Pressure bulk compensation to stabilize trim and deposition process cd variations

Abstract

A controller includes an accumulation determiner configured to determine a first accumulation value indicative of an amount of material accumulation on a surface within a process chamber, and a pressure controller configured to obtain the first accumulation value, obtain at least one of a setpoint pressure associated with an etch step and a duration of the etch step, and adjust a control parameter based on (i) the first accumulation value and (ii) at least one of the setpoint pressure and the duration of the etch step for controlling the pressure within the process chamber during the etch step.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Application No. 62 / 943,515, filed December 4, 2019. The entire disclosure of the above-cited application is incorporated herein by reference. Technical Field

[0003] This disclosure relates to a dual patterning process in an atomic layer deposition substrate processing chamber. Background Technology

[0004] The background description provided herein is for the purpose of presenting the general context of this disclosure. The work of the currently designated inventors, within the scope described in this background section and in the various aspects of the specification that could not be identified as prior art at the time of filing, neither expressly nor impliedly acknowledges that it is prior art to this disclosure.

[0005] Substrate processing systems can be used to process substrates, such as semiconductor wafers. Examples of substrate processing include etching, deposition, photoresist removal, and so on. During processing, the substrate is placed on a substrate support, such as an electrostatic chuck, and one or more processing gases can be introduced into the processing chamber.

[0006] The one or more process gases can be delivered to the processing chamber via a gas delivery system. In some systems, the gas delivery system includes a manifold that is connected via one or more conduits to a nozzle located in the processing chamber. In some examples, the process utilizes atomic layer deposition (ALD) to deposit a thin film on a substrate. Summary of the Invention

[0007] A controller includes: an accumulation determiner configured to determine a first accumulation value indicating the amount of material accumulated on a surface within a processing chamber; and a pressure controller configured to obtain the first accumulation value, obtain at least one of a setpoint pressure associated with an etching step and the duration of the etching step, and adjust control parameters based on (i) the first accumulation value and (ii) at least one of the setpoint pressure and the duration of the etching step in order to control the pressure within the processing chamber during the etching step.

[0008] In other features, the control parameter is an amount of the pressure, and the pressure controller is configured to determine a first adjustment factor corresponding to the first accumulation value using stored data and adjust the amount of the pressure according to the first adjustment factor. The stored data is a polynomial that associates the accumulation values with the respective adjustment factors. The first adjustment factor is a ratio of an amount of pressure needed to compensate for the accumulation to the setpoint pressure. The pressure controller is configured to multiply the setpoint pressure by the first adjustment factor to adjust the control parameter.

[0009] In other features, the accumulation determiner is configured to calculate the first accumulation value based on at least one of a number of etching steps performed in the processing chamber, a number of cycles of etching steps and deposition steps performed in the processing chamber, a total duration of etching steps and deposition steps performed in the processing chamber, and a number of substrates processed in the processing chamber. The control parameter is the duration of the etching steps, and the pressure controller is configured to determine a first adjustment factor corresponding to the first accumulation value using stored data and adjust the duration of the etching steps according to the first adjustment factor.

[0010] In other features, the first adjustment factor corresponds to an amount to increase the duration of the etching steps to compensate for the accumulation. The pressure controller is configured to multiply the duration of the etching steps by the first adjustment factor to adjust the control parameter. The etching steps are trim steps. A system includes a controller that is further configured to perform spacer deposition steps in the processing chamber after the trim steps.

[0011] A method includes obtaining a first accumulation value indicative of an amount of material accumulation on a surface in a processing chamber, obtaining at least one of a setpoint pressure associated with an etching step and a duration of the etching step, and adjusting a control parameter based on (i) the first accumulation value and (ii) at least one of the setpoint pressure and the duration of the etching step for controlling the pressure in the processing chamber during the etching step.

[0012] In other features, the control parameter is an amount of the pressure. The method further includes determining a first adjustment factor corresponding to the first accumulation value using stored data and adjusting the amount of the pressure according to the first adjustment factor. The stored data is a polynomial that associates the accumulation values with the respective adjustment factors. The first adjustment factor is a ratio of an amount of pressure needed to compensate for the accumulation to the setpoint pressure. The method further includes multiplying the setpoint pressure by the first adjustment factor to adjust the control parameter.

[0013] In other features, the method further includes determining the first accumulation value based on at least one of a number of etching steps performed within the processing chamber, a number of cycles of etching steps and deposition steps performed within the processing chamber, a total duration of etching steps and deposition steps performed within the processing chamber, and a number of substrates processed within the processing chamber. The control parameter is the duration of the etching step, and the method further includes determining a first adjustment factor corresponding to the first accumulation value using the stored data, and adjusting the duration of the etching step according to the first adjustment factor.

[0014] In other features, the first adjustment factor corresponds to an amount to increase the duration of the etching step to compensate for the accumulation. The etching step is a trim step, and the method further includes performing an spacer layer deposition step within the processing chamber after the trim step.

[0015] A controller includes an accumulation determiner configured to determine a first accumulation value indicative of an amount of material accumulation on a surface within a processing chamber, and a pressure controller configured to obtain the first accumulation value, obtain at least one of a setpoint pressure and a duration of a deposition step related to the deposition step, and adjust a control parameter based on (i) the first accumulation value and (ii) at least one of the setpoint pressure and the duration of the deposition step in order to control the pressure within the processing chamber during the deposition step.

