Silicon-based deposition for semiconductor processing

Abstract

A method for processing a stack having a carbon-based patterned mask is provided. The stack is placed in an etching chamber. A silicon oxide layer is deposited on the carbon-based patterned mask by atomic layer deposition by providing a plurality of cycles, wherein each of the plurality of cycles includes providing a silicon precursor deposition phase, which includes: flowing an atomic layer deposition precursor gas into the etching chamber, wherein the atomic layer deposition precursor gas is deposited without plasma, and stopping the flow of the atomic layer deposition precursor gas; and providing an oxygen deposition phase, which includes: flowing ozone gas into the etching chamber, wherein the ozone gas combines with the deposited precursor gas without plasma, and stopping the flow of the ozone gas into the etching chamber. A portion of the silicon oxide layer is etched. The stack is removed from the etching chamber.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Application No. 15 / 492,662, filed April 20, 2017, the entire contents of which are incorporated herein by reference for all purposes. Technical Field

[0003] The present disclosure relates to a method of forming a semiconductor device on a semiconductor wafer. More particularly, the present disclosure relates to forming a silicon-based deposition in the formation of a semiconductor device. Background Art

[0004] In forming semiconductor devices, various layers are deposited. Summary of the invention

[0005] To achieve the aforementioned objectives and in accordance with the objectives of the present disclosure, a method for processing a stack having a carbon-based patterned mask is provided. The stack is placed in an etching chamber. A silicon oxide layer is deposited on the carbon-based patterned mask by atomic layer deposition, by providing multiple cycles without consuming or corroding the carbon-based patterned mask, wherein each of the multiple cycles includes providing a silicon precursor deposition phase, which includes: flowing an atomic layer deposition precursor gas containing a silicon-containing component into the etching chamber, wherein the atomic layer deposition precursor gas is deposited on the carbon-based patterned mask without plasma, and stopping the flow of the atomic layer deposition precursor gas; and providing an oxygen deposition phase, which includes: flowing ozone gas into the etching chamber, wherein the ozone gas combines with the deposited precursor gas without plasma, and stopping the flow of the ozone gas into the etching chamber. Etching a portion of the silicon oxide layer, which includes: flowing a forming gas containing a fluorocarbon into the etching chamber, forming the forming gas into a plasma, thereby etching the silicon oxide layer, and stopping the flow of the forming gas. The stack is removed from the etch chamber.

[0006] In another embodiment, a device for etching an etch layer in a stack is provided, wherein the etch layer is below a carbon-based patterned mask. A processing chamber is provided. A substrate support is within the processing chamber. An inlet provides the processing gas into the processing chamber. A gas source provides the processing gas to the inlet, wherein the gas source includes: an ozone source, an atomic layer deposition precursor silicon-containing gas source, and a forming gas source. An exhaust pump extracts gas from the processing chamber. A lower electrode is disposed below the substrate support. An electrode or coil is within or near the processing chamber. At least one power source provides power to the lower electrode and the electrode or coil. A controller is controllably connected to the gas source and at least one power source. The controller includes at least one processor and a computer-readable medium. The computer-readable medium includes computer-readable code for the following operations: depositing a silicon oxide layer on the carbon-based patterned mask by atomic layer deposition by providing multiple cycles, wherein each of the multiple cycles includes providing a silicon precursor deposition phase, which includes: flowing an atomic layer deposition precursor gas containing a silicon-containing component into the etching chamber, wherein the atomic layer deposition precursor gas is deposited on the carbon-based patterned mask without plasma, and stopping the flow of the atomic layer deposition precursor gas; and providing an oxygen deposition phase, which includes: flowing ozone gas into the etching chamber, wherein the ozone gas combines with the deposited precursor gas without plasma, and stopping the flow of the ozone gas into the etching chamber; and computer-readable code for etching the silicon oxide layer, which includes: flowing a forming gas containing a fluorocarbon into the etching chamber, and forming the forming gas into plasma, thereby etching the silicon oxide layer.

