US20140106512A1 - Microchip charge patterning - Google Patents

Microchip charge patterning Download PDF

Info

Publication number
US20140106512A1
US20140106512A1 US13/652,220 US201213652220A US2014106512A1 US 20140106512 A1 US20140106512 A1 US 20140106512A1 US 201213652220 A US201213652220 A US 201213652220A US 2014106512 A1 US2014106512 A1 US 2014106512A1
Authority
US
United States
Prior art keywords
charge
scorotron
dry film
depositing
microchip
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
US13/652,220
Other versions
US8685769B1 (en
Inventor
Eugene M. Chow
JengPing Lu
Armin R. Volkel
Bing R. Hsieh
Gregory L. Whiting
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Xerox Corp
Original Assignee
Palo Alto Research Center Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Assigned to PALO ALTO RESEARCH CENTER INCORPORATED reassignment PALO ALTO RESEARCH CENTER INCORPORATED ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: LU, JENGPING, VOLKEL, ARMIN R., WHITING, GREGORY L., CHOW, EUGENE M., HSIEH, BING R.
Priority to US13/652,220 priority Critical patent/US8685769B1/en
Application filed by Palo Alto Research Center Inc filed Critical Palo Alto Research Center Inc
Priority to JP2013206542A priority patent/JP6279870B2/en
Priority to EP13188458.7A priority patent/EP2720260B1/en
Application granted granted Critical
Publication of US8685769B1 publication Critical patent/US8685769B1/en
Publication of US20140106512A1 publication Critical patent/US20140106512A1/en
Assigned to XEROX CORPORATION reassignment XEROX CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: PALO ALTO RESEARCH CENTER INCORPORATED
Assigned to CITIBANK, N.A., AS COLLATERAL AGENT reassignment CITIBANK, N.A., AS COLLATERAL AGENT SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: XEROX CORPORATION
Assigned to XEROX CORPORATION reassignment XEROX CORPORATION CORRECTIVE ASSIGNMENT TO CORRECT THE REMOVAL OF US PATENTS 9356603, 10026651, 10626048 AND INCLUSION OF US PATENT 7167871 PREVIOUSLY RECORDED ON REEL 064038 FRAME 0001. ASSIGNOR(S) HEREBY CONFIRMS THE ASSIGNMENT. Assignors: PALO ALTO RESEARCH CENTER INCORPORATED
Assigned to JEFFERIES FINANCE LLC, AS COLLATERAL AGENT reassignment JEFFERIES FINANCE LLC, AS COLLATERAL AGENT SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: XEROX CORPORATION
Assigned to CITIBANK, N.A., AS COLLATERAL AGENT reassignment CITIBANK, N.A., AS COLLATERAL AGENT SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: XEROX CORPORATION
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/93—Batch processes
    • H01L24/95—Batch processes at chip-level, i.e. with connecting carried out on a plurality of singulated devices, i.e. on diced chips
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
    • G03G5/02—Charge-receiving layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/544—Marks applied to semiconductor devices or parts, e.g. registration marks, alignment structures, wafer maps
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2223/00—Details relating to semiconductor or other solid state devices covered by the group H01L23/00
    • H01L2223/544—Marks applied to semiconductor devices or parts
    • H01L2223/5442—Marks applied to semiconductor devices or parts comprising non digital, non alphanumeric information, e.g. symbols
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2223/00—Details relating to semiconductor or other solid state devices covered by the group H01L23/00
    • H01L2223/544—Marks applied to semiconductor devices or parts
    • H01L2223/54426—Marks applied to semiconductor devices or parts for alignment
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2223/00—Details relating to semiconductor or other solid state devices covered by the group H01L23/00
    • H01L2223/544—Marks applied to semiconductor devices or parts
    • H01L2223/54433—Marks applied to semiconductor devices or parts containing identification or tracking information
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2223/00—Details relating to semiconductor or other solid state devices covered by the group H01L23/00
    • H01L2223/544—Marks applied to semiconductor devices or parts
    • H01L2223/54473—Marks applied to semiconductor devices or parts for use after dicing
    • H01L2223/5448—Located on chip prior to dicing and remaining on chip after dicing
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/93—Batch processes
    • H01L2224/95—Batch processes at chip-level, i.e. with connecting carried out on a plurality of singulated devices, i.e. on diced chips
    • H01L2224/95053—Bonding environment
    • H01L2224/95085—Bonding environment being a liquid, e.g. for fluidic self-assembly
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/93—Batch processes
    • H01L2224/95—Batch processes at chip-level, i.e. with connecting carried out on a plurality of singulated devices, i.e. on diced chips
    • H01L2224/9512—Aligning the plurality of semiconductor or solid-state bodies
    • H01L2224/95143—Passive alignment, i.e. self alignment, e.g. using surface energy, chemical reactions, thermal equilibrium
    • H01L2224/95145—Electrostatic alignment, i.e. polarity alignment with Coulomb charges
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/10—Details of semiconductor or other solid state devices to be connected
    • H01L2924/102—Material of the semiconductor or solid state bodies
    • H01L2924/1025—Semiconducting materials
    • H01L2924/10251—Elemental semiconductors, i.e. Group IV
    • H01L2924/10253—Silicon [Si]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/10—Details of semiconductor or other solid state devices to be connected
    • H01L2924/102—Material of the semiconductor or solid state bodies
    • H01L2924/1025—Semiconducting materials
    • H01L2924/1026—Compound semiconductors
    • H01L2924/1032—III-V
    • H01L2924/10329—Gallium arsenide [GaAs]

