WO2002081224A1 - Microinjector having drive circuit and method for making the same - Google Patents

Abstract

The present invention discloses a microinjector having drive circuit and method for making the same. The microinjector utilizes bubble as virtual valve to eject fluid medium, including manifold, multiple fluid chambers, multiple pairs of the first bubble generating member and the second bubble generating member, multiple nozzles and drive circuit, wherein, the drive circuit controls multiple pairs of the first bubble generating member and the second bubble generating member simultaneously to eject the fluid which in the corresponding fluid chamber from the corresponding nozzle, thereby attaining the effect for ejecting fluid; in addition, due to integrating the drive circuit with the bubble generating members in the same substrate, not only reduced the number of making steps, but also obtained the structure of less number of circuit unit and interconnecting lines.

Description

 Manual

 Micro-jet head with driving circuit

 And its production method [Technical Field]

 The present invention relates to a microinject head and a manufacturing method thereof, and more particularly, to a microinjection head with driving circuits and a one-piece molding and a manufacturing method thereof. 【Background technique】

 Today, liquid bead ejectors are widely used in printing by inkjet printers. However, liquid bead ejectors also have many other possible applications, such as: Fuel injection systems, Cell sorting, Drug release systems (Drug delivery systems), Direct print lithography, and Micro jet propulsion systems, etc. All these applications have in common that they all need to be reliable, low cost, and Provides high-quality liquid droplet ejectors with high frequency and high spatial resolution. '

 However, there are only a few types of devices capable of individually ejecting droplets of uniform shape. In the currently known and used liquid droplet ejection system, the method of using thermal driven bubbles to eject liquid droplets is simple and costly. Inexpensive, it has always been the more successful structure in such devices.

 In US Patent 6, 102, 530- "Apparatus and method for using bubbles as virtual valve in microinj ector to ej ect fluid", a liquid bead injection device with a virtual valve is mentioned, as shown in Figure 1. It is shown that the heater surrounds the injection hole. By the difference in the resistance value of the heater, a first bubble is generated at the position of the fluid cavity near the nozzle. The first bubble isolates the fluid cavity and the nozzle, and generates a similar gas. The function of the valve can reduce the effect of cross talk with adjacent fluid chambers. Then, a second bubble is generated, and this second bubble is used to push the fluid to make the fluid eject from the nozzle. Finally, the first The two bubbles are also combined with the first bubble, and the combination of these two bubbles is used to reduce the generation of satellite droplets.

In addition, in US Patent 5, 122, 812- "Thermal inkjet printhead having driver circuitry thereon and method for making the same", an inkjet head structure with a driving circuit was mentioned (as shown in Figure 2), It integrates the heating element and the driving circuit on the same substrate (Substrate). However, the number of steps required in the manufacturing process is large, and according to its structure, a barrier layer with a thickness of 20 ~ 30 μηι must be formed. 130, then attach a nozzle plate (Orifice plate) 140 on the shielding layer. This method will limit the spatial resolution of the nozzle due to the necessary assembly tolerance. In addition, the bonding step may not be compatible with the IC manufacturing process. (Army) and the driving circuit need to be integrated into one to reduce wiring and ensure tight packaging, this incompatibility problem will be more obvious. Therefore, this manufacturing process is not only complicated, but also costly. Therefore, at present, It has become an imperative trend to provide a micro-liquid bead ejection head with lower cost, fewer steps in the manufacturing process, and capable of achieving a driving circuit structure.

 [Objective and Summary of the Invention]

 The main object of the present invention is to provide a micro-jet head with a driving circuit, which is used for simultaneously controlling a plurality of pairs of first bubble generating pieces and second bubble generating pieces, and spraying the fluid inside a plurality of fluid chambers through the spray holes. To achieve the effect of ejecting fluid from a plurality of nozzle holes.

 Another object of the present invention is to provide a method for manufacturing a micro-jet head with a driving circuit, which is used to integrate a driving circuit and a bubble generating member on the same substrate, the number of steps in the manufacturing process is small, and circuit components and connections are The number of lines is small.

 The micro-jet head with a driving circuit disclosed in the present invention includes a plurality of fluid chambers, a manifold, a plurality of nozzle holes, a plurality of pairs of bubble generators, and a driving circuit, wherein the bubble generator includes a first bubble generator The component and a second bubble generating component.

