Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
  • B41J2/135—Nozzles
  • B41J2/16—Production of nozzles
  • B41J2/1621—Manufacturing processes
  • B41J2/1631—Manufacturing processes photolithography
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
  • B41J2/135—Nozzles
  • B41J2/14—Structure thereof only for on-demand ink jet heads
  • B41J2/14016—Structure of bubble jet print heads
  • B41J2/14088—Structure of heating means
  • B41J2/14112—Resistive element
  • B41J2/14129—Layer structure
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
  • B41J2/135—Nozzles
  • B41J2/16—Production of nozzles
  • B41J2/1601—Production of bubble jet print heads
  • B41J2/1603—Production of bubble jet print heads of the front shooter type
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
  • B41J2/135—Nozzles
  • B41J2/16—Production of nozzles
  • B41J2/1621—Manufacturing processes
  • B41J2/1626—Manufacturing processes etching
  • B41J2/1628—Manufacturing processes etching dry etching
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
  • B41J2/135—Nozzles
  • B41J2/16—Production of nozzles
  • B41J2/1621—Manufacturing processes
  • B41J2/1626—Manufacturing processes etching
  • B41J2/1629—Manufacturing processes etching wet etching
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
  • B41J2/135—Nozzles
  • B41J2/16—Production of nozzles
  • B41J2/1621—Manufacturing processes
  • B41J2/1632—Manufacturing processes machining
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
  • B41J2/135—Nozzles
  • B41J2/16—Production of nozzles
  • B41J2/1621—Manufacturing processes
  • B41J2/164—Manufacturing processes thin film formation
  • B41J2/1642—Manufacturing processes thin film formation thin film formation by CVD [chemical vapor deposition]
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
  • B41J2/135—Nozzles
  • B41J2/16—Production of nozzles
  • B41J2/1621—Manufacturing processes
  • B41J2/164—Manufacturing processes thin film formation
  • B41J2/1645—Manufacturing processes thin film formation thin film formation by spincoating
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
  • B41J2/135—Nozzles
  • B41J2/16—Production of nozzles
  • B41J2/1621—Manufacturing processes
  • B41J2/164—Manufacturing processes thin film formation
  • B41J2/1646—Manufacturing processes thin film formation thin film formation by sputtering

Definitions

• the present invention relates to a substrate for an ink jet head which discharges a functional liquid such as an ink to a recording medium including paper, plastic sheet, cloth, articles and the like; an ink jet head using the substrate; and a manufacturing method thereof.
• a head for use in ink jet recording there can be exemplified a constitution in which a plurality of discharge ports, ink flow paths connected to these discharge ports, and a plurality of electro-thermal conversion elements for generating thermal energy used to jet an ink are provided.
• Each of the electro-thermal conversion elements has a heating resistor and an electrode for supplying electric power to the heating resistor, and this electro-thermal conversion element is coated with an insulating film to secure insulation between the respective electro-thermal conversion elements .
• Each ink flow path is connected to a common liquid chamber at an end opposite to the discharge port of the ink flow path, and in the common liquid chamber, the ink supplied from an ink tank as an ink reservoir part is reserved.
• the ink supplied to the common liquid chamber is led to the respective ink flow paths so that the ink is held forming a meniscus in the vicinity of the discharge port.
• the electro-thermal conversion elements are selectively driven to generate thermal energy, and the thus generated energy is then utilized to rapidly heat the ink and to generate bubbles on a thermal action surface, so that the ink is discharged under a pressure caused by such a state change.
• the thermal action part of the ink jet head during the ink discharging time is heated by the heating resistor and hence exposed to a high temperature, and simultaneously, the thermal action part ⁇ ombinedly suffers a cavitation impact due to the bubbling and contraction of the ink, and a chemical action of the ink.
• This chemical action of the ink brings about the following phenomenon. Specifically, color materials, additives and the like contained in the ink are heated at a high temperature, whereby they are decomposed on a molecular level and change into hardly soluble substances, which are physically adsorbed on an upper protective layer. This phenomenon is called kogation. When the hardly soluble organic and inorganic substances are adsorbed on the upper protective layer in this way, thermal conduction from the heating resistor to the ink becomes uneven, and in consequence, the bubbling becomes unstable.
