Method of forming copper film
By spraying copper-containing precursors onto the substrate and performing a cyclic process involving blowing out gas and mixing gases, the problem of easy agglomeration of copper films was solved, enabling the formation and rapid growth of high-quality continuous copper films.
Patent Information
- Application Number
- CN202480044668.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-06-30
- Filing Date
- 2024-06-27
- Publication Date
- 2026-02-03
AI Technical Summary
Copper tends to agglomerate at high temperatures, leading to discontinuous copper film formation and affecting film quality.
A copper-containing precursor, a first purge gas, and hydrogen plasma are sprayed onto the substrate, followed by the spraying of a mixed gas containing hydrogen and nitrogen. This process is repeated in cycles, with the chamber temperature controlled between 50°C and 300°C, and the substrate is treated with plasma.
It effectively decomposes copper organic ligands, reduces copper aggregation, forms continuous copper films, improves film quality, increases growth per cycle, and shortens process time.
Smart Images
Figure CN121464737A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for forming a copper film on a substrate. Background Technology
[0002] Typically, to manufacture semiconductor devices, display devices, solar cells, etc., thin film layers, thin film circuit patterns, or optical patterns need to be formed on a substrate. For this purpose, the substrate undergoes processing techniques. Examples of these techniques include deposition processes that deposit films containing specific materials on the substrate, photoprocesses that selectively expose the thin film using photosensitive materials, and etching processes that remove the selectively exposed portions of the thin film to form patterns. Such processing techniques can also include copper film formation processes that form copper films on the substrate.
[0003] Copper film formation can be achieved by spraying a copper (Cu) precursor onto a substrate to form a copper film. However, due to the strong property of copper to agglomerate when the temperature rises, agglomeration problems may occur during the copper film formation process. Therefore, the copper film formed by this process is not continuous but sparse, resulting in low film quality. Summary of the Invention
[0004] Technical issues The present invention aims to solve the above-mentioned problems and to provide a copper film formation method that can solve the coalescence problem caused by the use of copper.
[0005] Technical solution To achieve the above objectives, the present invention may include the following elements.
[0006] The copper film formation method according to the present invention can be a method for forming a copper film on a substrate located in a chamber, and may include: step a), spraying a copper-containing precursor onto the substrate; step b), spraying a first purging gas onto the substrate; step c), forming a plasma on the substrate using hydrogen (H2); and step d), spraying a mixed gas comprising a hydrogen-containing gas and a nitrogen-containing gas onto the substrate. While performing steps a) to c), step d) may continuously spray the mixed gas.
[0007] In the copper film formation method according to the present invention, after repeating steps a) and b) N times (where N is a natural number greater than 1) in sequence, step c) is performed.
[0008] The copper film formation method according to the present invention can be repeated M times (where M is a natural number greater than 1) in a cycle of steps a), b), and c).
[0009] In the copper film forming method according to the present invention, the nitrogen-containing gas may include at least one of nitrogen (N2), ammonia (NH3), plasma-activated nitrogen (N2), and plasma-activated ammonia (NH3).
[0010] The copper film formation method according to the present invention may include: treating the substrate with a plasma of hydrogen or oxygen (O2) before performing step a).
[0011] In the copper film formation method according to the present invention, steps a) to d) are performed at an internal temperature of 50°C to 300°C in the chamber.
[0012] The copper film formation method according to the present invention may include: step e), spraying a second purging gas onto the substrate. Step e) may be performed after step c).
[0013] The copper film formation method according to the present invention can be repeated R times (where R is a natural number greater than 1) in a cycle of steps a), b), c), and e). While this cycle is being repeated, a mixed gas can be continuously injected in step d).
[0014] Beneficial effects According to the present invention, the following effects can be achieved.