[0016] In other features, a pressure profile corresponds to a range of variation of a deposition amount. The pressure controller is configured to increase a pressure within the processing chamber as a first accumulation value increases according to the pressure profile. The pressure controller is configured to decrease a pressure within the processing chamber as a first accumulation value decreases according to the pressure profile.

[0017] Further scope of the applicability of the present disclosure will become apparent from the detailed description, claims, and drawings. The detailed description and specific examples are given for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0018] The present disclosure will become more fully understood from the detailed description and drawings, wherein:

[0019] Figure 1 A functional block diagram of one example of a substrate processing system according to the present disclosure;

[0020] Figures 2A-2K One example of a dual patterning atomic layer deposition process is shown in accordance with the present disclosure;

[0021] Figures 3A-3D This disclosure illustrates an exemplary trimming step in a self-aligned dual patterning process;

[0022] Figure 4 This is an exemplary method for compensating for accumulations in the processing chamber to minimize wafer-to-wafer (WtW) variability during the trimming step, according to the present disclosure.

[0023] Figure 5 An exemplary controller configured to compensate for accumulation in a processing chamber according to this disclosure.

[0024] Figure 6 This is an exemplary method for compensating for accumulations in the processing chamber to minimize wafer-to-wafer (WtW) variability during the deposition step, according to the present disclosure.

[0025] In the accompanying drawings, reference numerals may be used repeatedly to identify similar and / or identical elements. Detailed Implementation

[0026] In film deposition processes such as atomic layer deposition (ALD), various properties of the deposited film vary spatially (i.e., in the xy coordinates of a horizontal plane). For example, substrate processing tools may have corresponding specifications for film thickness non-uniformity (NU). Film thickness NU can be measured as the full range, half range, and / or standard deviation of a set of measurements taken at predetermined locations on the surface of a semiconductor substrate. In some examples, NU can be reduced, for example, by addressing the direct cause of the NU. NU can also be addressed by introducing offsetting NUs to compensate for and eliminate existing NUs. In some examples, material may be intentionally deposited non-uniformly to compensate for known non-uniformities in other steps (e.g., previous or subsequent) in the process. Material may also be intentionally removed non-uniformly.

[0027] Dual patterning (DPT) ALD processes (e.g., self-aligned dual patterning (or SADP) processes) may include (but are not limited to) the following steps: various deposition steps, photolithography steps, trimming steps, and sacrificial spacer layer deposition steps. Each step may have a null dimension (NU) and an associated NU that affects the overall critical dimension (CD). For example, a trimming step may be performed between a photolithography step and a spacer layer deposition step to reduce the CD. However, trimming the NU may result in non-uniform dual patterning. Non-uniform dual patterning increases CD imbalance and leads to poor yield. Trimmed NUs can be characterized as radial NUs and azimuth NUs.

[0028] The CD NU and imbalance of a specific substrate can be characterized by in-wafer (WiW) variability. Conversely, the CD NU and imbalance between different substrates can be characterized by wafer-to-wafer (WtW) variability. Minimizing WtW variability in CD NU and imbalance can be challenging in DPT processes. For example, trimming and subsequent spacer deposition steps can be performed in the same processing chamber to increase throughput. The deposition step causes material to accumulate on the surfaces (e.g., inner walls) within the processing chamber. Additionally, etching byproducts (e.g., byproducts from the trimming step) accumulate on the surfaces of the processing chamber. This material accumulation within the processing chamber alters the overall impedance of the chamber. This change in overall impedance, in turn, affects the etching rate. Therefore, the accumulation of material and the resulting change in chamber impedance increase the WtW variability of the trimming step.

[0029] Systems and methods based on the principles of this disclosure are configured to reduce (e.g., in a trimming step) WtW deposition and etching variability caused by material accumulation on the inner surface of the processing chamber. For example, deposition and etching rates are further affected by the pressure within the processing chamber. Therefore, in one example, when the deposition or etching rate changes due to accumulation (e.g., increases or decreases), a pressure control parameter can be adjusted to compensate for the changed deposition and / or etching rates. In other words, the pressure can be adjusted to maintain desired deposition and etching rates. As an example, an accumulation value can be determined. The accumulation value represents the amount of material accumulated on the surface within the processing chamber. The setpoint pressure corresponding to the desired pressure within the processing chamber is adjusted based on the accumulation value. Therefore, variations caused by changes in the impedance of the processing chamber are reduced. In another example, the control parameter is the duration of deposition (e.g., the duration of the corresponding deposition step). In yet another example, the control parameter is the duration of etching (e.g., the duration of the corresponding trimming step). Therefore, the duration of deposition or etching can be increased or decreased based on the accumulation value to compensate for the changed rates.

[0030] Now refer to Figure 1 This image shows an example of a substrate processing system 100 according to the present invention, comprising a substrate support (e.g., an ALD base) 104. The substrate support 104 is disposed within a processing chamber 108. During processing, a substrate 112 is disposed on the substrate support 104.

[0031] The gas delivery system 120 includes gas sources 122-1, 122-2, ..., and 122-N (collectively referred to as gas sources 122), which are connected to valves 124-1, 124-2, ..., and 124-N (collectively referred to as valves 124) and mass flow controllers 126-1, 126-2, ..., and 126-N (collectively referred to as MFC 126). MFC 126 controls the gas flow from gas sources 122 to manifold 128, where the gas is mixed. The output of manifold 128 is supplied to manifold 136 via a selective pressure regulator 132. The output of manifold 136 is input to a gas distribution device, such as a multi-injector nozzle 140. Although manifolds 128 and 136 are shown, a single manifold can be used.

