KR20000026332A - Method for forming piezo-electric plate of ink jet printer head using piezo-electric effect - Google Patents

Abstract

PURPOSE: A method for forming a piezo-electric plate of an ink jet printer head is provided to simplify a process of forming a piezo-electric material on a vibration plate and making a nozzle and an ink manifold in unified forms, with a method for sintering the piezo-electric material in a low temperature, by using the piezo-electric material which does not lose its characteristics even after being sintered. CONSTITUTION: A method forming a piezo-electric plate of an ink jet printer head using a piezo-electric material comprises the steps of: measuring PbO, ZrO2, and TiO as regular amounts; mixing the PbO, the ZrO2, and the TiO, calcining the mixture in a temperature of 850 degrees centigrade for two hours, and making into a Pb(ZrxTi1-x)O3 crystal; inserting pleat glass powder into the Pb(ZrxTi1-x) crystal, and making Pb(ZrxTi1-x) powder by mixing the crystal; making the Pb(ZrxTi1-x)O3 and the pleat glass mixture powder into paste states by adding epoxy resin; making a piezo-electric plate pattern as the mixture paste; and forming a piezo-electric plate by sintering the piezo-electric pattern in a temperature of 950 degrees centigrade.

Description

Piezoelectric Plate Forming Method of Inkjet Printer Head Using Piezoelectric Effect

The present invention relates to a method of forming a piezoelectric plate of an ink jet printer head using a piezoelectric material.

Conventionally, a thermal bubble jet printer head has been mainly used as a print head. Thermal bubble jet (Cannon & HP basic patent) is a method of ejecting ink by generating bubbles as heat. Instantaneous current flows through the heat conversion film in direct contact with the ink inside the printhead to generate heat due to the intrinsic resistance of the heat conversion film. This heat is transferred to the ink in contact with the heat conversion film so that the water-soluble ink rapidly rises above the boiling point. When the temperature of the ink rises above the boiling point, bubbles are formed, and the formed bubbles apply pressure to the surrounding ink. The pressurized ink is ejected through the nozzle due to the pressure difference from the atmospheric pressure. At this time, the ejected ink is ejected to the ground while forming ink drops to minimize the surface energy inherent in the ink. This process is called drop-on-demand, which uses a computer to operate whenever needed.

At the moment when the bubbles disappear after the bubbles are generated in the thermal bubble jet, the high curvature of the smaller bubbles increases the impact of the bubbles on the protective film on the thermal conversion film, resulting in cavitation damage. Is generated. For this reason, there are many restrictions on extending the life of the print head. In addition, since the ink is ejected only when bubbles are generated, the ink must be boiled at an appropriate temperature, so only ink that can boil at such an appropriate temperature can be used. Due to the physical properties of these inks, there are not many kinds of inks that can be used in thermal bubble jets. The limiting factor in the use of ink results in narrowing the application of the thermal bubble jet itself, such as thermal bubble jets being primarily confined to desktop publications.

In addition, due to the high heat generated when bubbles are generated, the organic additives of the ink tend to react with the protective film located on the heat conversion film and adsorb to the protective film. These adsorbates interfere with heat transfer, so that the heat generated in the heat conversion film is not effectively transferred to the ink. Therefore, even if a sufficient amount of heat to generate bubbles is generated by the heat conversion film, in some cases, the adsorbents formed on the protective film are not sufficiently transferred to the ink, so that the ink cannot be ejected normally.

On the other hand, what has been proposed to solve the above problems is a printer head using a piezoelectric material of the non-heating method. However, ink jet printer heads using piezoelectric materials are generally limited in their use due to the cost increase resulting from complex assembly processes despite the excellent performance due to the assembly process due to the characteristics of piezoelectric materials.

That is, Piezo-electrinc impulse ink-jet is a printing method using a phenomenon that the volume changes when the piezoelectric element receives an electric field momentarily. When the piezoelectric element instantaneously changes its volume, it transmits a pressure wave to the ink, which travels to the nozzle at a speed of sound. Therefore, the nozzle ejects ink by the difference between the delivered pressure and atmospheric pressure. Various design examples using this principle have been published (Ulmann's encyclopedia of industrial chemistry).