 Wherein, the manifold is in communication with the fluid cavity and is used for supplying fluid into the fluid cavity; and a plurality of nozzle holes are in communication with the corresponding fluid cavity.

 The first bubble generating member and the second bubble generating member are disposed near the corresponding spray holes and are located above the corresponding fluid cavity. When the corresponding fluid cavity is filled with fluid, the first bubble generating element generates a first bubble in the fluid cavity. As a virtual air valve, after the first air bubble is generated, the second air bubble generating element generates a second air bubble, so that the fluid in the fluid cavity is ejected from the spray hole.

 In addition, the driving circuit includes a plurality of functional elements and is formed on the same substrate as a plurality of pairs of the first bubble generating member and the second bubble generating member. The driving circuit is used to independently transmit signals to separate bubble generators, and use them together. For driving multiple pairs of bubble generators, the function of controlling multiple pairs of bubble generators at the same time is achieved.

According to the method for manufacturing a micro-jet head with a driving circuit disclosed in the present invention, the method includes the following steps: providing a substrate, forming a driving circuit on the substrate, and the driving circuit including a plurality of functional elements, and then forming a sacrificial layer on the substrate -Without covering the driving circuit or using the driving circuit, the top dielectric material layer is used as a sacrificial layer, and then a low-stress material layer is formed on the sacrificial layer; the substrate and the sacrificial layer are etched to form a Manifold and multiple fluid chambers Communicating to supply fluid into the fluid cavity.

 Then, a plurality of pairs of the first bubble generating member and the second bubble generating member are formed on the low-stress material layer and communicate with the driving circuit. Finally, a plurality of spray holes are formed, which are located in the corresponding first bubble generating member and the second bubble generating member. Between the air bubble generating members, the corresponding fluid chambers are communicated to eject the fluid, so that a levitation spray head having a driving circuit and being integrally formed is completed.

 [Brief Description of the Drawings]

 FIG. 1 is a perspective structural view of an injection device having a virtual gas valve function in the prior art; FIG. 2 is a crusted sectional view of an inkjet head having a driving circuit in the prior art; and

 3-9 are schematic diagrams of the steps of manufacturing a levitation ejection head with a driving circuit and a structure of the levitation ejection head according to the present invention, wherein FIG. 9 is a schematic diagram of the complete structure of a micro-jet head with a driving circuit according to the present invention.

 10 to 12 are schematic structural diagrams of steps and steps of manufacturing a microjet head with a driving circuit according to another embodiment of the present invention.

 [Symbol description in the figure]

 10 array 12 microinjector

 14 Fluid chamber 16 Manifold

 20 first heater

 22 Second heater 24 Common electrode

 26 fluid 38 substrate

 40 sacrificial layer 42 low stress layer

 44 Conductive layer 45, 46 Low temperature oxide layer

 50 second part 51 dielectric layer

 52 First part 101 Thin oxide layer

 102 Silicon nitride layer 105 Polysilicon gate

 106 source 107 drain

 130 Shield 140 Nozzle Plate

 [Detailed description of the invention]

First, referring to the structure shown in FIG. 1, an array 10 of micro-injectors 12 is shown. The array 10 includes a plurality of adjacent micro-injectors 12. Each micro-injector includes a fluid chamber 14 and a manifold. (Manifold) 16, an injection hole (Orifice) 18, a first heater 20 and a second heater 22. The first heater 20 and the second heater 22 are connected in series to a common heater. Same electrode (Common electrode) 24.

 The working method of the first heater 20 and the second heater 22 is that the first heater 20 generates a first bubble to isolate the fluid cavity 14 and the nozzle hole 18, and generates a function similar to a gas valve, and the second heater 22 continues A second air bubble is generated, and the second air bubble is used to push the fluid 26 so that the fluid 26 is ejected from the injection hole 18 to achieve the function of ejecting the fluid 26.

 The fluid chamber 14 is filled with a fluid 26. The fluid 26 may include, but is not limited to, the following fluids: ink, gasoline, oils, chemicals, biomedical solution, water, and the like The choice of fluid depends on the particular application.

 However, in order to control multiple pairs of the first heater 20 and the second heater 22 at the same time in the present invention, a driving circuit needs to be added to the micro-jet head to achieve this purpose.

