein the third gas is NH ３ and a third gas source containing the same, The apparatus according to claim 1, further comprising a fourth gas source for supplying a fourth gas, wherein the fourth gas contains at least one of argon, helium, nitrogen, or neon.

5. The first layer contains aluminum oxide (Al ２ O ３ ), and the second layer contains yttrium oxide (Y ２ O ３ ). The apparatus according to claim 1

6. The first layer is aluminum oxide (Al ２ O ３ ) formed by atomic layer deposition (ALD), the apparatus according to claim 1.

7. The second layer is yttrium oxide (Y ２ O ３ ) formed by atomic layer deposition (ALD), the apparatus according to claim 1.

8. The first layer includes aluminum oxide (Al ２ O ３ ), formed by atomic layer deposition (ALD), and the second layer includes yttrium oxide (Y ２ O ３ ), formed by atomic layer deposition (ALD). The apparatus according to claim 1.

9. The apparatus according to claim 1, wherein the transport path contains a bulk quartz material.

10. A method for processing a semiconductor substrate, comprising: providing the apparatus according to claim 1; and performing an oxide conversion step on the substrate, the oxide conversion step including: (1) flowing a first gas into a first remote plasma unit to form a first radical gas; and (2) flowing the first radical gas onto the substrate. Performing an oxide sublimation process on the substrate, the oxide sublimation process including: (1) a first heating process and (2) a second heating process; Performing a carbon removal process on the substrate; The oxide conversion process, the oxide sublimation process, and the carbon removal process are each performed in the reaction chamber; Any one of the oxide conversion process, the oxide sublimation process, and the carbon removal process is repeated as necessary; The carbon removal process includes: Flowing a second gas into the second remote plasma unit to form a second radical gas; Flowing the second radical gas onto the substrate. A method.

11. The first gas is NF ３ , CF ４ , C ２ F ６ , C ４ F ６ , C ４ F ８ , COF ２ , SF ６ , or WF ６ The method according to claim 10, comprising at least one of them.

12. The second gas is H ２ , NH ３ , H ２ O, O ２ , or O ３ The method according to claim 10, comprising at least one of them.

13. A method for processing a semiconductor substrate, including: Providing the apparatus according to claim 1; Performing a carbon removal process on the substrate; Performing an oxide conversion process on the substrate, the oxide conversion process including: (1) flowing a first gas into a first remote plasma unit to form a first radical gas; and (2) flowing the first radical gas onto the substrate; Performing an oxide sublimation process on the substrate, the oxide sublimation process including: (1) a first heating process and (2) a second heating process; The carbon removal process, the oxide conversion process, and the oxide sublimation process are each performed in the reaction chamber; Any one of the carbon removal process, the oxide conversion process, and the oxide sublimation process is repeated as necessary; The carbon removal process includes: Flowing a second gas into the second remote plasma unit to form a second radical gas; Flowing the second radical gas onto the substrate. A method.

14. The first gas is NF ３ , CF ４ , C ２ F ６ , C ４ F ６ , C ４ F ８ , COF ２ , SF ６ , or WF ６ The method according to claim 13, comprising at least one of them.

15. The second gas is H ２ , NH ３ , H ２ O, O ２ , or O ３ The method according to claim 13, comprising at least one of them.

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