1 is a sectional view of a laminated ink jet recording head described in European Patent No. 0 659 562 A2. As shown, the laminated inkjet recording head basically comprises a nozzle plate 101 on which a nozzle 100 is formed, three communicating hole forming boards 201a, 201b, and 201c, and a pressure generating chamber forming board 301. ) And the diaphragm 400 are sequentially laminated (laminated) structure. In the pressure generating chamber 300, the ink stored in the ink storage container 800 is temporarily stored in the storage chamber 600a after passing through the inlet 700, and then filled through the ink inlet 600c and the communication hole 600b. Ink provided from an external ink container flows into the ink storage container 800 through the filter 900. The piezoelectric vibrator 500 is attached to the diaphragm 400 to generate pressure in the ink filled in the pressure generating chamber 300 according to a voltage signal applied thereto. The pressurized ink is discharged through the nozzle 100 through the communicating holes 200a, 200b, and 200c. However, in the inkjet recording head having such a structure, since the nozzle 100 and the ink injection hole 600c are together on the surface facing the diaphragm 400, the discharge pressure of the ink due to the vibration of the diaphragm 400 is divided. This exists. That is, since the pressure through which the ink is discharged through the nozzle 100 is transferred to the ink injection hole 600c, the phenomenon in which the ink injected into the pressure generating chamber 300 flows back easily occurs.

In addition, the method of manufacturing the shape of the piezoceramic by mechanical processing is less mass-producible than the method by SILK SCREEN, and cracks are likely to occur. In the case of the silk screen method, the driving unit, the diffusion barrier film, the electrode, the substrate part having the ink chamber and the ink channel should be sintered at once. In general 1200 ° C sintering, the driving part Pb and the substrate part silicon react with the contact part and lose their properties. If the sintering temperature is lowered, the properties of the piezoelectric ceramic plate are significantly reduced. In addition, the general sintering method of 1200 ° C or higher has high energy consumption due to high temperature. And if the sintering temperature is high, expensive metals withstanding high temperature should be used as electrode material. In case of sintering above 1200 ℃, evaporation of PbO is severe and special containers and atmosphere powder must be used, which is expensive and unstable.

The present invention was devised to improve the above-mentioned problems, and the piezoelectric material does not lose its characteristics after the sintering process by simple sintering at a low temperature by forming a piezoelectric material directly on the diaphragm and integrating the nozzle and the ink passage. It is an object of the present invention to provide a piezoelectric plate forming method of an inkjet printer head.

1 is a vertical sectional view of a conventional laminated inkjet recording head,

Fig. 2 is a schematic perspective plan view of the inkjet printer head using the previously-applied piezoelectric material as viewed from the nozzle face,

3 is a schematic perspective plan view of the inkjet printer head using the piezoelectric material of FIG. 2 as viewed from a diaphragm having a piezoelectric plate formed thereon;

4 is a vertical cross-sectional view showing a cross section taken along the line AA ′ of FIG. 3,

Figures 5a to 5o is a vertical cross-sectional view showing a cross-section after the process step by step in the manufacturing method of the inkjet printer head using the piezoelectric material according to the pre- filed,

6 is a schematic perspective view of an inkjet printer head to which the piezoelectric plate forming method according to the present invention is applied;

7A to 7C are cross-sectional views of FIG. 6 showing how the inkjet print head is driven by the piezoelectric plate;

8 is a view showing a fine structure of a ceramic,

9 is a flow chart showing a step-by-step process applied to the piezoelectric plate forming method according to the invention,

10 is a SEM photograph of the PZT / Pt / ZrO ₂ / Si structure,

11 is a graph showing an XRD peak in the structure of PZT / screen Pt / ZrO ₂ / Si after heat treatment of a screen printed Pt electrode;

12 is a SEM photograph of the structure of PZT / screen Pt / ZrO ₂ / Si after heat treatment of the screen printed Pt electrode;

FIG. 13 shows XRD showing that polycrystalline Ag-Pd and silicon were formed after heat treatment at 900 to 1000 ° C. in the structure of PZT / screen Ag-Pd / ZrO ₂ / Si, which is a case where Ag-Pd screen-printed instead of Pt is used as an electrode. Graph of peaks,

FIG. 14 is a SEM of a specimen in which polycrystalline Ag-Pd and silicon are formed after heat treatment at 900 to 1000 ° C. in the structure of PZT / screen Ag-Pd / ZrO ₂ / Si, in which a screen-printed Ag-Pd is used as an electrode instead of Pt. Picture,

15 is a SEM photograph taken after the heat treatment after depositing PZT in the case of forming a thin Pt as an electrode,

16 is a SEM photograph obtained during the 900-1000 ℃ heat treatment in the case of 54 specimens.