Definitions

  • the system uses the encoding to identify and position the microchips as part of the assembly process.
  • the fabrication process should be compatible with existing devices on the chips. In addition, the process should not increase the manufacturing costs, but still allow the patterning on a scalable level between larger areas and small features. In order to provide a flexible system, the system should allow for varying magnitudes of charge density, and ideally but not necessarily, both positive and negative polarity, for multiple levels of chip control and identification. The charge patterns should have good stability to allow long shelf life of the patterned devices.
  • chips being attracted to each other. They may gather together or conglomerate based upon their respective charges. The density of the chips needs to remain low enough the chips do not exchange charge by contact with each other.
  • FIG. 1 show an embodiment of an overall method of forming charge patterns on microchips.
  • FIG. 2 shows an embodiment of a method of forming charge patterns on a microchip.
  • FIG. 3 shows an embodiment of a method of printing charge patterns on a microchip.
  • FIGS. 4-7 show an embodiment of a method of photolithographically forming charge patterns on a microchip.
  • FIGS. 8-10 show an embodiment of a method of forming a charge pattern using a scorotron.
  • FIGS. 11-13 show an embodiment of a method of forming a bipolar charge template.
  • FIGS. 12-16 show an alternative embodiment of a method of forming a bipolar charge template.
  • FIG. 1 shows an overall embodiment of a method of forming charge patterns on a microchip.
  • the microchips are fabricated on a substrate, such as silicon, gallium arsenide, complementary metal oxide semiconductor (CMOS) etc.
  • CMOS complementary metal oxide semiconductor
  • the process then deposits materials on the microchips to enable charging at 13 .
  • the microchips are then submersed in a fluid that causes charge to develop on the materials deposited.
  • FIGS. 8-16 the materials on the microchips are charged using an external device. The end result is microchips with charge patterns on their surfaces in 19 .
  • FIG. 2 shows an embodiment of a method of forming charge patterns on a microchip.
  • the process will more than likely begin at the wafer level at 10 , after manufacture of the individual microchips on the wafer. This allows the process of charge patterning to occur in a more mass-produced manner, using techniques compatible with chip fabrication processes. However, no limitation is intended by this discussion and none should be implied.
  • the individual chips can be patterned using the same techniques after singulation from the wafer.
  • the manufactured microchip 12 has a shield 14 to protect the circuitry on the chip.
  • the shield has an insulator 16 .
  • the insulator allows charge or material patterns deposited on the surface to avoid interaction with the circuitry on the microchip.
  • the pattern ABBAB may represent different charges, such as + ⁇ + ⁇ , or a pattern of materials into which charge will be developed.
  • the charge pattern may consist of alternating regions of differing charge magnitude and/or polarity. The embodiment in this portion of the discussion has the patterns being charge.
  • the microchips can be placed into a fluid to create an ‘ink’ bottle 22 or other dispenser.
  • the fluid may contain other additives such as a charge control agent.
  • the charge control agent may either allow the charge to remain stable on the surface of the chips 12 , or may cause the charge to develop on the surface of the wafer.
  • the charge generation may take the form of depositing a material, and developing a charge in the material thorough the interaction of the charge patterning material with the fluid component of the ink.
  • One approach uses deposition of a thin-film of the charge patterning material using solution processing techniques such as spin-coating, printing, dip-coating or self-assembly, or vapor deposition techniques such as plasma enhanced chemical vapor deposition (PECVD) or atomic layer deposition (ALD), followed by immersion in solution after deposition of the film.
  • solution processing techniques such as spin-coating, printing, dip-coating or self-assembly
  • vapor deposition techniques such as plasma enhanced chemical vapor deposition (PECVD) or atomic layer deposition (ALD)
  • PECVD plasma enhanced chemical vapor deposition
  • ALD atomic layer deposition
  • materials that could be deposited by solution or vapor techniques include polymers such as polyethylene, polystyrene, polymethylmethacrylate, and parylene and polyvinylalcohol, as well as cationic and anionic polyelectrolytes such as polystyrenesulfonic acid, polyallylamine, polyacrylic acid, and poly(dial
  • organometallic salts such as zinc stearate or aluminum stearate as well as oxides, such as silica, alumina or titania.
  • oxides such as silica, alumina or titania.
  • materials which foam self-assembled monolayers such as octadecyltrichlorosilane, phenethyltrichlorosilane, hexamethyldisilazane, allyltrimethoxysilane or perfluorooctyltrichlorosilane may also be used.
  • the charge patterning material may not be a pure material but rather a blend of one or more materials, possibly to enhance charge generating properties, improve processing performance, or impart new functionality to the film such as making it light sensitive.
  • materials deposited from solution they would likely be first dissolved in a solvent such as toluene, hexane, water, isopropanol, or tetrahydrofuran to enable solution processing.
  • An example process may involve spin coating the material onto the surface of the microchip, patterning the material either using light directly if a light-sensitive formulation of the charge-patterning material is used, or in a separate step through photolithographic/etching cycles, and immersing the chip into solution where free charges are formed through interaction between the fluid and the material.
  • a first polymer is spun onto the insulator 16 and photolithographically defined in FIG. 5 , exposing a portion of the insulator 16 .
  • a second polymer 42 is then spun on or otherwise deposited on the first polymer and the exposed insulator in FIG. 6 .
  • the second polymer is then patterned to define a region separate from the first region, typically with a region of the insulator.
  • the two different polymers then retain different charges, or magnitudes of charge to form a charge pattern.
  • Typical functional groups that develop a negative surface change include sulfonic acids, phosphonic acids, and carboxylic acids amongst others.
  • Typical functional groups that develop positive surface charges include amines and imidazoles, amongst others.
