Method and apparatus for etching a metal layer disposed on a substrate, such as a photolithographic reticle, are provided. In one aspect, a method is provided for processing a photolithographic reticle including positioning the reticle in a first orientation on a reticle support in a processing chamber, wherein the reticle comprises a metal photomask layer formed on an optically transparent substrate, and a patterned resist material deposited on the metal photomask layer, etching the metal photomask layer in the first orientation, positioning the reticle in at least a second orientation, and etching the metal photomask layer in the at least second orientation.

Methods for substrate orientation

A method and apparatus to create two dimensional and three dimensional structures using a maskless photolithography system that is semi-automated, directly reconfigurable, and does not require masks, templates or stencils to create each of the planes or layers on a multi layer two-dimensional or three dimensional structure. In an embodiment, the pattern generator comprises a micromirror array wherein the positioning of the mirrors in the micromirror array and the time duration of exposure can be modulated to produce gray scale patterns to photoform layers of continuously variable thickness. The desired pattern can be designed and stored using conventional computer aided drawing techniques and can be used to control the positioning of the individual mirrors in the micromirror array to reflect the corresponding desired pattern. A fixture for mounting of the substrate can be incorporated and can allow the substrate to be moved three dimensions. The fixture can be rotated in one, two, or three directions.

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Method and apparatus for maskless photolithography

The present invention relates to maskless photolithography using a patterned light generator for creating 2-D and 3-D patterns on objects using etching and deposition techniques In an embodiment, the patterned light generator uses a micromirror array to direct pattern light on a target object In an alternate embodiment, the patterned light generator uses a plasma display device to generate and direct patterned light onto a target object Specifically, the invention provides a maskless photolithography system and method for photo stimulated etching of objects in a liquid solution, patterning glass, and photoselective metal deposition For photo stimulated etching of objects in a liquid solution, the invention provides a system and method for immersing a substrate in an etchant solution, exposing the immersed substrate to patterned light, and etching the substrate according to the pattern of incident light For patterning photoreactive glass, the invention provides a system and method for exposing photosensitive or photochromic glass, and washing the target glass with rinse and acid etchant solutions For photoselective metal deposition, the invention provides a system and method for coating and rinsing a substrate prior to exposure exposing the substrate to a patterned light generator to activate areas corresponding to the incident light pattern, and plating the substrate in the area activated by the light after exposure By providing a maskless pattern generator, the invention advantageously eliminates the problems associated with using masks for photo stimulated etching, patterning glass, and photoselective metal deposition

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Maskless photolithography for etching and deposition

The present invention is a system and method to create two dimensional and three dimensional structures using a maskless photolithography system that is semi-automated, directly reconfigurable, and does not require masks, templates or stencils to create each of the planes or layers on a multi layer two-dimensional or three dimensional structure. In an embodiment, the invention uses a micromirror array comprising up to several million elements to modulate light onto a substrate that has photoreactive or photoresist compounds applied to the exposed surface. The desired pattern is designed and stored using conventional computer aided drawing techniques and is used to control the positioning of the individual mirrors in the micromirror array to reflect the corresponding desired pattern. Light impinging on the array is reflected to or directed away from the substrate to create light and dark spots on the substrate according to the pattern. In addition, a fixture three dimensions, for mounting of the substrate and allows the substrate to be moved three dimensions, providing alignment in two, coplanar dimensions and the capability to produce three dimensional structures by aligning the substrate in a third dimension perpendicular to the two coplanar dimensions. The system and method is easily reconfigurable and allows rapid prototyping of microscopic and macroscopic devices.

Maskless 2-D and 3-D pattern generation photolithography

The present invention relates to maskless photolithography using a patterned light generator for creating 2-D and 3-D patterns on objects using photoreactive chemicals. In an embodiment, the patterned light generator uses a micromirror array to direct pattern light on a target object. In an alternate embodiment, the patterned light generator uses a plasma display device to generate and direct patterned light onto a target object. Specifically, the invention provides a maskless photolithography system and method for creating molecular imprinted array devices, integrated microsensors and fluidic networks on a substrate, integrated circuits of conducting polymers, and patterns on substrates using photochemical vapor deposition. For creating molecular imprinted array devices, the invention provides a system and method for applying a photoreactive reagent comprising photopolymer receptors and extractable target compounds, exposing the substrate to patterned light to activate the photopolymer to form molecular imprints of the target compounds corresponding to the pattern of incident light. For creating integrated circuits of conducting polymers, the invention provides a system and method for applying a photoreactive conducting polymer reagent to a substrate, exposing the substrate to patterned light to activate the photoreactive conducting polymer reagent to form integrated circuits corresponding to the circuit pattern of incident light. In an embodiment the substrate is a photoreactive conductive polymer. For creating integrated microsensors and fluidic networks on a substrate, the invention provides a system and method for applying a photoreactive sensor creating compound and a photoreactive fluid channel creating compound to a substrate, exposing the substrate to patterned light to activate the photoreactive compounds to form microsensor arrays and fluidic networks corresponding to the pattern of incident light. For creating patterns on substrates using photochemical vapor deposition, the invention provides a system and method for exposing a substrate to photoreactive gases and patterned light to deposit chemicals on the substrate corresponding to the pattern of incident light.