• a Ta film which can relatively withstand the cavitation impact and the chemical action of the ink has been formed so as to be a thickness of 0.2 to 0.5 ⁇ m, whereby both of life and reliability of the head has been intended.
• a curve (a) in Fig. 9 shows a change with time of surface temperatures of the upper protective layer from a moment when a voltage is applied to the heating resistor, in a case where a driving voltage
• V op 1.3 x V th (V th represents an ink bubbling threshold voltage), a driving frequency is set to 6 kHz and a pulse width is set to 5 ⁇ s. Furthermore, a curve (b) shows a growing state of formed bubbles from a moment when the voltage is applied to the heating resistor in a similar manner. As shown by the curve (a), the rise of the temperature starts from the moment when the voltage is applied, and a temperature rise peak is observed slightly behind a predetermined pulse time (because the heat from the heating resistor slightly late reaches the upper protective layer) . Afterward, the temperature mainly lowers due to thermal diffusion.
• the growth of the bubble starts from a time when the temperature of the upper protective layer reaches about 300°C, and after the maximum bubbling is reached, the bubbling stops. In the actual head, the above operation is repeated. In this way, the surface temperature of the upper protective layer rises up to, for example, about 600°C with the bubbling of the ink, which shows that ink jet recording is carried out with the thermal action at the high temperature. Accordingly, the upper protective layer which comes in contact with the ink is required to have film properties excellent in heat resistance, mechanical properties, chemical stability, oxidation resistance, alkali resistance and the like.
• noble metals As materials for use in the upper protective layer, in addition to the above-mentioned Ta film, noble metals, high-melting point transition metals, alloys of these metals, nitrides, borides, suicides or carbides of these metals, amorphous silicon or the like are known in the prior art.
• a process by dry etching is generally used in many cases.
• the upper protective layer with improved corrosion resistance to the ink although high durability can be maintained for a long time, it is predicted that a process of forming a desired pattern or the like by etching or the like becomes difficult.
• Figs. 8A to 8E illustrate it.
• the process by dry etching generally used in many cases may cause an insulating protective layer contacting the upper protective layer to be etched.
• etching selectivity between the insulating protective layer and the upper protective layer could be sufficiently secured as in a conventional substrate, it would be possible to etch the upper protective layer with the insulating protective layer being left.
• over-etching at a boundary portion with the upper protective layer may produce a step (between A and B in Fig. 8E) .
• the insulating protective layer becomes thinner at the boundary portion by etching so as to have a film thickness b smaller than a designed film thickness b, which leads to insufficient exertion of a protective function thereof.
• It is a still another object to provide a substrate for ink jet including a heating resistor generating thermal energy for discharging an ink from an ink discharge port, and an upper protective layer provided above the heating resistor and having a contacting surface with the ink, the upper protective layer being made of an amorphous alloy consisting of Ta and Cr in which the content of Ta is more than that of Cr, an ink jet head comprising the substrate, and a manufacturing method thereof.
• FIG. 1 is a fragmentally cross-sectional view showing a substrate for an ink jet head to which the present invention is applied.
• Figs. 2A, 2B, 2C, 2D, 2E, 2F, 2G and 2H are views illustrating a method for forming a jet element on the substrate for the ink jet head to which the present invention is applied.
• Fig. 3 is an exemplary view showing a film forming apparatus for forming respective layers of the substrate for the ink jet head to which the present invention is applied.
• Fig. 4 is an exemplary view showing one constitutional example of an ink jet recording apparatus equipped with the ink jet head to which the present invention is applied.
• Figs. 5A, 5B, 5C and 5D are explanatory views illustrating the states of burnt deposition and its separation in an upper protective layer.
• Figs. 6A, 6B and 6C are exemplary views showing cross-sections of heating elements observed in a discharge durability test.
• Fig. 7 is a graph showing an etching rate in relation to the content of Ta.
• Figs. 8A, 8B, 8C, 8D and 8E are views showing how the upper protective layer is subjected to dry etching.
• Fig. 9 is a graph illustrating changes in temperature and a bubbling state of the upper protective layer after applying a voltage.