[0007] These and other features of the present invention will be described in more detail below in the detailed description of the embodiments and in conjunction with the following figures. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The present disclosure is illustrated by way of example and not limitation in the accompanying figures and in which like reference numerals indicate similar elements and in which:

[0009] Figure 1 is a high-level flow chart of one implementation scheme.

[0010] Figure 2A -F is a schematic cross-sectional view of a stack processed according to one embodiment.

[0011] Figure 3 is a schematic diagram of an etching chamber that can be used in one embodiment.

[0012] Figure 4 is a schematic diagram of a computer system that can be used to practice an embodiment.

[0013] Figure 5 is a detailed flow chart of the deposition layer formation steps.

[0014] Figure 6 is a more detailed flow chart of the precursor deposition stage.

[0015] Figure 7 is a more detailed flow chart of the oxygen deposition stage.

[0016] Figure 8 is a more detailed flow chart of the steps for partially etching a silicon oxide based layer. DETAILED DESCRIPTION

[0017] Embodiments of the present invention will now be described in detail with reference to several preferred embodiments shown in the accompanying drawings. In the following description, many specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention can be implemented without some or all of these specific details. In other cases, known process steps and / or structures are not described in detail to avoid making the present invention unclear unnecessarily.

[0018] Figure 1 1 is a high-level flow chart of an embodiment. In this embodiment, the stack is placed in a processing chamber (step 104). The carbon mask of the stack is trimmed and the BARC is etched (step 108). A silicon oxide base layer is deposited over the carbon mask by atomic layer deposition (ALD) (step 112). The silicon oxide base layer is etched (step 116). The carbon mask and BARC are removed (step 120). The etch layer under the silicon oxide base layer is etched (step 124). The stack is removed from the processing chamber (step 128).

[0019] Implementation

[0020] In a preferred embodiment, the stack is placed in a processing chamber (step 104). Figure 2A 2 is a schematic cross-sectional view of a stack 200 on a substrate 204. The substrate 204 is below an etch layer 208, which is below an amorphous carbon layer 212, which is below a hard mask layer 216, which is silicon in this example. The hard mask layer 216 is below a BARC layer 220, which is below a carbon-based patterned mask layer 224. In this example, the carbon-based mask layer 224 is a photoresist. In other embodiments, there may be different, additional, or fewer layers between the layers of the stack 200. In addition, various layers such as the etch layer 208 may be made of multiple layers such as a carbon mask layer on a silicon-based layer.

[0021] Figure 3An example of a plasma processing system 300 that can be used to process a stack 200 according to one embodiment of the present invention is schematically shown. The plasma processing system 300 includes a plasma reactor 302 having a plasma processing chamber 304 surrounded by a chamber wall 362. A plasma power source 306 tuned by a matching network 308 provides power to a TCP coil 310 located near a power window 312 to generate a plasma 314 in the plasma processing chamber 304 by providing inductively coupled power. The TCP coil (upper power source) 310 can be configured to generate a uniform diffusion profile within the plasma processing chamber 304. For example, the TCP coil 310 can be configured to generate a toroidal power distribution in the plasma 314. The power window 312 is set to separate the TCP coil 310 from the plasma processing chamber 304 while allowing energy to be transferred from the TCP coil 310 to the plasma processing chamber 304. Wafer bias voltage power source 316 tuned by matching network 318 provides power to electrode 320 to set a bias voltage on process layer 204 supported above electrode 320. Controller 324 sets points for plasma power source 306 and wafer bias voltage power source 316.

[0022] The plasma power source 306 and the wafer bias voltage power source 316 can be configured to work with a specific radio frequency, for example, at 13.56MHz, 27MHz, 2MHz, 400kHz or a combination thereof. The plasma power source 306 and the wafer bias voltage power source 316 can be appropriately sized to provide a certain range of power to achieve desired processing performance. For example, in one embodiment of the present invention, the plasma power source 306 can provide a power in the range of 50 to 5000 watts, and the wafer bias voltage power source 316 can provide a bias voltage in the range of 20 to 2000V. In addition, the TCP coil 310 and / or the electrode 320 can be composed of two or more sub-coils or sub-electrodes, and the sub-coils or sub-electrodes can be provided with power by a single power source or by multiple power sources.