[0015] This invention is implemented by continuously injecting a gas, including at least one of a hydrogen-containing gas and a nitrogen-containing gas, while forming a copper film using a copper-containing precursor. Therefore, this invention can decompose the ligands of copper organic compounds in a short time to continuously weaken the agglomeration properties of copper. Therefore, this invention can solve the problem of copper agglomeration in the process of forming a copper film. Therefore, this invention can improve the morphology of the copper film to form a continuous copper film, thereby improving the film quality. Furthermore, this invention can increase the growth per cycle (GPC) of copper film formation, thus shortening the process time required for copper film formation. Attached Figure Description
[0016] Figure 1 A schematic configuration diagram illustrating an embodiment of a substrate processing apparatus for performing a copper film formation method according to the present invention.
[0017] Figure 2 and Figure 3 This is a schematic side sectional view of a gas injection unit in an embodiment of a substrate processing apparatus for performing a copper film formation method according to the present invention.
[0018] Figure 4 A schematic side sectional view is provided to illustrate a copper film formed on a substrate by the copper film formation method according to the present invention.
[0019] Figure 5 This is a schematic flowchart of the copper film formation method according to the present invention.
[0020] Figure 6 This is a timing diagram showing the moments when gas is ejected and plasma is generated in the substrate processing apparatus according to the present invention.
[0021] Figure 7 This is a schematic flowchart of a copper film formation method according to a variant embodiment of the present invention. Detailed Implementation
[0022] In the following, embodiments of the copper film formation method according to the present invention will be described in detail with reference to the accompanying drawings. When describing embodiments of the invention, if any structure is described as being formed "on" or "below" another structure, this description should be interpreted to include cases where a third structure is disposed between these structures and cases where these structures are in contact with each other. Furthermore, in Figure 6 In the time series diagram, the horizontal axis can represent time, and the vertical axis can represent the gas flow rate or the gas injection pressure.
[0023] Reference Figures 1 to 4 The copper film forming method according to the present invention is used to form a copper film 110 on a substrate 100. The substrate 100 may be a silicon substrate, a glass substrate, a metal substrate, etc. The copper film 110 may be included in a semiconductor device, a display device, a solar cell, etc. For example, the copper film 110 may be included in a capacitor.
[0024] The copper film formation method according to the present invention can be performed by substrate processing apparatus 1. Before describing an embodiment of the copper film formation method according to the present invention, an example of substrate processing apparatus 1 will be described in detail below.
[0025] Reference Figures 1 to 3 The substrate processing equipment 1 may include a chamber 2, a substrate support unit 3, and a spraying unit 4.
[0026] Chamber 2 provides a processing space 200. The process of forming a copper film can be performed in the processing space 200. The processing space 200 can be disposed within chamber 2. An exhaust port (not shown) for discharging gas from the processing space 200 can be attached to chamber 2. A substrate support unit 3 and an injection unit 4 can be disposed within chamber 2.
[0027] The substrate support unit 3 supports the substrate 100. The substrate support unit 3 can support one substrate 100 or multiple substrates 100. When the substrate support unit 3 supports multiple substrates 100, multiple substrates 100 can be processed simultaneously. The substrate support unit 3 can be integrated into the chamber 2. The substrate support unit 3 can be disposed within the chamber 2.
[0028] The injection unit 4 injects gas toward the substrate support unit 3. The injection unit 4 can be connected to the gas storage unit 40. In this case, the injection unit 4 can inject gas supplied from the gas storage unit 40 toward the substrate support unit 3. The injection unit 4 can be disposed in the chamber 2. The injection unit 4 can be positioned opposite the substrate support unit 3. The injection unit 4 can be disposed on the substrate support unit 3. The processing space 200 can be disposed between the injection unit 4 and the substrate support unit 3. The injection unit 4 can be attached to a cover (not shown). The cover can be attached to the chamber 2 to cover the upper part of the chamber 2.
[0029] The injection unit 4 may include a first gas flow path 4a and a second gas flow path 4b.
