Inkjet head wafer structure method

Abstract

An ink jet head wafer structure comprises a substrate layer which carries elements of the ink jet head wafer structure; a first oxide layer disposed on the substrate layer; a conductive layer disposed on the first oxide layer; the heating resistance layer is configured on the first oxide layer, and the heating resistance layer is adjacent to the contact conducting layer, is located at the same horizontal position and covers part of the surface of the first oxide layer; the dielectric layer covers the first oxide layer and wraps the heating resistance layer and the conductive layer; a control layer partially covering the dielectric layer; and the protective layer covers the dielectric layer and wraps the control layer in the middle. Wherein the control layer is electrically connected with a control transistor and the conductive layer respectively, so that the control transistor controls the heating resistance layer to heat the ink.

Description

Technical Field

[0001] The present invention relates to an inkjet head wafer structure. More specifically, it is an inkjet head wafer structure that improves the structures of the conductive layer and the heating resistance layer therein, thereby increasing the overall structural strength, as well as the electrical and printing performance. Background Art

[0002] Inkjet printing technology, commonly known as "Inkjet Printing", is a widely used printing technology. Its history can be traced back to the 1950s when the British company HP (Hewlett-Packard) invented inkjet printing technology. Since then, inkjet printing technology has developed rapidly, making inkjet printers the mainstream technology for home and commercial printing. Inkjet printers have many advantages, including: low cost, especially having an economic advantage in home and small business applications; high printing quality, which can provide high-resolution and high-quality images, especially in the case of photos or pictures; convenient to use. Inkjet printers are easy to install, and most inkjet printers can be printed through a computer or a mobile device. Combined with the office machines that have emerged in recent years with multi-functional capabilities (including fax, photocopying, scanning), it can quickly expand the flexibility of document operations and packaging printing in offices or any occasion where there is a need.

[0003] The operating principle of an inkjet printer is to spray fine ink dots on paper or a recording medium for text or image output. With the booming development of digital images, it has driven the demand for high-resolution inkjet printing. In order to control more spray dots to provide printing resolution, inkjet head technology has evolved from traditional single-point control to a combination with Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET for short) control. More specifically, please refer to Figure 1 , which shows the inkjet head wafer structure 100 in the current technology. The inkjet head wafer structure 100 generally includes a nozzle 101, a barrier layer 103, a protective layer 104, a conductive layer 105, a heating resistance layer 106, and a thermal barrier layer 107, and they are sequentially formed into a stacked structure to form the inkjet head wafer structure 100. An ink supply chamber 102 is formed between the protective layer 104 and the barrier layer 103. A part of the conductive layer 105 is formed on the heating resistance layer 106, such that the conductive layer 105 contacts the heating resistance layer 106 in a two-layer inclined stepped shape (as shown in the dotted circular frame in Figure 1 ). Therefore, the heating resistance layer 106 can generate bubbles by heating the ink through the electric energy supplied by the conductive layer 105, and finally eject the ink in the ink supply chamber 102 through the nozzle 101.

[0004] However, the drawback of the inkjet head wafer structure 100 of the current technology lies in that during the manufacturing process, the conductive layer 105 and the heating resistance layer 106 are sputtered successively after the corresponding MOSFET control elements are completed, and then the required dimensions and patterns are defined by the yellow light and etching processes. During the process of defining the dimension range, the above-mentioned two-layer inclined stepped shape will be generated at the junction of the conductive layer 105 and the heating resistance layer 106 due to erosion. This two-layer inclined stepped shape in the inkjet head wafer structure 100 is likely to cause problems such as stress concentration and poor step coverage in the innate structure.

[0005] As mentioned above, further, during the printing process, both the heating resistance layer 106 and the conductive layer 105 in contact with the ink for heating at the bottom layer of the ink supply chamber 102 need to work in an environment of high current, high temperature, mechanical shock, and ink chemical erosion. Since the two-layer inclined stepped structure of the heating resistance layer 106 and the conductive layer 105 itself has a problem of poor physical mechanical strength, it is likely to generate cracks or holes at the stepped junction in practice, further causing the nearby protective layer 104 to rupture, enabling the ink to penetrate into the inkjet head wafer, resulting in component damage, and leading to poor service life or reliability of the existing inkjet head wafer structure 100, thus directly affecting the performance during inkjet printing. Therefore, in the current market, there is still an urgent need to improve the structure of the known inkjet head wafer structure 100. Summary of the Invention

