WO1989002697A1 - Induced metallization process by way of dissociating aluminum nitride ceramic - Google Patents

Induced metallization process by way of dissociating aluminum nitride ceramic Download PDF

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Publication number
WO1989002697A1
WO1989002697A1 PCT/US1988/002577 US8802577W WO8902697A1 WO 1989002697 A1 WO1989002697 A1 WO 1989002697A1 US 8802577 W US8802577 W US 8802577W WO 8902697 A1 WO8902697 A1 WO 8902697A1
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Prior art keywords
laser energy
substrate
ceramic substrate
nonconductive
electrically conductive
Prior art date
Application number
PCT/US1988/002577
Other languages
French (fr)
Inventor
Randolph E. Root
Thanh T. Vu
Original Assignee
Hughes Aircraft Company
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Publication date
Application filed by Hughes Aircraft Company filed Critical Hughes Aircraft Company
Priority to KR1019890700839A priority Critical patent/KR890702417A/en
Publication of WO1989002697A1 publication Critical patent/WO1989002697A1/en

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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/10—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
    • C04B41/0072—Heat treatment
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
    • C04B41/009—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone characterised by the material treated
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C17/00—Apparatus or processes specially adapted for manufacturing resistors
    • H01C17/28—Apparatus or processes specially adapted for manufacturing resistors adapted for applying terminals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/48—Manufacture or treatment of parts, e.g. containers, prior to assembly of the devices, using processes not provided for in a single one of the subgroups H01L21/06 - H01L21/326
    • H01L21/4814—Conductive parts
    • H01L21/4846—Leads on or in insulating or insulated substrates, e.g. metallisation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/48—Manufacture or treatment of parts, e.g. containers, prior to assembly of the devices, using processes not provided for in a single one of the subgroups H01L21/06 - H01L21/326
    • H01L21/4814—Conductive parts
    • H01L21/4846—Leads on or in insulating or insulated substrates, e.g. metallisation
    • H01L21/486—Via connections through the substrate with or without pins
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/10—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern
    • H05K3/105—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern by conversion of non-conductive material on or in the support into conductive material, e.g. by using an energy beam
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/40—Forming printed elements for providing electric connections to or between printed circuits
    • H05K3/4038—Through-connections; Vertical interconnect access [VIA] connections
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
    • C04B2111/00844—Uses not provided for elsewhere in C04B2111/00 for electronic applications
    • 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
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/4805—Shape
    • H01L2224/4809—Loop shape
    • H01L2224/48091—Arched
    • 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
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/481—Disposition
    • H01L2224/48151—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/48221—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/48225—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation
    • H01L2224/48227—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation connecting the wire to a bond pad of the item
    • 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
    • H01L2924/01—Chemical elements
    • H01L2924/01039—Yttrium [Y]
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/03—Use of materials for the substrate
    • H05K1/0306—Inorganic insulating substrates, e.g. ceramic, glass
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
    • H05K2203/10—Using electric, magnetic and electromagnetic fields; Using laser light
    • H05K2203/107—Using laser light
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
    • H05K2203/11—Treatments characterised by their effect, e.g. heating, cooling, roughening
    • H05K2203/1136—Conversion of insulating material into conductive material, e.g. by pyrolysis
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/0011—Working of insulating substrates or insulating layers
    • H05K3/0017—Etching of the substrate by chemical or physical means
    • H05K3/0026—Etching of the substrate by chemical or physical means by laser ablation
    • H05K3/0029—Etching of the substrate by chemical or physical means by laser ablation of inorganic insulating material

