Method and apparatus for adjusting film uniformity

Abstract

A method for processing a substrate is provided, wherein the substrate is located below a showerhead within a processing chamber. A deposition layer is deposited on the substrate, wherein at least one deposition gas is provided through the showerhead. During the deposition of the deposition layer, a second purge gas containing at least one component gas is caused to flow in from a position outside the showerhead within the processing chamber, thereby forming a flow curtain around an outer edge of the showerhead. A partial pressure of the at least one component gas is varied over time during the deposition of the deposition layer, where the deposition of the deposition layer has a non-uniformity, where the varying partial pressure varies the non-uniformity over time during the deposition of the deposition layer.

Description

This application is a divisional application of the invention patent application with application number 201980055085.4, application date August 16, 2019, and invention name “Method and apparatus for adjusting film uniformity”. CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority to U.S. Application No. 16 / 108,592, filed August 22, 2018, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present disclosure relates to the formation of semiconductor devices. More particularly, the present disclosure relates to the formation of semiconductor devices in a system wherein a plurality of stations are within a processing chamber. Summary of the Invention

[0003] To achieve the foregoing objectives, and in accordance with the purposes of the present disclosure, a method for processing a substrate is provided, wherein the substrate is located below a showerhead within a processing chamber. A deposition layer is deposited on the substrate, wherein at least one deposition gas is provided through the showerhead. During the deposition of the deposition layer, a second purge gas is caused to flow from a location outside the showerhead within the processing chamber to form a flow curtain around the outer edge of the showerhead, wherein the second purge gas comprises at least one component gas. During the deposition of the deposition layer, the partial pressure of the at least one component gas is varied over time, wherein the deposition of the deposition layer has a non-uniformity, and wherein the varying the partial pressure varies the non-uniformity over time during the deposition of the deposition layer.

[0004] In another implementation, a method for processing a substrate is provided, wherein the substrate is positioned below a showerhead within a processing chamber. A deposition layer is deposited on the substrate using a deposition process, wherein the deposition process causes at least one deposition gas to flow through the showerhead. During the deposition process, a second purge gas is flowed from a location outside the showerhead within the processing chamber to form a flow curtain around an outer edge of the showerhead, wherein the second purge gas can be adjusted to impart a dome-shaped or bowl-shaped non-uniformity to the deposition process.

[0005] In another embodiment, an apparatus for depositing a layer on a substrate is provided. A processing chamber is provided. At least two substrate supports are in the processing chamber. At least two nozzles are positioned in the processing chamber, wherein each of the at least two nozzles is positioned above a substrate support in the at least two substrate supports. At least two purge gas outlets are provided, wherein each of the at least two purge gas outlets is located above a nozzle in the at least two nozzles and is adapted to allow a second purge gas to flow in such that each of the at least two nozzles has a second purge gas curtain around an outer edge of each of the at least two nozzles. At least two actuators are provided, wherein each of the at least two actuators is adapted to tilt a nozzle in the at least two nozzles. A controller is controllably connected to the at least two actuators.

[0006] These and other features of the present disclosure will be described in more detail below in the detailed description of the disclosure and in conjunction with the following figures. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The present disclosure is illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements and in which:

[0008] Figure 1 It is a flow chart of the implementation plan.

[0009] Figure 2A is a schematic top cross-sectional view of a processing chamber that can be used in one embodiment.

[0010] Figure 2B yes Figure 2A A side cross-sectional view of the embodiment shown.

[0011] Figure 3 is a schematic diagram of a computer system that can be used to practice an embodiment.

[0012] Figure 4 is a flow chart of another embodiment.

[0013] Figure 5 It is a cross-sectional schematic diagram of another embodiment. DETAILED DESCRIPTION

[0014] The disclosed content will now be described in detail with reference to several preferred embodiments thereof as shown in the accompanying drawings. In the following description, numerous specific details are set forth to provide a thorough understanding of the present disclosure. However, it will be apparent to those skilled in the art that the present disclosure can be practiced without some or all of these specific details. In other instances, well-known processing steps and / or structures have not been described in detail to avoid unnecessarily obscuring the present disclosure.