<Description of the symbols for the main parts of the drawings>

1. pressure chamber 2. nozzle

3. ink feed-in channel 4. common manifold

5. Main ink flow path 6. Upper electrode

7. Piezoelectric Plate 8. Common electrode

9. Diaphragm 10. SiO ₂ thin film

11.Si substrate 12.SiO ₂ thin film

13. Si thin film (nozzle plate) 14. SiO ₂ thin film (ink spreading prevention film)

15. Diffusion barrier

31.SINGLE CRYSTAL 32.Glass

In order to achieve the above object, the piezoelectric plate forming method of the inkjet printer head using the piezoelectric material according to the present invention comprises the steps of: (a) basis weight of PbO, ZrO ₂ and TiO by an appropriate amount; (B) mixing the basis weighted PbO, ZrO ₂ and TiO and calcining at 850 ° C. for 2 hours to form Pb (Zr _x Ti _1-x ) O ₃ single crystals; (C) adding an appropriate amount of frit glass powder to the Pb (Zr _x Ti _1-x ) O ₃ single crystal, mixing and pulverizing to form Pb (Zr _x Ti _1-x ) O ₃ powder; (D) adding an epoxy resin to the Pb (Zr _x Ti _1-x ) O ₃ and flit glass mixed powder to form a paste; (E) forming a piezoelectric plate pattern from the Pb (Zr _x Ti _1-x ) O ₃ and flit glass mixing paste; And (bar) sintering the printed piezoelectric plate pattern at a temperature of 950 ° C. or less to form a piezoelectric plate.

In the present invention, the piezoelectric plate pattern in the step (e) is preferably formed by printing by the silk screen method.

In order to achieve the above object, a piezoelectric plate forming method of an inkjet printer head using another piezoelectric material according to the present invention may be formed on both sides of a bulk silicon substrate on which an ink chamber and an ink flow path are formed, with one partition interposed therebetween. In a method of forming a piezoelectric plate of an inkjet printer head using a piezoelectric material formed with a nozzle plate and a vibrating plate, the piezoelectric material attached to the outside of the nozzle plate and the piezoelectric plate outside the vibrating plate with the ink chamber therebetween. (A) basis weighting PbO, ZrO ₂ and TiO by an appropriate amount; (B) mixing the basis weighted PbO, ZrO ₂ and TiO and calcining at 850 ° C. for 2 hours to form Pb (Zr _x Ti _1-x ) O ₃ single crystals; (C) adding an appropriate amount of frit glass powder to the Pb (Zr _x Ti _1-x ) O ₃ single crystal, mixing and pulverizing to form Pb (Zr _x Ti _1-x ) O ₃ powder; (D) adding an epoxy resin to the Pb (Zr _x Ti _1-x ) O ₃ and flit glass mixed powder to form a paste; (E) forming a piezoelectric plate pattern on an upper surface of the diaphragm with the Pb (Zr _x Ti _1-x ) O ₃ and flit glass mixing paste; And (bar) sintering the printed piezoelectric plate pattern at a temperature of 950 ° C. or less to form a piezoelectric plate.

In the present invention, the piezoelectric plate pattern in the step (e) is preferably formed by printing by the silk screen method.

Hereinafter, a piezoelectric plate forming method of an inkjet printer head using a piezoelectric material according to the present invention will be described in detail with reference to the drawings.

The piezoelectric plate is made into a thick film by forming a fine shape on the silicon body by the silk screen method and sintering at low temperature. Piezoelectric plates made of piezoelectric ceramics such as PZT are integrated with silicon ink channels and chambers, and are sintered at low temperatures by adding FRIT GLASS in addition to the diffusion barrier to prevent diffusion reactions occurring during sintering.

The structure and manufacturing method of the inkjet print head using the piezoelectric material to which such low temperature sintering method is applied are demonstrated.

Fig. 2 is a schematic perspective plan view of the ink jet printer head using the piezoelectric material to which the low temperature sintering method of the present invention is viewed from the nozzle face. As shown in FIG. 1, since the nozzle 100 and the ink injection hole 600c are present together on the surface facing the diaphragm 400, the discharge pressure of the ink due to the vibration of the diaphragm 400 is divided into two parts. As a structure of an inkjet print head proposed to improve the problem that is proposed, it has been previously filed by the applicant. Here, the figure shows the structure of the ink flow channel and the position of the nozzle as seen from the nozzle face of the printhead. An ink flow channel of a head manufactured using a silicon on insulator (SOI) is manufactured by etching a silicon substrate. A reference numeral 1 denotes a pressure chamber positioned below the piezoelectric plate (see FIG. 3), a reference numeral 2 denotes a nozzle through which ink is discharged, and a reference numeral 3 denotes an ink injection channel for supplying ink to the pressure chamber 1. (ink feed-in channel), reference numeral 4 denotes a common ink manifold for supplying ink through the ink injection channel 3 to each of the pressure chambers 1 located below the piezoelectric plate (see FIG. 3). And reference numeral 5 denotes holes of the flow path or diaphragm for supplying ink from the ink bottle to the common ink flow path 4.

