Measuring in-situ UV intensity in UV cure tool
AssigneeNovellus Systems, Inc.
InventorEugene Smargiassi
Life of this patent
Estimating the term…
Abstract
Consistent ultraviolet (UV) intensity for a semiconductor UV cure chamber is measured in-situ with a hot pedestal in vacuum by measuring reflected UV light from a calibration substrate at a UV detector mounted in the lamp assembly. The measurement apparatus includes a UV detector, a cover that protects the detector from UV light while not in use, and a mirror disposed between the chamber window and the UV detector. Measured UV intensity from the substrate reflection and from the mirror reflection help determine a course of maintenance action to maintain wafer-to-wafer uniformity.
Claims19
An ultraviolet (UV) apparatus for semiconductor processing, the apparatus comprising:
- (a) a process chamber comprising a substrate holder and a window;
- and,
- (b) a UV radiation assembly external to the process chamber, the assembly comprising
- i) at least two UV lamps,
- ii) one or more reflectors operable to direct a portion of the UV radiation from the at least two UV lamps through the window towards the substrate holder,
- iii) an in situ UV intensity detector disposed between the at least two UV lamps, and
- iv) a shutter or iris configured to isolate the UV intensity detector from the UV radiation between measurements;
- and,
- (c) a controller configured to execute a set of instructions, the set of instructions comprising:
- opening the shutter or iris to expose a UV detector to the UV radiation;
- measuring a UV intensity at a UV radiation power with the UV detector;
- after measuring, closing a shutter or iris to isolate the UV detector from the UV radiation;
- calculating a deviation based on the measurement and a baseline intensity;
- and,
- adjusting the UV radiation power or exposure duration to compensate for the deviation.
An ultraviolet (UV) apparatus for semiconductor processing, the apparatus comprising:
- (a) a process chamber comprising a substrate holder and a window;
- and,
- (b) a UV radiation assembly external to the process chamber, the assembly comprising
- i) at least two UV lamps,
- ii) one or more reflectors operable to direct a portion of the UV radiation from the at least two UV lamps through the window towards the substrate holder,
- iii) an UV intensity detector positioned between the at least two UV lamps to receive UV radiation from the at least two UV lamps reflected through the window,
- iv) a cover configured to isolate the UV detector from radiation from the at least two UV lamps.
A method of calibrating an ultraviolet (UV) apparatus, the method comrising:
- (a) receiving a calibration indication or determining that a calibration is required;
- (b) setting a UV radiation power from at least two UV lamps to a first power;
- and,
- (c) measuring an output over a duration of an in situ UV intensity detector disposed between the at least two UV lamps;
- wherein a chamber vacuum is maintained during the calibration and wherein the method further comprises opening a shutter to expose a UV detector to the UV radiation prior to (c);
- and closing a shutter to isolate the UV detector from the UV radiation after (c).
Dependencies are inferred from the claim text.