[0015] Figure 1 Flowchart of one embodiment. A second purge gas is changed (step 104). The second purge gas includes at least one component gas. The change in the second purge gas changes the partial pressure of the at least one component gas over time. Simultaneously, an atomic layer deposition (ALD) process is performed (step 108). The ALD process (step 108) includes a plurality of cycles, wherein each cycle includes providing a first reactant (step 112), purging the first reactant (step 114), providing a second reactant (step 116), and purging the second reactant (step 118).

[0016] Figure 2A FIG. 1 is a schematic cross-sectional top view of a process chamber 200 having four process stations used in one embodiment. Figure 2B yes Figure 2A 2. The process chamber 200 is shown in FIG. 2. The process chamber 200 has a chamber wall 204. Four processing stations are positioned within the chamber wall 204. Each processing station comprises a pedestal 212 for supporting a substrate 208, a showerhead 216 for providing gas to the substrate 208 below a showerhead 216, and a manifold 220 connecting the showerhead 216 to a gas source 222. In this embodiment, the gas source 222 comprises a first reactant source 228, a second reactant source 232, and a primary purge gas source 236. A second purge gas outlet 224 is fluidically connected to the second purge gas source 226. In this embodiment, the second purge gas outlet 224 is in the shape of a cylindrical collar around the manifold 220. The cylindrical collar has holes so that the second purge gas flows outward in a radial direction above the top of the showerhead 216. Controller 235 is controllably connected to gas source 222, second sweep gas source 226, radio frequency (RF) power system 240, and vacuum system 244. An example of such a chamber is the Striker manufactured by Lam Research Corporation (Fremont, CA). TM Oxide system.

[0017] Figure 33 is a high-level block diagram illustrating a computer system 300 suitable for implementing the controller 235 used in the embodiments. Computer systems can have many physical forms, from integrated circuits, printed circuit boards, and small handheld devices to large-scale computers. The computer system 300 includes one or more processors 302 and may also include an electronic display device 304 (for displaying graphics, text, and other data), a main memory 306 (e.g., random access memory (RAM)), a storage device 308 (e.g., a hard drive), a removable storage device 310 (e.g., an optical drive), a user interface device 312 (e.g., a keyboard, touch screen, keypad, mouse or other pointing device, etc.), and a communication interface 314 (e.g., a wireless network interface). The communication interface 314 allows software and data to be transferred between the computer system 300 and external devices via a link. The system may also include a communication infrastructure 316 (e.g., a communication bus, crossbar, or network) connected to the above-mentioned devices / modules.

[0018] The information transmitted via the communication interface 314 can be in the form of signals such as electronic, electromagnetic, optical, or other signals that can be received by the communication interface 314 via a communication link that carries the signals and can be implemented using wires or cables, optical fibers, telephone lines, cellular telephone links, radio frequency links, and / or other communication channels. Utilizing such a communication interface, it is contemplated that the one or more processors 302 can receive information from a network or output information to a network while performing the above-described method steps. Furthermore, the method embodiments of the present invention can be executed solely on a processor or can be executed over a network such as the Internet in conjunction with a remote processor that shares a portion of the processing.

[0019] The term "non-transitory computer-readable medium" is generally used to refer to media such as main memory, secondary memory, removable storage devices, and storage devices such as hard disks, flash memory, disk drive memory, CD-ROMs, and other forms of persistent memory, and should not be interpreted as encompassing transient subject matter such as carrier waves or signals. Examples of computer code include machine code (such as that produced by a compiler) and files containing higher-level code that are executed by a computer using an interpreter. A computer-readable medium may also be computer code that is transmitted by a computer data signal embodied in a carrier wave and represents a sequence of instructions that can be executed by a processor.

