MXPA00012718A - A process for making a heater chip module - Google Patents

Abstract

A process is provided for forming a heater chip (160) module comprising a carrier (52) adapted to be secured to an ink-filled container, at least one heater chip having a base coupled to the carrier, and at least one nozzle plate (70) coupled to the heater chip. The carrier includes a support substrate (54) having at least one passage which defines a path for ink to travel from the container (22) to heater chip. The heater chip is secured at its base to a portion of the support substrate. At least the portion of the support substrate is formed from the material having substantially the same coefficient of thermal expansion as the heater chip base. A flexible circuit is coupled to the heater chip module such as by TAB bonding or wire bonding.

Description

A PROCESS TO DEVELOP A HEATING CIRCUIT MODULE CROSS REFERENCE TO RELATED APPLICATIONS This application relates to the United States Patent Applications, filed contemporaneously, Serial No. 09 / 100,070, entitled "AN INK JET HEATER CHIP MODULE IIT SEALANT MATERIAL"; Serial No. 09 / 100,485, entitled "A HEATER CHIP MODULE AND PROCESS FOR MAKING SAME", Serial No. 09 / 100,544 entitled "AN INK JET HEATER CHIP MODULE", Serial No. 09 / 100,538, entitled "A HEATER CHIP MODULE FOR USE IN AN INK JET PRINTER "; and Serial No. 09 / 100,100,218, entitled "AN INK JET HEATER CHIP MODULE INCLUDING A NOZZLE PLATE COUPLING TO HEATER CHIP TO A CARRIER" LE9-98-003, the disclosures of which are incorporated herein by reference.

FIELD OF THE INVENTION This invention relates to a process for forming a heating circuit module adapted to be secured to an ink filled container.

BACKGROUND OF THE INVENTION Inkjet printers, drop-on-demand, use thermal energy to produce a vapor bubble in a chamber filled with ink to eject a drop. A thermal energy generator or heating element, usually a resistor, is located in the chamber in a heating circuit near a discharge nozzle. A plurality of cameras, each provided with an individual heating element, are provided in the printing head of the printer. The print head typically comprises the heating circuit and a nozzle plate having a plurality of discharge nozzles formed therein. The print head is part of an inkjet print cartridge that also comprises an ink filled container. A plurality of dots comprising a row of printed data are printed as the ink jet print cartridge makes a single scan through a printing medium, such as a sheet of paper. The row of data has a given length and width. The length of the data row, which extends transversely to the scanning direction, is determined by the size of the heating circuit. Printer manufacturers are constantly looking for techniques that can be used to improve printing speed. One possible solution involves the use of larger heating circuits. However, larger heating circuits are expensive to manufacture. Heating circuits are typically found on a silicon wafer having a generally circular shape. The cost of normally rectangular heating circuits becomes large, you can use less of the silicon wafer in the manufacturing of heating circuits. In addition, as the size of the heating circuit increases, the probability that a circuit will have a defective heating element, conductor of another element formed therein, also increases. In this way, manufacturing yields decrease as the size of the heating circuit increases. Accordingly, there is a need for an improved printhead or print head assembly that allows for an increased printing speed while still being capable of being manufactured or processed in an inexpensive manner.