  • the range of Coulomb interaction of the charged microchips is controlled by the ionic strength of the solution, but is typically rather short, in the range of 1 to 10 micrometers due to the high ion content.
  • non-polar fluids In this embodiment the use of non-polar fluids is desired however, since such Coulomb interactions between charged entities are felt over much larger length scales, in the range of 10-100 micrometers.
  • non-polar fluids include isoparaffinic liquids such as the isopar series of fluids, and other hydrocarbon liquids such as dodecane.
  • charge control agents typically amphiphilic surfactant materials (both ionic and non-ionic), such as phosphatidylcholine (lecithin), sorbitan monooeleate (span-80), aluminum-di-tert-butyl salicylate (ALOHOS), polyisobutylene succinimide (OLOA), or sodium dioctylsulfosuccinate (AOT) amongst others may need to be added to the liquid to assist in developing charge.
  • amphiphilic surfactant materials both ionic and non-ionic
  • phosphatidylcholine lecithin
  • sorbitan monooeleate sub-80
  • ALOHOS aluminum-di-tert-butyl salicylate
  • OLOA polyisobutylene succinimide
  • AOT sodium dioctylsulfosuccinate
  • charging of the surface can be done through tribo-actions.
  • the toner particles are charged by contacting specifically designed developer particles.
  • the charge patterning material has to be selected such that it charges in specific ways when contacted with the developer material.
  • the density of the chips should stay low enough to control charge exchange between microchips accidentally hitting each other.
  • an ink-jet head 30 can deposit the charge-patterning material.
  • Candidate material may include waxes, polymers, such as polyelectrolytes, or blends of materials amongst others. After deposition of the charge patterning material, as in previous descriptions the chips would be singulated and immersed in a fluid where free charges would be generated.
  • a self-assembled monolayer can be used along with another material, such as an oxide, to create charged regions on the chip. This could be accomplished, for example, by first depositing the oxide, then depositing the self-assembled monolayer having the desired functionality over the oxide. Using photolithography and etching this self-assembled monolayer could then be patterned revealing the oxide underneath.
  • the oxide could be deposited followed be patterning of a sacrificial blocking material (such as photoresist), deposition of the self-assembled monolayer could then take place, followed by removal of the sacrificial material, again revealing the underlying oxide surface, creating an oxide, self-assembled monolayer pattern.
  • This second approach has the benefit in that the self-assembled monolayer deposition and blocking material removal steps can be carried out either at the wafer scale, or at the chiplet scale after wafer singulation.
  • FIGS. 4-7 show processes of an embodiment in which photolithographic patterned polymers, inorganic materials or a mixture of the two are used. These materials can either be tribo-charged or chemically charged using a charge control agent, in a dielectric fluid to carry different polarities of charge. Photolithographic defined charging of a dielectric with a corona device is another approach, using dry film resist. Commercially available dry film resists express substantial conductivity difference between exposed ultraviolet and unexposed regions. FIGS. 4-7 show a process for photolithographic materials.
  • a photoconductor coating In a photoconductor coating embodiment, one may use inorganic photoconductor materials such as amorphous silicon and selenium, or single layer or multilayer organic photoconductors. If such a photoconductor coating is used, it receives charge from a corotron or scorotron to give the desired charge signs and patterns.
  • a corotron is a corona charging device typically used in electrophotography/Xerography that has a wire connected to a high voltage power source. In a typical application, the wire generates an electric field that charges up a photoreceptor in preparation for receiving charged toner particles.
  • a scorotron is a screen corotron.
  • FIGS. 8-10 show one embodiment of such a process.
  • a dry film resist is laminated onto the insulator layer 16 over the microchip or microchip wafer 12 .
  • ultraviolet light exposes a portion 52 of the dry resist, creating high and low conductivity regions.
  • the wafer or microchip 12 is grounded by connection 54 and charged with a scorotron or corotron 56 , to form charge patterns based upon the previously exposed regions 50 and 52 of the dry film resist.
  • This forms a single charge template, where the surface has one polarity of charge.
  • One may verify the charge patterns by spreading beads of known charge and imaging with a camera, or measuring the field directly in air with a non-contact electrostatic volt meter.
  • FIGS. 11-13 show an embodiment of a method of forming a dual charge template.
  • Ultraviolet light exposes a portion of the dry film resist 50 to form a low conductivity region 52 .
  • Using a stencil mask 62 on top of the dry film resist allows exposure of only a portion of the low conductivity region formed by the UV exposure.
  • the scorotron 64 applies charge of a first polarity to a portion of the low conductivity region not protected by the mask 62 .
  • the process shifts the mask 62 to cover the charged portion of the low conductivity region.
  • the scorotron then charges the uncharged portion of the low conductivity region with a lower dose of the opposite sign ions to create the other sign charge pattern.
  • the opposite sign charge pass of the scorotron is referred to as 66 .
  • a bipolar or a dual charge template can result from a dual exposure, shown in FIGS. 14-16 .
  • FIG. 14 shows a first exposure forming a first low conductivity region 52 on the dry film resist 50 . This first region then receives a first polarity charge from a scorotron 62 . The dry film resist then receives a second exposure of UV light to form a second low conductivity region 70 . This second region then receives a charge of the opposite polarity from the scorotron 64 .
  • charge patterns can be generated on the surface of microchips, either before or after singulation from a wafer.
  • the techniques used are compatible with semiconductor fabrication processes, either using scorotron or corotron charging, tribo-charging, or by application of charged materials. Free charges may then be generated directly or through the interaction of these materials with the surrounding fluid in the chip “ink.”
  • the charge patterns contain information usable in automated systems to sort, organize and arrange microchips into larger circuits.