[0032] In some examples, a resistance heater 160 may be used to control the temperature of the substrate support 104. The substrate support 104 may include a coolant channel 164. Cooling fluid is supplied to the coolant channel 164 from a fluid storage device 168 and a pump 170. Pressure sensors 172 and 174 may be disposed in manifold 128 or manifold 136, respectively, to measure pressure. Valve 178 and pump 180 may be used to evacuate reactants from the processing chamber 108. Valve 178 and pump 180 may also be used to control the pressure within the processing chamber 108.

[0033] Controller 182 includes a dispensing controller 184 that controls the dispensing provided by the multi-injector nozzle 140. Controller 182 also controls the gas delivery from the gas delivery system 120. Controller 182 utilizes valve 178 and pump 180 to control the pressure in the processing chamber. Controller 182 utilizes valve 178 and pump 180 to control the evacuation of reactants. Controller 182 controls the temperature of substrate support 104 and substrate 112 based on temperature feedback in the substrate support (e.g., from a sensor (not shown) and / or a sensor (not shown) measuring the coolant temperature).

[0034] In some examples, the substrate processing system 100 may be configured to etch the substrate 112 within the same processing chamber 108. For example, as described in more detail below, according to this disclosure, the substrate processing system 100 may be configured to perform both a trimming step and a spacer deposition step. Therefore, the substrate processing system 100 may include an RF generation system 188 configured to generate and supply RF power (e.g., a voltage source, a current source, etc.) to a lower electrode (e.g., the base plate of the substrate support 104, as shown) and an upper electrode (e.g., a nozzle 140). For example only, the output of the RF generation system 188 will be described herein as an RF voltage. The lower and upper electrodes may be DC grounded, AC grounded, or floating. For example, the RF generation system 188 may include an RF generator 192 configured to generate an RF voltage fed by a matching and distribution network 196 to generate plasma within the processing chamber 108 to etch the substrate 112. In other examples, the plasma may be generated inductively or remotely. As shown for illustrative purposes, although the RF generation system 188 corresponds to a capacitor-coupled plasma (CCP) system, the principles of this disclosure can also be implemented in other suitable systems. For example, the principles of this disclosure can be implemented in transformer-coupled plasma (TCP) systems, CCP cathode systems, remote microwave plasma generation and transport systems, and so on.

[0035] The controller 182 according to this disclosure is also configured to adjust control parameters of the pressure within the processing chamber 108 to compensate for variations in etching and deposition rates caused by material accumulation on the surfaces within the processing chamber 108. The controller 182 may also be configured to adjust the duration of etching (e.g., trimming) or deposition steps to compensate for variations in etching and deposition rates caused by accumulation. The control parameters may correspond to, for example, the amount of pressure. The amount of pressure can be controlled by controlling valve 178 and / or pump 180. In other words, the controller 182 controls pump 180 to regulate the pressure within the processing chamber 108.

[0036] Now refer to Figures 2A-2K It describes an exemplary SADP process. Figure 2AA hard mask layer 204 comprising, for example, a substrate 200 formed thereon is shown. By way of example only, the substrate 200 comprises a silicon (Si) substrate. The hard mask layer 204 may be made of silicon nitride (Si3N4), but other materials may also be used. Multiple core layers (e.g., mandrel layers) 208, 212, and 216 are deposited on the hard mask layer 204 (e.g., using chemical vapor deposition (CVD), plasma-enhanced CVD (PECVD), atomic layer deposition (ALD), etc.). By way of example only, the core layers 208, 212, and 216 may comprise amorphous silicon (a-Si). In some examples, the core layers 208, 212, and 216 may have a height of about 50-150 nm (e.g., 100 nm). A patterned layer (e.g., a patterned photoresist layer or mask) 220 is formed on the core layer 216. The patterned layer 220 is patterned using photolithography.

[0037] A substrate 200, comprising a hard mask layer 204, core layers 208, 212, and 216, and a mask 220, is disposed within a processing chamber (e.g., an inductively coupled plasma chamber for an etching tool). Figure 2B As shown, the core layer 216 is etched (e.g., using anisotropic etching or other processes) to form a plurality of mandrels 224. During the etching of the core layer 216, a mask 220 protects the portions of the core layer 216 corresponding to the mandrels 224. If the mask 220 is a photoresist mask, it can be removed using oxygen-containing plasma. If the mask 220 is a material similar to the spacer layer 228 described below, it can remain on the mandrels 224 and can be etched during the etching of the spacer layer 228.

[0038] exist Figure 2C In this process, spacer layer 228 is deposited on substrate 200 (i.e., on core layer 212 and mandrel 224). By way of example only, spacer layer 228 can be deposited conformally using an ALD. ALD can include oxide-type deposition (using precursors including silicon tetrachloride (SiCl4), silane (SiH4), etc.), nitride-type deposition (using precursors including molecular nitrogen, ammonia (NH3), etc.) and / or carbon-based deposition (using precursors including methane (CH4), fluoromethane (CH3F), etc.).

