Semiconductor device manufacturing: process – Making field effect device having pair of active regions... – On insulating substrate or layer
Reexamination Certificate
2002-04-23
2003-02-18
Nelms, David (Department: 2818)
Semiconductor device manufacturing: process
Making field effect device having pair of active regions...
On insulating substrate or layer
Reexamination Certificate
active
06521489
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to systems and methods for producing electrical circuit elements for control. More particularly, the invention relates to the use of printing technology to manufacture electrical circuit control elements.
BACKGROUND OF THE INVENTION
Most conventional electronic displays are driven by electrical circuit elements that are produced using a multistep process that makes extensive use of photolithographic patterning techniques. Photolithographic processes are technically well-suited for modern displays, offering high resolution capability and excellent device performance. Unfortunately, the capital equipment and related infrastructure associated with these processes is extremely expensive. It is therefore highly desirable to find lower-cost alternatives to conventional microfabrication processes.
Specifically, it is desirable to develop alternative processes that are all-additive; that is, functional materials are directly deposited in an arrangement that leads to the formation of functional electrical circuit elements. Moreover, such processes promise reduced material and consumable costs, dramatically simplified process flows, and higher throughput manufacturing.
SUMMARY OF THE INVENTION
In one aspect the invention relates to a method of manufacturing an addressing device for an electronic display. The method includes providing a substrate and fabricating the addressing device adjacent a surface of the substrate by treating the surface to control one of a contact angle of a liquid with the surface, a surface roughness and a surface energy, and printing at least one circuit element of the addressing device.
In one embodiment, the contact angle is controlled to be less than 90 degrees. In a preferred embodiment, the contact angle is controlled to be less than 60 degrees.
In another aspect, the invention relates to a method of manufacturing an addressing device for an electronic display. The method includes providing a substrate, and fabricating the addressing device adjacent a surface of the substrate by printing at least one circuit element by (i) screen printing a gate structure, (ii) ink jet printing a dielectric material and a semiconductor, (iii) screen printing coarse features of a source structure and a drain structure, and (iv) printing by use of soft lithography the high resolution features of the source structure and the drain structure. In one embodiment, screen printing involves using a conductive paste. The conductive paste has a viscosity between about 1000 cP and about 50000 cP.
In another embodiment, the method includes printing an encapsulant for protecting a portion of the addressing device. In still another embodiment, the method includes ink jet printing at least one circuit element using an ink having a viscosity of less than about 100 cP. In another embodiment, ink jet printing involves using a plurality of particles that are smaller than ¼ of a diameter of an orifice of an ink jet head. In a preferred embodiment, ink jet printing is performed using a plurality of particles that are smaller than {fraction (1/10)} of a diameter of an orifice of an ink jet head.
In another embodiment, the method includes ink jet printing at least one circuit element using an ink comprising a semiconductor dissolved in a solvent. In another embodiment, ink jet printing includes ink jet printing using an ink comprising a dielectric material dissolved in a solvent.
In still another embodiment, the method includes ink jet printing at least one circuit element by moving an ink jet head relative to the substrate at a speed U, where U is less than the quantity 2RF, where R is a drop radius and F is a drop ejection frequency.
In a further embodiment, ink jet printing includes freezing an ink jet drop upon the substrate upon impact. In yet another embodiment, an ink jet drop is frozen by independent control of the substrate temperature.
In an additional embodiment, printing by use of soft lithography includes printing at least one circuit element by microcontact printing using one of an elastomeric stamp and a rigid stamp. In still further embodiments, printing by use of soft lithography includes printing through one of a contact mask and a proximity mask, printing at least one circuit element using one of evaporation, sputtering and chemical vapor deposition, and printing at least one circuit element by transferring an ink from a mold to the substrate and curing the ink. In another embodiment, printing by use of soft lithography includes printing at least one circuit element using a mold having the surface property that an ink when dried adheres preferentially to a surface upon which the ink is being printed rather than to the mold.
In yet further embodiments, ink jet printed semiconductor material is selected from the class of materials consisting of polythiophenes, oligothiophenes, polythienylenevinylene, polyphenylenevinylene, and their derivatives, and colloidal suspensions of inorganic semiconductive particles, and ink jet printed insulating material is selected from the class of materials consisting of soluble polymers, glasses, inorganic films, and composite materials.
In still an additional embodiment, an ink jet printing step is replaced by a printing step involving a vacuum based process selected from evaporation, sputtering, reactive gas processing and chemical vapor deposition.
In other embodiments, a screen printing step is replaced by a printing step involving a vacuum based process selected from evaporation, sputtering, reactive gas processing and chemical vapor deposition, a step involving printing using soft lithography is replaced by a printing step involving a vacuum based process selected from evaporation, sputtering, reactive gas processing and chemical vapor deposition, and a plurality of, but not all, steps are replaced by a plurality of printing steps, each of the plurality of printing steps involving a vacuum based process selected from evaporation, sputtering, reactive gas processing and chemical vapor deposition.
In another aspect, the invention relates to a method of manufacturing an electronic device. The method includes (a) providing a substrate, (b) depositing a gate structure on the substrate using flexo-gravure printing, and (c) depositing a layer of dielectric material using slot coating, the layer of dielectric material covering the gate structure and a portion of the substrate. The method also includes (d) depositing adjacent the dielectric layer on a side thereof opposite the gate structure using screen printing a low resolution feature of a source structure and a low resolution feature of a drain structure, the source structure and the drain structure being deposited in a patterned structure having a space therebetween, (e) depositing a semiconductor material adjacent the dielectric layer in the space between the source structure and the drain structure using ink jet printing. and (f) disposing at least one electronic element adjacent the addressing device, such that the addressing device addresses the at least one electronic element to control a behavior of the electronic element
In one embodiment the method can additionally include, after step (c) and before step (d), depositing adjacent the dielectric layer on a side thereof opposite the gate structure a high resolution feature of a source structure and a high resolution feature of a drain structure using soft lithography techniques, the source structure and the drain structure having a space therebetween.
In another aspect, the invention relates to a transistor for addressing an electronic display. The transistor includes a substrate, a gate structure disposed adjacent a portion of the substrate, the gate structure formed by flexo-gravure printing, and a dielectric film disposed adjacent the gate and the substrate, the dielectric film formed by slot coating. The transistor also includes a source and a drain disposed adjacent the dielectric film, the source and the drain separated one from the other, the source and the drain formed us
Amundson Karl R.
Drzaic Paul
Duthaler Gregg
Kazlas Peter
Wang Jianna
E Ink Corporation
Le Thao P
Nelms David
Testa Hurwitz & Thibeault LLP
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