SUMMARY OF THE INVENTION According to the present invention, there is provided a process for forming a heating circuit module comprising a suitable carrier to be secured to an ink filled container, at least one heating circuit having a base coupled to the carrier, and at least one nozzle plate coupled to the heating circuit. The carrier includes a support substrate having at least one passage defining a path for the ink to travel from the container to the heating circuit. The heating circuit is secured at its base to a portion of the support substrate. A flexible circuit is coupled to the connector circuit module such as by bonding with TAB or wire bonding. Two or more heating circuits can be secured, placed end-to-end, side by side or at an angle to each other, to an individual support substrate. Each of the two or more heating circuits coupled to an individual support substrate can be placed in a different color. For example, three heater circuits placed side by side can be coupled to an individual support substrate where each connector circuit receives ink from one of the three primary colors. At least the portion of the support substrate is formed from a material having substantially the same coefficient of thermal expansion as the base of the heating circuit. In this way, the base of the heating circuit and the supporting substrate portion expand or contract essentially to the same proportion. This is advantageous for various reasons. First, the bonding material that binds the heating circuit to the carrier is less likely to fail. Additionally, if two or more heater circuits are secured to the carrier, the accuracy of the placement of the point is increased since the location of the heater circuits relative to the paper is less likely to vary. It is also preferred that the support substrate portion is formed of a material having a thermal conductivity that is substantially the same as or greater than the thermal conductivity of the material from which the base of the heating circuit is formed. Therefore, the carrier provides a dissipation path for the heat generated by the heating circuit. Consequently, heat buildup in the heating circuit is prevented, which could occur if the thermal connectivity of the supporting substrate portion is less than that of the base of the heating circuit.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view, partially separated, of an inkjet printing apparatus having a print cartridge constructed in accordance with the present invention; Figure 2 is a plan view of a portion of a heating circuit module constructed in accordance with a first embodiment of the present invention; Figure 2A is a view taken along the line 2A-2A seen in Figure 2; Figure 2B is a view taken along line 2B-2B seen in Figure 2; Figure 2C is a plan view of the support, separator and heater circuit substrate of the module illustrated in Figures 2, 2A and 2B with the nozzle plate and flexible circuit removed; Figures 3-7 are schematic cross-sectional views illustrating the process for forming the support substrate illustrated in Figures 2A and 2B. Figure 8 is a cross-sectional view of a portion of the support substrate of the heating circuit module of Figures 2, 2A and 2B; Figure 9 is a cross-sectional view of a portion of a heating circuit module constructed in accordance with a second embodiment of the present invention; Figure 10 is a plan view of a portion of the heater circuit module illustrated in Figure 9; and Figure 11 is a plan view of a marker on the bottom surface of a heating circuit.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to Figure 1, there is shown an inkjet printing apparatus 10 having a print cartridge 20 constructed in accordance with the present invention. The cartridge 20 is supported on a carriage 40 which in turn is slidably supported on a guide rail 42. A drive mechanism 44 is provided to effect the reciprocating movement of the carriage 40 and the print cartridge 20 backwards and forwards. forwardly along the guide rail 42. As the print cartridge 20 is moved back and forth, it ejects ink droplets onto the paper substrate 12 provided below it. The print cartridge 20 comprises a container 22, shown only in Figure 1, filled with ink and a heating circuit module 50. The container 22 can be formed from the polymeric material. In the illustrated embodiment, the container 22 is formed from polyphenylene oxide, which is commercially available from the General Electric Company under the trademark "NORYL SE-1". The container 22 can be formed from other materials not explicitly stated herein. In the embodiment illustrated in Figures 2, 2A and 2B, the module 50 comprises a carrier 52, an edge feed heater circuit 60 and a nozzle plate 70. The heater circuit 60 includes a plurality of resistive heating elements 62 which are located in a base 64, see Figure 2A. In the illustrated embodiment, the base 64 is formed of silicon. The nozzle plate 70 has a plurality of apertures 72 which extend therethrough and define a plurality of nozzles 74 through which the ink drops are ejected. The carrier 52 is secured directly to a bottom side (not shown) of the container 22, that is, the side in Figure 1 closest to the paper substrate 12, such as by an adhesive (not shown). In this way, the embodiment illustrated there is no other element placed between the carrier 52 and the container 22 except for the adhesive joining together the two elements. An exemplary adhesive that can be used to secure the carrier 52 to the container 22 is one that is commercially available from Emerson and Cuming Specialty Polymers, a division of National Starch and Chemical Company under the product designation "ECCOBOND 3193-17." The nozzle plate 70 can be formed from a substrate of flexible polymeric material that adheres to the heater circuit 60 by an adhesive (not shown). Examples of polymeric materials from which nozzle plate 70 and adhesives can be formed to secure plate 70 to heater circuit 60 are set forth in the commonly assigned patent applications., Serial No. 08 / 966,281, entitled "METHOD OF FORMING AN INKJET PRINTHEAD NOZZLE STRUCTURE", by Ashok Murthy et al., Filed on November 7, 1997 which is a request for continuation in part of the serial No. 08 / 519,906, entitled "METHOD OF FORMING AND INKJET PRINTHEAD NOZZLE STRUCTURE", by Tonya H. Jackson et al., Filed August 28, 1995, the descriptions of which are incorporated herein by reference. As noted herein, the plate 70 may be formed from a polymeric material such as polyimide, polyester, fluorocarbon polymer, or polycarbonate which is preferably from about 15 to about 200 microns thick and more preferably from about 20 to about 80 microns thick. Examples of commercially available nozzle plate materials include a polyimide material available from E.I. DuPont de Nemours &; Co. under the trademark "KAPTON" and a polyimide material available from Ube (of Japan) under the trademark "UPILEX". The adhesive for sealing the plate 70 of the heating circuit 60 may comprise a phenolic butyral adhesive. A material composed of phenolic butyral adhesive / polyimide substrate is commercially available from Rogers Corporation, Chandler, AZ, under the product name "RFLEX 1100". The nozzle plate 70 can be attached to the circuit 60 by any technique recognized in the art, including a thermocompression bonding process. When the plate 70 and the heating circuit 60 are joined together, the sections 76 of the plate 70 and the portions 66 of the heating circuit 60 define a plurality of bubble chambers 65. The ink supplied by the container 22 flows into the bubble chambers 65 through the ink supply channels 65a. As illustrated in Figure 2A, the supply channels 65a extend from the bubble chambers 65 beyond the first and second outer edges 60a and 60b of the heating circuit 60. The resistive heating elements 62 are placed in the heating circuit 60. such that each bubble chamber 65 has only the heating element 62. Each bubble chamber 65 communicates with a nozzle 74.

The carrier 52 comprises a support substrate 54 and a spacer 56, see Figures 2A and 2B. The support substrate 54 includes a silicon plate 58 having first and second outer surfaces 58a and 58b, see Figures 2A and 8.

The silicon plates 58 are also referred to herein as a portion of the support substrate 54. The plate 58 has a thickness Tp of about 400 microns to about 2500 microns and preferably about 500 microns to about 1000 microns. The first and second passage 58c and 58d extend through the silicon plate 58. In the illustrated embodiment, the passages 58c and 58d are generally rectangular where they engage the first and second outer surfaces 58a and 58b. They also converge inwardly from the first outer surface 58a to the second surface 58b. Alternatively, the passages 58c and 58d may be of an oval, elliptical and other geometric shape. A first layer 59 of etch-resistant material is formed on the first outer surface 58a of the silicon plate 58, see Figure 8. The first layer 59 can be formed from any number of known materials resistant to acid etching including, for example, silicon nitride, silicon carbide, aluminum, tantalum and silicon dioxide. Other materials not explicitly stated herein may also be used when the layer 59 is formed. The first layer 59 has a thickness in the Z direction, see Figure 8, from about 1 micron to about 20 microns, including all ranges covered herein, and preferably from about 1 miera to about 2.5 microns.

The first layer 59 includes a first and a second opening 59a and 59b that extend completely through it, which communicate with the passages 58c and 58d. The first opening 59a has in general the same shape and size as the first passage 58c, where the passage 58c meets the first surface 58a of the silicon plate. The second opening 59b has in general the same shape and size as the second passage 58d where the passage 58d meets the first surface 58a of silicon plate. The first and second passages 58c and 58d of silicon plate and the first and second apertures 59a and 59b of the first layer define a first and a second passage 52a and 52b on the support substrate 54. An outer surface 59c of the first layer 59 defines a first outer surface 54a of the support substrate 54. The second outer surface 58b of the silicon plate 58 defines a second outer surface 54b of the support substrate 54. The separator 56 is formed of a material selected from the group consisting of ceramics, metals, silicon and polymers. The support substrate 54 is secured with an adhesive 56a. Exemplary adhesives that can be used to secure the separator 56 to the support substrate 54 include a preform of? thermally curable B-stage adhesive film (polysulfone) which is commercially available from Alpha Metals Inc. under the product designation "Staystik 415" and other adhesive material that is commercially available from Mitsui Toatsu Chemicals Inc. under the product designation "REGULUS" " The separator 56 has, in the illustrated embodiment, an opening 56b generally defined by four interior side walls 56c, see Figure 2C. A central section 54c of the second outer surface 54b of the supporting substrate 54 and the inner side walls 56c and the spacer 56 differ an inner cavity 52c of the carrier 52, see Figures 2C and 8. The heating circuit 60 is located in the inner cavity 52c of the carrier and secured to the second surface 54b of the support substrate 54. As seen from Figure 2A, the first and second passage 52a and 52b of the support substrate communicate with the interior cavity 52c. The inner cavity 52c and the heating circuit 60 are made such that the portions 60c and 60d of the opposite side of the heating circuit 60 are separated from the adjacent inner side walls 56c of the separator 56 to form separations 80a and 80b of sufficient size to allow the ink to flow freely between the side portions of the circuit 60c and 60d, and the adjacent inner side walls 56c, see Figure 2C.