FIG. 3 is a schematic perspective plan view of the inkjet printer head using the piezoelectric material of FIG. 2 as viewed from a diaphragm having a piezoelectric plate. This figure mainly shows the structure of the ink flow path as seen from the diaphragm of the printer head, the piezoelectric plate and the arrangement of the upper and lower electrodes. Here, members 1, 3, 4, and 5 represent elements as described in FIG. 2, wherein member 6 is an upper electrode, member 7 is a piezoelectric plate, and member 8 is a common electrode formed under the piezoelectric plate ( common electrode).

4 is a vertical cross-sectional view showing a cross section taken along the line AA ′ of FIG. 3. This figure shows in detail the structure of the thin films as a cross-sectional view in the y direction of the coordinates shown in FIGS. 2 and 3. As shown, the inkjet printer head using the piezoelectric material according to the present invention basically includes a pressure chamber 1, an ink feed-in channel 3, and a common ink flow path 4. SiO ₂ thin films 10 and 12 are formed on both sides of the Si substrate 11 in which the chamber space is formed to form the Si thin film 13 and the SiO ₂ thin film 12 on the SiO ₂ thin film 12 to form the nozzle 2. SiO ₂ thin film 14 is formed. And Si diaphragm 9 for generating the pressure which causes the ink in the pressure chamber 1 to discharge through the nozzle 2 is formed on the surface which opposes a nozzle. On the upper surface of the Si diaphragm 9, a piezoelectric element formed of the upper electrode 6, the piezoelectric plate 7, and the lower electrode 8 for vibrating the diaphragm 9 is attached. In some cases, a diffusion barrier 15 formed of Si ₃ N ₄ or ZrO ₂ may be inserted between the diaphragm 9 and the lower electrode 8 to prevent diffusion of the piezoelectric material when the piezoelectric plate 7 is formed. Here, the piezoelectric plate 7 is made of PbZrTi (lead zirconium titanate) compound, in particular Pb (Zr _x Ti _1-x ) O ₃ . In particular, the size of the ink chamber 1 is about 200 μm between the nozzle plate surface and the diaphragm surface, and the distance between both wall surfaces is about 100 μm between the nozzle plate side, and the pressure generated by the vibration of the diaphragm 9. The ink chamber 1 is manufactured so as to be transferred toward the nozzle 2 as much as possible to facilitate ink ejection.

As described above, the inkjet printer head using the piezoelectric material according to the present invention has a structure in which the nozzle 2, the common ink flow passage 4 and the ink injection channel 3 are formed integrally with the pressure chamber 1 using Si. Can be made simple but its size is small. In addition, the piezoelectric plate 7 processes the piezoelectric material in a simple form and attaches it to the diaphragm 9 or forms a pattern of the piezoelectric material directly on the diaphragm 9 and sinters it directly on the diaphragm 9. Is produced by. In the latter case, a diffusion barrier 15 is inserted between the diaphragm 9 and the lower electrode 8 to prevent the piezoelectric material material from diffusing into the diaphragm 9 when the piezoelectric material is sintered.

An inkjet printer head using a piezoelectric material having the above structure is manufactured as follows.

In the inkjet printer head using the piezoelectric material according to the present invention, the nozzle and the ink flow path are integrally formed with the pressure chamber using a silicon-on-insulator (SOI), and the piezoelectric plate is processed into a vibrating plate by processing the piezoelectric material in a simple form. It is produced by attaching or forming a pattern of piezoelectric material directly on the vibration plate and sintering it directly on the vibration plate 9. Such a manufacturing method will be described in detail with reference to FIGS. 5A to 5O.

First, a process for forming an ink feed-in channel for supplying ink to a pressure chamber and a pressure chamber through bulk etching, as shown in FIG. 5A, an ink injection channel (ink) It is necessary to form an etching pattern of a portion corresponding to a feed-in channel. In FIG. 5A, SiO ₂ thin films 10a and 12 are respectively coated on both surfaces of a bulk (100) plane Si substrate 11. Here, the SiO ₂ thin films 10a and 12 used as the etch stop layer may be formed of Si ₃ N ₄ . Next, an upper surface of the SiO ₂ thin film 12 is coated with a Si thin film for forming a nozzle or a previously prepared Si thin plate is sealed, and a photoresist is coated on the SiO ₂ thin film 10a on the opposite surface. Afterwards, the UV light is exposed to a portion corresponding to an ink feed-in channel. Subsequently, when the exposed portion is removed, the portion corresponding to the ink feed-in channel is exposed.