Abstract

A method of forming a charge pattern on a microchip includes depositing a material on the surface of the microchip, and using an external device to develop charge in the material.

Description

    BACKGROUND
  • Systems exist that assemble microchips automatically based upon some sort of encoding such as electrostatic or magnetic coding. The system uses the encoding to identify and position the microchips as part of the assembly process.
  • Examples of these systems can be found in U.S. Pat. No. 7,861,405, and its related cases, US Patent Publications 20100192365, 20100186221, and 20100186222, owned by the assignee of this application. Another example is shown in U.S. Pat. No. 7,332,361, that teaches charge-encoded elements having basic or acidic surfaces capable of carrying charge in non-polar liquids with charge control agents. Examples include two-particle electrophoretic ink, liquid toner, inorganic oxides and polymers. Standard photolithography or ink-jet technology can be used to pattern these materials to form charge-encoded elements. All of these references are incorporated by reference here. The system uses a charge or magnetic polarity on the chip to sort and position the microchips.
  • These references make general mention of possible methods of how chips have the charge or polarity, but give no details. For example, issues can arise with the deposition of the charge or polarity. Currently, no current technique exists to deposit a charge pattern on isolated microchips. One approach has charged one end of a nanowire, another has charged up one side of a symmetric microchip, but no work appears to be done on isolated microchips or charge patterning.
  • The fabrication process should be compatible with existing devices on the chips. In addition, the process should not increase the manufacturing costs, but still allow the patterning on a scalable level between larger areas and small features. In order to provide a flexible system, the system should allow for varying magnitudes of charge density, and ideally but not necessarily, both positive and negative polarity, for multiple levels of chip control and identification. The charge patterns should have good stability to allow long shelf life of the patterned devices.
  • Another issue with patterning may arise with the chips being attracted to each other. They may gather together or conglomerate based upon their respective charges. The density of the chips needs to remain low enough the chips do not exchange charge by contact with each other.
    • BRIEF DESCRIPTION OF THE DRAWINGS
  • FIG. 1 show an embodiment of an overall method of forming charge patterns on microchips.
  • FIG. 2 shows an embodiment of a method of forming charge patterns on a microchip.
  • FIG. 3 shows an embodiment of a method of printing charge patterns on a microchip.
  • FIGS. 4-7 show an embodiment of a method of photolithographically forming charge patterns on a microchip.
  • FIGS. 8-10 show an embodiment of a method of forming a charge pattern using a scorotron.
  • FIGS. 11-13 show an embodiment of a method of forming a bipolar charge template.
  • FIGS. 12-16 show an alternative embodiment of a method of forming a bipolar charge template.
    •  DETAILED DESCRIPTION OF THE EMBODIMENTS
  • FIG. 1 shows an overall embodiment of a method of forming charge patterns on a microchip. At 11, the microchips are fabricated on a substrate, such as silicon, gallium arsenide, complementary metal oxide semiconductor (CMOS) etc. The process then deposits materials on the microchips to enable charging at 13. In one approach, shown in more detail in FIGS. 2-7, the microchips are then submersed in a fluid that causes charge to develop on the materials deposited. In another approach, shown in more detail in FIGS. 8-16, the materials on the microchips are charged using an external device. The end result is microchips with charge patterns on their surfaces in 19.
  • FIG. 2 shows an embodiment of a method of forming charge patterns on a microchip. The process will more than likely begin at the wafer level at 10, after manufacture of the individual microchips on the wafer. This allows the process of charge patterning to occur in a more mass-produced manner, using techniques compatible with chip fabrication processes. However, no limitation is intended by this discussion and none should be implied. The individual chips can be patterned using the same techniques after singulation from the wafer.
  • Using manufacturing techniques compatible with chip processing, the manufactured microchip 12 has a shield 14 to protect the circuitry on the chip. The shield has an insulator 16. The insulator allows charge or material patterns deposited on the surface to avoid interaction with the circuitry on the microchip. The pattern ABBAB may represent different charges, such as +−−+−, or a pattern of materials into which charge will be developed. Through the techniques discussed in more detail further, the charge pattern may consist of alternating regions of differing charge magnitude and/or polarity. The embodiment in this portion of the discussion has the patterns being charge.