[0023] like Figure 3As shown, the plasma processing system 300 also includes a gas source / gas supply mechanism 330. In this embodiment, the gas source 330 includes a trim gas source 350, a silicon precursor source 352, an ozone gas source 354, a forming gas source 356, a stripping gas source 358, and a feature etching gas source 360. The gas source / gas supply mechanism 330 provides gas to a gas feed 336 in the form of a nozzle. The process gas and byproducts are removed from the plasma processing chamber 304 by a pressure control valve 342 and a pump 344, which are also used to maintain a specific pressure in the plasma processing chamber 304. The gas source / gas supply mechanism 330 is controlled by a controller 324. The embodiments of the present invention can be implemented using Kiyo from Lam Research Corp. of Fremont, California.

[0024] Figure 4 4 is a high-level block diagram showing a computer system 400, which is suitable for implementing the controller 324 used in the embodiment. The computer system can have a variety of physical forms, ranging from integrated circuits, printed circuit boards, and small handheld devices to giant supercomputers. The computer system 400 includes one or more processors 402, and can further include an electronic display device 404 (for displaying graphics, text and other data), a main memory 406 (e.g., random access memory (RAM)), a storage device 408 (e.g., a hard disk drive), a removable storage device 410 (e.g., an optical drive), a user interface device 412 (e.g., a keyboard, a touch screen, a keypad, a mouse or other positioning devices, etc.) and a communication interface 414 (e.g., a wireless network interface). The communication interface 414 enables software and data to be transmitted between the computer system 400 and an external device through a link. The system can also include a communication infrastructure 416 (e.g., a communication bus, a cross-over bar (cross-over bar), or a network), and the aforementioned device / module is connected to the communication infrastructure 416.

[0025] The information transmitted via the communication interface 414 may be in the form of a signal that can be received by the communication interface 414 through a communication link, such as an electronic, electromagnetic, optical, or other signal, which carries the signal and can be a communication link implemented using wires or cables, optical fibers, telephone lines, cellular phone links, radio frequency links, and / or other communication channels. Using such a communication interface, it is expected that one or more processors 402 can receive information from a network or can output information to a network during the implementation of the above-mentioned method steps. In addition, the method implementation can be executed only on the processor or can be executed in conjunction with a remote processor on a network such as the Internet, and the remote processor shares part of the processing.

[0026] The term "non-transitory computer-readable medium" is generally used to refer to media such as main memory, auxiliary memory, removable storage devices, and storage devices (e.g., hard disks, flash memory, hard drive memory, CD-ROMs, and other forms of permanent memory), and should not be interpreted as covering 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 including higher-level code executed by a computer using an interpreter. Computer-readable media may also be computer code transmitted by a computer data signal embodied in a carrier wave and represented as a sequence of instructions executable by a processor.

[0027] After the stack 200 is placed in the plasma processing system 300, the carbon-based mask layer 224 is trimmed and the BARC layer is etched (step 108). In this example, a trimming gas containing 50 sccm N2, 15 sccm O2, and 150 sccm He is flowed into the plasma processing chamber, providing a pressure of 5 mTorr. The plasma power source 306 provides 900 watts of TCP power. The BARC layer 220 can be etched before or after the trimming step. An example of BARC etching is to flow a BARC etching gas of 15 sccm O2, 5 sccm CH4, and 50 sscm Cl2 into the plasma processing chamber 304 at a pressure of 8 mTorr. The plasma power source 306 provides 400 watts of TCP power. A bias voltage of 60V is provided. Figure 2B is a cross-sectional view of the stack 200 after trimming the carbon-based mask layer 224 and etching the BARC layer 220 .

