摘要:
A method of aligning a wafer when lithographically fabricating a light-emitting diode (LED). The method includes forming on the wafer at least one roughened alignment mark having a root-mean-square (RMS) surface roughness σS. The roughened alignment mark is formed as a consequence of forming a plasma etch to roughen a LED surface on which the wafer alignment mark resides. The method also includes imaging the at least one roughened wafer alignment mark with alignment light having a wavelength λA that is in the range from about 2 σS to about 8 σS. The method also includes comparing the detected image to an alignment reference to establish wafer alignment. Once wafer alignment is established, p-contacts and n-contacts can be formed on the LED upper surface in their proper locations.
摘要:
An alignment system for aligning a wafer when lithographically fabricating LEDs having an LED wavelength λLED is disclosed. The system includes the wafer. The wafer has a roughened alignment mark with a root-mean-square (RMS) surface roughness σS. The system has a lens configured to superimpose an image of the reticle alignment mark with an image of the roughened alignment mark. The roughened alignment marked image is formed with alignment light having a wavelength λA that is in the range from about 2σS to about 8σS. An image sensor detects the superimposed image. An image processing unit processes the detected superimposed image to measure an alignment offset between the wafer and the reticle.
摘要:
A method of aligning a wafer when lithographically fabricating a light-emitting diode (LED). The method includes forming on the wafer at least one roughened alignment mark having a root-mean-square (RMS) surface roughness σS. The roughened alignment mark is formed as a consequence of forming a plasma etch to roughen a LED surface on which the wafer alignment mark resides. The method also includes imaging the at least one roughened wafer alignment mark with alignment light having a wavelength λA that is in the range from about 2σS to about 8σS. The method also includes comparing the detected image to an alignment reference to establish wafer alignment. Once wafer alignment is established, p-contacts and n-contacts can be formed on the LED upper surface in their proper locations.
摘要:
An alignment system for aligning a wafer when lithographically fabricating LEDs having an LED wavelength λLED is disclosed. The system includes the wafer. The wafer has a roughened alignment mark with a root-mean-square (RMS) surface roughness σS. The system has a lens configured to superimpose an image of the reticle alignment mark with an image of the roughened alignment mark. The roughened alignment marked image is formed with alignment light having a wavelength λA that is in the range from about 2σS to about 8σS. An image sensor detects the superimposed image. An image processing unit processes the detected superimposed image to measure an alignment offset between the wafer and the reticle.
摘要:
A hybrid tuning circuit is used consisting of a digital finite state machine and an analog tuning circuit to effectively keep the RC product of the continuous time integrator constant across process, temperature, supply, and sampling rate variations. Since the implementation is continuous, the tracking is more accurate than traditional techniques. Using a carefully chosen clocking scheme, the technique gets rid of inter-symbol interference in the feedback DAC. The technique does not use a reference frequency, thereby eliminating the need for a user to identify a reference frequency.
摘要:
A photomask etch chamber, which includes a substrate support member disposed inside the chamber. The substrate support member is configured to support a photomask substrate. The chamber further includes a ceiling disposed on the chamber and an endpoint detection system configured to detect a peripheral region of the photomask substrate.
摘要:
A digital to analog converter (DAC) includes a first continuous-time stage that receives an input signal associated with a digital signal and performs continuous-time digital-to-analog conversion operations on the input signal. The first continuous-time stage outputs a first output signal. A second switched-capacitor stage receives the first output signal and performs switched-capacitor filtering of the first output signal. The second switched-capacitor stage outputs a second output signal that is sent to a low pass filter to form a continuous analog signal associated with the digital signal.
摘要:
Method and apparatus for supporting and transferring a substrate in a semiconductor wafer processing system are provided. In one aspect, an apparatus is provided for supporting a substrate comprising-a cover ring comprising a base having a bore disposed therethough, the base having an upper surface and one or more raised surfaces disposed adjacent the bore, wherein the raised surface comprise one or more first substrate support members disposed adjacent an edge of the bore and a capture ring disposed on the cover ring, the capture ring comprising a semi-circular annular ring having an inner perimeter corresponding to the bore of the cover ring and one or more second substrate support members disposed on the inner perimeter and adapted to receive a substrate, wherein the capture ring is adapted to mate with the cover ring and form one contiguous raised surface on the cover ring.
摘要:
A hybrid tuning circuit is used consisting of a digital finite state machine and an analog tuning circuit to effectively keep the RC product of the continuous time integrator constant across process, temperature, supply, and sampling rate variations. Since the implementation is continuous, the tracking is more accurate than traditional techniques. Using a carefully chosen clocking scheme, the technique gets rid of inter-symbol interference in the feedback DAC. The technique does not use a reference frequency, thereby eliminating the need for a user to identify a reference frequency.
摘要:
The embodiments of the invention relate to a method and apparatus for measuring the etch depth between etching for an alternate phase shift photomask in a semiconductor photomask processing system. The apparatus for measuring the etch depth of a substrate in an etch processing system comprises a measurement cell coupled to a mainframe of the etch processing system, and an etch depth measurement tool coupled to the bottom of the measurement cell, wherein an opening at the bottom of the measurement cell allows light beams to pass between the etch depth measurement tool and the substrate. The embodiments of the invention also relate to the method of preparing an alternate phase shift mask by partially etching the quartz substrate to an initial etch depth, followed by measuring the etch depth with an integrated measurement tool. The substrate is then etched and measured repeatedly until the targeted etch depth has been reached.