  • Once singulated, the microchips can be placed into a fluid to create an ‘ink’ bottle 22 or other dispenser. The fluid may contain other additives such as a charge control agent. The charge control agent may either allow the charge to remain stable on the surface of the chips 12, or may cause the charge to develop on the surface of the wafer. The charge generation may take the form of depositing a material, and developing a charge in the material thorough the interaction of the charge patterning material with the fluid component of the ink.
  • One approach uses deposition of a thin-film of the charge patterning material using solution processing techniques such as spin-coating, printing, dip-coating or self-assembly, or vapor deposition techniques such as plasma enhanced chemical vapor deposition (PECVD) or atomic layer deposition (ALD), followed by immersion in solution after deposition of the film. Examples of materials that could be deposited by solution or vapor techniques include polymers such as polyethylene, polystyrene, polymethylmethacrylate, and parylene and polyvinylalcohol, as well as cationic and anionic polyelectrolytes such as polystyrenesulfonic acid, polyallylamine, polyacrylic acid, and poly(diallyldimethylammonium chloride). Other examples include organometallic salts such as zinc stearate or aluminum stearate as well as oxides, such as silica, alumina or titania. In addition materials which foam self-assembled monolayers such as octadecyltrichlorosilane, phenethyltrichlorosilane, hexamethyldisilazane, allyltrimethoxysilane or perfluorooctyltrichlorosilane may also be used.
  • The charge patterning material may not be a pure material but rather a blend of one or more materials, possibly to enhance charge generating properties, improve processing performance, or impart new functionality to the film such as making it light sensitive. For materials deposited from solution, they would likely be first dissolved in a solvent such as toluene, hexane, water, isopropanol, or tetrahydrofuran to enable solution processing. An example process may involve spin coating the material onto the surface of the microchip, patterning the material either using light directly if a light-sensitive formulation of the charge-patterning material is used, or in a separate step through photolithographic/etching cycles, and immersing the chip into solution where free charges are formed through interaction between the fluid and the material.
  • In FIG. 4, a first polymer is spun onto the insulator 16 and photolithographically defined in FIG. 5, exposing a portion of the insulator 16. A second polymer 42 is then spun on or otherwise deposited on the first polymer and the exposed insulator in FIG. 6. The second polymer is then patterned to define a region separate from the first region, typically with a region of the insulator. The two different polymers then retain different charges, or magnitudes of charge to form a charge pattern. In addition to the use of two solution processed polymers, other embodiments may use a combination of a solution processed material to generate one polarity/magnitude of charge and a vapor deposited material to generate another polarity/magnitude of charge, other embodiments could use two different vapor deposited materials.
  • If immersed in a polar liquid, such as water, most surfaces become charged, as some of the surface molecules dissociate, Charge tends to be more negative or positive depending on the chemical composition of the surface. Typical functional groups that develop a negative surface change include sulfonic acids, phosphonic acids, and carboxylic acids amongst others. Typical functional groups that develop positive surface charges include amines and imidazoles, amongst others. The range of Coulomb interaction of the charged microchips is controlled by the ionic strength of the solution, but is typically rather short, in the range of 1 to 10 micrometers due to the high ion content.
  • In this embodiment the use of non-polar fluids is desired however, since such Coulomb interactions between charged entities are felt over much larger length scales, in the range of 10-100 micrometers. Examples of non-polar fluids include isoparaffinic liquids such as the isopar series of fluids, and other hydrocarbon liquids such as dodecane. In non-polar liquids charge control agents, typically amphiphilic surfactant materials (both ionic and non-ionic), such as phosphatidylcholine (lecithin), sorbitan monooeleate (span-80), aluminum-di-tert-butyl salicylate (ALOHOS), polyisobutylene succinimide (OLOA), or sodium dioctylsulfosuccinate (AOT) amongst others may need to be added to the liquid to assist in developing charge.
  • If the surrounding liquid is air, charging of the surface can be done through tribo-actions. For example; in Xerography, the toner particles are charged by contacting specifically designed developer particles. The charge patterning material has to be selected such that it charges in specific ways when contacted with the developer material. The density of the chips should stay low enough to control charge exchange between microchips accidentally hitting each other.
  • In another approach, shown in FIG. 3, an ink-jet head 30 can deposit the charge-patterning material. Candidate material may include waxes, polymers, such as polyelectrolytes, or blends of materials amongst others. After deposition of the charge patterning material, as in previous descriptions the chips would be singulated and immersed in a fluid where free charges would be generated.