The nozzle plate 70 is sized to extend over an outer portion 56d of the spacer 56 surrounding the opening 56b such that the inner cavity 52c is sealed to prevent ink from leaking from the inner cavity 52c, see Figure 2A. The passages 52a and 52b provide a route for the ink to travel from the container 22 to the interior cavity 52c. From the inner cavity 52c, the ink flows into the ink supply channels 65a. The resistive heating elements 62 are individually addressed by voltage pulses provided by a circuit (not shown) and power supply of the printer. Each voltage pulse is applied to one of the heating elements 62 to momentarily evaporate the ink in contact with that heating element 62 to form the bubble within the bubble chamber 65 in which the heating element 62 is located. The function of the The bubble is displacing the ink within the bubble chamber 65 such that a drop of ink is ejected from a nozzle 74 associated with the bubble chamber 65. A flexible circuit 90, secured to the polymer container 22 and the separator 56, is used to provide a path for the energy pulses to travel from the printer's power supply circuit to the heater circuit 60.

The linear pads 68 in the heater circuit 60 are wired to the sections 92a of the traces 92 in the flexible circuit 90, see Figures 2 and 2B. The current flows from the power supply circuit of the printer to the traces 92 in the flexible circuit 90 and from the traces 92 to the pads 68 in the heater circuit 60. The conductors (not shown) are formed in the base 64 of the heating circuit and extend from the connecting pads 68 and the heating elements 62. The current flows from the connecting pads 68 along the conductors to the heating elements 62. The process for forming the support substrate 54 will now be described with reference to Figures 3-7. The silicon wafer 158 having a thickness Tp of about 400 microns to about 2500 microns and preferably about 500 microns to about 1000 microns is provided. The thickness of the most critical wafer 158 may fall outside this range. A plurality of support substrates 54 are formed on a single wafer 158. For ease of illustration, only the wafer portion 158 is illustrated in Figures 3-7. The first and second layers 159 and 161 of the etch resist acid are formed on the first and second sides 158a and 158b of the wafer 158, see Figure 3. The layers 159 and 161 can be formed from any number of known materials resistant to etching, including for example, silicon nitride, silicon carbide, aluminum, tantalum, silicon dioxide and the like. In the illustrated embodiment, silicon nitride is deposited simultaneously on the outer surfaces of wafer 158 using a conventional low pressure steam deposition process or an improved plasma chemical vapor deposition process. Alternatively, the silicon dioxide layers may be thermally grown on the wafer 158, or aluminum or tantalum layers may be formed on the opposite surfaces of the wafer via a conventional sputtering or evaporation process. The first layer 159 has a thickness in the Z direction, see Figure 3, from about 1 micron to about 20 microns, preferably from about 1.0 microns to about 2.5 microns. The second layer 161 has a thickness in the Z direction from about 1 micron to about 20 microns, preferably from about 1.0 microns to about 2.5 microns. After the first and second layers 159 and 161 are deposited on the wafer 158, a photoresist first layer 170 is formed on the first layer 159 of etch resistant material via a conventional turning process. Layer 170 has a thickness Tpl of about 100 Anglestrom to about 50 microns, and preferably from about 1.0 micron to about 5.0 micron. The photoresist can be a negative or positive photoresist material. In the illustrated embodiment, the layer 170 is formed of a negative photoresist material that is commercially available from Olin Microelectronic Materials under the product designation "SC-100 Resist". After the photoresist layer 170 is turned over the wafer 158, it is gently fired at an appropriate temperature to partially evaporate the photoresist solvents to promote adhesion of the layer 170 to the first layer 159. An additional reason for the gentle firing of the layer 170 is to prevent a first mask, which is discussed below, from adhering to the layer 170. On the first photoresist layer 170 a first mask (not shown) is placed, which has a plurality of blocked or covered areas corresponding to the first and second apertures 59a and 59b in the first layer 59. The first marking is aligned in a conventional manner such that the wafer is flat (not shown). Subsequently, the unblocked portions of the first photoresistile layer 170 are exposed to ultraviolet light to effect curing or polymerization of the exposed portions. The first mask is then removed. Subsequently, the unexposed or uncured portions of the first photoresist layer 170 are removed using a conventional developer chemical. In an illustrated embodiment, the unpolymerized portions are removed by spraying a developer, such as one that is commercially available from Olin Microelectronic Materials under the designation "PF developer" product, on the first side of the wafer as long as the Wafer 158. After the developing process has begun, a mixture of approximately 90% relay chemical and 10% isopropyl alcohol, by volume, is sprayed onto the first side of the turning wafer 158. Finally, the development process is stopped by spraying only isopropyl alcohol onto the turning wafer 158. After the unpolymerized portions of the first photoresist layer 170 are removed from the wafer 158, the portions 159a of the first layer 159 of the etch-resistant material are exposed, see Figure 4. Instead of spraying the three different compositions On developing the wafer 158, the wafer 158 can be sequentially placed in three baths containing, respectively, 100% developer, a mixture of approximately 90% developer and 10% isopropyl alcohol and 100% isopropyl alcohol. The wafer 158 remains in the first bath until the development process has begun. The second bath is removed and placed in the third bath after the unpolymerized portions of the first layer 170 have been removed. The wafer 158 is preferably agitated when it is in each of the baths. After the development of the first photoresist layer 170, the first layer 170 is roughly baked in a conventional manner to effect the final evaporation with the remaining solvents in the layer 170. The pattern formed in the first photoresist layer 170 is transferred to the first layer 159 of material resistant to acid etching, see Figure 5, using a conventional acid etching process. For example, a conventional acid etching process with reactive ions can be used. When the first layer 159 of etch material is formed from silicon nitride, the reactive gas supplied to the acid etch and reactive CF4 ions. For the etching of aluminum acid, a chlorine gas can be supplied. When the layer 159 is formed of tantalum, it is preferably provided by a CF gas. After