[0020] In one example embodiment, substrate 208 is placed on susceptor 212. A modified flow of a second purge gas is provided (step 104). In this example, the second purge gas is oxygen (O2). Oxygen is at least one component gas of the second purge gas. In this example, the flow rate of the second purge gas is modified by increasing the flow rate of O2 (step 104). As a result, the partial pressure of O2 increases over time.

[0021] While changing the flow rate of the second purge gas (step 104), an atomic layer deposition process (step 108) is provided, which deposits the ALD layer. The atomic layer deposition process (step 108) includes multiple cycles, each of which includes providing a first reactant (step 112), purging the first reactant (step 114), providing a second reactant (step 116), and purging the second reactant (step 118). An example of a recipe for the atomic layer deposition process (step 108) provides a first reactant that is 400 seem of aminosilane (step 112). A silicon-containing precursor layer is deposited. After 0.4 seconds, the flow of the first reactant through the showerhead 216 is stopped. The first purge gas flows through the showerhead 216 to the station (step 114). In this example, the first purge gas is argon and oxygen (O2). The flow of the first purge gas is stopped. The second reactant flows into the processing chamber through the showerhead 216 (step 116). In this example, an oxidizing gas of 13,000 sccm of Ar and 1500 sccm of O2 is flowed as the second reactant. The oxidizing gas is converted into a plasma. In this example, 100 to 500 watts of RF is provided at a frequency of 13.56 (megahertz) MHz. The plasma from the oxidizing gas converts the deposited silicon-containing precursor layer into silicon oxide, which is part of the ALD layer. After 0.25 seconds, the flow of the second reactant into the processing chamber is stopped. A purge gas is flowed into the processing chamber to purge the second reactant gas (step 118). The flow of the second purge gas is stopped. The cycle is then repeated starting with the step of flowing the precursor gas into the processing chamber.

[0022] The second purge gas 248 flows from the second purge gas outlet 224 to the top of the showerhead 216 to form a second purge gas curtain 252 around the outer edge of the showerhead 216 .

[0023] Without wishing to be bound by theory, it is believed that temporal variation of the second purge gas affects deposition at the outer edge of substrate 208, thereby providing tuned radial non-uniformity. Radial non-uniformity can result in increasing or decreasing deposition along the radial distance from the center. In one example, the thickness of the deposition increases rather than decreases along the radial distance. In another example, the thickness of the deposition decreases rather than increases along the radial distance. This radial non-uniformity can result in a bowl-shaped or dome-shaped profile. In this example, temporal variation of the second purge gas produces a tuned variation of the bowl-shaped profile. Furthermore, temporal variation improves pattern loading. When the second purge gas is oxygen, oxygen is difficult to ignite. Increasing the flow rate of the second purge gas over time can make the outer processing region more difficult to ignite over time. Furthermore, increasing the flow rate of the second purge gas over time can increase the effect of the purge gas on the outer regions of the wafer over time.

[0024] A complementary non-uniform process is provided (step 122). The ALD process (step 108) and the complementary non-uniform process (step 122) are considered complementary when the resulting product is more radially uniform than the product formed by the complementary non-uniform process (step 122) alone and the ALD process (step 108) alone. Examples of the complementary non-uniform process (step 122) can be an etch-back process, a double patterning process, or a gap, trench, hole, or seam fill process used in applications such as shallow trench isolation (STI) or in the manufacture of memory devices such as dynamic random access memory (DRAM), NAND gates, static random access memory (SRAM), and phase change random access memory (PCRAM).