[0006] For the above reasons, the object of the present invention is to improve the two-layer inclined stepped structure at the junction of the heating resistance layer and the conductive layer in the heating architecture of the existing inkjet head wafer. By integrating the above two on the same layer of material, the step phenomenon can be eliminated when the protective layer is subsequently configured, thereby improving its mechanical strength, service life, and reliability. In addition, the present invention simultaneously combines the improved and integrated structure with the MOSFET control element, so that the printing performance of the inkjet head wafer structure, such as subsequent encryption identification, control of the number of nozzles for simultaneous printing, printing mode processing, vividness control, and saturation control, can be further improved due to better structural integration, and it can more effectively reduce the requirements of the manufacturing process and additional manufacturing costs. The detailed technical proposal will be described in detail later.

[0007] To achieve the above object, the present invention provides an inkjet head wafer structure, comprising: a substrate layer for carrying components of the inkjet head wafer structure; a first oxide layer disposed on the substrate layer; a conductive layer disposed on the first oxide layer; a heating resistor layer disposed on the first oxide layer, wherein the heating resistor layer is adjacent to and in the same horizontal position as the conductive layer and covers a partial surface of the first oxide layer; a dielectric layer covering the first oxide layer and encapsulating the heating resistor layer and the conductive layer therein; a control layer partially covering the dielectric layer; a protective layer covering the dielectric layer and encapsulating the control layer therein; wherein the control layer is electrically connected to the conductive layer and a control transistor respectively, enabling the control transistor to control the heating of ink by the heating resistor layer during printing.

[0008] According to the content of the present invention, the above control transistor is a metal-oxide-semiconductor field-effect transistor (MOSFET), and the control transistor can be selected from an N-type metal-oxide-semiconductor field-effect transistor (N-MOSFET) or a P-type metal-oxide-semiconductor field-effect transistor (P-MOSFET).

[0009] According to the content of the present invention, the inkjet head wafer structure includes a plurality of contact layers disposed on the conductive layer and the control transistor and electrically connected to the control layer, enabling the control transistor to control the heating of ink by the heating resistor layer during printing.

[0010] According to the content of the present invention, when the control transistor is a MOSFET, the control transistor includes a source electrode, a drain electrode, and a gate electrode. The source electrode and the drain electrode are embedded in the substrate layer, and the gate electrode is disposed on the substrate layer and connected to the source electrode and the drain electrode to control the operation of the control transistor.

[0011] According to the content of the present invention, the gate electrode further includes a second oxide layer and a polysilicon layer, which are sequentially stacked on the substrate layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The following detailed description of the present invention and the schematic diagrams of the embodiments should enable the present invention to be more fully understood; however, it should be understood that this is only for reference in understanding the application of the present invention and does not limit the present invention to a specific embodiment.

[0013] Figure 1 Showing the inkjet head wafer structure in the prior art.

[0014] Figure 2 Explaining the stacked structure of the inkjet head wafer of the present invention.

[0015] Figure 3 Explaining how the conductive layer and the heating resistor layer are integrated in the present invention to avoid the drawbacks of the two-layer inclined stepped structure in the prior art.

[0016] SYMBOL DESCRIPTION

[0017] 100: Inkjet head chip structure

[0018] MJ24A-1325CN_24A459 1TWCN_Chinese Simplified version 101: Inkjet orifice

[0019] 102: Ink supply chamber

[0020] 103: Barrier layer

[0021] 104: Protective layer

[0022] 105: Conductive layer

[0023] 106: Heating resistance layer

[0024] 107: Thermal barrier layer

[0025] 200: Inkjet head chip structure

[0026] 201: Substrate layer

[0027] 202: First oxide layer

[0028] 203: Dielectric layer

[0029] 204: Conductive layer

[0030] 205: Heating resistance layer

[0031] 206: Connection layer

[0032] 207: Control layer

[0033] 208: Protective layer

[0034] 208A: First protective layer

[0035] 208B: Second protective layer

[0036] 209: Control transistor

[0037] 209A: Second oxide layer

[0038] 209B: Polysilicon layer

[0039] S: Source

[0040] D: Drain

[0041] G: Gate Detailed implementation manners

[0042] The present invention will be described in detail with preferred embodiments and viewpoints. The following description provides specific implementation details of the present invention to enable readers to thoroughly understand the implementation methods of these embodiments. However, those skilled in the art must understand that the present invention can also be implemented without these details. In addition, the present invention can also be applied and implemented through other specific embodiments. The details described in this specification can also be applied based on different requirements, and various different modifications or changes can be made without departing from the spirit of the present invention. Therefore, the present invention will be described with preferred embodiments and viewpoints. Such descriptions are to explain the structure of the present invention and are only used for illustration rather than to limit the scope of the patent application of the present invention. The terms used in the following description will be interpreted in the broadest reasonable manner so that they can be used together with the detailed description of a specific embodiment of the present invention.

