Upstream process monitoring for deposition and etching chambers

Abstract

The semiconductor manufacturing system includes a mixing bowl, a distribution system that receives a mixture of gases from the mixing bowl, and a process chamber in fluid communication with the distribution system for performing various semiconductor processes, such as deposition and etch processes, on a substrate. A plurality of mixing bowl sensors are disposed within the cavity of the mixing bowl and generate gas signals indicative of the type and flow rate of detected gases. Additionally, at least one process chamber sensor is provided within the process chamber and positioned proximate to the substrate. The process chamber sensor has a resonant characteristic that changes upon exposure to a semiconductor process, i.e., deposition material accumulates on the surface of the sensor, and generates a material process signal indicative of the predicted material on the surface of the substrate.

Description

【Technical Field】 【0001】 (Cross - Reference to Related Applications) In accordance with 35 U.S.C. § 119 and the relevant parts of U.S. Patent Rule 1.53, this application claims the benefit and priority of U.S. Patent Application No. 63 / 219,032, filed on July 7, 2021, the entire content of which is incorporated herein by reference. 【Background Art】 【0002】 Deposition and etching processes in semiconductor manufacturing plants are widely and commonly used during device fabrication in the semiconductor integrated circuit (IC) industry. The attempts in the semiconductor industry to reduce dimensions have been conventionally limited by the lithographic resolution of two - dimensional structures, but are shifting towards the control of deposition and etching processes for three - dimensional structures (e.g., 3D gates and 3D NAND). Gas mixtures containing multiple gas species are used many times throughout the sequence of deposition and etching processes, both in the pre - stage and the post - stage of the main sequence. Furthermore, the critical dimensions of devices are increasingly affected by the ability to control deposition and etching processes. 【0003】 Plasma etching processes are often used to remove dielectric, semiconductor, or metal layers by a plasma - state ignition gas (which drives the activation energy of chemical reactions). The removal of materials can also be performed by flowing reactive gases (in a non - plasma state) or through a wet - etching (in a liquid state) station. The deposition of films on chamber components and processed substrates can be applied by various methods such as plasma - enhanced (PE) chemical vapor deposition (CVD), low - pressure CVD, thermal CVD, atomic layer deposition (ALD), plasma - enhanced atomic layer deposition, etc. Etching and deposition processes can be isotropic or anisotropic (such as reactive ion etching - RIE) depending on the process step. 【0004】 In substrate deposition processes such as IC manufacturing processes, the deposition of many different layers on a wafer (which is the substrate) can be achieved through different reactions and various states of process materials. Examples of technologies include plasma (PECVD and high-density plasma-HDP), gas-low atmospheric pressure CVD (SACVD), and liquid (electroplating). Some examples of important parameters for controlling the deposition layer and device manufacturing characteristics include thickness, stress, mass, resistance, particle size, and refractive index. These parameters are measured and controlled not only as average values ​​(across wafers or batches of wafers) but also in terms of wafer variability and interstitial wafer variability. Reducing process variability contributes to improving manufacturing yield in end-of-line (EOL) processes. 【0005】 For example, the following steps are used in substrate etching: wafer etching steps to apply patterns to the manufactured device (in conjunction with lithography steps), cleaning of the wafer from contamination, creation of trenches between transistors, possible separation between contacts and isolators, and reaction of the wafer surface for pre-deposition and photoresist removal. Key parameters for controlling the etching process on the wafer are limit dimensions for defined characteristics such as etching rate, thickness, stress, particle and defect control, and other electrical and optical parameters. 【0006】 The etching and deposition of the substrate may be performed simultaneously within the same process chamber (for example, in some HDP processes, etching and deposition may occur sequentially or simultaneously), continuously within the chamber, discontinuously within the chamber, or in different chambers, or not. 