US-12628603-B2 - Sensor array, apparatus for dispensing a vapor phase reactant to a reaction chamber and related methods

Abstract

An apparatus for dispensing a vapor phase reactant to a reaction chamber is disclosed. The apparatus may include: a vessel having an inner volume configured to contain a liquid chemical; an array of sensors configured for detecting a fill level of the liquid chemical disposed within the inner volume, wherein the array of sensors are vertically distributed within the inner volume with an irregular vertical interval between adjacent sensors. The apparatus may also include: an inlet disposed in the vessel and configured for providing a carrier gas into the inner volume; and an outlet disposed in the vessel and configured for dispensing the vapor phase reactant from the inner volume to the reaction chamber. A sensor array for detecting the fill level of a liquid chemical is also disclosed, as well as methods for dispensing a vapor phase reactant to a reaction chamber.

Inventors

• Yoshio SUSA

Assignees

• ASM IP HOLDING B.V.

Dates

Publication Date

20260512

Application Date

20220823

Claims (13)

1. 1 . A precursor delivery system comprising: a first vertical support; a first array of sensors configured for detecting a fill level of the liquid disposed within an inner volume of the vessel, wherein the first array of sensors comprises a plurality of sensors which are vertically distributed along the vertical support with an irregular vertical interval between adjacent sensors; a second vertical support; and a second array of sensors configured for detecting a fill level of the liquid disposed within an inner volume of the vessel, wherein the second array of sensors comprises a plurality of sensors which are vertically distributed along the vertical support, wherein one or more of the first array of sensors and the second array of sensors generate a control output dependent upon the fill level; an inlet disposed in the vessel and configured for providing a carrier gas into an inner volume of the vessel, wherein the inlet extends into a liquid; an outlet disposed in the vessel and configured for dispensing the vapor phase reactant from the inner volume; one or more heaters that control a temperature of the liquid chemical in the inner volume; and a controller, wherein the controller is programmed to receive the control output and, in response, generate a control signal that regulates operations of the one or more heaters to modify the temperature of the liquid based on the fill level, and wherein when the control output indicates that the fill level is decreasing, the control signal instructs the one or more heaters to increase the temperature of the liquid in the inner volume to maintain a vapor pressure of the liquid.
2. 2 . The precursor delivery system of claim 1 , wherein each sensor of the first array of sensors and the second array of sensors are disposed at a different vertical position within the inner volume.
3. 3 . The precursor delivery system of claim 1 , wherein the controller is configured to generate additional control signals in response to the fill level to adjust one or more of a substrate temperature, the flow rate of the carrier gas, the flow rate of the vapor phase reactant, and a pulse period of the vapor phase reactant.
4. 4 . The apparatus precursor delivery system of claim 1 , wherein the increase of the temperature of the liquid is based on a decrease in the fill level to maintain the vapor pressure of the liquid is non-linear.
5. 5 . The precursor delivery system of claim 1 , wherein the first array of sensors comprises a linear array of sensors.
6. 6 . The precursor delivery system of claim 1 , wherein the vertical interval between adjacent sensors increases from an upper-most sensor to a lower-most sensor.
7. 7 . The precursor delivery system of claim 1 , wherein a sensor of the first array of sensors is a digital sensor that detects either the presence of the liquid or the absence of the liquid.
8. 8 . The precursor delivery system of claim 1 , wherein a sensor of the first array of sensors is a digital sensor that detects either the presence of the liquid or the absence of the liquid.
9. 9 . The precursor delivery system of claim 1 , wherein the first array of sensors comprises an array of digital ultrasonic sensors.
10. 10 . The precursor delivery system of claim 1 , wherein each of the first array of sensors and the second array of sensors of sensors comprises a linear array of a plurality of sensors.
11. 11 . The precursor delivery system of claim 1 , wherein a concentration of sensors of the first array of sensors is greater in an upper portion of the inner volume compared with a concentration of sensors of the first array of sensors in a lower portion of the inner volume.
12. 12 . The precursor delivery system of claim 1 , wherein a concentration of sensors of the second array of sensors is greater in an upper portion of the inner volume compared with a concentration of sensors of the second array of sensors in a lower portion of the inner volume.
13. 13 . A semiconductor processing apparatus comprising the precursor delivery system of claim 1 .

