Patent Publication Number: US-7585052-B2

Title: Topography layer

Description:
BACKGROUND 
   A primer layer disposed between two layers may promote adhesion between the two layers. A primer layer disposed between two layers may also be used to reduce stress between the two layers. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The embodiments of a primer layer can be better understood with reference to the following drawings showing an embodiment of an inkjet printing system. The elements of the drawings may not be to scale relative to each other. Rather, emphasis has instead been placed upon clearly illustrating the embodiments of the primer layer in the embodiment of an inkjet printing system. Certain dimensions have been exaggerated in relation to other dimensions in order to provide a clearer illustration and understanding of the present disclosure. Furthermore, like reference numerals designate corresponding similar parts through the several views. 
       FIG. 1  shows a cross sectional diagram of layers deposited on a substrate according to an exemplary embodiment of an inkjet printing system. 
       FIG. 2  illustrates a cross sectional diagram of a primer layer over the layers and the substrate according to an exemplary embodiment of an inkjet printing system. 
       FIG. 3  shows a cross sectional diagram of an exposed primer layer according to an exemplary embodiment of an inkjet printing system. 
       FIG. 4  shows a cross sectional diagram of a developed primer layer according to an exemplary embodiment of an inkjet printing system. 
       FIG. 5   a  illustrates a cross sectional diagram of a chamber layer over the developed primer layer showing a relatively small surface topography according to an exemplary embodiment of an inkjet printing system. 
       FIG. 5   b  illustrates a cross sectional diagram of a chamber layer over an unpatterned primer layer showing a relatively large surface topography according to an exemplary embodiment of an inkjet printing system.  FIG. 5   b  is provided in contrast to  FIG. 5   a  as an exemplary embodiment of an inkjet printing system showing a non-reduced surface topography. 
       FIG. 6  shows a cross sectional diagram of an exposed chamber layer according to an exemplary embodiment of an inkjet printing system. 
       FIG. 7  illustrates a cross sectional diagram of a developed chamber layer according to an exemplary embodiment of an inkjet printing system. 
       FIG. 8  shows a cross sectional diagram of a wax layer over a developed chamber layer according to an exemplary embodiment of an inkjet printing system. 
       FIG. 9  illustrates a cross sectional diagram of an exemplary embodiment of a thermal inkjet printing system after chemical mechanical polishing (CMP) according to an exemplary embodiment of an inkjet printing system. 
       FIG. 10  shows a cross sectional diagram of a nozzle layer over a CMP wax filled chamber layer according to an exemplary embodiment of an inkjet printing system. 
       FIG. 11  illustrates a cross sectional diagram of an exposed nozzle layer according to an exemplary embodiment of an inkjet printing system. 
       FIG. 12  shows a cross sectional diagram of a developed nozzle layer according to an exemplary embodiment of an inkjet printing system. 
       FIG. 13  illustrates a cross sectional diagram of an etched substrate according to an exemplary embodiment of an inkjet printing system. 
       FIG. 14  shows a flow diagram having procedural acts for making an inkjet print-head according to an exemplary embodiment of an inkjet printing system. 
   

   DESCRIPTION 
   Primer layers can be useful in promoting adhesion between two layers. An example without a primer layer may occur where, a first layer may be a substrate and the second layer may be a protective overcoat. If the overcoat is applied to the substrate, the overcoat may peel, delaminate, blister, etc. 
   Separation of the overcoat from the substrate may be due to physical, chemical, or other types of incompatibilities between two materials. Also, the separation may be due to thermal cycling whereby the substrate and the overcoat expand at different rates. Thermal cycling may occur during manufacture of a product, use of the product, and the like. Separation may also be due to other factors. 
   A primer layer may be used as an intermediate layer between a substrate and a protective overcoat. The primer can have adhesion properties which are compatible with both the substrate and the protective overcoat thereby increasing the overall bond strength between the substrate and the protective overcoat. Increased bond strength may result in less peeling, blistering, delamination, etc. of the protective overcoat from the substrate. The intermediate primer layer can also serve to limit the interfacial stress between the substrate and the protective overcoat. Distributing the stress through the primer layer may also reduce the peeling, blistering, delamination, and the like. 