[0043] To achieve the goal of improving the prior art, please refer to Figure 2 and Figure 3 , in the present invention, an inkjet head wafer structure 200 with a novel structure is explored, including: a substrate layer 201, which bears the components of the inkjet head wafer structure 200; a first oxide layer 202, which is disposed on the substrate layer 201; a conductive layer 204, which is disposed on the first oxide layer 202; a heating resistance layer 205, which is disposed on the first oxide layer 202, wherein the heating resistance layer 205 is adjacent to and in contact with the conductive layer 204 and is located at the same horizontal position, and covers a part of the surface of the first oxide layer 202; a dielectric layer 203, which covers the first oxide layer 202 and encapsulates the heating resistance layer 205 and the conductive layer 204 therein; a control layer 207, which partially covers the dielectric layer 203; a protective layer 208, which covers the dielectric layer 203 and encapsulates the control layer 207 therein; wherein, the control layer 207 is electrically connected to a control transistor 209 and the conductive layer 204 respectively, so that the control transistor 209 can control the heating of the ink by the heating resistance layer 205 during the printing process. Among them, the above control transistor 209 can be a metal-oxide-semiconductor field-effect transistor (MOSFET). When the control transistor 209 is a MOSFET, the control transistor 209 includes a source S, a drain D, and a gate G. The source S and the drain D are buried in the substrate layer 201, and the gate G is disposed on the substrate layer 201 and connected to the source S and the drain D, thereby controlling the operation of the control transistor 209. Among them, according to an embodiment of the present invention, the gate G further includes a second oxide layer 209A and a polysilicon layer 209B, which are sequentially stacked on the substrate layer 201.

[0044] In an embodiment of the present invention, when the control transistor 209 is a MOSFET, the control transistor 209 can be selected from an N-type metal-oxide-semiconductor field-effect transistor (N-MOSFET) or a P-type metal-oxide-semiconductor field-effect transistor (P-MOSFET). And when the inkjet head wafer structure 200 contains multiple control transistors 209, the MOSFETs described in the present invention can also be any combination of N-MOSFETs or P-MOSFETs.

[0045] In an embodiment of the present invention, when the control transistor 209 is a MOSFET, the polysilicon layer 209B of the gate G, the heating resistance layer 205, and the conductive layer 204 can be made of the same material, such as a polysilicon material (Polycrystalline Silicon), but with different doping ratios. According to a viewpoint of the present invention, based on the need to improve the two-layer inclined stepped structure in the heating structure, and the fact that there are still differences in the resistance values of the gate G, the heating resistance layer 205, and the conductive layer 204 that need to be individually adjusted according to actual application requirements, during the manufacturing process of the inkjet head wafer structure 200, by forming the above-mentioned polysilicon material on the first oxide layer 202, then defining the size and position of the polysilicon material by means of photoresist masking to form the heating resistance layer 205, and finally doping the unmasked area of the polysilicon material by ion implantation, ion diffusion or other methods to improve conductivity to form the conductive layer 204, so that the heating resistance layer 205 and the conductive layer 204 are formed simultaneously and are located on the same layer (that is, they are adjacent to each other and are located at the same horizontal position). In this way, the problem of the inclined stepped shape at the junction between the two caused by separate sputtering and etching in the current known structure can be avoided.