[0039] In one example, a SiCl4 precursor is used to deposit spacer layer 228 in the presence of O2. Other exemplary process parameters for performing the deposition of spacer layer 228 include a temperature variation between a minimum temperature below 10°C and 120°C, a plasma power between 200 and 1800 W, a bias voltage between 0 and approximately 1000 volts, and a chamber pressure between 2 mTorr and 2000 mTorr.

[0040] In some examples, a trimming step may be performed on the mandrel 224 before the spacer layer 228 is deposited. For example, in the trimming step, the mandrel 224 may be etched to adjust the width of the mandrel 224 and the size of the spacer layer 228.

[0041] exist Figure 2D In this process, spacer layer 228 is etched (e.g., using anisotropic etching) to remove portions of spacer layer 228 from the upper surfaces of core layer 212 and mandrel 224, while simultaneously allowing sidewall portions 232 of spacer layer 228 to remain. In some examples, in Figure 2D Following the etching described herein, a penetration step (e.g., fluoride-containing plasma treatment) can be performed. Furthermore, depending on the material of the spacer layer 228, an oxygen-containing plasma treatment can be performed prior to the fluoride-containing plasma treatment. Figure 2E In this process, the mandrel 224 is removed (e.g., by anisotropic etching). Thus, the sidewall portion 232 remains formed on the substrate 200.

[0042] like Figure 2F As shown, the core layer 212 is etched (e.g., using anisotropic etching or other processes) to form a plurality of mandrels 236. During the etching of the core layer 212, the sidewall portions 232 serve as masks to protect the portions of the core layer 212 corresponding to the mandrels 236. The sidewall portions 232 may be removed in an additional plasma etching step, during the etching of the spacer layer 240 as described below, etc.

[0043] exist Figure 2G In this process, spacer layer 240 is deposited on substrate 200 (i.e., on core layer 208 and mandrel 236). By way of example only, spacer layer 240 can be deposited conformally using ALD in a manner similar to that of spacer layer 228. In some examples, a trimming step can be performed on mandrel 236 prior to the deposition of spacer layer 240.

[0044] exist Figure 2H In this process, spacer layer 240 is etched (e.g., using anisotropic etching) to remove portions of spacer layer 240 from the upper surfaces of core layer 208 and mandrel 236, while simultaneously allowing sidewall portions 244 of spacer layer 240 to remain. In some examples, in Figure 2H Following the etching described herein, a penetration step (e.g., fluoride-containing plasma treatment) can be performed. Alternatively, depending on the material of the spacer layer 240, an oxygen-containing plasma treatment can be performed prior to the fluoride-containing plasma treatment. Figure 2I In this process, the mandrel 236 is removed (e.g., by anisotropic etching). Thus, the sidewall portion 244 remains formed on the substrate 200.

[0045] like Figure 2JAs shown, the core layer 208 is etched (e.g., using anisotropic etching or other processes) to form a plurality of mandrels 248. During the etching of the core layer 208, the sidewall portions 244 serve as masks to protect the portions of the core layer 208 corresponding to the mandrels 248. The sidewall portions 244 can be removed, for example, in an additional plasma etching step, such as... Figure 2K As shown.

[0046] like Figure 2K As shown, the SADP process creates mandrels 248 in a spaced pattern on substrate 200 (e.g., on hard mask layer 204). The spacing between the mandrels 248 is based on... Figure 2I The spacing between the sidewall portions 244 shown is determined by the distance between them. The spacing between the sidewall portions 244 is further determined according to... Figure 2E The spacing between the sidewall portions 232 shown is used to determine the spacing. The width of the mandrel 236 determines the respective spacing between the sidewall portions 244 and between the sidewall portions 232, and thus determines the spacing between the mandrels 248. Therefore, trimming steps can be performed on the mandrels 236 to ensure a uniform spacing between the mandrels 248. For example, the corresponding widths of the mandrels 236 can be trimmed to achieve a uniform spacing such that a = b = c, as shown. Figure 2K As shown.

[0047] Now refer to Figure 3A , 3B The diagrams 3C and 3D illustrate exemplary trimming steps in SADP processing. For simplicity, only a single core layer 300 and mandrel 304 are shown. Figure 3A The image shows the mandrel 304 before the finishing step (e.g., after the etching step used to form the mandrel 304 on the core layer 300, for example...). Figure 2B (As shown in the diagram). The width of the mandrel 304 corresponds to the critical dimension CD1. (As shown in the diagram). Figure 3B The mandrel 304 is trimmed as shown to adjust its width. Therefore, the critical dimension of the mandrel 304 is reduced to CD2. Figure 3C In this process, spacer layer 308 is deposited on core layer 300 and mandrel 304. For example, spacer layer 308 is deposited conformally using ALD as described above.

[0048] Figure 3D The diagram shows the sidewall portions 312 of the spacer layer 308 remaining on the core layer 300 after one or more etching steps have been performed to remove portions of the spacer layer 308 and the mandrel 304. The spacing between the sidewall portions 312 (e.g., S1, S2, etc.) corresponds to the respective widths (e.g., CD2) of the mandrel 304. Therefore, the pitch of the sidewall portions 312 can be defined as S1 + S2 + 2L, where L corresponds to the linewidth (i.e., the width of one of the sidewall portions 312).