   In some embodiments, conductive and/or dielectric films may be deposited on the surface of a substrate, for example, in an integrated circuit. The films on the substrate may form topography. Adding a primer layer to a surface may promote adhesion and absorb stress, although primer layers over a surface may not substantially reduce surface topography. In some situations, it may be desirable to create a coating which does not substantially translate the topography of a film on a substrate to the topography of a surface layer, which may result in a substantially planar top surface. For instance, in an inkjet print-head, a relatively flat planar surface topography allows ejected ink from spatially arranged nozzles to strike paper with less misdirection. An inkjet print-head may be formed from an integrated circuit which may have topographical variations. Reducing topographical variations in a subsequent layer, such as an orifice layer over the integrated circuit can control the directionality of the ejected ink thereby increasing print quality and reducing the likelihood that the ink will mix. 
   For at least these reasons, it is desirable to retain the stress absorbing and adhesion promoting properties of a primer layer while also using the primer layer to aid in surface planarization thereby reducing topographical surface variations. 
   Exemplary embodiments which aid planarization using a primer layer while retaining the adhesion and stress reducing properties of the primer layer are described in reference to the following figures. 
     FIG. 1  shows a cross sectional diagram of layers deposited on a substrate  102  according to an exemplary embodiment of an inkjet printing system. The layers may be thin film layers such as, but not limited to, thin film layers deposited by vacuum deposition. A substrate  102  forms the basis for an inkjet print-head. The substrate  102  may be silicon, silicon carbide, aluminum oxide, gallium arsenide, germanium, glass or another type of material useful in the formation of an inkjet print-head. The silicon substrate may selectively doped. The silicon substrate may be n-doped with phosphorus, p-doped with boron or doped with other materials. The doping may be by diffusion, ion implantation, or by other methods. Glass or other substrates may have amorphous semiconductors, conductors, dielectric layers, solution based compositions, or combinations thereof thereon. 
   Semiconducting, dielectric and conducting layers may form control logic  108  on the substrate  102 . The control logic  108  serves to command a drop of ink from an inkjet print-head. The control logic  108  may contain: transistors formed from doped semiconductors; interconnects formed from conductors such as aluminum and gold; and insulating layers formed from dielectric materials such as oxides of silicon, silicon carbide, silicon nitride and the like. 
   An ejector  104  may be used to eject ink from an inkjet print-head. The ejector  104  may be formed from a heater resistor in the case of a thermal inkjet print-head, a piezoelectric drive element in a piezoelectric inkjet print-head, an electromechanical drive element, or other types of drive elements. A transistor (not shown) in the control logic  108  may turn on and off the ejector  104 . A thermal inkjet heater resistor may be formed from tantalum, aluminum, tungsten, alloys of tantalum, aluminum, tungsten, or other types of materials or alloys. 
   Connector  106  serves to conduct current and voltage from the thin film control logic  108  to the ejector  104 . Connector  106  may have electrical conductors such as aluminum and may have electrical dielectrics such as silicon nitride, silicon carbide, and other oxides of silicon. The dielectrics may serve as electrical insulators between electrical conductors and also to passivate the electrical conductors, thereby protecting the electrical conductors from corrosion of ink. Tantalum can be applied to the electrical conductors and may aid adhesion. Tantalum may also be used for cavitation protection on the ejector  104 . The ejector  104 , connector  106 , and control logic  108  may all together be considered a first layer  110  having a topography on a substrate  102 . 
     FIG. 2  illustrates a cross sectional diagram of a primer layer  202  coating over a substrate  102 , control logic  108 , connector  106  and ejector  104  according to an exemplary embodiment of an inkjet printing system. The primer layer  202  coating may be an epoxy based photoresist and may be coated as a liquid, a solid, or in vapor form. A liquid primer layer  202  may be spun on, sprayed on, or applied by other methods to form a coating. A solid film primer layer  202  may be rolled on to form a coating. The primer may be volatilized into a vapor and condensed to form a coating. Other methods of applying a primer layer  202  may also be used to form a coating. The primer layer  202  may be about 4 microns thick, although other thicknesses may be used. The foregoing examples are intended to describe the application of the primer layer  202 , substances used for the primer layer  202 , and processes used to apply the primer layer  202 . Thus, these examples are therefore not limited. The primer layer  202  may be used to increase adhesion and reduce stress between the under layer and a subsequently applied over layer. The primer layer  202  may be considered a second layer. 