【0007】 Some known methods for process monitoring using integrated sensors include mass spectrometers, optical spectrometers, RF sensors, and vacuum gauges. However, such methods are not localized and cannot provide detailed information about films accumulated or removed at different chamber locations. Examples of non-localized process control include plasma cleaning methods such as emission spectrometry, residual gas analyzers, and chamber impedance measurements. However, all of these methods measure convolutional signals from the entire chamber and do not determine the uniformity or homogeneity of the process material at different chamber locations. Other known sensors, such as temperature sensors, can be located along the surfaces of various chamber components and read measurements, but they do not provide detailed information about the state of films related to the coatings on these surfaces. 【0008】 Current solutions for monitoring timing issues related to gas mixtures or flows are located in the process chamber and exhaust line. By the time a process fault ("wrong" gas mixture) reaches the process chamber or chamber exhaust, it is already too late, and material damage has already occurred. 【0009】 Patent Document 1 (Wajid) discloses a QCM that provides information on film coating or etching, but employs a single position and cannot provide information on process uniformity or homogeneity at different chamber positions. Here, as the chamber size increases, the accuracy and values ​​of the process data decrease. 【0010】 Patent document 2 (Martinson et al.) describes a QCM probe that moves between different chamber positions. However, this solution is limited to laboratory use and is only suitable for manufacturing environments where vacuum is required for production. Furthermore, this solution does not facilitate simultaneous monitoring of QCM sensors at different chamber positions. 【0011】 Therefore, there is a need to (i) identify inaccurate or unbalanced gas mixtures and (ii) control the timing of deposition and etching tools to enable more precise process control during the deposition and etching processes. [Prior art documents] [Patent Documents] 【0012】 [Patent Document 1] U.S. Patent Application Publication No. 2012 / 0201954 [Patent Document 2] U.S. Patent Application Publication No. 2014 / 0053779 Specification [Overview of the Initiative] 【0013】 The semiconductor manufacturing system includes a mixing bowl, a distribution system for receiving a gas mixture from the mixing bowl, and a process chamber that is in fluid communication with the distribution system for performing various semiconductor processes on a substrate, such as deposition and etching processes. Multiple mixing bowl sensors are positioned within the cavity of the mixing bowl and emit gas signals indicating the type and flow rate of the detected gas. In addition, at least one process chamber sensor is provided within the process chamber and positioned in close proximity to the substrate. The process chamber sensor has resonant characteristics that change when exposed to a semiconductor process, i.e., when deposition material accumulates on the surface of the sensor, and emits a material process signal indicating the predicted material on the surface of the substrate. A controller controls the mixing of gases in the mixing bowl and the predicted material on the surface of the substrate in response to the gas and material process signals. 【0014】 In yet another embodiment, a method for monitoring a semiconductor process is provided. The method includes (i) placing a plurality of mixing bowl sensors in the cavity of a mixing bowl to detect at least one gas of a gaseous material and emitting a gas signal indicating the detected gas; (ii) distributing the flow of gaseous material into a semiconductor process chamber by a distribution system; (iii) supporting a substrate and a process chamber sensor adjacent to the substrate in the semiconductor process chamber, wherein the process chamber sensor detects a deposition process and an etching process on its detection surface and correlates them with the deposition process and etching process on the surface of the substrate; and (iv) controlling the flow of gas into the mixing bowl and the semiconductor process performed in the process chamber to optimize the manufacture of a semiconductor circuit. 【0015】 The embodiments described above are merely illustrative. Other embodiments described herein are also within the scope of the disclosed subject matter. [Brief explanation of the drawing] 【0016】 To help you understand the features of this disclosure, a detailed description can be given by referring to specific embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings illustrate only specific embodiments and therefore should not be considered limiting in scope, as the scope of the disclosed subject matter similarly encompasses other embodiments. The drawings are not necessarily to scale and are generally focused on illustrating the features of specific embodiments. In the drawings, similar numbers are used to indicate similar parts throughout the various figures. 