[0049] Various inhomogeneities affect the amount of material deposited (e.g., during the ALD step) and removed (e.g., during the etching step) during processing. For example, such as Figure 3C The deposition of spacer layer 308 as shown and as Figure 3B The etching of mandrel 304 during the trimming step shown causes material to deposit on the surface of the processing chamber (e.g., on the inner wall). The accumulation of this deposited material alters the impedance of the processing chamber and the etch rate during subsequent etching process steps, causing WtW variability in the trimming step. For example, as the accumulation of material in the processing chamber increases, the etch amount 400 (e.g., in angstroms for a trimming step of a predetermined duration) decreases. More specifically, as the accumulation increases and causes a change in the impedance of the processing chamber, the effective pressure decreases. In other words, the effective pressure is lower than the desired (e.g., setpoint) pressure. The accumulation can be quantified as the number of trimming / deposition cycles relative to the last cleaning of the processing chamber. Conversely, the etch amount increases with increasing pressure. This increase can typically be linear.

[0050] The controller 182 according to this disclosure is configured to increase the setpoint pressure based on the accumulated amount (e.g., increasing the pressure from a predetermined default setpoint to an adjusted pressure). For example, the setpoint pressure is adjusted according to a pressure adjustment factor. When the accumulated amount is low (e.g., below 900 angstroms), the pressure adjustment factor is approximately 1.0000. In other words, when the accumulated amount is low, adjusting the setpoint pressure may not be necessary. Conversely, as the accumulated amount increases, the pressure adjustment factor increases from 1.0000 to a value greater than 1.0000 (e.g., 1.01, 1.02, ..., 1.06, etc.).

[0051] For example, if the required pressure at a cumulative 3900 angstroms is 7.00 Torr, the effective pressure of a setpoint pressure of 7.00 Torr corresponds to 7.00 * 0.94 or 6.58 Torr. Therefore, the setpoint pressure is increased according to a pressure adjustment factor of 1.06 corresponding to a cumulative 3900 angstroms, so that the effective pressure remains at the desired pressure indicated by the setpoint pressure. In other words, the setpoint pressure is adjusted according to 7.00 * 1.06 = 7.42 Torr. The pressure can be adjusted in a similar manner at cumulative levels greater than 3900 angstroms (e.g., up to a cumulative 1.5 μm or greater).

[0052] Pressure adjustment factors can be calculated or determined for various cumulative values. These cumulative values ​​can correspond to measured, estimated, or determined cumulative amounts. In some examples, the pressure adjustment factors can be fitted to curves and / or expressed as formulas. In one example, the curve is expressed as a cubic polynomial. Controller 182 is configured to calculate the adjusted setpoint power based on this cumulative amount, the desired setpoint pressure (e.g., received as input from the user, process recipe, etc.), and the formula. In other examples, controller 182 can store data (e.g., a lookup table) that associates multiple cumulative values ​​with corresponding pressure adjustment factors.

[0053] Now for reference Figure 4 An exemplary method 800 for compensating for accumulation in a processing chamber to minimize wafer-to-wafer (WtW) variability during a trimming step begins at 804. At 808, method 800 determines the correlation between an increase in material accumulation within the processing chamber (and a corresponding change in the impedance of the processing chamber) and a change in the amount of etching for a given trimming step. For example, method 800 collects and stores first data indicating the correlation between a decrease in the amount of etching (e.g., in angstroms) and an increase in the amount of accumulation. For example, accumulation could be measured in the number of trimming / deposition cycles since the last cleaning of the processing chamber, where one cycle corresponds to a trimming step and a subsequent spacer layer deposition step. In other examples, accumulation could be measured in another way. For example, accumulation could be measured in the total duration of etching and deposition performed within the processing chamber since the last cleaning; the total number of substrates processed since the last cleaning; the amount of time elapsed since the last cleaning, etc. For example only, the collected first data corresponds to an accumulation value and an etching amount.

[0054] In step 812, method 800 determines the correlation between the amount of etching and the pressure within the processing chamber. For example, method 800 collects and stores second data indicating the correlation between changes in pressure provided during the finishing step and corresponding changes in the amount of etching. By way of example only, the collected second data may correspond to a relationship between pressure and the amount of etching. Generally, increased pressure leads to an increased amount of etching, while decreased pressure leads to a decreased amount of etching.

[0055] At 816, method 800 uses the collected first and second data to calculate the required pressure to achieve the target etching amount at different cumulative values. For example, method 800 calculates the effective pressure for a given cumulative value, the ratio of the effective pressure to the setpoint pressure, and a pressure adjustment factor (e.g., the ratio of the pressure required to compensate for the cumulative value to the setpoint pressure). At 820, method 800 uses the pressure adjustment factor to calculate and store the correlation between various cumulative values ​​and their corresponding pressure adjustment factors. For example, the correlation between the cumulative value and the pressure adjustment factor may correspond to stored data, a formula such as a polynomial representing curve 708, etc. For example only, controller 182 may store this formula.

[0056] At 824, method 800 performs a trimming step based on the correlation between the stored accumulated value and the pressure adjustment coefficient. For example, prior to the trimming step, method 800 (e.g., controllers 182, 900) determines the accumulated value and the pressure adjustment coefficient based on the accumulated value and a stored formula. Method 800 uses the pressure adjustment coefficient to adjust the desired setpoint pressure. Method 800 uses the setpoint pressure adjusted by the pressure adjustment coefficient to perform the trimming step. Method 800 ends at 828.