     FIG. 3  shows a cross sectional diagram of an exposed primer layer  202  according to an exemplary embodiment of an inkjet printing system. The primer layer  202  is selectively exposed to radiation  302  and may form features in the primer layer  202 . The selective exposure of the primer layer  202  to radiation  302  may be accomplished by use of a primer mask  304 . A primer mask  304  may be made of a transparent substrate  306  such as, but not limited to, glass, and a blocking layer  308 , such as, but not limited to, chrome. The primer mask  304  allows radiation  302  to pass through areas that are not blocked by a blocking layer  308  thereby radiating into exposed primer areas  310  of primer layer  202 . The primer layer  202  under the blocking layer  308  is not exposed to radiation  302 . The radiation  302  may be ultraviolet radiation. Upon exposure to radiation  302 , the exposed primer areas  310  of the primer layer  202  are crosslinked by the radiation  302  and become at least partially cured. The primer thus may serve as a negative acting photoresist. 
   Three exposed primer areas  310  are shown between the connectors  106  for illustrative purposes. There may be more or less than three exposed primer areas  310  between the connectors  106 . The exposed primer areas  310  between the connectors  106  may form the base of pillars. The pillars may be circular shaped, square shaped, rectangular shaped or have another shape. The pillars may serve to filter particles from ink in an inkjet print-head. The pillars may also serve to filter particles from a liquid in an inkjet print-head. The liquid may be ink, but is not limited to ink. The liquid may be a chemical binder, a chemical fixer, an assay, and the like. 
   However, the exposed primer areas  310  may be located in other areas. Thus the exposed primer areas  310  are not restricted to being placed between the connectors  106 . For example, the exposed primer areas  310  may be located on a portion of a substrate  102  which does not have control logic  108  or other features such as a layer of tantalum and gold which may be used on a print-head for passivation purposes. In one embodiment of a print-head, the height of tantalum and gold is about 1.7 microns. Thus, exposed primer areas  310  may be formed on a portion of the substrate  102  where tantalum and gold is absent in order to aid in planarizing the thickness of subsequent layers. In other words, the exposed primer areas  310  may be used to compensate for the thickness of the tantalum and gold layers in areas where tantalum and gold is not present. 
   In one embodiment of a print-head, the exposed primer areas  310  to compensate for the about 1.7 micron height of tantalum and gold are circular shaped with a diameter of about 39 microns and a thickness of about 4 microns. The circular shaped structure having a thickness forms a cylinder. One or more of these cylinders may be placed adjacent to each other in areas where tantalum and gold is absent. 40 percent of the area may be uniformly filled with the cylinders. This 40 percent area fill may be used to compensate for the thickness of a tantalum and gold layer in areas where tantalum and gold is not present. 
     FIG. 4  shows a cross sectional diagram of a developed primer layer according to an exemplary embodiment of an inkjet printing system. The primer layer  202  which has not been exposed to radiation due to the blocking layer  308  on the mask  304  is not crosslinked, and can be rinsed away by a developer solution such as ethyl lactate. The at least selectively exposed primer areas  310  are at least partially cured, and therefore are not developed away by the developer solution. Hence, the selectively exposed primer areas  310  remain and become patterned primer features  402  in the primer layer  202 . The patterned primer features  402  between the connectors  106  may form the base of pillars. The pillars may be circular shaped, square shaped, rectangular shaped or have another shape. The pillars may serve to filter particles from ink in an inkjet print-head. 
   However, the patterned primer features  402  may be located in other areas. Thus the patterned primer features  402  are not restricted to being placed between the connectors  106 . For example, the patterned primer features  402  may be located on a portion of a substrate  102  which does not have control logic  108  or other features such as a layer of tantalum and gold which may be used on a print-head for passivation purposes. In one embodiment of a print-head, the height of tantalum and gold is about 1.7 microns. Thus, patterned primer features  402  may be formed on a portion of the substrate  102  where tantalum and gold is absent in order to aid in planarizing the thickness of subsequent layers. In other words, the patterned primer features  402  may be used to compensate for the thickness of the tantalum and gold layers in areas where tantalum and gold is not present. 
   In one embodiment of a print-head, the patterned primer features  402  compensate for the about 1.7 micron height of the tantalum and gold and are circular shaped with a diameter of about 39 microns and a thickness of about 4 microns. The circular shaped structure forms a cylinder. One or more of these cylinders may be placed side by side where about 40 percent of the area lacking tantalum and gold is uniformly filled with the cylinders. This 40 percent area fill may be used to compensate for the thickness of a tantalum and gold layer in areas where tantalum and gold is not present. 
   The patterned primer features  402  partially cover the control logic  108  and the connector  106  layers. The patterned primer features  402  may overlap the connector layers  106  and the control logic  108  a lateral distance (D 1 )  404  and (D 2 )  406  respectively. These lateral distances (D 1 )  404  and (D 2 )  406  may be different. If the lateral distance (D 2 )  406  is greater than about 10 times the thickness of a height difference (D 3 )  408  then the stress within the patterned primer feature  402  and the stress of subsequent layers at the topographical boundary interface may be reduced. As an example, a topographical boundary occurs between the substrate  102  and the control logic  108  layer as indicated by the height difference (D 3 )  408  of the topographical boundary. 