【0017】 [Figure 1] This is a perspective view of a semiconductor manufacturing system including a mixing bowl, a dispensing system, and a process chamber. [Figure 2] This is a cross-sectional view substantially aligned with line 2-2 in Figure 1. [Figure 3]This is a cross-sectional view substantially aligned with line 3-3 in Figure 2, along a plane perpendicular to the vertical axis defined by the mixing bowl and process chamber. [Figure 4] This is a perspective view of another embodiment of a semiconductor manufacturing system, in which the distribution system includes multiple conduits, at least one of which distributes gas directly into the process chamber. [Figure 5] This is a perspective view of another embodiment of a semiconductor manufacturing system, in which a mixing bowl sensor comprises multiple quartz crystal microbalance (QCM) sensors and multiple optical spectrometers / mass spectrometers, and a distribution system guides the gas mixture into multiple process chambers. 【0018】 Corresponding reference letters indicate the corresponding parts through several figures. The examples described herein illustrate several embodiments, but should not be construed as limiting the scope. [Modes for carrying out the invention] 【0019】 This disclosure relates to the field of semiconductor manufacturing, including semiconductor manufacturing control. More specifically, in one example, a semiconductor manufacturing system utilizes sensors placed at strategic upstream and downstream locations, i.e., upstream mixing bowls and downstream process chambers, to monitor the semiconductor manufacturing process and improve the accuracy and homogeneity of the deposition and etching processes. For example, this specification discloses a specific method for monitoring the gas mixture at an upstream position in the mixing bowl, before distribution by sprinkler heads and upstream of the process chamber. Advantageously, placing sensors at both upstream and downstream locations facilitates the measurement of different material properties (mass density and stress) due to process heterogeneity in the upstream mixing bowl and downstream process chamber. 【0020】 In FIGS. 1, 2, and 3, schematic perspective and cross-sectional views of the manufacturing system 10 include a mixing bowl 12, a distribution system 16 in fluid communication with the mixing bowl 12, and a process chamber 20 in fluid communication with the distribution system 16. The mixing bowl 16 receives a gas mixture from several external gas sources 18 and includes a plurality of gas sensors 22 disposed inside the cavity 24 defined by the mixing bowl 16. Although the gas sensors 22 are described in more detail below, suffice it to say at this point that the gas sensors 22 detect at least one gas of the gaseous mixture and emit a gas signal along line 26. The gas sensors 22 may be uniformly dispersed within the mixing bowl cavity 24, but they are preferably disposed in proximity to each opening of the mixing bowl cavity, i.e., disposed in proximity via the lateral or cylindrical cavity wall 28 (best seen in FIG. 3). The openings are in fluid communication with a plurality of radial pipes or conduits 30 of the distribution system 16, and then the distribution system 16 distributes the gaseous mixture to several sprinkler heads 34 disposed above the process chamber 20. The distribution system 16 may include a plurality of conduits 30 in fluid communication with the mixing bowl 12 at one end and with one or more sprinkler heads 34 at the other end. Alternatively, the distribution system 16 may include one or more conduits 30 each leading directly to a dedicated process chamber 20. This embodiment is shown in FIG. 4 of the present disclosure. 【0021】 Many different types of sensors can be utilized in the present disclosure. For example, a quartz crystal microbalance (QCM) sensor or a microelectromechanical (MEM) sensor can be deployed. The quartz crystal microbalance (QCM) sensor 22 within the mixing bowl 16 enhances the deposition and etching processes performed within the process chamber 20. The QCM sensor 22 disposed near the area or region being monitored provides information regarding the semiconductor process, as it can be assumed that changes to the surface of the QCM are correlated with the same processes being performed on the surface of the substrate 36. In one embodiment, the QCM sensor 22 has resonant characteristics that change when exposed to the semiconductor process. A change in mass changes the resonant response of the QCM crystal, which indicates the expected changes occurring on the substrate 36. As will be described in a later paragraph with respect to the process chamber 20 and the process chamber sensor 42, the same or similar metrics can be assumed for the semiconductor manufacturing process within the process chamber 20. In one embodiment of the present disclosure, the QCM sensors 22 and 42 monitor process conditions such as temperature, flow rate, pressure, etc. in known accumulations of thickness and stress in order to monitor local process conditions. Instead of a QCM sensor, a MEM sensor can be used as well. 【0022】 An example of a MEM sensor for use in the present disclosure is a surface acoustic wave sensor. Those skilled in the art will readily understand how QCM and MEM sensors are fabricated and used. The present disclosure utilizes such various sensors disposed at different locations within the mixing bowl 16 to identify the type of gas detected, temperature, flow rate, concentration, etc. 