Next, an ink injection channel and etching the exposed SiO ₂ layer (10a) to form a SiO ₂ pattern (10b), and the SiO ₂ pattern (10b) as a mask, as shown in Figure 5b (ink feed- in the channel corresponding to the (in channel) is etched. At this time, the exposed SiO ₂ layer 10a portion is wet etched using a water-soluble HF solution.

When the SiO ₂ layer 10 reaches the Si substrate 11 as the etching proceeds, the etching of the Si substrate 11 proceeds at a relatively slow speed, so Si is an etch barrier in the SiO ₂ etching process using HF aqueous solution. Play a role. If the Si ₃ N ₄ layer 10 is formed instead of the SiO ₂ layer as an etch stop layer, etching is performed by reactive ion etching. The Si substrate 11 is etched using a KOH aqueous solution. When etching Si using an aqueous KOH solution, SiO ₂ serves as an etch barrier.

Next, as shown in FIG. 5D, the SiO ₂ layer 10c is again coated. This is necessary to form a mask pattern for etching an Si substrate for forming a pressure chamber and a common ink manifold.

Next, as shown in FIG. 5E, the SiO ₂ layer 10c is etched using a photolithograpy process as in FIGS. 5A and 5B to form a pressure chamber and a common ink manifold. An etching SiO ₂ pattern 10d is formed. The SiO ₂ applied on the upper surface of the ink feed-in channel and the upper surface of the portion forming the one side partition of the pressure chamber remains, and the remaining SiO ₂ layer is removed.

Next, as shown in FIG. 5F, the pressure chamber 1 and the common ink manifold 4 are formed by etching the (100) plane Si substrate 11 using the SiO ₂ pattern 10d as a mask. do. In this case, since the bulk Si substrate 11 is a (100) plane, the bulk Si substrate 11 is etched to form an inclined surface having an inclination of about 35.26 ° with the vertical direction of the substrate when etched with a KOH solution. That is, the inclination of the inclined surface formed by etching is determined within the range of 30 ° to 40 ° from the vertical direction of the substrate.

Next, as shown in FIG. 5G, the pressure chamber 1 and the common ink flow path 4 and the ink feed-in channel 3 are replaced to prevent the mutual chemical interaction between the ink and Si. coated with SiO ₂ to form an SiO ₂ film (10e).

Next, as shown in FIG. 5H, the SiO ₂ layers 10e and 12 are etched using an excimer laser to form a nozzle.

Next, as shown in FIG. 5I, the nozzle 2 is formed by wet etching the exposed Si layer 13 by etching with an excimer laser.

Next, as shown in Fig. 5J, in order to prevent the water-soluble ink from spreading on the surface of the Si layer 13, SiO ₂ is deposited to form a non-wetting coating film 43.

Next, as shown in Fig. 5K, a single-crystal Si diaphragm 9 secured in advance is attached to the opposing surface of the nozzle plate 13 in the structure formed in the above process. At this time, the Si diaphragm is attached to the structure by using anodic bonding (anodic bonding) method or by high temperature heating bonding.

Next, FIG. 5L forms a diffusion barrier 15 of Si ₃ N ₄ or ZrO ₂ to prevent the piezoelectric material from diffusing when the piezo-electrinc materials are sintered.

Next, as shown in FIG. 5M, a lower common electrode 8 is formed. The lower common electrode 8 is formed by coating a conductive paste by screen printing. This conductive paste serves as an adhesive for attaching the piezoelectric plate 7.

Next, as shown in FIG. 5N, a piezoelectric plate 7 made of a lead zirconium titanate (PbZrTi) -based compound, in particular, Pb (Zr _x Ti _1-x ) O ₃ , is used as a lower common electrode 8, that is, a conductive paste. Attach with adhesive and sinter.

Next, as shown in FIG. 5O, the upper electrode 6 is formed on the upper surface of the piezoelectric plate to complete the device.

The inkjet head manufactured by the above process is comprised from the piezoelectric plate 7 of PZT piezoceramic which has the ink channel 3, the ink chamber 1, and the electrode, as shown in FIG. As shown in FIG. 7A, in the piezoelectric plate 7 of the piezoelectric ceramic, the piezoelectric ceramic having electrodes is connected to the ink chamber 1 through the diffusion barrier 15 and the thin film. When the piezoelectric ceramic expands and contracts, ink flows in as the volume of the ink chamber 1 expands as shown in FIG. 7B, and ink moves in the nozzle as the volume of the ink chamber 1 shrinks as shown in FIG. 7C. Squirt through.