   This partial coverage of the patterned primer feature  402  having a lateral distance (D 2 )  406  can increase the interfacial adhesion and reduce stress within the patterned primer features  402 . The partial coverage having a lateral distance (D 2 )  406  may also reduce the stress between the control logic  108  layer and a subsequent layer applied over the control logic  108  layer. Similarly, the partial coverage of the patterned primer features  402  may increase interfacial adhesion and reduce stress within the patterned primer features  402  and between the connector  106  layer and a subsequent layer applied over the connector  106  layer. 
   Another stress reduction technique is to overlap the control logic  108  with the patterned primer features  402  a lateral distance (D 2 )  406  of at least 3 times the thickness (D 4 )  410  of the patterned primer features  402 . The lateral distance (D 2 ) extends from an exposed boundary  412 . As an example, the thickness (D 4 )  410  of the patterned primer features  402  can be 4 microns. Therefore, the overlap lateral distance (D 2 )  406  of the patterned primer feature  402  is 3 times 4 microns, or 12 microns. The overlap lateral distance (D 2 )  406  can also be 10 times the thickness (D 4 )  410  of the patterned primer features  402  to provide more stress reduction. Furthermore, the overlap lateral distance (D 2 )  406  can be 15 times the thickness (D 4 )  410  of the patterned primer features  402 . Increasing the overlap lateral distance (D 2 )  406  from 10 to 15 times the thickness (D 4 )  410  of the patterned primer features  402  may not proportionally increase stress reduction, but can provide margin. Similarly connector  106  may be overlapped with the patterned primer features  402 . The overlap lateral distance extends from an exposed boundary  412 . The overlap lateral distance (D 1 )  404  ranges from about 3 to 15 times the thickness (D 4 )  410  of the patterned primer features  402 . 
   Yet another stress reduction technique is for patterned primer features  402  to have a lateral distance (D 5 )  414  which is at least 3 times greater than the thickness (D 4 ) of the patterned primer feature  402 . The lateral distance (D 5 ) may be 15 times greater than the thickness (D 4 ) to provide for margin. 
   These techniques of stress reduction may be applied to high stress areas within an inkjet print-head. Other areas in an inkjet print-head which are not subject to high stresses such as the patterned primer features  402  between the connectors  106  may not apply this stress reduction technique. 
     FIG. 5   a  illustrates a cross sectional diagram of a chamber layer  502   a  coating over the patterned primer features  402  according to an exemplary embodiment of an inkjet printing system showing reduced surface topography. The chamber layer  502   a  has a relatively small peak-to-valley height (H 1 )  504   a  of about 0.3 microns on an inkjet print-head. This relatively small peak-to-valley height (H 1 )  504   a  decreases the amount of chemical mechanical polishing (CMP) planarization in a subsequent process step thereby saving time and processing materials. The chamber layer  502   a  may be considered a third layer. 
   A chamber layer  502   a  is deposited over the patterned primer features  402 . The chamber layer  502   a  may be about 15 microns thick; however other thicknesses may be used. The chamber layer  502   a  is used to form a cavity  702  as shown in  FIG. 7  which serves as an ink reservoir over the ejector  104 , whereby the ejector  104  jets ink from the formed cavity  702 . The chamber layer  502   a  may be an epoxy based photoresist and may be coated as a liquid, a solid, or a vapor. A liquid chamber layer  502   a  may be spun on, sprayed on, or applied by other methods. A solid film chamber layer  502   a  may be rolled on. The chamber layer  502   a  may be vaporized and condensed on. Other methods of coating a chamber layer  502   a  may also be used. The foregoing examples are intended to describe application of the chamber layer  502   a , substances used for the chamber layer  502   a , and methods used to apply the chamber layer  502   a , and therefore are not limiting. 
   If the patterned primer features  402  are spaced apart with a first spacing (S 1 )  506  of about 250 microns or less, then the chamber layer  502   a  coats the patterned primer features  402  relatively uniformly. The first spacing (S 1 )  506  is the distance between the patterned primer features  402 . The first spacing (S 1 )  506  between the patterned primer features  402  may be about 4 microns. Tests have shown that if the distance between the patterned primer features  402  is about 4 microns, a subsequent layer—such as the chamber layer which is over the patterned primer features  402 —can planarize the surface of the subsequent layer to less than 0.3 microns. The patterned primer features  402  may be spaced apart about 10 to 12 microns and can result in a subsequent surface planarity of about 0.3 microns. 