【0023】 In one or more embodiments, any combination of the following sensor types can be used as sensors: capacitor sensors, photocathodes, photodetector sensors, microfabricated ultrasonic transducers, oscillator devices configured to measure changes in energy or mass, resonant electro / optical devices, resistance measuring sensors, sensors having dielectric waveguides in contact with a metal layer or pattern suitable for generating plasmon reactions, light-emitting devices, electron beam sources, ultrasonic sources, optical resonators, microring resonators, photonic crystal structure resonators, and temperature sensors. 【0024】 By using QCM sensors at both upstream locations within the mixing bowl 16 and downstream locations within the process chamber 20, important information reflecting real-time process homogeneity occurring within the chamber and on the substrate 36 can be obtained. 【0025】 Process homogeneity can be measured by measuring the QCM frequency values, starting from the beginning of the deposition sequence and ending at the plasma cleaning sequence (for a given manufacturing method). Furthermore, the frequency difference or delta between different runs from end to start provides important information regarding the stability of the process at a particular location. 【0026】 Another example of measuring process homogeneity concerns the frequency difference between the start and end of wafer deposition between different wafers (using the same method). Certain correlation parameters or equations (based on the QCM location) can then be calculated to predict wafer thickness and thickness variation. This can help avoid using test wafers for thickness measurement, or it can be used as feedforward or backward information to control different process operations before or after substrate deposition. Instead of a QCM sensor, a MEM sensor can be used as well. 【0027】 Process homogeneity can also be measured by obtaining the maximum frequency during plasma cleaning from different QCM locations, allowing the user to know whether the film is accumulating under-etched or over-etched at a particular location. Algorithms for determining the process endpoint can use frequency information from multiple QCM sensors distributed at different locations and can be used to optimize the process endpoint (EP) of the cleaning. For example, the moving average of the frequency derivative can be monitored until a threshold is reached, i.e., until the cleaning endpoint is reached and the frequency derivative drops significantly. For example, this over-etching or under-etching in different areas can be intentionally reached or achieved. The same or similar approaches can be applied to other time-based processes that use the addition or removal of materials, such as undercoats and precoats. 【0028】 Endpoint detection for wafer-based processes such as deposition, etching, densification, and decontamination using plasma or heat (pretreatment or bake-out) can also be achieved using signal inputs from multiple QCM sensors 22, 42 distributed at different locations. The QCM sensors 22, 42 located at different positions within the mixing bowl 16 and process chamber 20 can measure different deposition and etching rates to provide information about process uniformity. 【0029】 Furthermore, by mounting at least two QCM sensors 22 and 42 at different angles (relative to the surface of the substrate 36) in the mixing bowl 16 and the process chamber 20, the process speed at different angles on the substrate 36 can be measured and / or calculated to provide three-dimensional information regarding the process and process speed on the substrate surface. 【0030】 The gaseous mixture is dispersed within the process chamber 20 at various locations, and in the embodiments shown in Figures 1, 2, and 3, the gaseous mixture enters the process chamber 20 at four locations, or in each of the four quadrants. As described above, the process chamber sensor 42 is positioned at several locations within the process chamber 20 and emits a material process signal indicating the semiconductor process occurring at that location. 【0031】 In other embodiments shown in Figures 4 and 5, the mixing bowl 12 can supply multiple process chambers 20. Rather than having a single mixing bowl 12 dedicated to each process chamber 20, the mixing bowl 16 can supply several process chambers 20 directly. In Figure 5, the mixing bowl 16 includes a combination of a QCM sensor 22 and an optical spectrometer / mass spectrometer 52 to provide further additional information at an upstream position in the process chamber 20. The QCM sensor is positioned around the inner circumference of the mixing bowl 16, while the optical spectrometer / mass spectrometer is positioned along its upper surface or surface. 