 As shown in Figs. 3 to 5, to fabricate the sparger array 10 with a driving circuit on a substrate 38, such as a Si wafer, first, a thin oxide layer 101 is formed on the substrate 38, and then a A silicon nitride (SiNx) layer 102 is formed on a thin oxide layer (as shown in FIG. 3). After exposing and developing the silicon nitride 102, etching is performed (as shown in FIG. 4 and then local oxidation is used for oxidation) An unprotected thin oxide layer 101 to form a field oxide. So far, a dielectric layer 51 (see FIG. 5) is formed, which includes a first portion 52 and a second portion 50, and the first portion 52 Is the part of the thin oxide layer 101 covered by the silicon nitride layer 102, and the second part 50 is a field oxide layer formed by a local thermal oxidation method. The field oxide layer can be etched in the subsequent manufacturing process, The fluid cavity 14 is formed. Then, the silicon nitride layer 102 is removed, and a blanket boron implant (Blanket boron implant) is placed on the first portion 52 and the second portion 50 (as shown in FIG. 5) to adjust the driving circuit. Threshold voltage, A polysilicon gate 105 is formed on the first part 52, and phosphorus ions are doped onto the polysilicon gate 105 to reduce its resistance value. Finally, arsenic ions are doped on the substrate. 38 to form a source 106 and a drain 107 adjacent to the gate. At this point, multiple functional elements can be formed on the substrate 38 (as shown in FIG. 6).

 Referring to FIG. 7, a low stress layer 42, such as a silicon nitride (SiNx) material, is deposited on the second portion 50 as an upper layer of the fluid cavity 14.

Referring to FIG. 8, next, an etching solution of potassium hydroxide (KOH) is etched from the back surface of the substrate 38 to form a manifold 16 as a main flow channel for supplying a fluid, and then the second portion 50 is treated with an etching solution of hydrogen. Fluoric acid (HF) was removed. Perform another etching with an etching solution of potassium hydroxide (KOH) under precise control of the etching time to increase the depth of the fluid cavity 14, and thus, the fluid cavity 14 is connected to the manifold 16 Pass and fill the fluid; pay special attention during this etching step, because the convex corners of the fluid cavity 14 will also be eroded and etched into the shape of an arc.

 A redeposition heater, wherein the heater includes a first heater 20 and a second heater 22, and patterning the same; for the first heater 20 and the second heater 22, a preferred material Aluminum 4 denier alloy (Alloys of tantalum and aluminum) and other materials such as platinum (platinum), hafnium boride (Hffi2), etc. can also achieve the same role; In addition, in order to protect the first heater 20 and the second heater 22 The plurality of functional elements are isolated, and a low-temperature oxide layer 45 is further deposited as a protective layer on the entire substrate 38 including the gate 105, the source 106, the drain 107, and the second portion 50.

 Next, a conductive layer 44 is formed on the first heater 20 and the second heater 22 to conduct the first heater 20, the second heater 22, and the functional elements of the driving circuit, wherein the driving circuit For transmitting signals to separate heaters (first heater 20 and second heater 22) independently, and for driving multiple pairs of heaters (first heater 20 and second heater 22), and so on The same circuit control effect can be achieved with a smaller number of circuit elements and connecting lines. For example: In this embodiment, the first heater 20 and the second heater 22 are connected in series, and the driving circuit controls a plurality of bubble generators in a matrix manner, for example, one column of bubble generators is powered on at the same time, and the other row is It is used to input transmission signals (or data) separately, so as to achieve the function of controlling the first and second heaters 20 and 22 independently. The preferred material of the conductive layer 44 is a metal material such as Alloys of Aluminum-Silicon-Copper, Aluminum, Copper, Gold, or Tungsten; and then, a low temperature is deposited. The oxide layer 46 is provided on the conductive layer 44 as a protective layer.

 Finally, referring to FIG. 9, the spray holes 18 are formed between the first heater 20 and the second heater 22. If Lithography allows a line width of 3 μm, the spray holes 18 can be as small as about 2 μm, And the pitch (Pitch) between the spray holes 18 and adjacent spray holes can be as small as about 15 μm. At this point, an integrated micro-injector array with a driving circuit can be formed. Not only can the driving circuit and the heater be integrated on the same substrate, but the structure of the entire micro-injecting head can be completed without additionally attaching a nozzle plate.