[0046] Continuing from the above, please further refer to Figure 3, where the heating resistance layer 205 is the heater area for heating the ink required for inkjet printing. According to an embodiment of the present invention, the conductive layer 204 can be located on the two adjacent sides of the heating resistance layer 205. During the doping process of the polysilicon material, the doping concentration can be in the form of high-low-high to form a structure with better conductivity - higher impedance - better conductivity, that is, the structure of conductive layer 204 - heating resistance layer 205 - conductive layer 204. In this way, the conductive layer 204 and the heating resistance layer 205 can be located on the same layer as described above. When the problem of their inclined stepped shape is eliminated and the mechanical strength is improved, when the subsequent dielectric layer 203 is formed on both of them and wraps them between the first oxide layer 202, it is natural that the adhesion of the dielectric layer 203 and the protective layer 208 can be more firm, thus having better mechanical strength, service life and reliability, making the inkjet head wafer structure 200 operate more stably, avoiding the ink from infiltrating due to the rupture of the thin film therein, so as to achieve the purposes of subsequent encryption identification, control of the number of nozzles printed simultaneously, printing mode processing, control of vividness, control of saturation, etc. for improving the printing performance of the present invention.

[0047] According to the content of the present invention, the inkjet head wafer structure 200 includes several connection layers 206, which are disposed on the conductive layer 204, the source S and the drain D of the control transistor 209, and are electrically connected to the control layer 207 used as a wire, so that the control transistor 209 can control the heating of the ink by the heating resistance layer 205 during the printing process. Among them, in an embodiment of the present invention, the dielectric layer 203 can define the connection layer 206 by contact hole technology (Contact Hole) in the way of yellow light and etching to form the control layer 207 used as a wire. In the present invention, the material of the control layer 207 can be selected from aluminum copper alloy (AlCu) or gold (Au) according to the application requirements. In the protective layer 208, the perforations (not shown in the figure) of the required wires can also be defined by via hole (VIAHole) technology according to the application requirements, and the material of the wires can also be selected from aluminum copper alloy (AlCu) or gold (Au).

[0048] According to another embodiment of the present invention, in addition to being formed by doping polysilicon material, the heating resistance layer 205 can also be selected from one of tantalum aluminide (TaAl), tantalum (Ta), tantalum nitride (TaN), tantalum disilicide (Si2Ta), carbon (C), silicon carbide (SiC), indium tin oxide (ITO), zinc oxide (ZnO), cadmium sulfide (CdS), hafnium diboride (HfB2), titanium tungsten alloy (TiW), titanium nitride (TiN).

[0049] According to another embodiment of the present invention, the control layer 207 can be selected from among the aforementioned aluminum-copper alloy (AlCu), gold (Au), and can also be selected from one of aluminum-silicon alloy (AlSi), palladium (Pd), palladium-silver alloy (PdAg), platinum (Pt), aluminum-silicon-copper (AlSiCu), niobium (Nb), vanadium (V), hafnium (Hf), titanium (Ti), zirconium (Zr), yttrium (Y).

[0050] According to an embodiment of the present invention, the aforementioned first oxide layer 202 is an electrically insulating and heat-insulating material, and the electrically insulating and heat-insulating material can be selected from one of field oxide (FOX), silicon dioxide (SiO2), silicon nitride (Si3N4), and phosphosilicate glass (PSG).

[0051] According to an embodiment of the present invention, the protective layer 208 can be configured with an appropriate number of layers according to the needs of the application. In one embodiment of the present invention, it can be two layers, namely Figure 2 and Figure 3 The first protective layer 208A and the second protective layer 208B in are stacked in sequence from bottom to top. The first protective layer 208A can be a passivation material, and the passivation material can be one of silicon nitride (Si3N4), silicon dioxide (SiO2), titanium dioxide (TiO2), hafnium dioxide (HfO2), zirconium dioxide (ZrO2), tantalum pentoxide (Ta2O5), rhenium heptoxide (Re2O7), niobium pentoxide (Nb2O5), uranium pentoxide (U2O5), tungsten trioxide (WO3), silicon oxynitride (Si4O5N3), silicon carbide (SiC). The second protective layer 208B is a metal material, and the metal material can be one of tantalum (Ta), tantalum nitride (TaN), titanium nitride (TiN), titanium tungsten (TiW).

[0052] In one embodiment of the present invention, the resolution (Dots Per Inch, the number of dots or ink droplets per inch) of the inkjet head wafer structure 200 in this case can be set within the range of at least 150 DPI to 48000 DPI.

[0053] In summary, the present invention provides an inkjet head wafer structure. By modifying the two-layer inclined stepped structure at the junction of the heating resistance layer and the conductive layer in the heating architecture of the existing inkjet head wafer in the prior art to be on the same layer, compared with the known technology, its mechanical strength, service life, and reliability are increased. The architecture combined with the MOSFET control element benefits from the improved operational stability brought about by the increased mechanical strength, enabling further improvement in printing performance such as subsequent encryption identification, control of the number of ink dots printed simultaneously, printing mode processing, colorfulness control, and saturation control of the inkjet head wafer structure, and more effectively reducing the requirements of the manufacturing process and additional manufacturing costs, making it highly industrially applicable.