[0030] The first gas flow path 4a is used to inject a first gas. One side of the first gas flow path 4a can be connected to the gas storage unit 40 via a pipe, hose, gas block, etc. The other side of the first gas flow path 4a can be connected to the processing space 200. Therefore, the first gas supplied from the gas storage unit 40 can flow along the first gas flow path 4a and then be injected into the processing space 200 through the first gas flow path 4a. The first gas flow path 4a can serve as a flow path for the first gas to flow and can also serve as an injection port for injecting the first gas into the processing space 200.
[0031] The second gas flow path 4b is used to inject a second gas. The second gas and the first gas can be different gases. For example, when the first gas is the source gas, the second gas can be the reactant gas. One side of the second gas flow path 4b can be connected to the gas storage unit 40 via a pipe, hose, gas block, etc. The other side of the second gas flow path 4b can be connected to the processing space 200. Therefore, the second gas supplied from the gas storage unit 40 can flow along the second gas flow path 4b and then be injected into the processing space 200 through the second gas flow path 4b. The second gas flow path 4b can be used as a flow path for the second gas to flow and can be used as an injection port for injecting the second gas into the processing space 200.
[0032] The second gas flow path 4b and the first gas flow path 4a can be configured to be spatially separated from each other. Therefore, the second gas supplied from the gas storage unit 40 to the second gas flow path 4b can be injected into the processing space 200 without passing through the first gas flow path 4a. The first gas supplied from the gas storage unit 40 to the first gas flow path 4a can be injected into the processing space 200 without passing through the second gas flow path 4b. The second gas flow path 4b and the first gas flow path 4a can inject gas towards different portions of the processing space 200.
[0033] For example, such as Figure 2 As shown, the injection unit 4 may include a first plate 41 and a second plate 42.
[0034] A first plate 41 is disposed on a second plate 42. The first plate 41 and the second plate 42 may be spaced apart from each other. A plurality of first gas holes 411 may be formed in the first plate 41. Each first gas hole 411 may serve as a path for the flow of a first gas. The first gas holes 411 may be included in a first gas flow path 4a. A plurality of second gas holes 412 may be formed in the first plate 41. Each second gas hole 412 may serve as a path for the flow of a second gas. The second gas holes 412 may be included in a second gas flow path 4b. A plurality of protruding members 413 may be attached to the first plate 41. The protruding members 413 may protrude from the lower surface of the first plate 41 toward the second plate 42. Each first gas hole 411 may be formed to penetrate the first plate 41 and the protruding member 413.
[0035] Multiple openings 421 can be formed in the second plate 42. The openings 421 can be formed to penetrate the second plate 42. The openings 421 can be positioned corresponding to the protruding members 413. Therefore, as... Figure 2 As shown, the protruding member 413 can be formed to a length that allows it to be inserted into the opening 421 respectively. Although not shown, the protruding member 413 can be formed to a length that allows it to be disposed on the opening 421 respectively. The protruding member 413 can be formed to a length that protrudes downward from the second plate 42. The second gas hole 412 can be configured to spray gas toward the upper surface of the second plate 42. Although not shown, the lower surface of the first plate 41 can be formed to be flat and without the protruding member 413.
[0036] The injection unit 4 can generate plasma using a second plate 42 and a first plate 41. In this case, plasma power, such as radio frequency (RF) power, can be applied to the first plate 41, while the second plate 42 can be grounded. The first plate 41 can be grounded, while plasma power is applied to the second plate 42.
[0037] For example, such as Figure 3 As shown, multiple first openings 422 and multiple second openings 423 can be formed in the second plate 42.
[0038] The first opening 422 can be formed to penetrate the second plate 42. The second opening 423 can be formed to penetrate the second plate 42. The second plate 42 and the first plate 41 can be spaced apart from each other. The lower surface of the first plate 41 facing the second plate 42 can be formed to be flat and without protruding members 413 (e.g., Figure 2(As shown). The first gas and the second gas can be supplied to the space between the first plate 41 and the second plate 42 through the first gas hole 411 and the second gas hole 412, and then injected into the processing space 200 through the first opening 422 and the second opening 423. In this case, when the first gas is supplied through the first gas hole 411 and the second gas is supplied through the second gas hole 412 simultaneously, the first gas and the second gas can mix in the space between the first plate 41 and the second plate 42, and then be injected into the processing space 200 through the first opening 422 and the second opening 423.