Hereinafter, another embodiment of the present invention will be described. Different from the above embodiment, the manufacturing process shown in FIGS. 7, 8 and 9 of the above embodiment is to directly contact the second part 50 shown in FIG. 6 to form the fluid cavity 14. In this embodiment, a part of the second portion 50 is etched first, and then a sacrificial layer 40 is formed at the position of the etched portion, and then a subsequent manufacturing process is performed on the sacrificial layer 40. Please refer to FIG. 10. FIG. 10 is a manufacturing process following FIG. 6. First, the second part 50 shown in FIG. 6 is partially processed. Etching, and depositing another oxide layer on the substrate 38 that does not cover the driving circuit, as a sacrificial layer 40 of the fluid cavity 14 (refer to FIG. 11), and then depositing a low stress layer 42 ', Is the upper layer of the fluid cavity 14.

 Next, reference is made to Figs. 11 and 12 are subsequent to FIG. 10 and are similar to the manufacturing process described in FIGS. 8 and 9. As shown in FIG. 11, first, the substrate 38 and the sacrificial layer 40 are etched from the back surface to form the manifold 16 and the fluid cavity 14, and then a first heater 20, a second heater 22, and a low-temperature oxidation layer 45 having a protective effect are deposited. . Then, a conductive layer 44 is formed to turn on the first and second heaters 20 and 22 and the driving circuit, and another low-temperature oxide layer 46 is deposited on the conductive layer 44 as a protective layer. Finally, as shown in FIG. 12, a spray hole 18 is formed between the first heater 20 and the second heater 22 by photolithography, so that a micro-injector array with integral driving and a driving circuit is completed.

 Of course, the order of the manufacturing process steps described above can be adjusted according to the situation, and it is not limited to the order described above, and the same micro-liquid bead ejection head with a driving circuit can also be formed.

 [Effect of the invention]

 According to the disclosure of a liquid-collecting bead jetting head with a driving circuit and a manufacturing method thereof, the effects are:

 1. Provide an improved micro-liquid bead jetting head that can be applied to technologies such as inkjet printing;

2. Provide an integrally formed micro-liquid bead ejection head, which integrates the driving circuit and the heater on the same substrate, and does not need to attach a nozzle plate to complete the overall crusting;

 3. The number of production process steps required to complete the overall structure can be simplified, which can simplify the required production process steps; and

 4. The overall number of circuit components and connection lines is small, which can reduce production costs and achieve the same circuit control effect.

 Although the present invention is described by the above-mentioned preferred embodiments, it is not intended to limit the present invention. Those skilled in the art can make various changes and improvements without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be Subject to the definition in the attached claim.