the pattern has been transferred to the first layer 159 of etch-resistant material, the polymerized photoresist material remaining on the wafer 158 is removed in a conventional manner. For example, a conventional reactive ion acid etchant that receives a 02 plasma can be used. Alternatively, a commercially available resistant solvent such as one that is available from Olin Microelectronic Materials under the product designation "Microstrip" can be used. Then, a micro-machined step is implemented to form the passages 58c and 58d on the silicon wafer 158. This step comprises placing the wafer 158 in the etching bath such that the exposed portions of the silicon are etched into the acid. A bath based on tetramethylammonium hydroxide (TMAH) can be used. The TMAH-based bath comprises, by weight, from about 5% to about 40%, preferably 10% tetramethylammonium hydroxide, and from about 60% to about 95%, and preferably about 90%, of Water. The TMAH / water solution is passivated by dissolving silicon and / or silicic acid in the TMAH / water solution until the solution has a pH of about 11 to about 13. A more detailed analysis of the TMAH solutions of passivation in the article: U. Schnakenberg, W. Benecke, and P. Lange, THAH Etchants for Silicon Micromachining, "In Proc. Int. Conf. on Solid State Sensors and Actuators (Transducers 1991), pp. 815-818, San Francisco, June 1991, the description of which is incorporated herein by reference.The solution of the inactivated water TMAH is advantageous, since it will not attack the metal layer resistant to acid etching. etched in acid is formed from a non-metal, such as silicon nitride, a bath based on potassium hydroxide (KOH) can be used.The KOH bath comprises, by weight, from about 5% to about 75%, and preferably approximately 45% potassium hydroxide and from about 25% to about 95% and preferably about 55% water. Thus, if the first layer 159 of etch-resistant material is formed from a metal, such as aluminum or tantalum, a bath based on tetramethyl ammonium hydroxide (TMAH) should be used since a bath of KOH will attack the metal layer 159. When sufficient acid etching has occurred such that the passages 58c and 58d are formed, see Figure 6, the wafer 158 is removed in the bath. When using a KOH solution, the following equations describe the resulting geometry of passages 58c and 58d: WE? = E 2 + TP (1. 4 1 4) LE? = Le2 + TP (1. 4 1 4) Where WE? is the width of the entrance of each of the passages 58c and 58d, see Figure 8. WE2 is the width of the exit of each of the passages 58c and 58d. LEÍ is the length of the entrance of each of the passages 58c and 58d, where the length of the entrance extends transversely to the width of the entrance (not shown in the drawings but extends to and out of the paper as seen in Figure 8); Y LE2 is the length of the exit of each of the passages 58c and 58d, wherein the length of the exit extends transversely to the width of the exit (not shown in the drawings but extends to and out of the paper as seen in FIG. Figure 8). When using a TMAH solution, the following equations describe the resulting geometry of the 58c and 58d passages: WE? = E2 + TP (2 / tan Q) LE? = LE2 + TP (2 / tan Q) where E? is the width of the entrance of each of the passages 58c and 58d; E2 is the width of the output of each of the passages 58c and 58d; YOU? is the length of the entrance of each of the passages 58c and 58d, where the length extends transversely to the width of the entrance (not shown in the drawings, but extends to and out of the paper as seen in Figure 8); LE2 is the length of the exit of each of the passages 58c and 58d, where the length extends transversely to the width of the exit (not shown in the drawings but extends to and out of the paper as indicated in Figure 8); Q is the angle formed by a side wall of each of the passages 58c and 58d and a horizontal plane, see Figure 8. Subsequently, the second layer 161 of the etch-resistant material is removed using a conventional ionic acid stirrer. reagents Alternatively, only the sections 161a of the layer 161 can be removed during a wafer wash step using a conventional wafer washer, see Figures 6 and 7. In this embodiment, an upper surface 163 of the second layer 161 defines the upper surface 154b of the support substrate 54. In this way, the heating circuit 60 is joined to the upper surface 163 of the second layer 161 in this embodiment. If the second complete layer 161 is removed, the heating circuit 60 is joined to the second outer surface 58b of the silicon layer 58.

After removal of the second layer 161 or sections 161a of the second layer 161, the wafer 158 is shortened to individual support substrates 54. The heater circuit 60 is preferably formed with two alignment markers 100 on its bottom surface 64a, see Figure 2C. An alignment marker 100 formed in accordance with the present invention is illustrated in Figure 11. It contains a line 100a, two thinner side lines 100b placed on opposite sides of the center line 100a and two dotted 100c lines placed outside the two lines 100a. side lines 100b. The center line 100a and the dotted lines each have a width of approximately 10 microns. The side lines 100b have a width of about 5 microns. The lines 100a, 100b and 100c are separated from each other by approximately 10 microns. The markers 100 are formed in the following manner. A positive photoresist layer formed for example from a material commercially available from Shipley Company Inc. under the product designation "positive strength 1827" is turned on an outer surface and a silicon wafer (not shown) to a thickness of about 3 mm. mieras Typically, a plurality of heating circuits 60 are formed in a single wafer. Preferably, the markers 100 are formed on the wafer after the heating elements, conductors and other elements of the heating circuits are formed. After the wafer is turned, the photoresist layer is gently fired at an appropriate temperature to partially evaporate the photoresist solvents. A second mask (not shown) having a plurality of blocked or covered areas corresponding to the background areas between lines 100a, 100b and 100c, are placed on the photoresist layer. The mask is aligned in a conventional manner such as by an infrared mask aligner to two or more elements, for example heating elements or conductors, previously formed on the opposite side of the wafer. Subsequently, the unblocked portions of the photoresist layer is exposed to an ultraviolet light to change the chemical structure of the relatively insoluble photoresist to much more soluble. The mask is then removed. After removal of the mask, the photoresist layer is rinsed in a chlorobenzene bath for approximately five minutes. The photoresist is then disclosed using for example, a material commercially available from Shipley Co. Inc. under the product designation "Microposit MF319". During this development step, portions of the photoresist layer exposed to ultraviolet radiation are removed.