[0039] Furthermore, the first opening 422 can be disposed vertically below the first gas hole 411. In this case, the first opening 422 and the first gas hole 411 can be disposed on the same vertical line. Although not shown, the first opening 422 and the first gas hole 411 can be disposed in a position offset from each other. In this case, the first opening 422 and the first gas hole 411 can be disposed in a position that does not overlap with each other, or only a portion thereof can be disposed in a position that overlaps with each other.
[0040] Furthermore, the second opening 423 can be disposed below the second gas hole 412 in the vertical direction. In this case, the second opening 423 and the second gas hole 412 can be disposed on the same vertical line. Although not shown, the second opening 423 and the second gas hole 412 can be disposed in a position offset from each other. In this case, the second opening 423 and the second gas hole 412 can be disposed in a position that does not overlap with each other, or only a portion thereof can be disposed in a position that overlaps with each other.
[0041] The injection unit 4 may include a third gas flow path 4c.
[0042] The third gas flow path 4c is used to inject a third gas. One side of the third gas flow path 4c can be connected to the gas storage unit 40 via a pipe, hose, gas block, etc. The other side of the third gas flow path 4c can be connected to the processing space 200. Therefore, the third gas supplied from the gas storage unit 40 can flow along the third gas flow path 4c and then be injected into the processing space 200 through the third gas flow path 4c. The third gas flow path 4c can be used as a flow path for the third gas to flow and can also be used as an injection port for injecting the third gas into the processing space 200. The third gas flow path 4c, the second gas flow path 4b, and the first gas flow path 4a can be arranged to be spatially separated from each other. The third gas can be supplied to the space between the first plate 41 and the second plate 42 through the third gas flow path 4c, and then injected into the processing space 200 through the first opening 422 and the second opening 423 formed in the second plate 42.
[0043] The copper film formation method according to the present invention can be performed using substrate processing equipment 1.
[0044] Reference Figures 1 to 6 The copper film formation method according to the present invention is used to form a copper film 110 on a substrate 100 in a chamber 2. The copper film formation method according to the present invention may include steps a) S11, b) S12, c) S13 and d) S20.
[0045] Step a) S11 is used to spray a copper-containing precursor onto the substrate 100. Step a) S11 can be performed by spraying the copper-containing precursor into the processing space 200 using the spraying unit 4. In this case, the spraying unit 4 can spray the copper-containing precursor through the first gas flow path 4a. Through step a) S11, an adsorption process for adsorbing a copper layer containing copper can be performed.
[0046] Step b) S12 is used to spray a first purging gas onto the substrate 100. Step b) S12 can be performed by spraying the first purging gas into the processing space 200. In this case, the spraying unit 4 can spray the first purging gas through at least one of the first gas flow path 4a and the second gas flow path 4b. The first purging gas can be an inert gas, such as argon (Ar). Through step b) S12, a purging process can be performed to remove copper-containing precursors not used in the adsorption process from the processing space 200.
[0047] Step S13 is used to form plasma on substrate 100 using hydrogen (H2). Step c) S13 can be performed by forming plasma in processing space 200 using hydrogen. Hydrogen for forming plasma can be injected into processing space 200 through second gas flow path 4b. When plasma is formed in processing space 200 using hydrogen, a deposition process can be performed to form a copper film 110 from a copper layer adsorbed by an adsorption process. In this case, copper film 110 can be formed by atomic layer deposition process.
[0048] Step d) S20 is used to spray a mixed gas including hydrogen-containing gas and nitrogen-containing gas onto the substrate 100. Step d) S20 can be performed by spraying the mixed gas into the processing space 200 using the spraying unit 4. In this case, the spraying unit 4 can spray the mixed gas through the third gas flow path 4c.
