Method and apparatus for monitoring the deposition rate of films during physical vapor deposition

Claim 2

A deposition rate monitor comprising: a fixture adapted to hold a deposition substrate; a light source which directs light over said fixture; an optical detector disposed to receive said light after said light passes over said fixture, wherein said optical detector produces a first signal prior to initiation of a deposition process and wherein said optical detector produces a second signal during a deposition process; and a signal processor which stores a first measured value of said second signal obtained during said deposition process, said signal processor comparing a subsequently measured value of said second signal obtained during a subsequent deposition process to said first measured value.

Claim 3

A deposition rate monitor in accordance with claim 1 further comprising a semiconductor wafer as a deposition substrate.

Claim 4

A deposition rate monitor in accordance with claim 1 wherein said light source comprises a semiconductor laser.

Claim 5

A deposition rate monitor in accordance with claim 1 further comprising means for forming a ratio between said second signal and said first signal.

Claim 6

A deposition rate monitor in accordance with claim 1 further comprising a control system that adjusts deposition parameters in response to said first and said second measured values produced by said optical detector.

Claim 7

A physical vapor deposition system having a processing environment, which has at least one characteristic absorption line, comprising: a fixture adapted to hold a semiconductor wafer; a physical vapor deposition source disposed adjacent to said fixture, said physical vapor deposition source providing material to be deposited; a light source which directs light through a region between said source and said fixture, wherein said light source emits light at a wavelength range that avoids said at least one characteristic absorption line of the processing environment; and an optical detector disposed to receive said light after said light passes over said fixture, wherein said optical detector produces a first signal prior to initiation of a deposition process and wherein said optical detector produces a second signal during said deposition process.

Claim 8

A physical vapor deposition system having a processing environment, which has at least one characteristic absorption line, comprising: a fixture adapted to hold a semiconductor wafer; a physical vapor deposition source disposed adjacent to said fixture, said physical vapor deposition source providing material to be deposited; a light source which directs light through a region between said source and said fixture, wherein said light source emits light at a wavelength range that avoids said at least one characteristic absorption line of the processing environment; and an optical detector disposed to receive said light after said light passes over said fixture, wherein said optical detector produces a first signal prior to initiation of a deposition process and wherein said optical detector produces a second signal during said deposition process.

Claim 9

A physical vapor deposition system according to claim 6 wherein said deposition source is a sputtering target.

Claim 10

A physical vapor deposition system according to claim 6 further comprising a shield disposed around said fixture and said deposition source, said shield having at least one optical port, wherein said light passes through said at least one optical port.

Claim 11

A physical vapor deposition system according to claim 8 further comprising: a first mirror disposed so as to direct said light toward said fixture; and a second mirror disposed so as to direct said light toward said optical detector.

Claim 12

A physical vapor deposition system according to claim 6 further comprising a control system that adjusts deposition parameters in response to said second signal generated by said optical detector.

Claim 13

A physical vapor deposition system according to claim 10 further comprising a power supply coupled to said deposition source, wherein said power supply is coupled to and is at least partially controlled by said control system.

Claim 14

A physical vapor deposition system in accordance with claim 6 further comprising means for forming a ratio between said second signal and said first signal.

Claim 15

A physical vapor deposition system in accordance with claim 12 further comprising a control system that adjusts deposition parameters in response to said first and said second signal produced by said optical detector.

Claim 18

A method in accordance with claim 14 further comprising the step of calculating a deposition rate from said first intensity and said second intensity.

Claim 19

A method in accordance with claim 14 further comprising the steps of passing said beam of light through a first optical port and through a second optical port.

Claim 20

A deposition rate monitor comprising: a fixture adapted to hold a deposition substrate so that said deposition substrate is exposed to a deposition transport region through which deposition material is transported during a deposition process; a light source which directs light through said deposition transport region; an optical detector disposed to receive said light after said light has passed through said deposition transport region, wherein said optical detector generates a signal indicative of a density of material within said deposition transport region; and a signal processor coupled to receive said signal from said optical detector; wherein said signal processor stores an initially measured value of said signal obtained during said deposition process, said signal processor comparing a subsequently measured value of said signal obtained during a subsequent deposition process to said initially measured value to generate a signal characteristic of a change in said density of material within said deposition transport region as a function of time.