Definitions

  • the disclosed invention relates to the formation of electrically conductive circuitry on a nonconductive substrate, and is more particularly directed to a tech ⁇ nique for selectively dissociating the localized portions of an aluminum nitride ceramic substrate or insulating layer to form electrically conductive circuitry thereon.
  • Hybrid circuit structures also known as hybrid microcircuits, implement the interconnection and packaging of discrete circuit devices, and may include one or more nonconductive ceramic substrates or layers for supporting circuit elements, which may be mounted on both sides of the icrocircuit. Conductor runs for interconnecting circuit elements are formed on the surfaces of the sub ⁇ strate or subsequent layers, and metallized vias may be provided for interconnecting circuitry on the two sides of a ceramic substrate or between layers.
  • Conductor runs for example, can be formed by thick film screen printing or thin film metallization tech ⁇ niques, and via metallization can be provided by thick film screen printing techniques.
  • thick film screen printing requires the preparation and use of silk screens and the applica ⁇ tion of conductive paste
  • thin film metallization requires chemical vapor deposition, masking and etching.
  • a further consideration with conductor runs formed with known techniques is the inability to trim resistors to decrease resistance values. Generally, trimming of resistors with present techniques can only increase resistance values.
  • Another advantage would be to provide a process for forming electrically conductive circuitry on a nonconduc ⁇ tive ceramic substrate or insulating layer which avoids thick film and thin film metallization processes. i would also be an advantage to provide a process for forming electrically conductive circuitry on a noncon ⁇ ductive ceramic substrate or insulating layer which avoids the application of conductive material thereto.
  • a further advantage would be to provide a process for forming electrically conductive circuitry on a noncon ⁇ ductive ceramic substrate or insulating layer which allows for trimming resistors to decrease resistance values.
  • a still further advantage would be to provide a process for metallizing vias through insulating layers or metallic nonconductive substrates.
  • a process for forming electrically conductive circuitry on a metallic nonconductive substrate or insula ⁇ ting layer which includes the step of providing a nonconductive ceramic substrate having a metallic component .and which can dissociate into its constituent components to provide dissociated metal bonded to the ceramic substrate upon application of laser energy. Laser energy in then applied to predetermined areas of the surface of the nonconductive ceramic substrate to provide dissociated metallic conductors in the predetermined areas.
  • a further aspect of the invention is the formation of metallized through holes by application of laser energy to the nonconductive ceramic substrate to form a through hole, whereby dissociated metal ins formed on the inside of the through hole.
  • Still another aspect of the invention is the capability to down trim a thick film or thin film resistor which is conductively coupled between two areas of metallization.
  • Laser energy is applied to a portion of the thick film or thin film resistor and to a portion of the metallic nonconductive ceramic substrate in a predetermined pattern to provide a continuous dissociated metallic conductor which passes through the thick film or thin film resistor and is conductively connected to one of two areas of electrically conductive metallization.
  • FIG. 1 is a schematic illustration of a conductive structure made pursuant to the process of the invention.
  • FIG. 2 is a schematic illustration of a conductive structure made pursuant to the process of the invention for trimming a resistor to decrease its resistance value.
  • FIG. 3 is a schematic illustration of metal-coated through hole made pursuant to the process of the inven- tion.
  • FIG. 1 shown therein is a plan view schematically illustrating a nonconductive ceramic substrate or insulating layer 11, for example an aluminum nitride ceramic substrate, of a hybrid circuit.
  • the substrate 11 has a circuit device 13 mounted thereon, and further has bonding pads 15, 17, 19, 21 distributed about its periphery.
  • the bonding pads 15, 17, 19, 21 are metallized using known thick or thin film metallization techniques, as is a conductor trace 23.
  • wire bonds 25 are utilized to conductively connect terminals of the the circuit device 13 to the bonding pads 15, 17, 19, 21 and the conductor trace 23.
  • the aluminum nitride ceramic substrate 11 of FIG. 1 further includes bonding pads 27, 29 and conductor traces 31, 33. These pads and traces 27, 29, 31, 33 comprise dissociated aluminum bonded to the aluminum nitride ceramic substrate 11.