In the manufacturing step of the inkjet frit head using the piezoelectric material of the prior application driven by such an operation, the method of forming the piezoelectric plate according to the present invention is applied in the step as shown in Fig. 5N. That is, at this stage, the piezoelectric plate, that is, the piezoelectric ceramic 7, to be used as a driving source for ink ejection, is patterned and attached in the form of a thick film, as shown in FIG. 7) is sintered to have a mechanical strength. As shown in FIG. 8, frit glass is added to the calcined piezoelectric ceramic powder to lower the sintering temperature to 900 ° C., thereby maintaining the characteristics of the piezoelectric ceramic driven by sintering. Keep it. This can prevent the reaction between the respective films when sintering at 1200 ℃ as conventional.

The piezoelectric plate forming process according to the present invention will be described in detail with reference to the flowchart of FIG. 9.

In the piezoceramic, as shown in Fig. 8, single crystal grains are attached at the grain boundaries. The particle interior 31 is composed of a single crystal, but the grain boundary 32 is composed of glass (GLASS) and fragments. This piezoelectric ceramic is manufactured by a powder synthesis method, which is manufactured by a flow chart as shown in FIG.

First, PbO, ZrO ₂ and TiO, which are raw materials of the piezoelectric plate 7, are basis weighted by an appropriate amount, and then mixed and calcined at 850 ° C. for 2 hours to form Pb (Zr _x Ti _1-x ) O ₃ . .

Next, an appropriate amount of frit glass powder is put into Pb (Zr _x Ti _1-x ) O ₃ produced by calcination, mixed and ground to form Pb (Zr _x Ti _1-x ) O ₃ powder.

Next, an epoxy resin is added to Pb (Zr _x Ti _1-x ) O ₃ and flit glass mixed powder to make a paste state.

Next, Pb (Zr _x Ti _1-x ) O ₃ and flit glass mixed paste were printed by the silkscreen method to make a piezoelectric plate pattern as shown in FIG.

Next, the printed piezoelectric plate pattern is sintered at a temperature of 950 ° C. or lower to form a piezoelectric plate (piezoelectric ceramic) 7.

Next, the piezoelectric plate 7 is completed by attaching the electrodes described in the above printhead manufacturing step.

As described above, the piezoelectric plate forming method according to the present invention, in the process of bonding the sintering process after making the PZT powder through calcination, in order to lower the sintering temperature requiring a relatively high temperature of 1200 ° C. It can be used to bond firmly while maintaining the piezoelectric properties at a low temperature of 950 ℃ or less. Conventionally, liquid phase sintering has been frequently used to lower the sintering temperature of piezoelectric ceramics. In liquid sintering, however, glass-forming materials are mixed at the initial basis weight, and after the piezoelectric ceramics form a single crystal, the remaining material penetrates into the grain boundaries to form a glass phase. Therefore, grain boundary pores, etc., are mixed in the grain boundary in addition to the glass phase. On the other hand, after calcination of the quantitative glass to be formed and the surface of the single crystal particles are mixed while mixing, the glass phase is evenly distributed at the grain boundaries. In addition, homogeneous grain boundaries are formed by removing pores and impurities at grain boundaries. At the time of forming the crystal grains, glass is not added, so that the inside of the crystal is homogeneous. And since there is no reason to seep out during the crystal formation of the particles, the selection of the glass material at the grain boundary is also free and various compositions can be used.

Example

1. Mix 1, 3, 5, 7 WT% BBC (0.30 B ₂ O ₃ -0.25 Bi ₂ O ₃ -0.45 CdO) with PZT (PZ / PT = 52/48 + 0.4 wt% MnO ₂ ) The specimens were prepared by sintering at 4 ° C. and 950 ° C. for 4 hours. Sintered density, microstructure, dielectric and piezoelectric properties were analyzed after evaluation. As a result of the experiment, sintered density representing the degree of sintering and kp value, the electromechanical coefficient representing piezoelectric properties, are shown in Table 1 below.

