Image forming apparatus with improved transfer efficiency

• US 6,847,107 B2
• Filed: 08/15/2002
• Issued: 01/25/2005
• Est. Priority Date: 10/31/1995
• Status: Expired due to Term

• Current Assignee: Tessera, Inc. (Adeia Inc.)
• Original Assignee: Tessera, Inc. (Adeia Inc.)
• Inventors: Karavakis, Konstantine, Fjelstad, Joseph
• Primary Examiner(s): Jackson, Jerome
• Assistant Examiner(s): NGUYEN, JOSEPH H
• Application Number:
  US10/219,902
• Publication Number:
  US 20020195685A1
• Time in Patent Office: 894 Days
• Field of Search: 257/685, 257/686, 257/690, 257/668, 257/688, 257/777, 257/693, 257/678, 257/669, 257/784, 257/788
• US Class Current: 257/690
• CPC Class Codes: H01L 2224/0231 Manufacturing methods of the redistribution layers
• CPC Class Codes: H01L 2224/02311 Additive methods
• CPC Class Codes: H01L 2224/02313 Subtractive methods
• CPC Class Codes: H01L 2224/0236 Shape of the insulating layers therebetween
• CPC Class Codes: H01L 2224/024 Material of the insulating layers therebetween
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/04042 Bonding areas specifically adapted for wire connectors, e.g. wirebond pads
• CPC Class Codes: H01L 2224/05554 being square
• CPC Class Codes: H01L 2224/05624 Aluminium [Al] as principal constituent
• CPC Class Codes: H01L 2224/11334 using preformed bumps
• CPC Class Codes: H01L 2224/114 by blanket deposition of the material of the bump connector
• CPC Class Codes: H01L 2224/116 by patterning a pre-deposited material
• CPC Class Codes: H01L 2224/13099 Material
• CPC Class Codes: H01L 2224/131 with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
• CPC Class Codes: H01L 2224/1319 with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 2224/24011 Deposited, e.g. MCM-D type
• CPC Class Codes: H01L 2224/24226 the HDI interconnect connecting to the same level of the item at which the semiconductor or solid-state body is mounted, e.g. the item being planar
• CPC Class Codes: H01L 2224/24227 the HDI interconnect not connecting to the same level of the item at which the semiconductor or solid-state body is mounted, e.g. the semiconductor or solid-state body being mounted in a cavity or on a protrusion of the item
• CPC Class Codes: H01L 2224/274 by blanket deposition of the material of the layer connector
• CPC Class Codes: H01L 2224/45124 : Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/45144 : Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/45147 : Copper (Cu) as principal constituent
• CPC Class Codes: H01L 2224/45155 : Nickel (Ni) as principal constituent
• CPC Class Codes: H01L 2224/48624 : Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/48724 : Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/48824 : Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/85424 : Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 23/3114 : the device being a chip scale package, e.g. CSP
• CPC Class Codes: H01L 23/3121 : a substrate forming part of the encapsulation
• CPC Class Codes: H01L 23/4951 : Chip-on-leads or leads-on-chip techniques, i.e. inner lead fingers being used as die pad
• CPC Class Codes: H01L 23/498 : Leads, i.e. metallisations or lead-frames on insulating substrates, e.g. chip carriers shape of the substrate H01L23/13
• CPC Class Codes: H01L 23/525 : with adaptable interconnections
• CPC Class Codes: H01L 24/05 : of an individual bonding area
• CPC Class Codes: H01L 24/11 : Manufacturing methods for bumps on insulating substrates H01L21/4853
• CPC Class Codes: H01L 24/13 : of an individual bump connector
• CPC Class Codes: H01L 24/45 : of an individual wire connector
• CPC Class Codes: H01L 24/72 : Detachable connecting means consisting of mechanical auxiliary parts connecting the device, e.g. pressure contacts using springs or clips
• CPC Class Codes: H01L 24/82 : by forming build-up interconnects at chip-level, e.g. for high density interconnects [HDI] interconnection structure between a plurality of semiconductor chips H01L23/5389
• CPC Class Codes: H01L 24/94 : at wafer-level, i.e. with connecting carried out on a wafer comprising a plurality of undiced individual devices
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00011 : Not relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01004 : Beryllium [Be]
• CPC Class Codes: H01L 2924/01009 : Fluorine [F]
• CPC Class Codes: H01L 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01014 : Silicon [Si]
• CPC Class Codes: H01L 2924/01022 : Titanium [Ti]
• CPC Class Codes: H01L 2924/01024 : Chromium [Cr]
• CPC Class Codes: H01L 2924/01028 : Nickel [Ni]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01039 : Yttrium [Y]
• CPC Class Codes: H01L 2924/01046 : Palladium [Pd]
• CPC Class Codes: H01L 2924/01074 : Tungsten [W]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/01322 : Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/01327 : Intermediate phases, i.e. intermetallics compounds
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/10253 : Silicon [Si]
• CPC Class Codes: H01L 2924/12042 : LASER
• CPC Class Codes: H01L 2924/15153 : the die mounting substrate comprising a recess for hosting the device
• CPC Class Codes: H01L 2924/1517 : Multilayer substrate
• CPC Class Codes: H01L 2924/351 : Thermal stress

Abstract

By causing the movement of charge from a toner to a latent image carrier, the amount of charge of the toner is lowered to an amount of charge suitable for facilitating the transfer of toner so as to improve the transfer efficiency. For this, an image forming apparatus includes a latent image carrier and a developing means for forming a negatively chargeable toner layer composed of two stories or less on a toner carrier by a toner layer thickness regulating member. An electrostatic latent image on the latent image carrier is developed with the toner to form a visible image and the visible image is transferred to a transfer medium. Further, the work function (Φ_opc) of the surface of the latent image carrier is set to be larger than the work function (Φ_t) of the toner.

Claims

1. A microelectronic assembly comprising:

a microelectronic element having a first surface including a central region and a peripheral region surrounding said central region, said microelectronic element including a plurality of contacts disposed in said central region;

a compliant layer overlying said peripheral region of said first surface, said compliant layer having a bottom surface facing toward said first surface of said microelectronic element, a top surface facing upwardly away from the first surface of said microelectronic element and one or more edge surfaces extending between said top and bottom surfaces of said compliant layer; and

a plurality of bond ribbons disposed over said compliant layer so that said bond ribbons extend over said top surface and one or more of said edge surfaces and said bond ribbons electrically connect said contacts to conductive terminals overlying the top surface of said compliant layer.

2. The microelectronic assembly as claimed in claim 1, wherein said microelectronic element is a semiconductor chip.

3. The microelectronic assembly as claimed in claim 1, further comprising a dielectric passivation layer between the first surface of said microelectronic element and said compliant layer, wherein said dielectric passivation layer has apertures extending therethrough in substantial alignment with said contacts.

4. The microelectronic assembly as claimed in claim 1, further comprising an encapsulant layer overlying said bond ribbons.

5. The microelectronic assembly as claimed in claim 1, wherein said contacts are spaced apart from one another in an array.

6. The microelectronic assembly as claimed in claim 1, wherein said compliant layer is selected from the group of materials consisting of a curable liquid, silicone, flexibilized epoxy, a thermosetting polymer, fluoropolymer and thermoplastic polymer.

7. The microelectronic assembly as claimed in claim 1, further comprising a top dielectric layer overlying said bond ribbons so that only the conductive terminals are accessible at a top surface of said compliant layer.

8. The microelectronic assembly as claimed in claim 1, wherein said bond ribbons are flexible.