  • Such dissociated aluminum bonding pads and conductor traces are formed by applying laser energy to the regions of the ceramic substrate 11 where such bonding pads and conductor traces 27, 29, 31, 33 are to be formed.
  • the laser energy may be provided by a yttrium aluminum garnet (YAG) laser or by a carbon dioxide (C0 2 ) laser.
  • the laser beam is controlled to scan the regions where the aluminum is to be dissocia ⁇ ted from the substrate and which form the metallized interconnect pads and traces 27, 29, 31, 33.
  • a very fine line trace is achieved, having a dimension on the order of 0.001 inch in width. This permits the formation of micro- circuits which have a greater circuit density than micro- circuits formed with conventional processing techniques.
  • a YAG laser may be utilized to form the pads and traces 27, 29, 31, 33 with the following parameters: Equipment: ESI Model 44 YAG Laser Power Setting: 14.5 amps
  • Pulse Rate 2000 pps Speed: 4 mm/sec.
  • a particular advantage of the disclosed dissociative process is that it provides the capability of metallizing specific locations after other metallization has already been formed, for example by thick film or thin film techniques.
  • the disclosed dissociative process can be advantageously utilized to add bonding pads and conduc- tor traces to already fabricated circuits or prototype circuits.
  • FIG. 2 shows an aluminum nitride ceramic substrate 111, for example, having a thin film resistor 113 formed thereon.
  • the thin film resistor 113 is illustrated as being coupled between two conductor pads 115, 117.
  • a U-shaped dissocia ⁇ ted aluminum conductor 119 extends from the conductor pad 115 and traverses the thin film resistor at a location spaced from the conductor pad 115.
  • the resistance value of the thin film resistor 113 has been reduced relative to its original resistance value, since the resistive materi ⁇ al between the dissociated aluminum conductor 119 and the conductor pad 115 is effectively short circuited.
  • the disclosed dissociation process can be used to trim resistors to decrease resistance values.
  • the process of decreasing thick or thin film resistors formed in hybrid microcircuits was not possible with conventional resistor trimming techniques.
  • the resistors can also be trimmed to increase their value using the laser. This is generally accomplished by using a laser to cut through a portion of the resistor in the shape of an "U" , where the ends of the legs of the "U" are at an edge of the resistor. Such cut which effectively reduces the amount of resistor material.
  • a through hole 213 is formed in an aluminum nitride ceramic substrate 211, for example, by a laser.
  • dissociated aluminum is formed on the inside surface of the through hole and around the openings thereof.
  • a conductive through hole is formed without first forming a hole in the ceramic substrate 211 and then metallizing the hole as is done with known processes. Through holes formed in this manner can be utilized to interconnect circuitry on both sides of an aluminum nitride ceramic substrate or insula- ting layer.
  • the foregoing has been a disclosure of a metal dissociating process which provides several advantages and features including the capability of forming dissociated metal conductors quickly and easily without the use of known thick film or thin film metallization techniques. Further, the disclosed metal dissociating process provides for trimming resistors to decrease resistance values. Also, the dissociating process can be utilized to produce metallized through holes simply by forming a hole with a laser.
  • This process makes it possible to process surface layer interconnect metallization and metallize via through holes by programming a laser to directly write the conduc ⁇ tor lines and form metallized vias.
  • This process may be performed before or after other metallization techniques have been employed to form bonding pads or resistors or the like.
  • a significant increase in processing speed is achieved and laborious and costly screen printing and deposition, etching and masking processes are eliminated by employing the process of the present invention.
  • resistor trimming can be performed to decrease resistor values using the present invention.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Ceramic Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Structural Engineering (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Computer Hardware Design (AREA)
  • Power Engineering (AREA)
  • Thermal Sciences (AREA)
  • Apparatuses And Processes For Manufacturing Resistors (AREA)
  • Parts Printed On Printed Circuit Boards (AREA)
  • Laser Beam Processing (AREA)
  • Manufacturing Of Printed Wiring (AREA)