Following the development step, a chrome layer is sizzled on the wafer to a thickness of approximately 500 angstroms. The wafer is then rinsed in acetone for about five minutes to remove the remaining photoresist material and portions in the chromium layer formed on the remaining photoresist. The chromium material that remains after the acetone rinse process comprises the markers 100. The process for forming the heating circuit module 50 illustrated in Figures 2, 2A and 2B will now be described. As noted above, the nozzle plate 70 comprises a substrate of flexible polymer material. In the illustrated embodiment, the flexible substrate is provided with an overlay layer of phenolic butyral adhesive to secure the nozzle plate 70 to the heater circuit 60. Initially, the nozzle plate 70 is aligned and assembled to the heater circuit 60. In At this point, the heating circuit 60 has been separated from other heating circuits 60 formed in the same wafer. The alignment can take one as follows. One or more fiduciary first (not shown) can be provided on the nozzle plate 70 which is aligned with one or more fiduciary seconds (not shown) provided in the heater circuit 60. After the nozzle plate 70 is aligned and In the heating circuit 60, the plate 70 is fixed to the heating circuit 60 using, for example, a conventional thermocompression bonding process. The phenolic butyral adhesive in the nozzle plate 70 does not cure completely after the fixing step has been completed. Either before or after the nozzle plate 70 is attached to the heating circuit 60, the separator 56 is joined to the support substrate 54. At this junction, the support substrate 54 has been separated from the other support substrates 54 formed in the same wafer. A layer of the adhesive 56a, examples of which are noted above, is applied to the second outer layer 54b of the support substrate 54 where the spacer 56 is to be placed. The spacer 56 is then mounted to the support substrate 54. Subsequently, Adhesive 56a is completely cured using heat and pressure. An additional adhesive material (not shown), such as a 0.0051 cm (0.002 inch) die-cut phenolic adhesive film, which is commercially available from Rogers.

(Chandler, Arizona) under the product designation "1000B200", is placed in a portion 56e of the separator 56 to which the flexible circuit 90 has been secured. Subsequently, the flexible circuit 90 is placed on the adhesive film and fixed to the separator 56 using heat and pressure. In the illustrated embodiment, the flexible circuit 90 is coupled to the separator 56 after the separator 56 has been attached to the support substrate 54. It is also contemplated that the flexible circuit 90 may be coupled to the separator 56 before the separator 56 is secured to the support substrate 54. The nozzle plate / heater circuit assembly is then mounted to the support substrate / spacer assembly. Initially, a conventional die bonding adhesive 110, such as a substantially transparent phenolic polymer adhesive which is commercially available from Georgia Pacific under the product designation "BKS 2600", is applied to the second outer surface 54b of the supporting substrate 54 in locations where one or more heater circuits 60 are to be placed. It is contemplated that one or two or more heater circuits 60 may be secured to an individual support substrate 54. For example, two heater circuits 60 may be placed end-to-end, side-by-side or misaligned with each other on the support substrate 54. Two heating circuits 60 can be provided in the same or different lower cavities 52c. Subsequently, the two markers 100 on the bottom surface 64a of each heating circuit 60 are aligned in relation to the inner edges 58a and 58f of the silicon plate 58, see Figures 2A and 8. The heating circuit 60 is in alignment when the center line 100a of one of its two markers 100 is placed on the edge 58e in the centerline 100a of the other marker 100 is placed over the edge 58f. The markers 100 can be viewed using, for example, a video microscope (not shown) that generates an output signal provided to either a monitor for analysis by human vision or an optical analyzer for the analysis of an electronic device. It is also contemplated that an operator can see the markers through a lens of a normal microscope. Alternatively, alignment markers (not shown), two for each heating circuit 60, may be formed on the second outer surface 54b of support substrate 54. The markers 100 in the heater circuit 60 and the markers on the support substrate 54 are located respectively in the heater circuit 60 and in the support substrate 54 such that when the markers are in alignment with each other, the heater circuit 60 is properly aligned. to support substrate 54. A conventional infrared aligner can be used to effect the alignment of the markers in the heater circuit 60 and the support substrate 54. The nozzle plate / heater circuit assembly is attached to the support substrate / spacer assembly to hold two assemblies together until the die attachment adhesive 110 is covered. Before the nozzle plate / heater circuit assembly is mounted on the support / separator substrate, a conventional ultraviolet (UV) curable adhesive (not shown), such as one that is commercially available from Emerson and Cuming Specialty Polymers , a division of the National Starch and Chemical Company under the product designation UV9000, is applied to one or more locations of the support substrate 54 where the corners of the heating circuit 60 are to be located. After the nozzle plate / heater circuit assembly is mounted to the support substrate / separator assembly, the exposed adhesive is cured using ultraviolet radiation to effect fi xation. Subsequently, the nozzle plate / heating circuit assembly and the substrate / spacer substrate assembly are heated in a furnace at a temperature and for a sufficient time to effect the curing of the following materials: the phenolic butyral adhesive which binds the nozzle plate 70 to heater circuit 60 and separator 56; the phenolic adhesive film joining the flexible circuit 90 to the separator 56; and the die attachment adhesive 110 joining the heating circuit to the support substrate 54. During the heating step, the pressure may or may not be applied to the nozzle plate / heater circuit assembly and the support substrate / spacer assembly . After the nozzle plate / heater circuit assembly and the flexible circuit 90 for the support / spacer substrate assembly have been joined, the dashed sections 92a in the flexible circuit 90 are wired to the joint pads 68 in heating circuit 60, see Figures 2 and 2B. An individual band 112 extends between each pair of joint pad / stroke section after the wire joint has been completed. The wires 112 extend through windows or openings 71 formed in the nozzle plate 70. It is also contemplated that the nozzle plate 70 can be made in a size so that the wires 112 do not extend through the windows in the nozzle plate 70 as described in the above-referenced Patent Application entitled "AN INK JET HEATER CHIP MODULE ITH SEALANT MATERIAL ". It is also contemplated that the trace sections may be attached to tie pads 68 via an automated tape joining process ( ) such as in the manner described in the above-referenced patent application entitled "AN INK JET HEATER CHIP MODULE INCLUDING A NOZZLE PLATE COUPLING A HEATER CHIP TO A CARRIER ". After joining with wire or bonding with , an encapsulating liquid material 114, such as ultraviolet light (UV) curable adhesive, one of which is commercially available from Emerson and Cuming Specialty Polymers, a division of National Starch and Chemical Company under the product designation "UV9000", shown in Figure 2B, is applied over the trace sections 92a, the joint pads 68, the wires 112 and the windows 71. The UV adhesive is then cured using ultraviolet light. The heating circuit module 50, comprising the nozzle plate / heater circuit assembly and the support / spacer substrate assembly, and which the flexible circuit 90 is fixed, is aligned and directly attached to the polymer vessel 22. adhesive (not shown) such as that which is commercially available from Emerson and Cuming Specialty Polymers, a division of National Starch and Chemical, under the product designation "ECCOBOND 3193-17" is applied to a portion of the container where the module 50 is going to be located. The module 50 is then mounted to the container portion. Then, the module 50 of the heating circuit and the container 22 are heated in an oven at a temperature for a period of time sufficient to effect the curing of the adhesive joining the heating circuit module 50 to the container 22. A portion of the flexible circuit 90 which is not attached to the separator 56 is attached to the container 22 for example by a conventional free-standing pressure-sensitive adhesive film, such as described in co-pending Patent Application Serial No. 08 / 827,140, entitled "A PROCESS FOR JOINING A FLEXIBLE CIRCUIT TO A POLYMERIC CONTAINER AND FOR FORMING A BARRIER LAYER OVER SECTIONS OF THE FLEXIBLE CIRCUIT AND OTHER ELEMENTS USING AN ENCAPSULANT MATERIAL ", filed on March 27, 1997, the description of which is incorporated herein by reference . It is also contemplated that the heater circuit 60 may be secured to the support substrate 54 by the fusion junction of silicon, the eutectic bond, anodic junction. At the anodic junction, a thin layer of sizzled glass sits on the second outer surface 54b of the support substrate 54 where one or more heating circuits 60 are to be secured. An example ionic glass material is one that is commercially available from Corning Inc. under the product designation "Glass Code 7440". The anodic junction comprises the application of heat and the simultaneous application of a high voltage through support substrate 54 and heating circuit 60.