[0028] A silicon oxide-based layer is deposited using atomic layer deposition (step 112). Figure 5 is a more detailed flow chart of atomic layer deposition (step 112). Atomic layer deposition (step 112) includes multiple cycles, where each cycle includes a silicon precursor deposition (adsorption) phase (step 504) and an oxygen deposition (precursor oxidation) phase (step 508). Figure 6 is a more detailed flow chart of the precursor deposition phase (step 504). A silicon-containing precursor is introduced via vapor drawn from a container, which is maintained at a temperature to ensure consistent flow into the plasma processing chamber 304 (step 604). In this example, the silicon-containing precursor gas is aminosilane BTBAS (bis(tert-butylbutylamino)silane). Other precursors may also work, such as H2Si[N(C2H5)2]2 (SAM24). The silicon-containing precursor is deposited on the stack while the plasma is absent (step 608). After 4 seconds, the flow of the silicon-containing precursor is stopped (step 612). Figure 7is a more detailed flow chart of the oxygen deposition (SiO2 formation) phase (step 508). Ozone gas is flowed into the plasma processing chamber 304 (step 704). In this example, >50 sccm of O3 is flowed into the processing chamber 304. The pressure is maintained at >100 mTorr. Ozone gas is deposited on the stack while there is no plasma (step 708). After 2 seconds, the flow of ozone is stopped (step 712). Figure 2C is a cross-sectional view of the stack 200 after a silicon oxide-based layer 228 is deposited by atomic layer deposition for a specified number of cycles to achieve a target thickness of ALD oxide.

[0029] The silicon oxide-based layer 228 is partially etched or formed (step 116). Figure 8 804. FIG. 805 is a more detailed flow chart of the steps for partially etching the silicon oxide base layer 228. A forming gas is flowed into the plasma processing chamber 304 (step 804). In this example, the forming gas includes 100 sccm of CF4, 50 sccm of CHF3, and 9 sccm of O2 flowing into the processing chamber 304. The pressure is maintained at 5 mTorr. A plasma is formed from the forming gas (step 808). To form the forming gas into a plasma, 600 watts of TCP RF power is provided at 13.56 MHz. The bias voltage is maintained at 60 V. After the SiO2 is removed from the horizontal portion of the SiO2 layer at the top of the carbon lines and the space region, the flow of the forming gas is stopped (step 812). Figure 2D 2 is a cross-sectional view of the stack 200 after the silicon oxide-based layer 228 has been etched or formed (step 120). As shown, the horizontal surface of the silicon oxide-based layer 228 is etched away, thereby exposing the carbon-based mask layer 224. The remaining silicon oxide-based layer 228 forms sidewall spacers on the sides of the carbon-based mask layer 224.

[0030] The carbon mask is removed or stripped (step 120). In this example, the processing conditions provide a mask stripping gas of 150 sccm O2 and 150 sccm Ar at a chamber pressure of 10 mTorr. The mask stripping gas is formed into a plasma by providing a TCP power of 600 watts. Figure 2E is a cross-sectional view of stack 200 after removal of the carbon-based mask layer. In this embodiment, stripping of the carbon mask layer also removes the remaining BARC layer. The remaining silicon oxide-based layer 228 provides a pattern with twice the density of the carbon mask.

[0031] The amorphous carbon layer 212 and the hard mask layer 216 can be etched in situ after the carbon mask is stripped. An example of a Si (layer 216) etching process provides a Si etching gas of 50 sccm CF4 and 50 sccm Ar at a pressure of 5 mTorr. The Si etching gas is formed into a plasma by providing a 500 watt TCP power source with a 100V bias voltage. An example of a method for etching aC (layer 212) provides an amorphous carbon etching gas of 80 sccm SO2 and 90 sccm O2 at a pressure of 8 mTorr. The amorphous carbon etching gas is formed into a plasma by providing 800 watts of TCP power, a bias voltage of 350V. The recipe for etching the etching layer 208 (in this example, the Si film): 500 sccm HBr, 500 sccmHe, 15 sccm O2 at a pressure of 25 mTorr, a TCP power of 350W and a bias voltage of 300V. Etch the etching layer 208 (step 124). Figure 2E is a cross-sectional view of the stack 200 after etching the etch layer.