Abstract

A process for forming electrically conductive circuitry on a metallic nonconductive substrate or insulating layer which includes the steps of providing a nonconductive ceramic substrate having a metallic component and which can dissociate into its constituent components to provide dissociated metal bonded to the ceramic substrate upon application of laser energy. Laser energy is then applied to predetermined areas of the surface of the nonconductive ceramic substrate to provide dissociated metallic conductors in the predetermined areas. The disclosed process further includes the formation of metallized through holes by application of laser energy to the nonconductive ceramic substrate to form a through hole, whereby dissociated metal is formed on the inside of the through hole. The disclosed process also includes the capability to down trim a thick film or thin film resistor which is conductively coupled between two areas of metallization. Laser energy is applied to a portion of the thick film or thin film resistor and to a portion of the metallic nonconductive ceramic substrate in a predetermined pattern to provide a continuous dissociated metallic conductor which passes through the thick film or thin film resistor and is conductively connected to one of two areas of electrically conductive metallization.

Description

INDUCED METALLIZATION PROCESS BY WAY OF DISSOCIATING ALUMINUM NITRIDE CERAMIC BACKGROUND OF THE INVENTION The disclosed invention relates to the formation of electrically conductive circuitry on a nonconductive substrate, and is more particularly directed to a tech¬ nique for selectively dissociating the localized portions of an aluminum nitride ceramic substrate or insulating layer to form electrically conductive circuitry thereon.
Hybrid circuit structures, also known as hybrid microcircuits, implement the interconnection and packaging of discrete circuit devices, and may include one or more nonconductive ceramic substrates or layers for supporting circuit elements, which may be mounted on both sides of the icrocircuit. Conductor runs for interconnecting circuit elements are formed on the surfaces of the sub¬ strate or subsequent layers, and metallized vias may be provided for interconnecting circuitry on the two sides of a ceramic substrate or between layers.
Conductor runs, for example, can be formed by thick film screen printing or thin film metallization tech¬ niques, and via metallization can be provided by thick film screen printing techniques. However, as is well known, such techniques take time and require several steps. For example, thick film screen printing requires the preparation and use of silk screens and the applica¬ tion of conductive paste, while thin film metallization requires chemical vapor deposition, masking and etching. A further consideration with conductor runs formed with known techniques is the inability to trim resistors to decrease resistance values. Generally, trimming of resistors with present techniques can only increase resistance values.
SUMMARY OF THE INVENTION It would therefore be an advantage to provide a simplified process for forming electrically conductive circuitry on a nonconductive ceramic substrate or insula- ting layer.
Another advantage would be to provide a process for forming electrically conductive circuitry on a nonconduc¬ tive ceramic substrate or insulating layer which avoids thick film and thin film metallization processes. i would also be an advantage to provide a process for forming electrically conductive circuitry on a noncon¬ ductive ceramic substrate or insulating layer which avoids the application of conductive material thereto.
A further advantage would be to provide a process for forming electrically conductive circuitry on a noncon¬ ductive ceramic substrate or insulating layer which allows for trimming resistors to decrease resistance values.
A still further advantage would be to provide a process for metallizing vias through insulating layers or metallic nonconductive substrates.
The foregoing and other advantages and features are provided in a process for forming electrically conductive circuitry on a metallic nonconductive substrate or insula¬ ting layer which includes the step of providing a nonconductive ceramic substrate having a metallic component .and which can dissociate into its constituent components to provide dissociated metal bonded to the ceramic substrate upon application of laser energy. Laser energy in then applied to predetermined areas of the surface of the nonconductive ceramic substrate to provide dissociated metallic conductors in the predetermined areas.
A further aspect of the invention is the formation of metallized through holes by application of laser energy to the nonconductive ceramic substrate to form a through hole, whereby dissociated metal ins formed on the inside of the through hole.
Still another aspect of the invention is the capability to down trim a thick film or thin film resistor which is conductively coupled between two areas of metallization. Laser energy is applied to a portion of the thick film or thin film resistor and to a portion of the metallic nonconductive ceramic substrate in a predetermined pattern to provide a continuous dissociated metallic conductor which passes through the thick film or thin film resistor and is conductively connected to one of two areas of electrically conductive metallization.
BRIEF DESCRIPTION OF THE DRAWING
The advantages and features of the disclosed inven- tion will readily be appreciated by persons skilled in the art from the following detailed description when read in conjunction with the drawing wherein:
FIG. 1 is a schematic illustration of a conductive structure made pursuant to the process of the invention. FIG. 2 is a schematic illustration of a conductive structure made pursuant to the process of the invention for trimming a resistor to decrease its resistance value.
FIG. 3 is a schematic illustration of metal-coated through hole made pursuant to the process of the inven- tion.