A heater circuit module 250, formed according to a second embodiment of the present invention, is shown in Figures 9 and 10, where the reference number is similar and indicated in similar elements. Here, the support substrate 154 is formed having only one passage 152a for each heater circuit 160. The heater circuit 160 comprises a heater circuit of the conventional central location having a central ink receiving path 162. The ink from the container 22 travels through the passage 152a in the support substrate 154 to the path 162. From the path 162, the ink passes through the supply channels 165a in the nozzle plate 170 to the bubble channels 165 defined by the portions of the heating circuit 160 and the sections of the nozzle plate 170. The support substrate 154 can be formed from substantially the same materials from which the substrate 54 of the support is formed in the embodiment of Figure 2. Additionally, the process steps described above for forming the support substrate 54 are also they can be used when the support substrate 154 is formed. However, only one passage 158a is formed through the silicon plate 158 and an opening 159a is formed in the first etch-resistant layer 159 for each heating circuit 160.

The assembly of the components of the heating circuit module 250 can be presented in the following manner. Initially, the nozzle plate 170 is aligned and mounted to the heating circuit 160. Typically, a plurality of heating circuits 160 are formed in a single wafer. In this embodiment, a nozzle plate 170 is mounted to each heater circuit 160 before the wafer is cut. The alignment can take place as follows. One or more first fiduciaries (not shown) can be provided on the nozzle plate 170 that is aligned with one or more fiduciary seconds (not shown) provided in the heater circuit 160. After the nozzle plate 170 is aligned and located in the heating circuit 160, the plate 170 is fixed to the heating circuit 160. The nozzle plate 170 includes one or more openings 177, which, in the embodiment illustrated, are triangular in shape. See figure 10. The openings 177 can be circular, square or have another geometric shape. An ultraviolet (UV) curable adhesive (not shown), such as one that is commercially available from Emerson and Cuming Specialty Polymers, a division of the National Starch and Chemical Company under the product designation UV9000 that applies to openings 177 for contacting both the nozzle plate 170 and the heating circuit 160. subsequently, the adhesive is cured using UV radiation to effect fixation. Each heating circuit 160 in the heating circuit wafer receives a nozzle plate 170 which is fixed to its corresponding heating circuit 160 in this manner. After the fixation has been completed, the nozzle plates 170 are partially attached to the wafer heating circuits 160 of the wafer by curing the layer of the phenolic butyral adhesive provided on the underside of each nozzle plate 170 using for example a conventional process of union by thermocompression. Subsequently, the heating circuit wafer is cut to separate the assemblies of the nozzle plate / heating circuit from each other. After the wafer of the heating circuit has been cut, a flexible circuit 190 is attached to the heating circuit 160 of each nozzle plate / heater circuit assembly. The end sections 192a of the traces 192 in the flexible circuit 190 are joined by TAB to the connecting pads 168 in the heating circuit 160, see Figures 9 and 10. It is also contemplated that the dotted sections can be attached to the pads of joining 168 and to a joining process with wire. However, this wire joining step would more likely occur after the flexible circuit 190 is attached to the separator 156.