[0057] Now for reference Figure 5 The illustration shows an exemplary controller 900 configured according to this disclosure to compensate for accumulated pressure in a treatment chamber. The controller 900 includes a pressure controller or control module 904 that controls the pressure within the treatment chamber during a trimming step according to this disclosure. For example, the pressure controller 904 selectively signals valve 178 and pump 180 to adjust the pressure within treatment chamber 108.

[0058] The pressure controller 904 receives the desired setpoint pressure (e.g., based on the process recipe executed by the controller 900, from the user interface 908, etc.) and accumulated values ​​(e.g., from an accumulated determiner or calculation module 912 set as described above to determine the accumulated amount in the processing chamber). The pressure control module 904 retrieves stored data from the memory 916. For example, the stored data corresponds to formulas indicating the correlation between each accumulated value and the corresponding pressure adjustment coefficient. The pressure controller 904 calculates the adjusted pressure based on the determined accumulated pressure, the setpoint pressure, and the retrieved data. The pressure control module 904 then controls the pressure within the processing chamber 108 accordingly.

[0059] In another example, controller 900 may be configured to adjust the duration of the trimming step, rather than the amount of pressure adjustment, to compensate for the decrease in etch rate caused by the accumulation in the processing chamber. Alternatively, controller 900 may be configured to adjust the duration of the trimming step in addition to adjusting the amount of pressure to compensate for the decrease in etch rate. In particular, the duration of the trimming step may be increased to compensate for the decrease in etch rate. For example, pressure controller 904 receives the desired setpoint pressure, the duration of the trimming step, and the accumulated value. Pressure controller 904 retrieves stored data from memory 916 indicating the correlation between each accumulated value and the corresponding trimming step duration adjustment factor. In an example where the process recipe specifies the trimming step duration D, pressure controller 904 is configured to adjust the duration D according to the adjusted duration. adj = (Duration adjustment factor) * D to adjust the duration D. For example, the duration adjustment factor can be calculated based on accumulated values, according to a formula that associates each accumulated value with the corresponding duration adjustment factor, in a manner similar to the calculation of the pressure adjustment factor as described above.

[0060] Although the above text is Figures 4-6 The systems and methods described correspond to reducing WtW etch variability caused by material accumulation on the inner surface of the processing chamber, but the principles of this disclosure can also be implemented to reduce WtW deposition variability in a similar manner. For example, deposition may be affected by the pressure within the processing chamber. Therefore, when the deposition rate changes due to accumulation (e.g., increases or decreases), pressure control parameters can be adjusted to compensate for the changed deposition rate. Thus, pressure can be adjusted to maintain a desired deposition rate and reduce variability caused by changes in the impedance of the processing chamber. In other examples, the duration of the deposition step can be increased or decreased to compensate for the changed deposition rate.

[0061] For example, deposition steps can be performed based on a selected deposition distribution. This distribution can be based on a range of deposition amounts (i.e., deposition thickness) across the entire substrate. Each deposition distribution can be optimized for specific processing chambers, processes, and various process parameters to achieve the desired deposition thickness across the entire substrate. For example, deposition distributions can be calculated to achieve a uniform deposition thickness across the entire substrate, minimizing radial and / or azimuth variations in the deposition thickness (i.e., minimizing the deposition thickness range and maximizing range stability). Furthermore, deposition distributions can be optimized to minimize differences in the respective variability ranges of batch substrates processed within the same processing chamber.

[0062] However, as the accumulation of material within the processing chamber increases, the deposition rate also changes. Therefore, the range of deposition thickness variation on different substrates processed within the same processing chamber will differ with increasing accumulation. In other words, a deposition distribution optimized at a first accumulation level may not be optimized for a second accumulation level. The differences in the range stability of the batch of substrates will change accordingly. For example, a first substrate processed in the processing chamber using the same deposition distribution may have a first range of deposition thickness variability, while a second substrate processed using the same deposition distribution at the same accumulation level may have a second range of variability. The difference between the first and second ranges varies between different accumulation levels.

[0063] For different accumulation levels, the deposition thickness may vary across multiple regions. The deposition distribution can be optimized for high accumulation levels (e.g., accumulation greater than 10,000 angstroms). The range of variation and the differences between these ranges are generally larger at lower accumulation levels (e.g., accumulation less than 10,000 angstroms). The range of variation and the differences between these ranges decrease as accumulation increases. For example, at lower accumulation levels (e.g., less than 3,000 angstroms), the maximum difference between these ranges might be about 1 angstrom. Conversely, at higher accumulation levels (e.g., over 24,000 angstroms), the maximum difference between these ranges might be less than 0.5 angstroms.

[0064] The variation range of the processed substrate in a batch and the difference between the individual variation ranges of the processed substrate in the batch are inversely proportional to the accumulation level. Conversely, in examples where the deposition profile is optimized for low levels of accumulation (e.g., less than 10,000 angstroms), the difference between the variation range of the processed substrate in a batch and the individual variation ranges of the processed substrate in the batch can be directly proportional to the accumulation level. In other words, in examples where the deposition profile is optimized for low accumulation levels, the difference between the variation range of the processed substrate in a batch and the individual variation ranges of the processed substrate in the batch increases as the accumulation level in the processing chamber increases.

[0065] Therefore, variable pressure can be used to compensate for changes in the accumulation level. For example, at low accumulation (e.g., less than 3000 angstroms), the pressure can be maintained at a relatively low level (e.g., less than 1.5 Torr). As accumulation increases, the pressure increases accordingly. For instance, as accumulation increases to approximately 15,000 angstroms, the pressure increases. At accumulation levels greater than 15,000 angstroms, the pressure may tend to plateau and remain at a relatively constant level. The increase in pressure can typically be linear or non-linear (e.g., stepwise).