Changes in Density and Electromechanical Coupling Coefficients with BBC Amount and Sintering Temperature <Density (g / cm ³ ) / kp (%)> 1wt% 3wt% 5wt% 7wt% 9wt% 900 ℃ 4.44 /- 6.55 / 47.7 7.15 / 50.8 7.22 / 46.4 6.95 /- 950 ℃ 4.75 /- 7.05 / 51.9 7.77 / 49.8 7.09 / 50.6 6.71 /-

For sintering, the density when the 1250 ℃, 2 hours, and the firing atmosphere is ^{7.21g / cm 3, 1250 ℃,} 4 hour and the atmosphere of the firing in accordance with the general sintering process, because it is 7.03g / cm ³ as shown in Table 1 amount BBC If less, 4 ~ 6g / cm ^{3 It} falls a lot, but in the case of 5wt% and 7wt% BBC did not fall to 7 ~ 7.8g / cm ³ at all. In the case of the electromechanical coupling coefficient, when the BBC is less than 1wt%, the piezoelectric properties are not shown, but in the case of 5wt% and 7wt%, the electromechanical coupling coefficient is increased by 50% rather than the electromechanical coupling coefficient (45%) of 1250 ℃. .

2. Reaction and diffusion blocking with Pt / ZrO ₂ at 900 ℃

As in Example 1, even if BBC is added, in order to obtain a dense PZT thick film, heat treatment of at least 900 ° C. to 1000 ° C. is inevitable, and the PZT component and the Si substrate may react by interdiffusion. In order to prevent this, an experiment was performed to insert a diffusion barrier. First, ZrO ₂ spin-coated by the sol-gel method was selected as the buffer region, and Pt or Ag-Pd screen-printed or thick Pt and thin Pt were used as the lower electrode. PZT / electrode (Pt, etc.) / ZrO ₂ / Si structure was prepared as shown in Table 2.

(PZT thick film manufacturing experiment for diffusion barrier selection) NO Board and Buffer Bottom electrode PZT formation 1000 ° C. 15 min Annealing Analysis method Visual observation resistance Judgment 51 ZrO ₂ / Si no × × XRD, SEM, EDX 52 ○ △ 53 Sputter Method Thick Pt × blur 0.94 △ 54 ○ blur 0.96 ◎ 55 Screen Printed Pt × 0.76 ○ 56 ○ 0.76 △ 57 Screen Printed Ag-Pt × 0.83 ○ 58 ○ 1.40 × 59 Sputtered Thin Pt × blur 1.70 △ 60 ○ Peeling ×

As a result of SEM, XRD and EDX photo analysis, the PZT surface was analyzed by XRD photo before and after heat treatment, and it was confirmed that it was sintered by SEM image. Since the XRD peak maintains (111) oriented Pt after the heat treatment of the sputtered thick platinum electrode in the absence of PZT, the sputtered platinum electrode is considered to have no Si diffusion. As shown in the SEM photograph of FIG. 10 for the PZT / Pt / ZrO ₂ / Si structure, ZrO ₂ and Pt layers acted as a barrier to suppress the diffusion of Si and PZT. Screen 11 that the look and observe the XRD peak in a structure of the heat treatment of the printer Pt electrode after the PZT / screen Pt / ZrO ₂ / Si is polycrystalline Pt is formed, and after PZT deposition heat treatment is changed in a similar crystal phase, and PbTiO ₃ Can be seen at This is understood to be a phenomenon due to the non-uniform distribution of the diffused Zr component to the PZT surface through the SEM photograph and EDX analysis as shown in FIG. 12. In addition, in the structure of PZT / screen Ag-Pd / ZrO ₂ / Si, which is the case of using a screen-printed Ag-Pd instead of Pt, polycrystalline Ag-Pd and silicon were formed after heat treatment at 900 to 1000 ° C. in FIG. 13. It can be seen from the XRD peak that after the PZT deposition heat treatment, the electrode and the buffer do not prevent the interdiffusion of Si and PZT, and thus change into a crystal phase similar to that of PbTiO ₃ . SEM and EDX analysis of the specimen as shown in FIG. 14 showed that Si was diffused to the PZT surface, the Zr component was unevenly distributed, and Ag and Pd were separated. In the case of using the sputtered thin Pt electrode, cracking and peeling occurred as in specimen 52 during PZT deposition drying.

On the other hand, when Pt was thinly formed as an electrode by using a sputtering method, Si was diffused to the PZT surface and the Zr component was unevenly distributed as shown in the SEM photograph and EDX analysis result of FIG. It can be seen that it did not suppress the diffusion. As a result of XRD analysis of the PZT layer obtained through this experiment, as shown in FIG. 16, it was possible to suppress diffusion of Si and PZT during heat treatment at 900-1000 ° C. for 54 specimens. As a result, the following conclusions were obtained.

A) The screen printed electrode and the thin Pt electrode sputtered do not suppress the diffusion of Si regardless of the buffer area.