Claims

Profit requirements 1. A micro-jet head with a driving circuit, which uses a bubble as a virtual gas valve to eject a fluid, the micro-jet head comprising:  Multiple fluid chambers;  A manifold in communication with the fluid cavity for supplying fluid to the fluid cavity;  A plurality of spray holes, which are in communication with the corresponding fluid chambers;  A plurality of pairs of bubble generators, the bubble generator comprising a first bubble generating member and a second bubble generating member, the first bubble generating member and the second bubble generating member are arranged near the corresponding spray holes and located in the corresponding fluid cavity Above, when the corresponding fluid cavity is filled with fluid, the first bubble generating member generates a first bubble in the fluid cavity as a virtual gas valve, and after the first bubble is generated, the second bubble is generated The component generates a second bubble to cause the fluid in the fluid cavity to be ejected from the nozzle; and  The driving circuit includes multiple functional elements and is formed on the same substrate as the plurality of pairs of bubble generators. The driving circuit is used to independently transmit signals to separate bubble generators, and is used to drive the plurality of pairs of bubbles. Generator.  2. The micro-jet head with a driving circuit according to claim 1, wherein the functional element is a transistor.  3. The micro-jet head with a driving circuit according to claim 2, wherein the transistor is a metal oxide semiconductor field effect transistor (MOSFET).  4. The micro-jet head with a driving circuit according to claim 1, wherein the first bubble generating element includes a first heater, and the second bubble generating member includes a second heater.  5. The micro-jet head with a driving circuit according to claim 4, wherein the first bubble generating element and the second bubble generating element further include a conductive layer.  6. The micro-jet head with a driving circuit according to claim 5, wherein the material of the conductive layer is selected from aluminum, gold, copper, tungsten, and aluminum. Any one of the groups consisting of silicon copper alloy (Alloys of Aluminum-Silicon-Copper).  7. The micro-jet head with driving circuit according to claim 4, wherein the material of the first heater and the second heater is selected from the group consisting of Alloys of tantalum and aluminum, platinum (Platinum) and hafnium boride (HfB2). 8. A method of making a emblem jet head with a driving circuit, the jet jet head using a bubble as a virtual gas valve to eject a fluid, the method comprising the following steps:  Providing a substrate;  Forming a dielectric layer on the substrate, the dielectric layer including a first portion and a second portion; forming a driving circuit on the first portion of the dielectric layer, the driving circuit including a plurality of functional elements;  Forming a low-stress material layer on a second portion of the dielectric layer;  Etching the substrate and the dielectric layer to form a manifold and a plurality of fluid cavities, and the manifold is in communication with the fluid cavity to supply fluid to the fluid cavity;  Forming a plurality of pairs of bubble generators on the low-stress material layer and communicating with the driving circuit, wherein the bubble generator includes a first bubble generating member and a second bubble generating member; and forming a plurality of spray holes, It is located between the corresponding first bubble generating member and the second bubble generating member, and communicates with the corresponding fluid cavity to eject the fluid.  9. The method for manufacturing a micro-jet head with a driving circuit according to claim 8, wherein the step of forming the dielectric layer includes:  Forming a thin oxide layer on the substrate;  Forming a silicon nitride layer on the thin oxide layer;  Local oxidation is used to oxidize the thin oxide layer that is not covered by the silicon nitride layer to form a field oxide. The thin oxide layer covered by the silicon nitride layer is The first portion of the dielectric layer, and the field oxide layer is the second portion of the dielectric layer; and  Remove the silicon nitride layer.  10. The method for manufacturing a microjet head with a driving circuit according to claim 8, wherein the step of forming the driving circuit includes:  Holding a boron implant on the dielectric layer;  Forming a poly silicon gate on a first portion of the dielectric layer; and ion-doping arsenic ions in the substrate to form a source and a drain adjacent to the gate ( Drain). 11. The method for manufacturing a micro-jet head with a driving circuit according to claim 8, wherein the driving circuit is used to independently transmit signals to separate bubble generators, and is used to drive the plurality of pairs of bubbles. Generator. 12. The method for manufacturing a micro-jet head with a driving circuit according to claim 8, wherein the functional element is a transistor.  13. The method for manufacturing a micro-jet head with a driving circuit according to claim 12, wherein the transistor is a metal oxide semiconductor field effect transistor (MOSFET).  14. The method for manufacturing a micro-jet head with a driving circuit according to claim 8, wherein the steps of etching the substrate and the dielectric layer to form a manifold and a fluid cavity include:  Etching the substrate on the back to form a manifold;  Removing the second portion of the dielectric layer; and  The substrate is etched back again to form a fluid cavity.  15. The method for manufacturing a jetting head with a driving circuit according to claim 8, wherein the step of forming the first bubble generating member and the second bubble generating member includes:  Forming a resistance layer on the low-stress material layer to form a first heater and a second heater; and  A conductive layer is formed on the resistance layer, and the conductive layer is in communication with the driving circuit. 