【0032】 The controller 50 controls the mixture of gaseous material in both the mixing bowl 16 and the process chamber 20 in response to (i) a gas signal 26 emitted by a gas sensor 22 in the mixing bowl 16 and (ii) a material process signal 46 emitted by a process chamber sensor 42 in the process chamber 20. A closed-loop feedback loop can be used to control the mixing, flow rate, and concentration of the gaseous mixture entering the process chamber 20 in an attempt to predict the material to be deposited on or removed from the surface of the substrate 36. 【0033】 In summary, the semiconductor manufacturing system 10 of the present disclosure provides information about the gas mixture well in advance of the process chamber 20 or exhaust line (not shown) when it may already be too late to correct a defect. Furthermore, the present disclosure provides a semiconductor manufacturing system and method therefor that facilitates the detection of incorrect gas mixture and / or related timing problems (e.g., due to gas valve malfunction) within the process chamber of a semiconductor manufacturing device. A mixing bowl sensor (i.e., a QCM or mass spectrometer sensor) may be located at the inlet of the mixing bowl 12, inside the mixing bowl 12, or in an exhaust conduit 30 leading from the mixing bowl 12 to a sprinkler head 34 or directly to the process chamber 20. 【0034】 Therefore, the semiconductor manufacturing system 10 of this disclosure provides information about the gas mixture well in advance of the process chamber 20 or exhaust line (not shown) in case it may already be too late to correct a defect. In addition to the gas mixture, the semiconductor manufacturing system and method facilitate the identification of air leaks or internal leaks in the gas supply line. For example, O2 and SiH4 can cause exothermic reactions, which can result in particulate contamination. The semiconductor manufacturing system 10 of this disclosure can detect this reaction upstream of the mixing bowl 12 to avoid damage to the system. Similarly, the QCM sensor 22 can detect the solid state or particulate contamination of the product wafer. 【0035】 Additional embodiments include any one of the embodiments described above, in which one or more of its components, functions, or structures are replaced, substituted, or enhanced with one or more of the components, functions, or structures of the different embodiments described above. 【0036】 It should be understood that various changes and modifications to the embodiments described herein will be obvious to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of this disclosure and without diminishing the intended merits. Accordingly, such changes and modifications are intended to be included in the appended claims. 【0037】 While several embodiments of this disclosure are disclosed in the preceding specification, it will be understood that those skilled in the art will be able to envision many modifications and other embodiments of this disclosure that relate to this disclosure and that have teaching benefits as shown in the above description and the accompanying drawings. Therefore, it will be understood that this disclosure is not limited to the specific embodiments disclosed herein, and that many modifications and other embodiments are intended to be included within the scope of the appended claims. Furthermore, while certain terms are used herein and in the subsequent claims, these terms are used only in a general and descriptive sense and are not intended to limit the scope of this disclosure and the subsequent claims.

Claims

[Claim 1] A mixing bowl defining a cavity for receiving a gaseous mixture of materials used to perform a semiconductor process on a substrate, A plurality of mixing bowl sensors disposed within the cavity of the mixing bowl to detect at least one gas of the gaseous mixture of the material, wherein the plurality of mixing bowl sensors emit a gas signal indicating the detected gas, A material distribution system for receiving gaseous material from the mixing bowl and distributing the gaseous material into the process chamber, A process chamber for housing a substrate and at least one process chamber sensor located in close proximity to the surface of the substrate, wherein the process chamber receives the gaseous mixture of material from the mixing bowl in the presence of the at least one process chamber sensor and is in fluid communication with the material distribution system to perform a semiconductor process on the surface of the substrate. The process chamber sensor has resonant characteristics that change when exposed to the semiconductor process, and the process chamber sensor emits a material process signal indicating the predicted material on the surface of the substrate, and the process chamber A controller for controlling the mixing of gaseous material in the mixing bowl and the predicted material on the substrate in response to the gas signal and the material process signal, A semiconductor manufacturing system equipped with the following features. [Claim 2] The semiconductor manufacturing system according to claim 1, wherein the material distribution system includes a plurality of sprinkler heads for distributing the flow of the gaseous mixture into the process chamber. [Claim 3] The semiconductor manufacturing system