B) When the sputtered thick Pt (approximately 6000 mV) electrode is deposited on the ZrO ₂ buffer, the diffusion of Si can be suppressed to maintain the PZT perovskite crystal phase even after 900-1000 ° C. heat treatment. In this experiment, the best condition was a sample of PZT screen-printed after forming a thick Pt sputter in the ZrO ₂ buffer region.

As described above, the piezoelectric plate forming method of the inkjet printer head using the piezoelectric material according to the present invention is a silk screen on silicon in consideration of the problem that the piezoelectric plate of the piezoelectric ceramic is mechanically processed, causing cracks at the edges and difficult to mass-produce. It is relatively simple to make a fine shape and to produce a thick film by sintering. At this time, since the diffusion barrier, the electrode, and the piezoelectric ceramic slurry are attached together on the silicon, the high sintering temperature is more than 2 hours. Thickening the diffusion barrier to prevent diffusion, but not enough and thick diffusion, considering that some of the silicon material diffuses into the diffusion barrier, the electrode, and the piezoelectric ceramic to break down the insulation and reduce the piezoelectric effect. In consideration of the fact that the prevention film suppresses the stretching movement of the piezoelectric ceramic, if the sintering temperature is lowered to 950 ° C. or lower without deterioration of the piezoelectric effect by using frit glass, the diffusion and reaction phenomenon is remarkably reduced. Inkjet heads can be made small enough The piezoelectric plate is capable of sufficiently driving is formed.

Therefore, the piezoelectric plate forming method according to the present invention lowers the sintering temperature, thereby reducing the energy consumption and enabling the use of inexpensive low melting point metal as the electrode material. In addition, since the thickness of the diffusion barrier is minimized, mechanical properties such as peeling are also improved. In the case of sintering at 1200 ℃, PbO is highly evaporated, so special containers and atmosphere powder are used.

Claims (4)

(A) a basis weight of PbO, ZrO ₂ and TiO by an appropriate amount; (B) mixing the basis weighted PbO, ZrO ₂ and TiO and calcining at 850 ° C. for 2 hours to form Pb (Zr _x Ti _1-x ) O ₃ single crystals; (C) adding an appropriate amount of frit glass powder to the Pb (Zr _x Ti _1-x ) O ₃ single crystal, mixing and pulverizing to form Pb (Zr _x Ti _1-x ) O ₃ powder; (D) adding an epoxy resin to the Pb (Zr _x Ti _1-x ) O ₃ and flit glass mixed powder to form a paste; (E) forming a piezoelectric plate pattern from the Pb (Zr _x Ti _1-x ) O ₃ and flit glass mixing paste; And (Bar) sintering the printed piezoelectric plate pattern at a temperature of 950 ° C. or less to form a piezoelectric plate; Piezoelectric plate forming method of a print head using a piezoelectric material comprising a. The method of claim 1, The piezoelectric plate forming method of the printhead using a piezoelectric material, characterized in that the piezoelectric plate pattern is formed by the silkscreen printing in the step (e). A nozzle plate and a diaphragm are formed on both sides of a bulk silicon substrate on which an ink chamber and an ink flow path are formed, with one partition interposed therebetween, and a piezoelectric plate attached to the nozzle of the nozzle plate and an outer side of the diaphragm with the ink chamber therebetween. In the piezoelectric plate forming method of an inkjet printer head using a piezoelectric material formed integrally to face each other, (A) a basis weight of PbO, ZrO ₂ and TiO by an appropriate amount; (B) mixing the basis weighted PbO, ZrO ₂ and TiO and calcining at 850 ° C. for 2 hours to form Pb (Zr _x Ti _1-x ) O ₃ single crystals; (C) adding an appropriate amount of frit glass powder to the Pb (Zr _x Ti _1-x ) O ₃ single crystal, mixing and pulverizing to form Pb (Zr _x Ti _1-x ) O ₃ powder; (D) adding an epoxy resin to the Pb (Zr _x Ti _1-x ) O ₃ and flit glass mixed powder to form a paste; (E) forming a piezoelectric plate pattern on an upper surface of the diaphragm with the Pb (Zr _x Ti _1-x ) O ₃ and flit glass mixing paste; And (Bar) sintering the printed piezoelectric plate pattern at a temperature of 950 ° C. or less to form a piezoelectric plate; Piezoelectric plate forming method of a print head using a piezoelectric material comprising a. The method of claim 3, The piezoelectric plate forming method of the printhead using a piezoelectric material, characterized in that the piezoelectric plate pattern is formed by the silkscreen printing in the step (e).