DETAILED DESCRIPTION In the following detailed description and in the several figures of the drawing, like elements are iden¬ tified with like reference numerals. Referring now to FIG. 1, shown therein is a plan view schematically illustrating a nonconductive ceramic substrate or insulating layer 11, for example an aluminum nitride ceramic substrate, of a hybrid circuit. The substrate 11 has a circuit device 13 mounted thereon, and further has bonding pads 15, 17, 19, 21 distributed about its periphery. The bonding pads 15, 17, 19, 21 are metallized using known thick or thin film metallization techniques, as is a conductor trace 23. Pursuant to well- known techniques, wire bonds 25 are utilized to conductively connect terminals of the the circuit device 13 to the bonding pads 15, 17, 19, 21 and the conductor trace 23.
The aluminum nitride ceramic substrate 11 of FIG. 1 further includes bonding pads 27, 29 and conductor traces 31, 33. These pads and traces 27, 29, 31, 33 comprise dissociated aluminum bonded to the aluminum nitride ceramic substrate 11. Such dissociated aluminum bonding pads and conductor traces are formed by applying laser energy to the regions of the ceramic substrate 11 where such bonding pads and conductor traces 27, 29, 31, 33 are to be formed. By way of example, the laser energy may be provided by a yttrium aluminum garnet (YAG) laser or by a carbon dioxide (C02) laser. The laser beam is controlled to scan the regions where the aluminum is to be dissocia¬ ted from the substrate and which form the metallized interconnect pads and traces 27, 29, 31, 33. A very fine line trace is achieved, having a dimension on the order of 0.001 inch in width. This permits the formation of micro- circuits which have a greater circuit density than micro- circuits formed with conventional processing techniques.
By way of particular example, a YAG laser may be utilized to form the pads and traces 27, 29, 31, 33 with the following parameters: Equipment: ESI Model 44 YAG Laser Power Setting: 14.5 amps
Pulse Rate: 2000 pps Speed: 4 mm/sec.
A particular advantage of the disclosed dissociative process is that it provides the capability of metallizing specific locations after other metallization has already been formed, for example by thick film or thin film techniques. Thus, the disclosed dissociative process can be advantageously utilized to add bonding pads and conduc- tor traces to already fabricated circuits or prototype circuits.
A particular application of the capability of metallizing specific locations is illustrated in FIG. 2, which shows an aluminum nitride ceramic substrate 111, for example, having a thin film resistor 113 formed thereon. The thin film resistor 113 is illustrated as being coupled between two conductor pads 115, 117. A U-shaped dissocia¬ ted aluminum conductor 119 extends from the conductor pad 115 and traverses the thin film resistor at a location spaced from the conductor pad 115. As a result of the dissociated aluminum conductor 119, the resistance value of the thin film resistor 113 has been reduced relative to its original resistance value, since the resistive materi¬ al between the dissociated aluminum conductor 119 and the conductor pad 115 is effectively short circuited. Thus, the disclosed dissociation process can be used to trim resistors to decrease resistance values. Heretofore, the process of decreasing thick or thin film resistors formed in hybrid microcircuits was not possible with conventional resistor trimming techniques.
It is to be understood that the resistors can also be trimmed to increase their value using the laser. This is generally accomplished by using a laser to cut through a portion of the resistor in the shape of an "U" , where the ends of the legs of the "U" are at an edge of the resistor. Such cut which effectively reduces the amount of resistor material.
Referring now to FIG. 3, illustrated therein is a further use of the metal dissociating process of the present invention. A through hole 213 is formed in an aluminum nitride ceramic substrate 211, for example, by a laser. As a result of the laser energy, dissociated aluminum is formed on the inside surface of the through hole and around the openings thereof. Thus, a conductive through hole is formed without first forming a hole in the ceramic substrate 211 and then metallizing the hole as is done with known processes. Through holes formed in this manner can be utilized to interconnect circuitry on both sides of an aluminum nitride ceramic substrate or insula- ting layer.
The foregoing has been a disclosure of a metal dissociating process which provides several advantages and features including the capability of forming dissociated metal conductors quickly and easily without the use of known thick film or thin film metallization techniques. Further, the disclosed metal dissociating process provides for trimming resistors to decrease resistance values. Also, the dissociating process can be utilized to produce metallized through holes simply by forming a hole with a laser.
This process makes it possible to process surface layer interconnect metallization and metallize via through holes by programming a laser to directly write the conduc¬ tor lines and form metallized vias. This process may be performed before or after other metallization techniques have been employed to form bonding pads or resistors or the like. A significant increase in processing speed is achieved and laborious and costly screen printing and deposition, etching and masking processes are eliminated by employing the process of the present invention. Also, resistor trimming can be performed to decrease resistor values using the present invention.
Although the foregoing has been a description and illustration of specific embodiments of the invention, various modifications and changes thereto can be made by persons skilled in the art without departing from the scope and spirit of the invention as defined by the following claims. In particular, although aluminum nitride has been disclosed in the exemplary embodiment of the inventions, the present invention is not limited to only aluminum nitride substrates or insulating layers, but encompasses other nonconductive metallic materials which dissociate in the manner described herein.