Claims

1. An inkjet head wafer structure, comprising: A substrate layer; A first oxide layer disposed on the substrate layer; A conductive layer disposed on the first oxide layer; A heating resistance layer disposed on the first oxide layer, the heating resistance layer being adjacent to and in contact with the conductive layer and located at the same horizontal position, covering a partial surface of the first oxide layer; A dielectric layer covering the first oxide layer and encapsulating the heating resistance layer and the conductive layer therein; A control layer partially covering the dielectric layer; and A protective layer covering the dielectric layer and encapsulating the control layer in the middle; Wherein, the control layer is electrically connected to a control transistor and the conductive layer to control the heating of the ink.

2. The inkjet head wafer structure according to claim 1, wherein the control transistor is a metal-oxide-semiconductor field-effect transistor (MOSFET).

3. The inkjet head wafer structure according to claim 2, wherein the metal-oxide-semiconductor field-effect transistor is selected from an N-type metal-oxide-semiconductor field-effect transistor (N-MOSFET), a P-type metal-oxide-semiconductor field-effect transistor (P-MOSFET), or any combination thereof.

4. The inkjet head wafer structure according to claim 2, wherein the metal oxide semiconductor field effect transistor further comprises: A source electrode, a drain electrode, and a gate electrode; wherein, the source electrode and the drain electrode are disposed in the substrate layer, and the gate electrode is disposed on the substrate layer, connecting the source electrode and the drain electrode to control the operation of the metal-oxide-semiconductor field-effect transistor.

5. The inkjet head wafer structure according to claim 4, the gate electrode further includes a second oxide layer and a polysilicon layer, sequentially stacked on the substrate layer, wherein the polysilicon layer, the heating resistance layer, and the conductive layer are of the same material, but with different component doping ratios.

6. The inkjet head wafer structure according to claim 5, wherein the polysilicon layer, the heating resistance layer, and the conductive layer are all made of polysilicon material, the conductive layer is located at positions adjacent to both sides of the heating resistance layer, and their doping concentrations form a structure with better conductivity - higher impedance - better conductivity in the order of high - low - high.

7. The inkjet head wafer structure according to claim 4, wherein the material of the heating resistance layer is selected from one of polycrystalline silicon (Polycrystalline Silicon), tantalum aluminide (TaAl), tantalum (Ta), tantalum nitride (TaN), tantalum disilicide (Si2Ta), carbon (C), silicon carbide (SiC), indium tin oxide (ITO), zinc oxide (ZnO), cadmium sulfide (CdS), hafnium diboride (HfB2), titanium tungsten alloy (TiW), titanium nitride (TiN).

8. The inkjet head wafer structure according to claim 1, further comprising a plurality of connection layers disposed on the conductive layer and the control transistor and electrically connected to the control layer, enabling the control transistor to control the heating of the ink by the heating resistance layer.

9. The inkjet head wafer structure according to claim 1, wherein the material of the control layer is selected from aluminum copper alloy (AlCu) or gold (Au).

10. The inkjet head wafer structure according to claim 1, wherein the protective layer further has a first protective layer and a second protective layer, and are sequentially stacked from bottom to top in the inkjet head wafer structure.

11. The inkjet head wafer structure according to claim 10, wherein the material of the first protective layer is selected from one of silicon nitride (Si3N4), silicon dioxide (SiO2), titanium dioxide (TiO2), hafnium dioxide (HfO2), zirconium dioxide (ZrO2), tantalum pentoxide (Ta2O5), rhenium heptoxide (Re2O7), niobium pentoxide (Nb2O5), uranium pentoxide (U2O5), tungsten trioxide (WO3), silicon oxynitride (Si4O5N3), and silicon carbide (SiC).

12. The inkjet head wafer structure according to claim 10, wherein the material of the second protective layer is a metal material, and the metal material is selected from one of tantalum (Ta), tantalum nitride (TaN), titanium nitride (TiN), and titanium tungsten (TiW).

13. The inkjet head wafer structure according to claim 1, wherein the resolution range that the inkjet head wafer structure can print is between 150 DPI and 48000 DPI.

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