Either before or after the nozzle plate 170 is attached to the heating circuit 160, the separator 156 is attached to the support substrate 154 using the same process and adhesive described above for the attachment of the separator 56 to the support substrate 54. An additional adhesive material (not shown), such as a 0.0051 cm (0.02 inch) die-cut phenolic adhesive film that is commercially available from Rogers Corporation under the product designation "1000B200", is placed in a portion 156e of the separator. 156 to which the flexible circuit 190 is to be secured. After the nozzle plate 170 has been attached to the heating circuit 160, the separator 156 has been attached to the support substrate 154 and the phenolic adhesive film has been placed in the separator. 156, the nozzle plate / heater circuit assembly is aligned and fixed to the support / spacer substrate. Initially, the die attachment adhesive 110 is applied to the second outer surface 254b of the support substrate 154 at a location where the heating circuit 160 is to be located. A pair of markers 100, formed on the bottom surface 164a of the heating circuit base 164 on opposite sides of the track 162, then align with the inner edges 158b and 158c of the silicon plate 158. The edges 158b and 158c define an outer edge of passage 152a. The nozzle plate / heater circuit assembly is fixed to the support / spacer substrate assembly to hold the two assemblies together until the die attachment adhesive 110 is cured. Before the nozzle plate / heater circuit assembly is mounted on the support / spacer substrate assembly, a conventional ultraviolet (UV) curable adhesive (not shown), such as one that is commercially available from Emerson and Cuming Specialty Polymers, a division of the National Starch and Chemical Company under the product designation UV9000 is applied to one or more applications on the support substrate 154 where the corners of the heating circuit 160 are to be placed. After the assembly is assembled From nozzle plate / heater circuit to support / spacer substrate assembly, the exposed adhesive is cured using ultraviolet radiation to effect fixation. Once the nozzle plate / heater circuit assembly is mounted to the support / separator substrate assembly, the flexible circuit 190 contacts the phenolic adhesive film placed on the separator 156. The flexible circuit 190 is fixed to the separator 156. using a conventional thermocompression bonding apparatus.

Then, the nozzle plate / heater circuit assembly and the support / separator substrate assembly are heated in a furnace at a temperature and for a sufficient time to effect the curing of the following materials: the phenolic adhesive film joining the flexible circuit 190 to the separator 156 and the die attachment adhesive 110 joining the heating circuit 160 to the support substrate 154. A liquid encapsulating material (not shown) such as a UV curable adhesive, one which is commercially available from Emerson and Cuming Specialty Polymers, a division of the National Starch and Chemical Company under the product designation UV9000, is then applied over the stroked end sections 192a and the pads 168.

Subsequently, the UV adhesive is cured using UV light. The heating circuit module 250, comprising the nozzle plate / heater circuit assembly and the support / spacer substrate assembly, and to which the flexible circuit 190 is fixed, is aligned and directly attached to the polymer container 22. adhesive (not shown), such as one that is commercially available from Emerson and Cuming Specialty Polymers, a division of the National Starch and Chemical Company under the product designation "ECCOBOND 3193-17" is applied to a portion of the container where it is going to locate the module 250. The module 250 is then mounted to the container portion. Then, the heating circuit module 250 and the container 22 are heated in an oven at a temperature and for a sufficient time to effect the curing of the adhesive joining the module 250 of the heating circuit to the container 22. A portion of the flexible circuit 190 that is not attached to the separator 156 is attached to the container 22 for example, by a conventional film of pressure sensitive adhesive, of free standing. It is also contemplated that the flexible circuit 190 may be coupled to the connecting pads 168 in the heating circuit 160 after the nozzle plate / heater circuit assembly is secured to the support / spacer substrate assembly. It is further contemplated that the nozzle plate 70, 170 may be coupled to the heater circuit 60, 160 after the heater circuit 60, 160 is bonded to the support substrate 54, 154. Because a substantial portion 58 of the support substrate 54, 154 is formed from a material having substantially the same coefficient of thermal expansion as the base 64, 164 of the heating circuit, the base 64, 164 of the heating circuit and the substrate 54, 154 expand and contract essentially to the same proportion. This is advantageous for several reasons. First, the bonding material that binds the heating circuit to the carrier is less likely to fail. Additionally, if two or more heater circuits are secured to the carrier, the accuracy of the placement of the points is increased since the location of the heater circuits is less likely to vary with respect to the paper. The support substrate portion 58 is also formed from a material having a thermal conductivity that is substantially the same as the thermal conductivity of the material from which the base 64, 164 of the heating circuit is formed. Therefore, the carrier provides a dissipation path for the heat generated by the heating circuit. As a result, heat buildup in the heating circuit, which could occur if the thermal conductivity of the supporting substrate portion is less than that of the base of the heating circuit, is prevented. The portion of the support substrate can also be formed from a material having a thermal conductivity that is greater than the thermal conductivity of the material from which the base of the heating circuit is formed. Additionally it is contemplated that the support substrate may be formed from a commercially available chemical vapor deposition diamond (CVD) wafer. The CVD diamond wafer material has a coefficient of thermal expansion that is approximately equal to that of silicon. Additionally, it has a thermal conductivity that is greater than silicon. This material is commercially available from Norton Diamond Film of Northboro, MA. Having described the present invention, it is considered as a novelty and, therefore, the content of the following is claimed as property:

Claims (24)

1. NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following CLAIMS is claimed as property: 1. A process for forming a heating circuit assembly / jet support substrate. ink, comprising the steps of: providing a support substrate; forming at least one passage in the support substrate; providing a heating circuit having a first alignment marker formed on a lower surface of the circuit; aligning the alignment marker in the circuit with an alignment portion of the support substrate; securing the heating circuit aligned to the support substrate. A process for forming a heater circuit / ink jet support substrate assembly according to claim 1, wherein the alignment portion of the support substrate comprises an edge on the support substrate defining an outer edge of the substrate. passage and the alignment step comprises the step of aligning the alignment marker in the circuit with the edge on the support substrate. 3. A process for forming a heater circuit / ink jet support substrate according to claim 1, wherein the alignment portion of the support substrate comprises a second alignment marker formed on the support substrate and the step of alignment comprises aligning the first marker with the second marker. . A process for forming an ink jet heating circuit module comprising the steps of: providing a carrier including a support substrate having at least one passage extending through the support substrate; providing a heating circuit having a first alignment marker formed on the lower surface of the heating circuit; provide a nozzle plate; securing the nozzle plate to the heating circuit; aligning the alignment marker in the heating circuit with an alignment portion of the support substrate; and securing the heating circuit aligned to the support substrate. A process for forming an ink jet heating circuit module according to claim 4, wherein the alignment portion of the support substrate comprises an edge on the support substrate defining an outer edge of the passage and the passage of alignment comprises aligning the alignment marker in the circuit with the edge of the support substrate. A process for forming an ink jet heating circuit module according to claim 4, wherein the alignment portion of the support substrate comprises a second alignment marker formed on the support substrate and the alignment step comprises Align the first marker with the second marker. A process for forming an ink jet heating circuit module according to claim 4, wherein the step of providing a carrier includes a support substrate having at least one passage comprising the steps of: providing a plate of silicon having first and second outer surfaces; ^ forming a first layer of etch-resistant material on the first plate surface, the first layer including at least one opening extending through the first layer; and forming a second layer of etch-resistant material on the second plate surface. 8. A process for forming an ink jet heating circuit module according to claim 7, wherein the step of providing a carrier including a support substrate having at least one passage further comprises the step of forming at least one a passage through the silicon plate that communicates with the opening in the first layer. 9. A process for forming an ink jet heating circuit module according to claim 8, wherein the step of forming at least one passage through the silicon plate comprises the step of etching the acid through the silicon plate from an exposed portion of the first outer surface of the silicon plate to the silicon plate. second layer resistant to acid etching such that the passage has a shape converging inward from the first outer surface of the silicon plate to the second outer surface of the silicon plate. A process for forming an ink jet heating circuit module according to claim 8, wherein the step of forming at least one passage through the silicon plate comprises the step of etching the acid through the Silicon plate from an exposed portion of the first outer surface of the silicon plate using an acid etching solution of tetramethylammonium hydroxide. A process for forming an ink jet heating circuit module according to claim 8, wherein the step of forming at least one passage through the silicon plate comprises the step of etching the acid through the silicon plate from an exposed portion of the first outer surface of the silicon plate using an acid etching solution of potassium hydroxide. 12. A process for forming an ink jet heating circuit module according to claim 4, wherein the step of providing a carrier including a support substrate having at least one passage further comprises the steps of: providing a separator; and securing the separator to the support substrate, the separator having an opening defined by the interior side walls, the support substrate having a first and a second exterior surfaces, a section of the second exterior surface of the support substrate and the walls lateral interiors of the separator defining an interior cavity of the carrier, the heating circuit that is placed in the interior cavity and at least one passage communicating with the interior cavity. 13. A process for forming an ink jet heating circuit module according to claim 12, wherein the step of providing a heating circuit comprises the step of providing a central supply heating circuit. A process for forming an ink jet heating circuit module according to claim 12, wherein the step of providing a heating circuit comprises the step of providing an edge feeding heater circuit. A process for forming an ink jet heating circuit module comprising the steps of: providing a carrier including a support substrate having at least one passage extending therethrough, at least one position of the substrate of support that is formed of silicon; provide a heater circuit; provide a nozzle plate; securing the nozzle plate to the heating circuit; and securing the heating circuit to the support substrate. 16. A process for forming an ink jet heating circuit module according to claim 15, wherein the step of providing, wherein the step of providing a carrier including a support substrate having at least one passage that extends through this comprises the steps of: providing a silicon plate having first and second outer surfaces; forming a first layer of etch-resistant material on the first plate surface, the first layer including at least one opening extending through the first layer; and forming a second layer of etch-resistant material to the second surface of the plate. A process for forming an ink jet heating circuit module according to claim 16, wherein the step of providing a carrier including a support substrate having at least one passage extending therethrough comprises , in addition, the step of forming at least one passage through the silicon plate communicating with the opening in the first layer. 18. A process for forming an ink jet heating circuit module according to claim 17, wherein the step of forming at least one passage through the silicon plate comprises the step of etching the acid through the silicon plate from an exposed portion of the first outer surface of the silicon plate to the second etch-resistant layer such that the passage has a shape converging inwardly from the first outer surface of the silicon plate to the second outer surface of the silicon plate. A process for forming an ink jet heating circuit module according to claim 17, wherein the step of forming at least one passage through the silicon plate comprises the step of etching the acid through the Silicon plate from an exposed position of the first outer surface of the silicon plate using an acid etching solution of tetramethyl ammonium hydroxide. A process for forming an ink jet heating circuit module according to claim 17, wherein the step of forming at least one passage through the silicon plate comprises the step of etching the acid through the Silicon plate from an exposed position of the first outer surface of the silicon plate using an acid etching solution of potassium hydroxide. A process for forming an ink jet heating circuit module according to claim 16, wherein the step of providing a carrier including a support substrate having at least one passage extending therethrough comprises , further, the steps of: forming at least one passage through the silicon plate communicating with the opening in the first layer; and forming at least one opening in the second layer communicating with at least one passage. 22. A process for forming an ink jet heating circuit module according to claim 15, wherein the step of providing a carrier including a support substrate having at least one passage further comprising the steps of : provide a separator; and - securing the spacer of the support substrate, the spacer having an opening defined by inner side walls, the support substrate having a first and a second outer surface, a section of the second outer surface of the supporting substrate and the walls lateral interiors of the separator defining an interior cavity of the carrier, the heating circuit is deposited in the interior cavity and at least one passage communicating with the interior cavity. 23. A process for forming an ink jet heater circuit module according to claim 22, wherein the step of providing a heater circuit comprises the step of providing a heater power supply circuit. 24. A process for forming an ink jet heating circuit module according to claim 22, wherein the step of providing a heating circuit comprises the step of providing an edge feeding heater circuit.