   The patterned primer features  402  translate to reduced surface topography of the chamber layer  502   a  and therefore can substantially reduce the amount of subsequent chemical mechanical polishing (CMP) processing. As an example,  FIG. 5   a  shows a relatively small peak-to-valley height (H 1 )  504   a  of 0.3 microns. The relatively small peak-to-valley height (H 1 )  504   a  decreases the amount of CMP planarization and can save time and processing material. 
   The patterned primer features  402  between the connectors  106  when spaced apart about 10 microns to 12 microns may trap particles embedded in ink. If particles in the ink are not trapped, the particles may clog nozzles and reduce print quality. The patterned primer features  402  may thus serve to create a filter for ink particles thereby creating a particle tolerant architecture for a print-head. The use of ink is not limiting since an inkjet print-head may also use other fluids or liquids. The patterned primer features  402  serving to trap particles are shown in  FIG. 13 . Although three patterned primer features  402  are shown between the conductors  106 , more or less than three patterned primer features  402  may be used. The patterned primer features  402  between the conductors  106  may be pillars. 
     FIG. 5   b  illustrates a cross sectional diagram of a chamber layer  502   b  over a primer layer  202  according to a prior art exemplary embodiment of an inkjet printing system.  FIG. 5   b  is provided in contrast to  FIG. 5   a  as an exemplary embodiment of a prior art inkjet printing system showing a relatively large surface topography. The relatively large surface topography results from the primer layer  202  being removed from areas between the connectors  106 , and not being removed in areas over the control logic  108  and the connectors  106 . 
   The primer layer  202  is spaced apart by a second spacing (S 2 )  508  so that ink may be fed through the etched away area  1304  of substrate  102  as shown in  FIG. 13 . An ink feed hole may have a second spacing (S 2 )  508  up to 1 millimeter or more. The primer layer  202  in  FIG. 2  is exposed, and developed to form the second spacing (S 2 )  508  in  FIG. 5 . The primer layer  202  in  FIG. 2  is also exposed and developed to remove the primer above the ejector  104  such that ink may be allowed to come in contact with the ejector. 
   The measured peak-to-valley height (H 2 )  504   b  of chamber layer  502   b  on an inkjet print-head having spacing (S 2 )  508  is about 3 microns. This relatively large peak-to-valley height (H 2 )  504   b  of 3 microns increases the amount of subsequent chemical mechanical polishing (CMP) to planarize the inkjet print-head. 
   The ratio of the peak-to-valley height (H 2 )  504   b  relative to the peak-to-valley height (H 1 )  504   a  is; 3 microns divided by 0.3 microns or 10. Therefore, patterned primer features  402  have reduced the surface topography of chamber layer  502  about 10 times. The chamber layer  502  may be considered a third layer. 
     FIG. 6  shows a cross sectional diagram of an exposed chamber layer according to an exemplary embodiment of an inkjet printing system. The chamber layer  502   a  may be a negative acting epoxy based photoresist. Radiation  302  exposes the chamber layer  502   a  through a chamber mask  602 . The radiation  302  may be ultraviolet radiation. Exposed chamber areas  604  of the chamber layer  502   a  may become crosslinked by the radiation  302  and can be at least partially cured. 
     FIG. 7  illustrates a cross sectional diagram of a developed chamber layer  704  according to an exemplary embodiment of an inkjet printing system. The exposed chamber areas  604  shown in  FIG. 6  remain intact and thereby become the developed chamber layer  704 . The rest of the chamber layer  502   a  is shown in  FIG. 5   a  but not shown in  FIG. 7  because the rest of the chamber layer  502   a  is selectively developed away by a developer, such as, but not limited to, ethyl lactate. The cavity  702  which is developed away serves as an ink reservoir over ejector  104 . 
     FIG. 8  shows a cross sectional diagram of a wax layer  802  over the exposed and developed chamber areas  704  according to an exemplary embodiment of an inkjet printing system. The wax layer  802  may be formed from a polymer in a solvent and serves to prepare a partially finished print-head assembly  804  for a subsequent chemical mechanical polishing (CMP) process. The wax layer may be spun on or deposited using other methods. The subsequent CMP process polishes away exposed chamber areas  704  to remove the relatively small peak-to-valley height (H 1 )  504   a . In contrast,  FIG. 5   b  shows the relatively large peak-to-valley height (H 2 )  504   b  to be CMP processed. CMP processing the relatively large peak-to-valley height (H 2 )  504   b  takes substantially more time and material than CMP processing the relatively small peak-to-valley height (H 1 )  504   a.    