[0032] The resulting stack has features etched in the etch layer 208 with twice the density of the original pattern of the carbon-based mask layer. The method and apparatus enable ALD and etching for feature doubling and etching to be performed in the same process chamber on the same chuck without moving the stack.

[0033] Typically, fluorocarbon gases such as CF4 can be used to partially etch the silicon oxide based layer. In various embodiments, the carbon based layer can be amorphous carbon, an organic material, or a photoresist.

[0034] In various embodiments, the etching layer 208 may include multiple layers, including another carbon-based layer. The silicon oxide-based layer 228 may be used as a mask for etching the carbon-based layer. The silicon oxide-based layer 228 may be removed, and another silicon oxide-based layer may be provided by ALD. The silicon oxide layer may be partially etched and the carbon-based layer may be removed, thereby providing a patterned mask having a density four times that of the original pattern. Such a subsequent ALD process may use plasma for ALD. The apparatus is capable of providing ALD without plasma and ALD with plasma.

[0035] Although the present invention has been described according to several preferred embodiments, there are changes, modifications, permutations and various alternative equivalents that fall within the scope of the present invention. It should also be noted that there are many alternatives to the method and apparatus of the present invention. 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 invention.

Claims

1. A method for in-situ processing of a stack having a carbon-based patterned mask, comprising: placing the stack in an etching chamber; Depositing a silicon oxide layer on the carbon-based patterned mask by atomic layer deposition without consuming or corroding the carbon-based patterned mask by providing a plurality of cycles, wherein each cycle of the plurality of cycles comprises: A silicon precursor deposition phase is provided, comprising: flowing an atomic layer deposition precursor gas comprising a silicon-containing component into the etch chamber, wherein the atomic layer deposition precursor gas is deposited on the carbon-based patterned mask while in the absence of a plasma; and stopping the flow of the atomic layer deposition precursor gas; and An oxygen deposition stage is provided, comprising: flowing only an oxygen deposition gas consisting essentially of ozone gas into the etching chamber, wherein the ozone gas combines with the deposited precursor gas while being free of plasma, and stopping the flow of the oxygen deposition gas into the etching chamber; Etching a portion of the silicon oxide layer, comprising: flowing a forming gas comprising a fluorocarbon into the etching chamber; forming the forming gas into plasma to etch the silicon oxide layer; and stopping the flow of the shaping gas; and The stack is removed from the etch chamber. 2 . The method of claim 1 , further comprising trimming the carbon-based patterned mask after placing the stack in the etching chamber and before depositing the silicon oxide layer over the carbon-based patterned mask.

3. The method according to claim 2, further comprising: stripping the carbon-based patterned mask after etching the silicon oxide layer; as well as After stripping the carbon-based patterned mask and before removing the stack from the etching chamber, an etch layer beneath the silicon oxide layer is etched.

4. The method according to claim 3, wherein: The carbon-based patterned mask includes at least one of amorphous carbon, an organic material, or a photoresist.

5. The method according to claim 4, wherein: A BARC layer is below the carbon-based patterned mask, further comprising etching the BARC layer before depositing the silicon oxide layer over the carbon-based patterned mask.

6. The method according to claim 5, wherein: The silicon-containing component of the atomic layer deposition precursor gas is aminosilane BTBAS (bis(tert-butylbutylamino)silane) or H2Si[N(C2H5)2]2.

7. The method according to claim 6, wherein: The flow of ozone gas into the etching chamber provides a pressure greater than 100 mTorr.

8. The method according to claim 1, further comprising: stripping the carbon-based patterned mask after etching the silicon oxide layer; as well as After stripping the carbon-based patterned mask and before removing the stack from the etching chamber, an etch layer beneath the silicon oxide layer is etched.

9. The method according to claim 1, wherein: The carbon-based patterned mask includes at least one of amorphous carbon, an organic material, or a photoresist.

10. The method according to claim 1, wherein: A BARC layer is below the carbon-based patterned mask, further comprising etching the BARC layer before depositing the silicon oxide layer over the carbon-based patterned mask.