according to claim 1, wherein the material distribution system includes at least one conduit for directly delivering the flow of the gaseous mixture to the process chamber. [Claim 4] The semiconductor manufacturing system according to claim 1, wherein the material distribution system includes a plurality of conduits, each of which distributes the flow of the gaseous mixture to the process chamber. [Claim 5] The semiconductor manufacturing system according to claim 1, wherein the plurality of mixing bowl sensors include sensors from the group consisting of quartz crystal microbalance (QCM) sensors, optical spectrometer sensors, and mass spectrometer sensors. [Claim 6] The semiconductor manufacturing system according to claim 1, wherein the at least one process chamber sensor includes sensors from the group consisting of quartz crystal microbalance (QCM) sensors and micro-electromechanical (MEM) sensors. [Claim 7] The semiconductor manufacturing system according to claim 2, wherein the mixing bowl defines a circular planar shape having several cavity wall openings, and a mixing bowl sensor is positioned near each cavity wall opening to detect gaseous material flowing out of the mixing bowl toward one of the plurality of sprinkler heads. [Claim 8] The semiconductor manufacturing system according to claim 5, wherein the mixing bowl defines an opening in the cavity wall to facilitate the flow of gaseous material into each conduit, and at least one of the plurality of mixing bowl sensors is positioned near the cavity wall opening to detect gaseous material flowing out of the mixing bowl toward one of a plurality of sprinkler heads. [Claim 9] The semiconductor manufacturing system according to claim 5, wherein the mixing bowl defines a cavity for containing the gaseous mixture, and at least one of the plurality of mixing bowl sensors is positioned along the upper surface of the cavity to detect gaseous material flowing out of the mixing bowl. [Claim 10] The semiconductor manufacturing system according to claim 1, wherein the mixing bowl defines a cavity for containing the gaseous mixture, at least one of the plurality of mixing bowl sensors is a quartz crystal microbalance (QCM) positioned along the inner surface of the cavity, and at least another of the plurality of mixing bowl sensors is a mass spectrometer sensor positioned along the upper surface of the cavity for detecting gaseous material flowing out of the mixing bowl. [Claim 11] The semiconductor manufacturing system according to claim 1, further comprising a plurality of process chamber sensors, each process chamber sensor being in close proximity to the surface of the substrate, and the material process signals being correlated according to the distance and direction of the process chamber sensors relative to the substrate to enhance interphase data between the substrate and the process chamber sensors. [Claim 12] A method for monitoring a semiconductor manufacturing process in a semiconductor process chamber that receives a mixture of gases from a gas distribution system, wherein the gas distribution system comprises a plurality of sprinkler heads that are in fluid communication with the semiconductor process chamber at its downstream end, and a plurality of conduits that are in fluid communication with a mixing bowl at its upstream end, and the method is The steps include: placing a plurality of mixing bowl sensors in the cavity of the mixing bowl to detect at least one gas of a gaseous material, and emitting a gas signal indicating the detected gas; The steps include distributing the flow of gaseous material to the semiconductor process chamber via the plurality of sprinkler heads of the gas distribution system, A step of supporting a substrate and at least one process chamber sensor adjacent to the substrate within the semiconductor process chamber, wherein the at least one process chamber sensor detects a deposition process and an etching process on its detection surface and correlates them with the deposition process and etching process on the surface of the substrate. Methods that include... [Claim 13] The resonance characteristics of the at least one process chamber sensor change when exposed to the semiconductor process and when material deposited on the detection surface of the at least one process chamber sensor accumulates. Steps include generating a material process signal indicating the predicted material on the surface of the substrate. The method according to claim 12, further comprising: [Claim 14] A step of arranging a plurality of process chamber sensors in a process chamber and measuring material process data generated near each of the plurality of process chamber sensors, wherein a first process chamber sensor defines a first spatial position in the process chamber, a second process chamber sensor defines a second spatial position in the process chamber, and the first spatial position has a different angular direction from the second spatial position. The method according to claim 12, further comprising:

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