  • In another approach, a self-assembled monolayer can be used along with another material, such as an oxide, to create charged regions on the chip. This could be accomplished, for example, by first depositing the oxide, then depositing the self-assembled monolayer having the desired functionality over the oxide. Using photolithography and etching this self-assembled monolayer could then be patterned revealing the oxide underneath. In another approach, the oxide could be deposited followed be patterning of a sacrificial blocking material (such as photoresist), deposition of the self-assembled monolayer could then take place, followed by removal of the sacrificial material, again revealing the underlying oxide surface, creating an oxide, self-assembled monolayer pattern. This second approach has the benefit in that the self-assembled monolayer deposition and blocking material removal steps can be carried out either at the wafer scale, or at the chiplet scale after wafer singulation.
  • FIGS. 4-7 show processes of an embodiment in which photolithographic patterned polymers, inorganic materials or a mixture of the two are used. These materials can either be tribo-charged or chemically charged using a charge control agent, in a dielectric fluid to carry different polarities of charge. Photolithographic defined charging of a dielectric with a corona device is another approach, using dry film resist. Commercially available dry film resists express substantial conductivity difference between exposed ultraviolet and unexposed regions. FIGS. 4-7 show a process for photolithographic materials.
  • In a photoconductor coating embodiment, one may use inorganic photoconductor materials such as amorphous silicon and selenium, or single layer or multilayer organic photoconductors. If such a photoconductor coating is used, it receives charge from a corotron or scorotron to give the desired charge signs and patterns. As the terms are used here, a corotron is a corona charging device typically used in electrophotography/Xerography that has a wire connected to a high voltage power source. In a typical application, the wire generates an electric field that charges up a photoreceptor in preparation for receiving charged toner particles. A scorotron is a screen corotron.
  • Another embodiment uses photolithographic define charging of a dielectric with a corona device. Commercially available dry film resist expresses substantially conductivity difference between ultraviolet exposed and unexposed regions. FIGS. 8-10 show one embodiment of such a process. In FIG. 8, a dry film resist is laminated onto the insulator layer 16 over the microchip or microchip wafer 12. In FIG. 9, ultraviolet light exposes a portion 52 of the dry resist, creating high and low conductivity regions. In FIG. 10, the wafer or microchip 12 is grounded by connection 54 and charged with a scorotron or corotron 56, to form charge patterns based upon the previously exposed regions 50 and 52 of the dry film resist. This forms a single charge template, where the surface has one polarity of charge. One may verify the charge patterns by spreading beads of known charge and imaging with a camera, or measuring the field directly in air with a non-contact electrostatic volt meter.
  • FIGS. 11-13 show an embodiment of a method of forming a dual charge template. Ultraviolet light exposes a portion of the dry film resist 50 to form a low conductivity region 52. Using a stencil mask 62 on top of the dry film resist allows exposure of only a portion of the low conductivity region formed by the UV exposure. The scorotron 64 applies charge of a first polarity to a portion of the low conductivity region not protected by the mask 62. The process shifts the mask 62 to cover the charged portion of the low conductivity region. The scorotron then charges the uncharged portion of the low conductivity region with a lower dose of the opposite sign ions to create the other sign charge pattern. In order to differentiate between the two scorotron processes, the opposite sign charge pass of the scorotron is referred to as 66.
  • In an alternative embodiment, a bipolar or a dual charge template can result from a dual exposure, shown in FIGS. 14-16. FIG. 14 shows a first exposure forming a first low conductivity region 52 on the dry film resist 50. This first region then receives a first polarity charge from a scorotron 62. The dry film resist then receives a second exposure of UV light to form a second low conductivity region 70. This second region then receives a charge of the opposite polarity from the scorotron 64.
  • In this manner, charge patterns can be generated on the surface of microchips, either before or after singulation from a wafer. The techniques used are compatible with semiconductor fabrication processes, either using scorotron or corotron charging, tribo-charging, or by application of charged materials. Free charges may then be generated directly or through the interaction of these materials with the surrounding fluid in the chip “ink.” The charge patterns contain information usable in automated systems to sort, organize and arrange microchips into larger circuits.
  • It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.