Claim 21

A deposition rate monitor comprising: a fixture adapted to hold a deposition substrate so that said deposition substrate is exposed to a deposition transport region through which deposition material is transported during a deposition process; a light source which directs light through said deposition transport region; an optical detector disposed to receive said light after said light has passed through said deposition transport region, wherein said optical detector generates a signal indicative of a density of material within said deposition transport region; and a signal processor coupled to receive said signal from said optical detector; wherein said signal processor stores an initially measured value of said signal obtained during said deposition process, said signal processor comparing a subsequently measured value of said signal obtained during a subsequent deposition process to said initially measured value to generate a signal characteristic of a change in said density of material within said deposition transport region as a function of time.

Claim 22

A deposition rate monitor in accordance with claim 17 wherein said fixture is adapted to hold a semiconductor wafer.

Claim 23

A deposition rate monitor in accordance with claim 17 wherein said light source comprises a semiconductor laser.

Claim 24

A deposition rate monitor in accordance with claim 17 further comprising means for determining a deposition rate from said signal indicative of a density of material within said deposition transport region.

Claim 25

A deposition rate monitor in accordance with claim 20 wherein said means for determining a deposition rate generates a measured deposition rate signal based on an empirically derived relationship between an attenuation of said light received by said optical detector and a previously measured deposition rate.

Claim 26

A deposition rate monitor in accordance with claim 17 further comprising a control system for adjusting a deposition parameter in accordance with said signal indicative of a density of material within said deposition transport region.

Claim 27

A physical vapor deposition system having a processing environment which has at least one characteristic absorption line, comprising: a fixture adapted to hold a deposition substrate; a physical vapor deposition source disposed in relation to said fixture so as to define a deposition transport region through which deposition material is transported during a physical vapor deposition process; a light source which directs light through said deposition transport region; an optical detector disposed to receive said light after said light has passed through said deposition transport region, wherein said optical detector generates a signal indicative of a deposition rate; and a filter disposed between said light source and said optical detector, said filter selecting at least one wavelength range to avoid said at least one characteristic absorption line of the processing environment.

Claim 28

A physical vapor deposition system having a processing environment which has at least one characteristic absorption line, comprising: a fixture adapted to hold a deposition substrate; a physical vapor deposition source disposed in relation to said fixture so as to define a deposition transport region through which deposition material is transported during a physical vapor deposition process; a light source which directs light through said deposition transport region; an optical detector disposed to receive said light after said light has passed through said deposition transport region, wherein said optical detector generates a signal indicative of a deposition rate; and a filter disposed between said light source and said optical detector, said filter selecting at least one wavelength range to avoid said at least one characteristic absorption line of the processing environment.

Claim 29

A physical vapor deposition system in accordance with claim 23 further comprising means for determining a deposition rate from said signal indicative of a deposition rate.

Claim 30

A physical vapor deposition system in accordance with claim 24 wherein said means for determining a deposition rate generates a measured deposition rate signal based on an empirically derived relationship between an attenuation of said light received by said optical detector and a previously measured deposition rate.

Claim 31

A physical vapor deposition system in accordance with claim 25 further comprising a control system for adjusting a deposition parameter in accordance with said signal indicative of a deposition rate.

Claim 32

A physical vapor deposition system in accordance with claim 23 further comprising a shield disposed around said fixture and said deposition source, said shield having at least one optical port, wherein said light passes through said at least one optical port.

Claim 35

The method of claim 28 further comprising the step of determining a deposition rate from said signal indicative of a density of material within said deposition transport region.

Claim 36

The method of claim 29 further comprising the step of adjusting a deposition parameter in accordance with said signal indicative of a deposition rate.