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a divisional of and claims priority to U.S. patent application Ser. No. 16/108,950 filed Aug. 22, 2018 titled SENSOR ARRAY, APPARATUS FOR DISPENSING A VAPOR PHASE REACTANT TO A REACTION CHAMBER AND RELATED METHODS, the disclosure of which is hereby incorporated by reference in its entirety. FIELD OF INVENTION The present disclosure relates generally to sensor arrays and an apparatus for dispensing a vapor phase reactant to a reaction chamber and in particular to an apparatus including a vessel for containing a liquid chemical, which includes an array of sensors configured for detecting the fill level of the liquid chemical. The disclosure also includes methods for dispensing a vapor phase reactant to a reaction chamber. BACKGROUND OF THE DISCLOSURE Semiconductor processing apparatus commonly use one or more vapor phase reactants, i.e., precursors, as source chemicals for performing semiconductor substrate processes, such as, for example, deposition, cleaning, and etching processes. The vapor phase reactants may be contained in a source vessel in a liquid state and are subsequently converted to a vapor state for transport to a reaction chamber associated with a semiconductor processing apparatus. High volume semiconductor fabrication facilities may utilize a large volume of liquid chemicals resulting in the requirement to either regularly re-charge the vessel with additional precursor, or alternatively, frequently exchange the discharged vessel for full vessels. However, there are some forms of liquid chemical precursor which are not readily adaptable for re-charge of the vessel. For example, a particular liquid chemical may be easily degraded or a particular liquid chemical may become strongly attached to the inner surface of the vessel during the re-charge procedure. In addition, the exchange of the discharged vessel for a full vessel may incur undesirable down time for the semiconductor processing apparatus and may also necessitate the need for safe storage of a large number of chemical vessels. Therefore, there is a desire to limit the frequency of chemical vessel exchanges or chemical vessel re-charges. One fundamental method for reducing the frequency of chemical vessel exchange or chemical vessel re-charge is to increase the size of the vessel thereby allowing the vessel to store more liquid chemical precursor. For example, deposition processes, such as, for example, atomic layer deposition processes, may utilize one or more chemical vessels as the precursor source(s) for the deposition of materials. The chemical vessel may be connected to a source of one or more carrier gases. The carrier gases may be introduced into the chemical vessel and drawn over the surface of, or bubbled through, the liquid chemical contained within the vessel. The resulting evaporation of the liquid chemical causes a vapor of the liquid chemical to become entrained in the carrier gas to thereby produce the vapor phase reactant which can be dispensed to a reaction chamber. It has been found that the maximum evaporation rate of the liquid chemical occurs directly below the carrier gas inlet, i.e., where the carrier gas flow is most proximate to the liquid chemical. It has also been found that as the liquid chemical is consumed, the fill level of the liquid chemical reduces, increasing the distance between the carrier gas inlet and the exposed surface of the liquid chemical. The increase in distance between the carrier gas inlet and the exposed surface of the liquid chemical can result in an unwanted variation in the vapor phase reactant flow out from the chemical vessel to the reaction chamber. For example, as the liquid chemical within the vessel is consumed and the distance between the carrier gas inlet and the exposed surface of the liquid chemical increases, the flow of vapor phase reactant from the chemical vessel to the reaction chamber may decrease, resulting in an undesirable variation in semiconductor processing conditions. Accordingly, apparatus and methods are desirable for monitoring the fill level of a liquid chemical disposed within a vessel and regulating a semiconductor process in response to the fill level of the liquid chemical within the vessel. SUMMARY OF THE DISCLOSURE This summary is provided to introduce a selection of concepts in a simplified form. These concepts are described in further detail in the detailed description of example embodiments of the disclosure below. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. In some embodiments of the disclosure, an apparatus for dispensing a vapor phase reactant to a reaction chamber is provided. The apparatus may comprise: a vessel having an inner volume configured to contain a liquid chemical; an array of sensors configured for detecting a fill level of the liquid