Claims (9)

1. A method of forming a charge pattern on a microchip, comprising:
depositing a material on the surface of the microchip;
using an external device to develop charge in the material; and
singulating the wafer into microchips after charging.
2. The method of claim 1, wherein using an external device to develop the charge comprises charging the material with one of either a corotron or a scorotron.
3. The method of claim 1, wherein depositing the material comprises depositing a photoconductor.
4. The method of claim 1, wherein depositing the material comprises laminating a dry film photoresist onto a wafer and exposing the dry film photoresist to ultraviolet light, and developing the charge comprises charging the exposed photoresist with a scorotron.
5. The method of claim 4, wherein exposing the dry film comprises applying a stencil mask to the dry film resist to expose a portion of a low conductivity region and applying a first charge with a scorotron.
6. The method of claim 4, further comprising re-exposing the dry film resist with a second charge with a scorotron.
7. (canceled)
8. The method of claim 1, wherein the depositing of the material comprises depositing one of a polymer, an inorganic material or a mixture of an inorganic and a polymer.
9. The method of claim 8, wherein developing the charge comprises tribo-charging.
US13/652,220 2012-10-15 2012-10-15 Microchip charge patterning Active US8685769B1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US13/652,220 US8685769B1 (en) 2012-10-15 2012-10-15 Microchip charge patterning
JP2013206542A JP6279870B2 (en) 2012-10-15 2013-10-01 Microchip charge pattern formation
EP13188458.7A EP2720260B1 (en) 2012-10-15 2013-10-14 Microchip charge patterning

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US13/652,220 US8685769B1 (en) 2012-10-15 2012-10-15 Microchip charge patterning

Publications (2)

Publication Number Publication Date
US8685769B1 US8685769B1 (en) 2014-04-01
US20140106512A1 true US20140106512A1 (en) 2014-04-17

Family

ID=49328425

Family Applications (1)

Application Number Title Priority Date Filing Date
US13/652,220 Active US8685769B1 (en) 2012-10-15 2012-10-15 Microchip charge patterning

Country Status (3)

Country Link
US (1) US8685769B1 (en)
EP (1) EP2720260B1 (en)
JP (1) JP6279870B2 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10141285B2 (en) * 2013-09-19 2018-11-27 Palo Alto Research Center Incorporated Externally induced charge patterning using rectifying devices

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU607347B2 (en) * 1988-11-15 1991-02-28 Olin Hunt Specialty Products Inc. Method of high resolution electrostatic transfer of a high density image to a nonconductive receiving substrate
EP1297387A2 (en) * 2000-06-30 2003-04-02 President And Fellows of Harvard College Electric microcontact printing method and apparatus
JP4175531B2 (en) * 2000-11-13 2008-11-05 株式会社リコー Charger
US6825970B2 (en) * 2001-09-14 2004-11-30 E Ink Corporation Methods for addressing electro-optic materials
US7843621B2 (en) * 2002-06-10 2010-11-30 E Ink Corporation Components and testing methods for use in the production of electro-optic displays
JP3967202B2 (en) * 2002-06-11 2007-08-29 株式会社タムラ製作所 Method for forming protruding electrode
US6710436B1 (en) * 2002-12-12 2004-03-23 Sun Microsystems, Inc. Method and apparatus for electrostatically aligning integrated circuits
US7332361B2 (en) * 2004-12-14 2008-02-19 Palo Alto Research Center Incorporated Xerographic micro-assembler
US8066967B2 (en) * 2005-06-13 2011-11-29 Electrox Corporation System and method for the manipulation, classification sorting, purification, placement, and alignment of nano fibers using electrostatic forces and electrographic techniques
US7861405B2 (en) 2008-03-03 2011-01-04 Palo Alto Research Center Incorporated System for forming a micro-assembler
EP2342742B1 (en) * 2008-09-26 2018-08-22 IMEC vzw Method for performing parallel stochastic assembly
JP2012085515A (en) * 2010-09-16 2012-04-26 Murata Mfg Co Ltd Charging device of electret, charging method of electret, and vibration power generating device
US10014261B2 (en) * 2012-10-15 2018-07-03 Palo Alto Research Center Incorporated Microchip charge patterning