[0025] In other embodiments, the partial pressure of at least one component gas can be varied by maintaining a constant flow rate of the second sweep gas and varying the ratio of at least one component gas to another gas in the second sweep gas. In various embodiments, the at least one component gas is one of argon (Ar), helium (He), nitrogen (N2), and O2. In exemplary embodiments, the second sweep gas can be pure O2, N2, Ar, carbon monoxide (CO), carbon dioxide (CO2), ozone (O3), or He. In other exemplary embodiments, the second sweep gas can be a mixture of O2 and N2 with a flow ratio of molecules ranging from 3:1 to 1:3. In other exemplary embodiments, the second sweep gas can be a mixture of O2 and Ar or He with a flow ratio of molecules ranging from 3:1 to 1:3. In other embodiments, other gases that are inert to the ALD process and are not ignited by the plasma during the ALD process can be used. Because the second sweep gas is not ignited by the ALD process and is inert, the second sweep gas can provide isolation between adjacent sites to prevent crosstalk.

[0026] In other embodiments, instead of providing the complementary non-uniform process (step 122) after the ALD process (step 108) and changing the second purge gas (step 104), the complementary non-uniform process (step 122) can be performed before the ALD process (step 108) and the changing of the second purge gas (step 104). In such embodiments, the complementary non-uniform process (step 122) forms a stack having radial non-uniformity that is complementary to the radial non-uniformity of the ALD process (step 108) performed simultaneously with the changing of the second purge gas (step 104).

[0027] In some embodiments, the changing of the second purge gas (step 104) involves changing the second purge gas during the entire duration of the ALD process (step 108). In some embodiments, the changing of the second purge gas (step 104) does not involve changing the second purge gas during the entire duration of the ALD process (step 108), but rather involves changing the second purge gas during at least a portion of the duration of the ALD process (step 108). In an exemplary embodiment, the changing of the second purge gas (step 104) involves changing the second purge gas during at least half of the duration of the ALD process (step 108).

[0028] Figure 4 4 is a high-level flow chart of a method used in another embodiment. A substrate 208 is processed by performing an ALD process using a second sweep gas (step 404). The flow rate and composition of the second sweep gas can adjust radial non-uniformity. An additional process is performed on the substrate 208 (step 408), wherein the additional process (step 408) causes radial non-uniformity. The radial non-uniformity of the resulting product on the substrate is measured (step 412). The measured radial non-uniformity is the sum of the radial non-uniformity of the ALD process (step 404) and the radial non-uniformity of the additional process (step 408). If the measured radial non-uniformity is unsatisfactory, the second sweep gas formulation is adjusted (step 420). This may require adjusting the flow rate of the second sweep gas and / or the composition of the second sweep gas. Steps 404 to 420 are repeated until the measured radial non-uniformity is satisfactory (step 416). A satisfactory formulation for the second sweep gas has been determined. The determined satisfactory second sweep gas formulation is used to process a subsequent substrate (step 424). Additional processing is performed on each substrate (step 428).

[0029] The atomic layer deposition process (steps 404 and 424) can use the same atomic layer deposition process (step 108) as described in the previous embodiment. The recipe of the second purge gas causes the atomic layer deposition process (steps 404 and 424) to have radial non-uniformity that complements the radial non-uniformity of the additional process (steps 408 and 428).

[0030] In some embodiments, this additional process (step 428) can be performed before the ALD using a second purge gas (step 424). In various embodiments, the second purge gas used above can be used. An example of this additional process can be a carbon trimming process. Other examples of this additional process can be other processes used during double or multiple patterning. During double or multiple patterning, the feature size is reduced to a power of 2. As the feature size decreases, the number of defects caused by non-uniformity increases. Providing a method to increase uniformity in a double or multiple patterning process can reduce defects. Various embodiments use a second purge gas as an additional parameter to provide tuned non-uniformity that complements other processes used for double or multiple patterning.

[0031] In other embodiments, the second sweep gas can be used with a chemical vapor deposition (CVD) process or a plasma enhanced chemical vapor deposition (PECVD) process. In such embodiments, the flow rate of the second sweep gas can be varied while the CVD or PECVD process is being performed. In other embodiments, the flow rate of the second sweep gas is adjusted to impart a dome-shaped or bowl-shaped non-uniformity to the CVD or PECVD process.