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Maskless photolithography for using photoreactive agents

A half-tone phase shift mask process has been developed. The writing and process for normal masks are found to be applicable to HT-PSMs. A dry etch process has been adopted to etch the shifter. Several characteristics of HT-PSMs such as CD uniformity, CD linearity, edge roughness and corner rounding, positional accuracy in the EB process, selectivity in dry etch, pattern profile, durability against cleaning, pelliclization and a blind pattern are evaluated. The process shows a good performance sufficient for first generation 64 MDRAM mask making. The EB writing causes no charge-up problem. The selectivity of HT-shifter to an i-line resist and an new type EB resist in dry etch is satisfactory and the selectivity to a fused silica substrate is more than 300. An exposure test was conducted with our HT-PSM. Coherency factor ((sigma) ) of a stepper is found to strongly affect the defocus range and exposure latitude.

Manufacturing of half-tone phase-shift masks II: writing and process

Characteristics of four chemically-amplified (CA), negative EB resists have been evaluated and compared with the requirements to resists for 64 Mb-DRAM reticles The four resists satisfy the requirements on sensitivity, side-wall angle, corner roundness, edge roughness, and dry- etch rate. In a wet-etch process three resists (resists B, C and D) have good CD linearity down to 0.5 micrometers whereas one resist (resist A) has a poor linearity owing to a large etching shift. A dry-etch process could extend CD linearity and resolution limits for all the resists. Storage of a resist-coated blank in a box with silica gel is found to be effective in extending the life of the blank after coating. Thus, the lives after coating for all the resists are long enough for practical use (CD deviation less than 0.1 micrometers per month) under the above storage conditions. Only two resists (resists A and D) have lives after exposure long enough for practical use (CD deviation less than 0.1 micrometers per 10h). Reducing the contribution of post-exposure bake to CD uniformity is achieved by the use of a hot-plate that can give good uniformity in the surface temperature of a Cr/Qz-substrate. In conclusion, CA resists can meet the requirements to resists for 64 Mb-DRAM reticles.

Application of chemically amplified resists to photomask fabrication

The loading effect is becoming a great issue in mask fabrication. To reduce CD error due to resist load, we have developed a developer based on a new concept, Proximity Gap Suction Development (PGSD), involving the use of a nozzle to spout developer and suck in dirty developer. In this paper, the performance of PGSD is reported.

Performance of Proximity Gap Suction Development (PGSD)

In recent years, more precise pattern dimension control (CD control) on a photomask has been required than ever as finer-line of IC pattern progresses. In the case of the conventional development (spray-development, puddle-development), CD control is difficult due to loading and micro-loading effect. The "loading and micro-loading effect" refers to the differences of exposed area around the pattern.
The low pattern density generates numerous dissolution products and decreases the concentration of developer. This phenomenon changes resist dissolution rate and causes difficulties in controlling the CD. To solve this problem, we have been developing a new type of developer, called "Proximity Gap Suction Development (PGSD)." Nozzle of PGSD has five slits; opening for supplying developer is in the center, two suction slits are on the both sides, and two slits for rinse are on the very end. The proximity gap is kept between the nozzle surface and resist during development. Contaminated developer is immediately sucked/removed and stable development can be achieved by the continuous dispense of fresh developer at high speed. Thus, a desired pattern size can be obtained without loading and micro loading effect. We reported the principle of PGSD at BACUS in 2002. In this thesis, we would like to report the following topics.
(1) System overview of α machine, which we are currently developing.
(2) Effect of the PGSD on CD uniformity and the number of defects.

Toshiharu Nishimura

Papers

Manufacturing of half-tone phase-shift masks II: writing and process

Application of chemically amplified resists to photomask fabrication

Performance of Proximity Gap Suction Development (PGSD)

New development method eliminating the loading and microloading effect