Claims

CLAIMSWhat is claimed is:
1. A process for forming electrically conductive elements on a ceramic substrate comprising the steps of: providing a nonconductive ceramic substrate having a metallic component and which can dissociate into its constituent components to provide dissocia¬ ted metal bonded to the ceramic substrate upon application of laser energy; and applying laser energy to predetermined areas of the surface of the nonconductive ceramic substrate to provide dissociated metallic conductors in the predetermined areas.
2. The process of Claim 1 wherein the step of providing a metallic nonconductive ceramic substrate includes the step of providing an aluminum nitride ceramic substrate.
3. The process of Claim 1 wherein the step of applying laser energy includes the step of applying laser energy provided by a YAG laser.
4. The process of Claim 1 wherein the step of applying laser energy includes the step of applying laser energy provided by a carbon dioxide laser.
5. . The process of Claim 1 wherein the step of applying laser energy includes the step of applying laser energy to said substrate to form a through hole in the ceramic substrate, whereby dissociated metal is formed on the inside of the through hole.
6. A process for forming electrically conductive elements on a ceramic substrate comprising the steps of: providing a nonconductive ceramic substrate having a metallic component and which can dissociate into its constituent components to provide dissocia¬ ted metal bonded to the ceramic substrate upon application of laser energy; forming at least two areas of electrically conductive metallization on the surface of said " conductive ceramic substrate; forming a thick film or thin film resistor on the surface of said nonconductive substrate between two areas of said electrically conductive metallization; and applying laser energy to a portion of the thick film or thin film resistor and to a portion of the metallic nonconductive ceramic substrate in a predetermined pattern to provide a continuous dissociated metallic conductor which passes through said thick film or thin film resistor and is conductively connected to one of said two areas of electrically conductive metallization.
7. The process of Claim 6 wherein the step of providing a metallic nonconductive ceramic substrate includes the step of providing an aluminum nitride ceramic substrate.
8. The process of Claim 6 the step of applying laser energy includes the step of applying laser energy provided by a YAG laser.
9. The process of Claim 6 wherein the step of applying laser energy includes the step of applying laser energy provided by a carbon dioxide laser.
10. The process of Claim 6 wherein said predetermined pattern includes a linear portion which passes through and extends beyond the thin film or thick film resistor and further includes linear portions which extend from the ends of such linear portion to one of said two areas of electrically conductive metallization.
11. A process of forming electrically conductive metallization on or through a nonconductive substrate or insulating layer of a hybrid microcircuit, said process comprising the steps of: providing a nonconductive substrate or insulating layer having a metallic component which dissociates into its constituent components upon the application of laser energy, said metallic component rebonding to said substrate or insulating layer; applying laser energy to predefined areas of the surface of said substrate or insulating layer to dissociate said metallic component from said substrate or insulating layer; and removing said laser energy from said predefined areas to allow said metallic component to rebond to the surface of said substrate or insulating layer, said rebonded. metallic component forming electrically conductive metallization on said surface.
12. The process of Claim 11 further comprising the steps of: forming a thick film or thin film resistor on the surface of said substrate or insulating layer between predetermined areas of said electrically conductive metallization; and applying and removing said laser energy to the surface of said substrate or insulating layer below said resistor so as to short circuit a portion thereof to decrease the resistance value thereof.
13. A process of forming electrically conductive metallization on or through a nonconductive substrate or insulating layer of a hybrid microcircuit, said process comprising the steps of: providing a nonconductive substrate or insulating layer having a metallic component which dissociates into its constituent components upon the application of laser energy, said metallic component rebonding to said substrate or insulating layer upon the removal of said laser energy; and dissociating predetermined portions of said substrate or insulating layer to provide electrically conductive metallization comprising dissociated metallic conductors thereon or therethrough.
PCT/US1988/002577 1987-09-14 1988-07-29 Induced metallization process by way of dissociating aluminum nitride ceramic WO1989002697A1 (en)

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KR1019890700839A KR890702417A (en) 1987-09-14 1988-07-29 Induction metallization method by separating aluminum nitride ceramics

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US9608387A 1987-09-14 1987-09-14
US096,083 1987-09-14