[0066] Therefore, the lower the cumulative level, the lower the pressure in the treatment room, resulting in a smaller range of variation and smaller differences between the ranges of variation.

[0067] Now for reference Figure 6 An exemplary method 1000 according to this disclosure for compensating for accumulation in a processing chamber to minimize WtW variability in a deposition step begins at 1004. At 1008, method 1000 determines the correlation between an increase in material accumulation in the processing chamber (and a corresponding change in the processing chamber impedance) and a change in the range of deposition variations in the deposition process and / or steps. Method 1000 may determine the corresponding deposition distribution. At 1012, method 1000 determines the correlation between the range of deposition variations and the pressure at various accumulation levels within the processing chamber. For example, method 1000 collects and stores second data indicating the correlation between pressure variations within the processing chamber and the corresponding range of deposition variations.

[0068] In step 1016, method 1000 uses the collected first and second data to calculate and store the pressure distribution corresponding to different cumulative values. In step 1020, method 1000 performs a deposition process on a batch of substrates based on the pressure distribution and the increase in accumulation within the processing chamber. For example, prior to a deposition process or step performed on a given substrate, method 1000 (e.g., controller 182, 900) determines the accumulation. Method 1000 determines the pressure based on the stored pressure distribution. Method 1000 performs deposition using the setpoint pressure determined based on the pressure distribution. In some examples, method 1000 can use the pressure distribution as described above. Figures 4-6 The pressure adjustment coefficient described in the text is used to adjust the setpoint pressure. Method 1000 ends at 1024.

[0069] The foregoing description is merely illustrative in nature and is in no way intended to limit this disclosure, its application, or its use. The broad teachings of this disclosure can be implemented in various forms. Therefore, while this disclosure includes specific examples, its true scope should not be so limited, as other modifications will become apparent upon examination of the drawings, specification, and appended claims. It should be understood that one or more steps in the method may be performed in different orders (or simultaneously) without altering the principles of this disclosure. Furthermore, while each embodiment is described above as having certain features, any one or more of those features described relative to any embodiment of this disclosure may be implemented in and / or combined with features of any other embodiment, even if such combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and substitution of one or more embodiments for each other remains within the scope of this disclosure.

[0070] Various terms are used to describe spatial and functional relationships between elements (e.g., between modules, between circuit elements, between semiconductor layers, etc.), including “connection,” “joint,” “coupled,” “adjacent,” “next to,” “on top of,” “above,” “below,” and “set.” Unless the relationship between the first and second elements is explicitly described as “direct,” the relationship described in the above disclosure can be a direct relationship, where no other intermediate element exists between the first and second elements, but it can also be an indirect relationship, where one or more intermediate elements exist between the first and second elements (spatially or functionally). As used herein, the phrase “at least one of A, B, and C” should be interpreted as meaning the use of a non-exclusive logical OR (A or B or C) logic and should not be interpreted as meaning “at least one of A, at least one of B, and at least one of C.”

[0071] In some implementations, the controller is part of a system, which may be part of the examples described above. Such a system may include semiconductor processing apparatus, which includes one or more processing tools, one or more chambers, one or more platforms for processing, and / or specific processing components (wafer pedestals, gas flow systems, etc.). These systems may be integrated with electronics for controlling their operation before, during, and after the processing of semiconductor wafers or substrates. The electronics may be referred to as a “controller”, which can control various components or sub-components of one or more systems. Depending on the processing requirements and / or system type, the controller may be programmed to control any process disclosed herein, including the delivery of processing gases, temperature settings (e.g., heating and / or cooling), pressure settings, vacuum settings, power settings, radio frequency (RF) generator settings, RF matching circuit settings, frequency settings, flow rate settings, fluid delivery settings, position and operation settings, wafer transfer tools and other transfer tools, and / or loading locks connected to or interfaced with a specific system.

[0072] In general, a controller can be defined as an electronic device having various integrated circuits, logic, memory, and / or software for receiving instructions, issuing instructions, controlling operations, enabling cleaning operations, enabling endpoint measurements, etc. Integrated circuits can include chips in the form of firmware storing program instructions, digital signal processors (DSPs), chips defined as application-specific integrated circuits (ASICs), and / or one or more microprocessors, or microcontrollers that execute program instructions (e.g., software). Program instructions can be instructions sent to the controller in the form of various individual settings (or program files), which define operating parameters for performing a specific process on or for a semiconductor wafer or system. In some embodiments, operating parameters can be part of a recipe defined by a process engineer to complete one or more processing steps during the fabrication of one or more layers, materials, metals, oxides, silicon, silica, surfaces, circuits, and / or the die of the wafer.