11. The method according to claim 1, wherein: The silicon-containing component of the atomic layer deposition precursor gas is aminosilane BTBAS (bis(tert-butylbutylamino)silane) or H2Si[N(C2H5)2]2.

12. The method according to claim 1, wherein: The flow of ozone gas into the etching chamber provides a pressure greater than 100 mTorr.

13. The method according to claim 5, wherein: The silicon-containing component of the atomic layer deposition precursor gas is H2Si[N(C2H5)2]2.

14. The method according to claim 1, wherein: The carbon-based patterned mask includes a photoresist.

15. An apparatus for etching an etching layer in a stack, wherein: The etching layer is below the carbon-based patterned mask, and the device comprises: Processing room; a substrate support within the processing chamber; a gas inlet for providing a process gas into the process chamber; a gas source for providing the process gas to the gas inlet, wherein the gas source comprises: Ozone sources; an atomic layer deposition precursor silicon-containing gas source; and a forming gas source; an exhaust pump for extracting gas from the process chamber; Lower electrode; Electrodes or coils; at least one power source for providing power to the lower electrode and the electrode or coil; and a controller controllably connected to the gas source and at least one power source, wherein the controller comprises: at least one processor; and A computer readable medium comprising: Computer readable code for depositing a silicon oxide layer on the carbon-based patterned mask by atomic layer deposition by providing a plurality of cycles, wherein each cycle of the plurality of cycles comprises: A silicon precursor deposition phase is provided, comprising: flowing an atomic layer deposition precursor gas comprising a silicon-containing component into the process chamber, wherein the atomic layer deposition precursor gas is deposited on the carbon-based patterned mask while in the absence of a plasma; and stopping the flow of the atomic layer deposition precursor gas; and An oxygen deposition stage is provided, comprising: flowing only an oxygen deposition gas consisting essentially of ozone gas into the process chamber, wherein the ozone gas combines with the deposited precursor gas while being free of plasma, and stopping the flow of the oxygen deposition gas into the process chamber; and Computer readable code for causing the silicon oxide layer to be etched by: flowing a forming gas comprising a fluorocarbon into the processing chamber; and The forming gas is formed into plasma to etch the silicon oxide layer.

16. The device according to claim 15, wherein: The gas source also includes: Trim gas source; a stripping gas source; and Feature etch gas source.

17. The device according to claim 16, wherein: The computer readable medium further comprises: Computer readable code for trimming the carbon-based patterned mask prior to depositing the atomic layer deposition, comprising: computer readable code for flowing a trim gas from the trim gas source into the process chamber; computer readable code for providing power to said electrode or coil, thereby converting said trimming gas into a plasma, resulting in said trimming of said carbon-based patterned mask; and computer readable code for stopping the flow of said stripping gas; and Computer readable code for stripping the carbon-based patterned mask after etching the silicon oxide layer, comprising: computer readable code for flowing a stripping gas from the stripping gas source into the processing chamber; computer readable code for providing power to said electrode or coil to convert said stripping gas into a plasma, resulting in said stripping of said carbon-based patterned mask; and computer readable code for stopping the flow of said stripping gas; and Computer readable code for etching the etch layer after stripping the carbon-based patterned mask, comprising: computer readable code for flowing a feature etch gas from the feature etch gas source into the process chamber; Computer readable code for providing power to the electrode or coil to convert the characteristic etching gas into a plasma, resulting in etching of the etching layer; and Computer readable code for stopping the flow of said feature etching gas.

18. The device according to claim 17, wherein: The atomic layer deposition precursor silicon-containing gas source provides aminosilane BTBAS (bis(tert-butylbutylamino)silane) or H2Si[N(C2H5)2]2.

19. The device according to claim 18, wherein: A BARC layer is below the carbon-based patterned mask, further comprising computer readable code for etching the BARC layer before depositing the silicon oxide layer over the carbon-based patterned mask.

20. The device according to claim 17, wherein: The atomic layer deposition precursor silicon-containing gas source provides H2Si[N(C2H5)2]2.

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