     FIG. 9  illustrates a cross sectional diagram of an exemplary embodiment of a thermal inkjet print-head after CMP according to an exemplary embodiment of an inkjet printing system. The exposed chamber area  704  is chemical mechanical polished and planarized. Due to the relatively small peak-to-valley height (H 1 )  504   a , a relatively small amount of exposed chamber area  704  material is removed, thereby saving CMP processing time and material. 
     FIG. 10  shows a cross sectional diagram of a nozzle layer  1002  coated over a CMP wax filled layer  802  and an exposed chamber  704  layer according to an exemplary embodiment of an inkjet printing system. The nozzle layer  1002  may be applied as a film, spun on, vapor deposited, or applied by another process. 
     FIG. 11  illustrates a cross sectional diagram of an exposed nozzle layer  1002  according to an exemplary embodiment of an inkjet printing system. Radiation  302  is selectively blocked by nozzle mask  1102  to form unexposed nozzle areas  1104 . The radiation may be an ultraviolet radiation or other types of radiation. 
     FIG. 12  shows a cross sectional diagram of a developed nozzle layer  1002  and a developed wax cavity  1204  according to an exemplary embodiment of an inkjet printing system. A developer such as ethyl lactate may be used to remove the unexposed nozzle areas  1104  as shown in  FIG. 11  and the wax layer  802  as shown in  FIGS. 8 through 11  to form the developed wax cavity  1204 . The wax cavity  1204  serves as a chamber for containing ink so that ejector  104  can fire ink from the nozzle  1206 . In an inkjet print-head, ink is fired from the nozzles  1206 . 
     FIG. 13  illustrates a cross sectional diagram of an etched away area  1304  of a substrate  102  according to an exemplary embodiment of an inkjet printing system. An etch resist mask  1302  may be applied below the substrate  102  to define the etched away area  1304  of the substrate  102 . A dry etch using a plasma, a wet etch using a liquid, or a laser etch may be used. Moreover, the etching may be a combination of wet, dry, or laser etching. Other methods of etching may also be used. In an inkjet printing system, ink fills the etched away area  1304  of the substrate  102 . Other liquids may be used in place of ink. 
     FIG. 14  shows a flow diagram having procedural acts for making an inkjet print-head according to an exemplary embodiment of an inkjet printing system. In act  1402 , an integrated circuit is provided having topography. An integrated circuit may be formed on a substrate  102 . Control logic  108 , connectors  106 , and ejectors  102  may be formed on the substrate as described in reference to  FIGS. 1 through 13 . Layers formed from the control logic  108 , connectors  106 , and ejectors  102  may have, as an example, a topographical height difference (D 3 )  408  causing a height variation at a topographical interface boundary as shown in  FIG. 4 . Layers formed from the control logic  108 , connectors  106 , and ejectors  102  may be considered as a first layer. 
   In act  1404 , a second layer such as the primer layer  202  in  FIG. 2  may be disposed over the integrated circuit having topography. The primer layer may be selectively disposed over the integrated circuit to form patterned primer features  402  as shown by masking, exposing, and developing in  FIGS. 3 and 4 . 
   In act  1406 , a third layer such as a chamber layer  502   a  may be disposed over the second layer as shown in  FIG. 5   a . The second layer may have a reduced surface topography (H 1 )  504   a  in  FIG. 5   a  in contrast with surface topography (H 2 ) in  FIG. 5   b.    
   The present embodiments of an inkjet printing system show cross sections of two inkjet nozzles for illustration and exemplary purposes. It should be appreciated that a multiplicity of inkjet nozzles may be formed in accordance to the information described herein. 
   While the present embodiments of an inkjet printing system have been particularly shown and described, those skilled in the art will understand that many variations may be made therein without departing from the spirit and scope of the embodiments defined in the following claims. The description of the embodiment is understood to include all novel and non-obvious combinations of elements described herein, and claims may be presented in this or a later application to any novel and non-obvious combination of these elements. The foregoing embodiments are illustrative, and no single feature or element would have to be included in all possible combinations that may be claimed in this or a later application. Where the claims recite “a” or “a first” element of the equivalent thereof, such claims should be understood to include incorporation of one or more such elements, neither specifically including nor excluding two or more such elements.