16. The method for manufacturing a microjet head with a driving circuit according to claim 15, wherein a material of the conductive layer is selected from aluminum, gold, copper, and tungsten (Tungsten). ) And an aluminum-silicon-copper alloy (Alloys of Aluminum-Silicon-Copper).  17. The method for manufacturing a micro-jet head with a driving circuit according to claim 15, wherein the material of the first heater and the second heater is selected from the group consisting of Alloys of tantalum and aluminum, Any one of the group consisting of platinum and hafnium boride (Hffi2).  18. The method for manufacturing a micro-jet head with a driving circuit according to claim 15, wherein the method further includes the following steps between forming the resistance layer and forming the conductive layer:  A first oxide layer is formed on the resistance layer to protect the first heater and the second heater.  19. The method for manufacturing a micro-jet head with a driving circuit according to claim 8, further comprising the following steps:  A second oxide layer is formed on the first bubble generating member and the second bubble generating member to protect the first bubble generating member and the second bubble generating member. 20. A method of manufacturing a micro-jet head with a driving circuit, the micro-jet head uses a bubble as a virtual gas valve to eject a fluid, and includes: Providing a substrate;  Forming a dielectric layer on the substrate, the dielectric layer including a first portion and a second portion; forming a driving circuit on the first portion of the dielectric layer, the driving circuit including a plurality of functional elements;  Etching a portion of the second portion of the dielectric layer, and forming a sacrificial layer on the portion of the second portion of the dielectric layer that is etched;  Forming a low-stress material layer on the sacrificial layer;  Etching the substrate and the sacrificial layer without a driving circuit to form a manifold and a plurality of fluid chambers, and the manifold is in communication with the fluid chamber to supply fluid to the fluid chamber;  Forming a plurality of pairs of bubble generators on the low-stress material layer and communicating with the driving circuit, wherein the bubble generator includes a first bubble generating member and a second bubble generating member; and forming a plurality of spray holes, It is located between the corresponding first bubble generating member and the second bubble generating member, and communicates with the corresponding fluid cavity to eject the fluid.  21. The method for manufacturing a micro-jet head with a driving circuit according to claim 20, wherein the step of forming the dielectric layer includes:  Forming a thin oxide layer on the substrate;  Forming a silicon nitride layer on the thin oxide layer;  Local oxidation is used to oxidize the part of the thin oxide layer that is not covered by the silicon nitride layer to form a field oxide. The thin oxide layer covered by the silicon nitride layer is the dielectric. A first portion of the layer, and a field oxide layer is a second portion of the dielectric layer; and  Remove the silicon nitride layer.  22. The method for manufacturing a jetting head with a driving circuit according to claim 20, wherein the step of forming the driving circuit includes:  Holding a boron ion on the dielectric layer;  Forming a polysilicon gate on a first portion of the dielectric layer; and ion-doping arsenic ions in the substrate to form a source and a drain adjacent to the gate ( Drain). 23. The method for manufacturing a micro-jet head with a driving circuit according to claim 20, wherein the driving circuit is used to independently transmit signals to separate bubble generators, and is used to drive the multiple pairs of bubble generation Device. 24. The method for manufacturing a micro-jet head with a driving circuit according to claim 20, wherein the functional element is a transistor.  25. The method for manufacturing a micro-jet head with a driving circuit according to claim 24, wherein the transistor is a metal oxide semiconductor field effect transistor (MOSFET).  26. The method for manufacturing a micro-jet head with a driving circuit according to claim 20, wherein the steps of etching the substrate and the sacrificial layer to form a manifold and a fluid cavity include:  Etching the substrate on the back to form the manifold;  Removing portions that do not cover the sacrificial layer of the driving circuit; and  The substrate is etched back again to form a fluid cavity.  27. The method for manufacturing a micro-jet head with a driving circuit according to claim 20, wherein the step of forming the first bubble generating member and the second bubble generating member includes:  Forming a resistance layer on the low-stress material layer to form a first heater and a second heater; and  A conductive layer is formed on the resistance layer, and the conductive layer is in communication with the driving circuit. 28. The method for manufacturing a microjet head with a driving circuit according to claim 27, wherein the material of the conductive layer is selected from aluminum, gold, copper, and tungsten ) And an aluminum-silicon-copper alloy (Alloys of Aluminum-Silicon-Copper).  29. The method for manufacturing a microjet head with a driving circuit according to claim 27, wherein the materials of the first heater and the second heater are selected from the group consisting of Alloys of tantalum and aluminum, Any one of the group consisting of platinum and hafnium boride (Hffi2).  30. The method for manufacturing a micro-jet head with a driving circuit according to claim 27, wherein the method further includes the following steps between forming the resistance layer and forming the conductive layer:  A first oxide layer is formed on the resistance layer to protect the first heater and the second heater. 31. The method for manufacturing a micro-jet head with a driving circuit according to claim 20, further comprising the following steps:  A second oxide layer is formed on the first bubble generating member and the second bubble generating member to protect the first bubble generating member and the second bubble generating member.