[0073] In some implementations, the controller may be part of or coupled to a computer integrated with, coupled to, or otherwise networked to the system, or a combination thereof. For example, the controller may be in the “cloud” or be all or part of a fab host system, allowing remote access to wafer processing. The computer may enable remote access to the system to monitor the current progress of manufacturing operations, examine the history of past manufacturing operations, examine trends or performance criteria of multiple manufacturing operations, change parameters of the current processing, set processing steps to follow the current processing, or initiate a new processing. In some examples, a remote computer (e.g., a server) may provide process recipes to the system via a network (which may include a local network or the Internet). The remote computer may include a user interface that enables input or programming of parameters and / or settings, which are then transmitted from the remote computer to the system. In some examples, the controller receives instructions in the form of data specifying parameters for each processing step to be performed during one or more operations. It should be understood that the parameters may be specific to the type of process to be performed and the type of tool, to which the controller is configured to interface with or control the tool. Therefore, as described above, a controller can be distributed, for example, by comprising one or more discrete controllers networked together and operating toward a common purpose (such as the process and control described herein). An example of a distributed controller for such a purpose is one or more integrated circuits on a room that communicate with one or more integrated circuits remotely (e.g., at the platform level or as part of a remote computer), which together control the process on the room.

[0074] Example systems may include, but are not limited to, plasma etching chambers or modules, deposition chambers or modules, rotary rinsing chambers or modules, metal plating chambers or modules, cleaning chambers or modules, chamfering edge etching chambers or modules, physical vapor deposition (PVD) chambers or modules, chemical vapor deposition (CVD) chambers or modules, atomic layer deposition (ALD) chambers or modules, atomic layer etching (ALE) chambers or modules, ion implantation chambers or modules, orbital chambers or modules, and any other semiconductor processing systems that may be associated with or used in the manufacture and / or preparation of semiconductor wafers.

[0075] As described above, depending on one or more processing steps to be performed by the tool, the controller may communicate with one or more other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, neighboring tools, tools located throughout the plant, a host computer, another controller, or tools used in the transport of materials to and from the tool location and / or loading port in the semiconductor manufacturing plant.

Claims

1. A pressure compensation control system, comprising: An accumulation determiner is configured to determine a first accumulation value that indicates the amount of material accumulated on the surface within the processing chamber during the etching step; and A controller configured to adjust control parameters based on the first accumulated value during the etching step; The control parameters wherein the pressure in the processing chamber is controlled based on a setpoint pressure associated with the etching step, wherein the setpoint pressure is adjusted according to a pressure adjustment factor, and the controller is configured to use stored data to determine the pressure adjustment factor corresponding to the first accumulated value and the amount by which the pressure is adjusted according to the pressure adjustment factor, wherein the pressure adjustment factor is (i) the ratio of the amount of pressure required to compensate for the accumulation to (ii) the ratio of the setpoint pressure; and / or The control parameter controls the duration of the etching step, wherein the duration of the etching step is adjusted according to a duration adjustment factor, and the controller is configured to use stored data to determine the duration adjustment factor corresponding to the first cumulative value, and to adjust the duration of the etching step according to the duration adjustment factor, the duration adjustment factor corresponding to an amount used to increase the duration of the etching step to compensate for the accumulation.

2. The pressure compensation control system according to claim 1, wherein, The stored data is a polynomial that associates the cumulative value with the corresponding adjustment coefficient.

3. The pressure compensation control system according to claim 1, wherein, The controller is configured to multiply the setpoint pressure by the pressure adjustment coefficient to adjust the control parameters.

4. The pressure compensation control system according to claim 1, wherein, The cumulative determiner is configured to determine the first cumulative value based on at least one of the following: the number of etching steps performed in the processing chamber, the number of cycles of etching and deposition steps performed in the processing chamber, the total duration of etching and deposition steps performed in the processing chamber, and the number of substrates processed in the processing chamber.

5. The pressure compensation control system according to claim 1, wherein, The controller is configured to adjust the control parameters by multiplying the duration of the etching step by the duration adjustment factor.

6. The pressure compensation control system according to claim 1, wherein, The etching step is a finishing step.

7. The pressure compensation control system of claim 6, wherein the controller is further configured to perform a spacer layer deposition step in the processing chamber after the trimming step.

8. A pressure compensation method, comprising: Obtain a first cumulative value indicating the amount of material accumulated on the surface of the processing chamber during the etching step; as well as The control parameters are adjusted based on the first accumulated value during the etching step; The control parameters are used to control the pressure within the processing chamber based on a setpoint pressure associated with the etching step, and the setpoint pressure is adjusted according to a pressure adjustment coefficient. The method further includes: The pressure adjustment coefficient corresponding to the first accumulated value is determined using the stored data; and The pressure is adjusted by the amount according to the pressure adjustment coefficient. The pressure adjustment coefficient thereon is (i) the ratio of the pressure required to compensate for the accumulation to (ii) the ratio of the setpoint pressure; and / or The control parameter controls the duration of the etching step, and the duration of the etching step is adjusted according to a duration adjustment coefficient. The method further includes: The stored data is used to determine the duration adjustment factor corresponding to the first cumulative value; and The duration of the etching step is adjusted according to the duration adjustment factor. The duration adjustment factor corresponds to the amount used to increase the duration of the etching step to compensate for the accumulation.

9. The pressure compensation method as described in claim 8, wherein, The stored data is a polynomial that associates the cumulative value with the corresponding adjustment coefficient.

10. The pressure compensation method according to claim 8, further comprising multiplying the setpoint pressure by the pressure adjustment coefficient to adjust the control parameters.

11. The pressure compensation method of claim 8, further comprising determining the first cumulative value based on at least one of the number of etching steps performed in the processing chamber, the number of cycles of etching and deposition steps performed in the processing chamber, the total duration of etching and deposition steps performed in the processing chamber, and the number of substrates processed in the processing chamber.

Images