[0049] While performing steps a) S11 to c) S13, a mixed gas can be continuously injected in step d) S20. The mixed gas can decompose the ligands of copper organic matter in a short time, thus continuously weakening the agglomeration properties of copper. Because the mixed gas is continuously injected in step d) S20 while performing steps a) S11 to c) S13, the mixed gas can continuously weaken the agglomeration properties of copper during these steps. Therefore, the copper film formation method according to the present invention can solve the problem of copper agglomeration in the process of forming the copper film 110. Therefore, the copper film formation method according to the present invention can improve the morphology of the copper film 110 to form a continuous copper film 110, thereby improving the film quality of the copper film 110. Furthermore, the copper film formation method according to the present invention can increase the growth per cycle (GPC) for forming the copper film 110, thus shortening the process time required to form the copper film 110.
[0050] In step d) S20, the nitrogen-containing gas may include at least one of nitrogen (N2), ammonia (NH3), plasma-activated nitrogen (N2), and plasma-activated ammonia (NH3). In this case, step d) S20 can be performed in a nitrogen and hydrogen gas environment, allowing steps a) S11 to c) S13 to be carried out. Furthermore, step d) S20 can decompose the ligands of copper organic compounds in a short time by using a nitrogen and hydrogen plasma density, thus continuously weakening the property of copper agglomeration.
[0051] Furthermore, while performing steps a) S11 and b) S12, a mixed gas can be continuously injected into the processing space 200 via step d) S20, thus allowing the copper-containing precursor to be adsorbed onto the copper-containing layer using the mixed gas. Subsequently, a hydrogen-based plasma is formed via step c) S13, and the mixed gas is continuously injected into the processing space 200 via step d) S20, allowing the removal of materials other than copper through a reduction process, thereby forming a copper film 110 with a further increased copper content. Therefore, the copper film formation method according to the present invention can further improve the film quality of the copper film 110. In this case, the copper film 110 can be formed solely from copper.
[0052] Furthermore, step d) S20 can be performed by spraying a mixed gas consisting only of hydrogen gas but excluding nitrogen gas. In this case, compared to a comparative example where the mixed gas is sprayed intermittently or periodically, the copper film formation method according to the present invention can continuously spray the mixed gas, thereby increasing the growth per cycle (GPC) of the copper film 110 by more than two times.
[0053] Reference Figures 1 to 6The copper film formation method according to the present invention can be implemented by repeating steps a) S11 and b) S12 sequentially N times (where N is a natural number greater than 1), and then performing step c) S13. Because steps a) S11 and b) S12 are performed sequentially and repeatedly, the copper film formation method according to the present invention can increase the supply of the copper-containing precursor before performing step c) S13, thus reducing the empty space of the copper layer. Therefore, the copper film formation method according to the present invention can further improve the morphology of the copper film 110, and thus further improve the film quality of the copper film 110. Figure 6 The diagram shows step c) S13 performed after repeating steps a) S11 and b) S12 twice in sequence. However, the invention is not limited to this, and step c) S13 can be performed after repeating steps a) S11 and b) S12 four or more times in sequence. In this case, steps a) S11 and b) S12 can be repeated six or more times in sequence. Furthermore, while performing the cycles of steps a) S11 and b) S12 in sequence, the mixed gas can be continuously injected into the processing space 200 via step d) S20.
[0054] The copper film formation method according to the present invention can be implemented by repeating steps a) S11, b) S12, and c) S13 sequentially M times (where M is a natural number greater than 1). Even when performing the sequential cycle of steps a) S11, b) S12, and c) S13, the mixed gas can be continuously injected into the processing space 200 via step d) S20. Therefore, the copper film formation method according to the present invention can form a copper film 110 with a high copper ratio at a relatively thick thickness. In this case, the copper film 110 can be formed solely of copper.