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KR (1) KR890702417A (en)
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WO1991009984A1 (en) * 1989-12-22 1991-07-11 Asea Brown Boveri Aktiengesellschaft Coating process
DE4342258A1 (en) * 1993-12-10 1995-06-14 Resma Gmbh Conductive region prodn. on or in ceramic
DE4401612A1 (en) * 1994-01-20 1995-07-27 Resma Gmbh Conductive region prodn. in or on ceramic workpiece
WO2005034598A1 (en) * 2003-09-26 2005-04-14 Medtronic Minimed, Inc. High reliability multilayer circuit substrates and methods for their formation
EP1845170A2 (en) * 2006-04-12 2007-10-17 LPKF Laser & Electronics AG Method for manufacturing a conductor path structure and such a conductor path structure
WO2007115546A2 (en) * 2006-04-12 2007-10-18 Lpkf Laser & Electronics Ag Method for production of a conductor track structure and a correspondingly produced conductor track structure
US7781328B2 (en) 2002-09-27 2010-08-24 Medtronic Minimed, Inc. Multilayer substrate
US8003513B2 (en) 2002-09-27 2011-08-23 Medtronic Minimed, Inc. Multilayer circuit devices and manufacturing methods using electroplated sacrificial structures
US9148956B2 (en) 2012-04-27 2015-09-29 Seiko Epson Corporation Base substrate, electronic device, and method of manufacturing base substrate
DE102016200062A1 (en) * 2016-01-06 2017-07-06 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Method for forming electrically conductive vias in ceramic circuit carriers
CN112420300A (en) * 2020-11-11 2021-02-26 昆山丰景拓电子有限公司 Novel resistor and manufacturing method thereof

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EP0227371A1 (en) * 1985-12-11 1987-07-01 Kabushiki Kaisha Toshiba Ceramic substrates and methods of manufacturing same
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DE3103986A1 (en) * 1981-02-05 1982-09-09 Reiner Dipl.-Phys. 8011 Vaterstetten Szepan Method for producing drilled holes for through-plated contact making in electronic printed-circuit boards
EP0227371A1 (en) * 1985-12-11 1987-07-01 Kabushiki Kaisha Toshiba Ceramic substrates and methods of manufacturing same
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Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1991009984A1 (en) * 1989-12-22 1991-07-11 Asea Brown Boveri Aktiengesellschaft Coating process
DE4342258A1 (en) * 1993-12-10 1995-06-14 Resma Gmbh Conductive region prodn. on or in ceramic
DE4401612A1 (en) * 1994-01-20 1995-07-27 Resma Gmbh Conductive region prodn. in or on ceramic workpiece
US7138330B2 (en) 2002-09-27 2006-11-21 Medtronic Minimed, Inc. High reliability multilayer circuit substrates and methods for their formation
US8003513B2 (en) 2002-09-27 2011-08-23 Medtronic Minimed, Inc. Multilayer circuit devices and manufacturing methods using electroplated sacrificial structures
US7781328B2 (en) 2002-09-27 2010-08-24 Medtronic Minimed, Inc. Multilayer substrate
US7659194B2 (en) 2002-09-27 2010-02-09 Medtronic Minimed, Inc. High reliability multilayer circuit substrates and methods for their formation
WO2005034598A1 (en) * 2003-09-26 2005-04-14 Medtronic Minimed, Inc. High reliability multilayer circuit substrates and methods for their formation
WO2007115546A3 (en) * 2006-04-12 2007-12-27 Lpkf Laser & Electronics Ag Method for production of a conductor track structure and a correspondingly produced conductor track structure
EP1845170A3 (en) * 2006-04-12 2007-11-21 LPKF Laser & Electronics AG Method for manufacturing a conductor path structure and such a conductor path structure
WO2007115546A2 (en) * 2006-04-12 2007-10-18 Lpkf Laser & Electronics Ag Method for production of a conductor track structure and a correspondingly produced conductor track structure
EP1845170A2 (en) * 2006-04-12 2007-10-17 LPKF Laser & Electronics AG Method for manufacturing a conductor path structure and such a conductor path structure
US9148956B2 (en) 2012-04-27 2015-09-29 Seiko Epson Corporation Base substrate, electronic device, and method of manufacturing base substrate
DE102016200062A1 (en) * 2016-01-06 2017-07-06 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Method for forming electrically conductive vias in ceramic circuit carriers
DE102016200062B4 (en) 2016-01-06 2023-08-10 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Process for the formation of electrically conductive vias in ceramic circuit carriers
CN112420300A (en) * 2020-11-11 2021-02-26 昆山丰景拓电子有限公司 Novel resistor and manufacturing method thereof

Also Published As

Publication number Publication date
KR890702417A (en) 1989-12-23
IL87417A0 (en) 1989-01-31
JPH02501253A (en) 1990-04-26

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