# US 2008/0188018 A1 · Method of manufacturing ink jet circuit board with heaters and electrodes constructed to reduce corrosion > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2008/0188018 A1 - Document ID: US20080188018A1 - Status: Published application - Kind: A1 - Application number: 12/098,886 - Filed: 2008-04-07 - Published: 2008-08-07 - Earliest claimed: 2004-08-16 - Assignees: Canon Kabushiki Kaisha - Inventors: Kazuaki Shibata; Kenji Ono; Teruo Ozaki; Satoshi Ibe; Ichiro Saito; Sakai Yokoyama; Toshiyasu Sakai - Web page: https://patentgrep.com/patent/US20080188018A1 ## CPC - B41J 2/14129: {Layer structure} - B41J 2/14072: {Electrical connections, e.g. details on electrodes, connecting the chip to the outside...} - B41J 2/1603: {of the front shooter type} - B41J 2/1628: {dry etching} - H05K 1/0212: {Printed circuits or mounted components having integral heating means} - H05K 1/167: {incorporating printed resistors} - Y10T 29/49083: Heater type - Y10T 29/49155: Manufacturing circuit on or in base - Y10T 29/49401: Fluid pattern dispersing device making, e.g., ink jet - B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract An ink jet head circuit board is provided which has heaters to generate thermal energy for ink ejection as they are energized. This circuit board has the heaters formed with high precision to reduce their areas. It also has provisions to protect the electrode wires against corrosion and prevent a progress of corrosion. The substrate is deposited with the thin first electrodes made of a corrosion resistant metal. This is further deposited with the resistor layer. The second electrodes made of aluminum are deposited to overlap the first electrodes to form the heater without causing large dimensional variations among the heaters. With this construction, if a defect should occur in a protective layer on or near the heater, a progress of corrosion can effectively be prevented because the material of the resistor layer is more resistant to encroachment than aluminum and the first electrodes are corrosion resistant. ## Claims ### Claim at position 1 -16. (canceled) ### Claim 17 A method of fabricating an ink jet head circuit board, said ink jet head circuit board having heaters to generate thermal energy for ejecting ink as they are energized, the method comprising the steps of: laying a SiC layer a substrate; forming on the substrate with the SiC layer first electrodes having a gap therebetween in which to form the heater, said first electrodes being formed of a corrosion resistant metal; forming a resistor layer on the first electrodes including the gap; forming on the first electrodes and the resistor layer a layer for second electrodes, the second electrodes having a greater thickness than that of the first electrodes; and then removing from the layer a gap portion larger than the gap of the first electrodes to form second electrodes, the gap portion having its ends situated over the first electrodes. ### Claim 18 (depends on 17) The method according to claim 17, wherein the step of forming the first electrodes has a step of depositing a layer for the first electrodes using Ta, Pt or an alloy containing at least one of them and a step of patterning the layer by dry etching to form the first electrodes. ### Claim 19 (depends on 17) The method according to claim 17, further including a step of partially removing the resistor layer over the first electrodes to split the resistor layer. ### Claim 20 (depends on 17) The method according to claim 17, further including a step of laying an electrode wire layer over the second electrodes through a protective layer and electrically connecting it to the second electrodes. ### Claim 21 A method of fabricating an ink jet head circuit board, said ink jet head circuit board having heaters to generate thermal energy for ejecting ink as they are energized, the method comprising the steps of: forming on a substrate first electrodes having a gap therebetween in which to form the heater; forming a resistor layer on the first electrodes including the gap; partially removing the resistor layer over the first electrodes to split the resistor layer; forming on the first electrodes and the resistor layer a layer for second electrodes, the second electrodes having a greater thickness than that of the first electrodes; and then removing from the layer a gap portion larger than the gap of the first electrodes to form second electrodes, the gap portion having its ends situated over the first electrodes. ### Claim 22 (depends on 21) The method according to claim 21, wherein the first electrodes are formed of a corrosion resistant metal. ### Claim 23 (depends on 22) The method according to claim 22, further including a step of laying a SiC layer on the substrate prior to forming the first electrodes. ### Claim 24 (depends on 23) The method according to claim 23, wherein the step of forming the first electrodes has a step of depositing a layer for the first electrodes using Ta, Pt or an alloy containing at least one of them and a step of patterning the layer by dry etching to form the first electrodes. ### Claim 25 (depends on 22) The method according to claim 22, wherein the step of forming the first electrodes has a step of depositing a layer for the first electrodes using TiW and a step of etching the layer with a water solution containing hydrogen peroxide as a main component to form the first electrodes. ### Claim 26 (depends on 21) The method according to claim 21, further including a step of laying an electrode wire layer over the second electrodes through a protective layer and electrically connecting it to the second electrodes. ### Claim 27 A method of fabricating an ink jet head circuit board, said ink jet head circuit board having heaters to generate thermal energy for ejecting ink as they are energized, the method comprising the steps of: forming on a substrate first electrodes having a gap therebetween in which to form the heater; forming a resistor layer on the first electrodes including the gap; forming on the first electrodes and the resistor layer a layer for second electrodes, the second electrodes having a greater thickness than that of the first electrodes; then removing from the layer a gap portion larger than the gap of the first electrodes to form second electrodes, the gap portion having its ends situated over the first electrodes; and laying an electrode wire layer over the second electrodes through a protective layer and electrically connecting it to the second electrodes. ### Claim 28 (depends on 27) The method according to claim 27, wherein the first electrodes are formed of a corrosion resistant metal. ### Claim 29 (depends on 28) The method according to claim 28, further including a step of laying a SiC layer on the substrate prior to forming the first electrodes. ### Claim 30 (depends on 29) The method according to claim 29, wherein the step of forming the first electrodes has a step of depositing a layer for the first electrodes using Ta, Pt or an alloy containing at least one of them and a step of patterning the layer by dry etching to form the first electrodes. ### Claim 31 (depends on 28) The method according to claim 28, wherein the step of forming the first electrodes has a step of depositing a layer for the first electrodes using TiW and a step of etching the layer with a water solution containing hydrogen peroxide as a main component to form the first electrodes.