Also Published As

Publication number Publication date
JP6279870B2 (en) 2018-02-14
EP2720260B1 (en) 2019-07-31
US8685769B1 (en) 2014-04-01
EP2720260A1 (en) 2014-04-16
JP2014082491A (en) 2014-05-08

Similar Documents

Publication Publication Date Title
US20230187373A1 (en) Microchip charge patterning
McCarty et al. Ionic electrets: electrostatic charging of surfaces by transferring mobile ions upon contact
CN104040694B (en) For the NW-TFT of nano-component and the tessellated forms of transfer
US7374867B2 (en) Enhancing photoresist performance using electric fields
JP2020109409A (en) Graphene-based magnetic hall sensor for fluid flow analysis at nanoscale level
Jeong et al. Electrical biomolecule detection using nanopatterned silicon via block copolymer lithography
BR112015029548B1 (en) MANUFACTURING METHOD AND INTEGRATED CIRCUIT SUBSTRATE
Cole et al. Nanocontact electrification: patterned surface charges affecting adhesion, transfer, and printing
Cole et al. Nanocontact electrification through forced delamination of dielectric interfaces
KR20070051004A (en) Fabrication method of stamp, fabrication method of thin film transistor and liquid crystal display device by using it
JP5871171B2 (en) Pattern board manufacturing method and component positioning method
RU2015102287A (en) MEDIA, TWO-COMPONENT DEVELOPER, AUXILIARY DEVELOPER, METHOD FOR FORMING THE IMAGE, TECHNOLOGICAL CARTRIDGE AND DEVICE FOR FORMING THE IMAGE
US20170077036A1 (en) Mixed Lithography Approach for E-Beam and Optical Exposure Using HSQ
US8685769B1 (en) Microchip charge patterning
KR100907787B1 (en) A method for focusing patterning of charged particles using a patterned perforated mask and a mask used therein
Palleau et al. Combinatorial particle patterning by nanoxerography
CN104934537A (en) Electronic device and manufacturing method of the same
Dickey et al. Transistors formed from a single lithography step using information encoded in topography
EP1424602A3 (en) Photoreceptor for electrophotography having an overcoat layer with salt
TWI740181B (en) Semiconductor process system and method
Komuro et al. Modeling and simulation of acid generation in anion-bound chemically amplified resists used for extreme ultraviolet lithography
JP5068950B2 (en) Toner and image forming method using the same
JP4327133B2 (en) Electronic circuit manufacturing method
Alqahtani et al. Influence of Environmental Fluctuations on Quantum Interference in Naphthalene and Azulene
US10353288B2 (en) Litho-litho-etch double patterning method

Legal Events

Date Code Title Description
AS Assignment

Owner name: PALO ALTO RESEARCH CENTER INCORPORATED, CALIFORNIA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:CHOW, EUGENE M.;LU, JENGPING;VOLKEL, ARMIN R.;AND OTHERS;SIGNING DATES FROM 20121003 TO 20121008;REEL/FRAME:029131/0539

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

STCF Information on status: patent grant

Free format text: PATENTED CASE

MAFP Maintenance fee payment

Free format text: PAYMENT OF MAINTENANCE FEE, 4TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1551)

Year of fee payment: 4

MAFP Maintenance fee payment

Free format text: PAYMENT OF MAINTENANCE FEE, 8TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1552); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

Year of fee payment: 8

AS Assignment

Owner name: XEROX CORPORATION, CONNECTICUT

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:PALO ALTO RESEARCH CENTER INCORPORATED;REEL/FRAME:064038/0001

Effective date: 20230416

AS Assignment

Owner name: CITIBANK, N.A., AS COLLATERAL AGENT, NEW YORK

Free format text: SECURITY INTEREST;ASSIGNOR:XEROX CORPORATION;REEL/FRAME:064760/0389

Effective date: 20230621

AS Assignment

Owner name: XEROX CORPORATION, CONNECTICUT

Free format text: CORRECTIVE ASSIGNMENT TO CORRECT THE REMOVAL OF US PATENTS 9356603, 10026651, 10626048 AND INCLUSION OF US PATENT 7167871 PREVIOUSLY RECORDED ON REEL 064038 FRAME 0001. ASSIGNOR(S) HEREBY CONFIRMS THE ASSIGNMENT;ASSIGNOR:PALO ALTO RESEARCH CENTER INCORPORATED;REEL/FRAME:064161/0001

Effective date: 20230416

AS Assignment

Owner name: JEFFERIES FINANCE LLC, AS COLLATERAL AGENT, NEW YORK

Free format text: SECURITY INTEREST;ASSIGNOR:XEROX CORPORATION;REEL/FRAME:065628/0019

Effective date: 20231117

AS Assignment

Owner name: CITIBANK, N.A., AS COLLATERAL AGENT, NEW YORK

Free format text: SECURITY INTEREST;ASSIGNOR:XEROX CORPORATION;REEL/FRAME:066741/0001

Effective date: 20240206