Delivery of liquid precursors to semiconductor processing reactors

• US 6,640,840 B1
• Filed: 09/21/2000
• Issued: 11/04/2003
• Est. Priority Date: 09/25/1999
• Status: Expired due to Fees

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Trillion Holdings Pty., Ltd.
• Inventors: MacNeil, John
• Primary Examiner(s): MAUST, TIMOTHY LEWIS
• Application Number:
  US09/667,329
• Time in Patent Office: 1,139 Days
• Field of Search: 141/1, 141/63, 141/64, 141/67, 141/69, 141/82, 141/94, 141/100, 141/102, 141/104, 141/105, 141/126, 141/127, 141/192, 141/198, 141/285, 118/715, 118/726, 427/248.1
• US Class Current: 141/1
• CPC Class Codes: C23C 16/401 containing silicon
• CPC Class Codes: C23C 16/56 After-treatment
• CPC Class Codes: F04B 19/04 Pumps for special use
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• CPC Class Codes: H01L 21/3105 After-treatment
• CPC Class Codes: H01L 21/31612 on a silicon body
• CPC Class Codes: Y02E 60/34 Hydrogen distribution

Abstract

This invention relates to methods and apparatus for delivering liquid precursors to semi-conductor processing apparatus. The liquid precursor delivery system is generally indicated at (10) and includes a source (11), an inlet tube (12), a two-way valve (13), a pump assembly (14), an outlet tube (15), a shut-off valve (16) and a flash evaporator (17). The pump assembly (14) is in the form of a syringe or variable volume pump and is controlled by a combination of a step motor (27) and a linear encoder (30). The arrangement is such that unused liquid precursor can be returned to the source.

Claims

1. Apparatus for delivering a desired volume of liquid precursor, comprising:

a semiconductor processing reactor having an evaporator connected thereto;

a source for the liquid precursor;

a variable volume pump that can deliver various volumes of the precursor from said source to said reactor via said evaporator, said variable volume pump including a pump chamber connected to said source for the precursor and to the evaporator, and a piston that is linearly displaceable to pump a volume of the precursor from said chamber corresponding to the displacement of said piston;

a detector which detects the relative position of said piston;

a motor connected to said piston and operable to drive said piston linearly; and

a control circuit operatively connected to said motor so as to control the operation of said motor and operatively connected to said detector so as to receive signals therefrom indicative of the relative position of said piston, said control circuit operating under feedback from said detector to stop said motor when said piston reaches a given position such that the desired volume of liquid precursor, independent of the volume of said chamber, is expelled from said chamber to said reactor;

wherein said apparatus further comprises an inlet tube leading from said chamber of said variable volume pump towards said source for the precursor, an outlet tube leading from said chamber of said variable volume pump towards said reactor, and a valve operable to selectively place said inlet tube and said outlet tube in open communication with said chamber; and

wherein said control circuit is operatively connected to said valve and to said reactor so as to control said valve to place said chamber of said variable volume pump in open communication with said inlet tube and to operate said motor to drive said piston in a direction that causes said precursor to be induced into said chamber, while said reactor is not processing with precursor from said source.

2. Apparatus for delivering a desired volume of liquid precursor, comprising:

a semiconductor processing reactor having an evaporator connected thereto;

a source for the liquid precursor;

a variable volume pump that can deliver various volumes of the precursor from said source to said reactor via said evaporator, said variable volume pump including a pump chamber connected to said source for the precursor and to the evaporator, and a piston that is linearly displaceable to pump a volume of the precursor from said chamber corresponding to the displacement of said piston;

a detector which detects the relative position of said piston;

a motor connected to said piston and operable to drive said piston linearly; and

a control circuit operatively connected to said motor so as to control the operation of said motor and operatively connected to said detector so as to receive signals therefrom indicative of the relative position of said piston, said control circuit operating under feedback from said detector to stop said motor when said piston reaches a given position such that the desired volume of liquid precursor, independent of the volume of said chamber, is expelled from said chamber to said reactor;

wherein said apparatus further comprises an inlet tube leading from said chamber of said variable volume pump towards said source for the precursor, an outlet tube leading from said chamber of said variable volume pump towards said reactor, and a valve operable to selectively place said inlet tube and said outlet tube in open communication with said chamber; and

wherein said control circuit is operative to control said valve to place said chamber of said variable volume pump in open communication with said outlet and inlet tubes and to operate said motor to drive said piston in a direction that expels precursor from said chamber after said piston has reached said given position in said chamber, whereby said variable volume pump returns undelivered precursor to said source.

3. Apparatus for delivering a desired volume of liquid precursor, comprising:

a semiconductor processing reactor having an evaporator connected thereto;

a source for the liquid precursor;

a variable volume pump that can deliver various volumes of the precursor from said source to the reactor via said evaporator, said pump having a pump chamber;

an inlet tube leading from said pump chamber towards said source for the precursor;

an outlet tube leading from said pump chamber towards the reactor;

a valve operable to selectively place said inlet tube and said outlet tube in open communication with said variable volume pump; and

a control circuit operative to control said valve to place said inlet tube in open communication with said variable volume pump and to concurrently operate said motor to drive said pump in a direction that expels precursor from said chamber after said pump has expelled the desired volume of precursor to the reactor via said outlet tube, wherein said variable volume pump returns undelivered precursor to said source via said inlet tube.

4. A method of delivering a liquid precursor to a semiconductor processing reactor, said method comprising:

determining a desired volume of the liquid precursor that is to be delivered to the reactor for carrying out a process therein;

charging a chamber of a variable volume pump, connected to the reactor via an outlet tube, with the liquid precursor from a source of the liquid precursor;

driving a piston of the pump to expel liquid precursor from the chamber and to the reactor via the outlet tube, the displacement of the piston from a starting position corresponding to the volume of liquid precursor expelled;

monitoring the position of the piston relative to the starting position thereof; and

stopping the piston, based on said monitoring, when the relative position of the piston is indicative of the piston having expelled the desired volume of the liquid precursor from the chamber of the pump, whereby the desired volume of liquid precursor delivered to the reactor is independent of the volume of the chamber of the pump;

said method further comprising alternately placing the chamber of the pump in open communication with an inlet tube, connected to a source of the liquid precursor, and then with the outlet tube; and

driving the piston of the pump in one direction when the chamber is opened to the inlet tube to induce the liquid precursor into the chamber;

wherein the piston of the pump is driven in the other direction when the chamber is placed in open communication with the outlet tube to expel the liquid precursor from the chamber; and

said method further comprising driving the piston of the pump in said another direction when the chamber is placed in open communication with the inlet tube to return to the source an amount of liquid precursor that remains in the chamber after the desired volume of the liquid precursor has been expelled from the chamber, and before the chamber is again charged with the liquid precursor.