[0055] In the copper film formation method according to the present invention, steps a) S11, b) S12, c) S13, and d) S20 can be performed at an internal temperature of 50°C to 300°C in the chamber 2. The internal temperature of the chamber 2 can represent the temperature of the processing space 200. While the agglomeration of copper may be enhanced at an internal temperature of 50°C to 300°C, the copper film formation method according to the present invention can weaken this agglomeration by step d) S20, thus enabling the formation of a copper film 110 with improved film quality at an internal temperature of 50°C to 300°C in the chamber 2.
[0056] Reference Figures 1 to 7 The copper film formation method according to the present invention may include a processing step S30.
[0057] Step S30 of the processing can be performed by treating the substrate 100 with a plasma of hydrogen (H2) or oxygen (O2). Step S30 of the processing can be performed before step a) S11. Therefore, after step S30 of the processing, the copper film formation method can proceed from step a) S11. Thus, the copper film formation method according to the present invention is implemented to form a copper film 110 on a substrate 100 that has had impurities removed by the processing, thereby improving the deposition rate of the copper film 110 and enhancing the film quality of the copper film 110. When a lower film is deposited between the substrate 100 and the copper film 110, step S30 of the processing can be performed by treating the lower film with a plasma of hydrogen or oxygen. In this case, impurities can be removed from the lower film. The lower film can be a metal film, an oxide film, a nitride film, etc.
[0058] Reference Figures 1 to 7 The copper film forming method according to the present invention may include step e) S14 of performing a processing.
[0059] Step e) S14 involves injecting a second purging gas onto the substrate 100. Step e) S14 can be performed after step c) S13. Step e) S14 can be performed by injecting the second purging gas into the processing space 200 using the injection unit 4. In this case, the injection unit can inject the second purging gas through at least one of the first gas flow path 4a and the second gas flow path 4b. The second purging gas can be an inert gas, such as argon. Through step e) S14, a purging process can be performed to remove material that was not used in the adsorption process and has been removed from the copper layer from the processing space 200.
[0060] The copper film formation method according to the present invention can be implemented by repeating steps a) S11, b) S12, c) S13, and e) S14 sequentially R times (where R is a natural number greater than 1). Even when performing the sequential cycle of steps a) S11, b) S12, c) S13, and e) S14, the mixed gas can be continuously injected in step d) S20. Therefore, the copper film formation method according to the present invention can form a copper film 110 with a high copper ratio at a relatively thick thickness. In this case, the copper film 110 can be formed solely of copper.
[0061] The present invention is not limited to the above embodiments and drawings. Those skilled in the art will clearly understand that various modifications, variations and substitutions can be made without departing from the scope and spirit of the present invention.
Claims
1. A method for forming a copper film, the method comprising forming a copper film on a substrate located in a chamber, the method comprising: Step a), spraying a copper-containing precursor onto the substrate; Step b), spraying a first purging gas onto the substrate; Step c), using hydrogen (H2) to form plasma on the substrate; as well as Step d), a mixed gas comprising hydrogen-containing gas and nitrogen-containing gas is sprayed onto the substrate. While performing steps a) to c), step d) continuously injects the mixed gas.
2. The method as described in claim 1, wherein, After repeatedly executing the loop of step a) and step b) N times, step c) is executed, where N is a natural number greater than 1.
3. The method as described in claim 1, wherein, Repeat the loop of executing steps a), b), and c) M times in sequence, where M is a natural number greater than 1.
4. The method of claim 1, wherein, The nitrogen-containing gas includes at least one of nitrogen (N2), ammonia (NH3), plasma-activated nitrogen (N2), and plasma-activated ammonia (NH3).
5. The method of claim 1, further comprising: Before performing step a), the substrate is treated with a plasma of hydrogen or oxygen (O2).
6. The method of claim 1, wherein, Steps a) to d) are performed while the internal temperature of the chamber is between 50°C and 300°C.
7. The method of claim 1, further comprising: Step e), a second purging gas is sprayed onto the substrate. Specifically, step e) is performed after step c).
8. The method of claim 7, wherein, Repeat the loop of executing steps a), b), c), and e) sequentially R times, where R is a natural number greater than 1, and In step d), the mixed gas is continuously injected while the cycle is repeated.