[0032] Figure 5 2 is a cross-sectional side view of a process chamber 200 used in another embodiment. The process chamber 200 has a chamber wall 204. Four process stations are positioned within the chamber wall 204. Each process station includes a base 212 for supporting a substrate 208, a showerhead 216 for providing gas to the substrate 208 below a showerhead 216, and a manifold 220 connecting the showerhead 216 to a gas source. A second purge gas outlet 224 is fluidically connected to a second purge gas source. In this embodiment, the second purge gas outlet 224 has the shape of a cylindrical collar surrounding the manifold 220. The cylindrical collar 224 has holes 502 so that the second purge gas flows outward in a radial direction above the top of the showerhead 216. A showerhead actuator 504 is mechanically connected to the showerhead 216. The controller 235 is controllably connected to the showerhead actuator 504.

[0033] The showerhead actuator 504 is capable of adjusting the tilt of the showerhead 216. The controller 235 enables adjustment of the showerhead 216 during or between treatments. Tilting the showerhead 216 can be used to create azimuthal non-uniformity in the flow of the second sweep gas. Tilting the showerhead 216 also changes the gap spacing between the showerhead 216 and the susceptor 212, thereby changing the power delivery between the showerhead 216 and the susceptor 212. This change in spacing is azimuthal non-uniform.

[0034] Subsequent processes may not be uniform in azimuth. The tilt of the showerhead 216 during the deposition process is designed to produce azimuth non-uniformity that is complementary to the azimuth non-uniformity caused by the subsequent process. These azimuth non-uniformities are considered complementary if the resulting product after both processes are performed is more uniform in azimuth than the product formed by the complementary non-uniform processes alone.

[0035] Although the present disclosure has been described in terms of several preferred embodiments, there are changes, modifications, permutations, and various alternative equivalents that fall within the scope of the present disclosure. It should also be noted that there are many alternative ways to implement the methods and apparatus of the present disclosure. Therefore, the following appended claims are intended to be interpreted as including all such changes, modifications, permutations, and various alternative equivalents that fall within the true spirit and scope of the present disclosure.

Claims

1. A method for processing a substrate, wherein the substrate is positioned below a showerhead within a processing chamber, the method comprising: depositing a deposition layer on the substrate, wherein at least one deposition gas is provided through the showerhead; During the deposition of the deposition layer, flowing a second purge gas from a location outside the showerhead within the processing chamber to form a flow curtain around an outer edge of the showerhead, wherein the second purge gas comprises at least one component gas; and During the depositing of the deposition layer, a partial pressure of the at least one component gas is varied over time, wherein the depositing of the deposition layer has non-uniformity, wherein during the depositing of the deposition layer, the varying the partial pressure varies the non-uniformity over time. 2 . The method of claim 1 , wherein varying the partial pressure of the at least one component gas comprises varying a flow rate of the at least one component gas.

3. The method of claim 1, wherein the at least one component gas comprises at least one of Ar, He, O2, CO, CO2, O3, or N2. The method of claim 1 , wherein the non-uniformity comprises radial non-uniformity. The method of claim 4 , wherein the deposited layers increase in radial distance from the center.

6. A method for processing a substrate, wherein the substrate is located below a showerhead in a processing chamber, the method comprising: depositing a deposition layer on the substrate using a deposition process, wherein the deposition process flows at least one deposition gas through the showerhead; and During the deposition process, a second purge gas is flowed from a location outside the showerhead within the processing chamber to form a flow curtain around an outer edge of the showerhead, wherein the second purge gas can be adjusted to provide a dome-shaped or bowl-shaped non-uniformity to the deposition process.

7. The method of claim 6, wherein the second purge gas comprises at least one of Ar, He, O2, CO, CO2, O3, or N2. The method of claim 6 , wherein the non-uniformity is a radial non-uniformity.

9. The method of claim 8, wherein the deposited layers increase in radial distance from the center.

10. The method of claim 8, wherein the deposited layers decrease along a radial distance from a center.

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