• Fig. 1 is an exemplary fragmentally cross- sectional view showing a substrate for the ink jet head to which the present invention may be applied.
• reference numeral 101 denotes a silicon substrate
• reference numeral 102 denotes a heat accumulating layer made of a thermal-oxidized film
• Reference numeral 103 denotes an interlayer film made of an SiO film, SiN film or the like which also has a function of accumulating heat
• reference numeral 104 denotes a heat resistive layer
• reference numeral 105 denotes a metal wiring layer serving as wiring made of a metallic material such as Al, Al-Si, and Al-Cu
• reference numeral 106 denotes a protective layer made of an SiO film, SiN film or the like which also serves as an insulating layer.
• Reference numeral 107 denotes an upper protective layer provided on the protective layer 106 for protecting an electrothermal conversion element from chemical and physical impact arising from heating of the heating resistor.
• reference numeral 108 denotes a thermal action part in which heat generated in the heat resistive element of the heating resistive layer 104 acts on ink.
• the thermal action part in the ink jet head is a part which is exposed to high temperatures due to the heat generation in the heating resistor and mainly suffers cavitation impact arising from ink bubbling and bubbling contraction after bubbling or a chemical action of the ink.
• the thermal action part therefore, is provided with the upper protective layer 107 for protecting the electro-thermal conversion element from this cavitation impact or chemical action of the ink.
• This upper protective layer 107 is subjected to dry etching by a chlorine gas or the like after applying a mask of a predetermined pattern or wet etching by hydrofluoric acid, boric acid, hydrochloric acid or the like after applying a resist of a predetermined pattern to be patterned. Thereafter, on the upper protective layer 107, a jet element provided with a discharge port 110 for discharging the ink is formed using a flow path forming member 109.
• Figs. 2A to 2H illustrate a method for forming the jet element of the ink jet head, in which a liquid flow path and the discharge port are formed on the patterned upper protective layer 107.
• an Si0 2 film 502 is formed with a thickness of about 2 ⁇ m on a lower surface of a substrate for an ink jet head 501 (including the silicon substrate 101, the heat accumulating layer 102, the interlayer film 103, and the heating resistive layer 104, the metal wiring 105, the insulating protective layer 106 and the upper protective layer 107 subjected to predetermined patterning, respectively) under a temperature condition of 400°C by CVD method.
• reference numeral 507 corresponds to the thermal action part 108.
• a resist is applied on this Si0 2 film 502 to form an opening 511 by dry etching or wet etching after exposure and development
• the Si0 2 film 502 will serve as a mask when a through- hole 513 is formed later and the through-hole 513 will be formed from the opening 511.
• Etching of the Si0 2 film 502 is performed, for example, in the case of dry etching, by reactive ion etching or plasma etching using CF 4 as an etching gas, and in the case of wet etching, using buffered hydrofluoric acid.
• a PSG (phosphosilicate glass) film 503 is formed with a thickness of about 20 ⁇ m on the upper surface side of the substrate under a temperature condition of 350°C by CVD method.
• the PSG film 503 is processed to form a predetermined flow path pattern.
• a silicon nitride film 504 is formed with a thickness of about 5 ⁇ m on the PSG film 503 formed in the flow path pattern under a temperature condition of 400°C by CVD method. At this time, an opening 512 is also filled with the silicon nitride film.
• the film thickness of the formed silicon nitride film defines a thickness of the discharge port and the film thickness of the PSG film formed previously defines a gap of the ink flow path, thereby largely affecting ink discharge properties of the ink jet, the film thicknesses of the silicon nitride film and the PSG film are determined according to the required properties.
• the through-hole 513 is formed on the silicon substrate 501 as an ink supply port by using the Si0 2 film as a mask, which has been shapened previously.
• ICP inductively coupled plasma
• etching method with CF 4 and oxygen used as an etching gas is preferable because it does not electrically damage the substrate and it allows the formation at low temperature.
• a discharge port 514 is formed by dry etching using the silicon nitride film 504 as a resist.
• reactive ion etching which is excellent at anisotropic etching, is used.
• the PSG film 503 is eluted and removed from the discharge port 514 and the through-hole 513 using buffered hydrofluoric acid. Thereafter, a water repellent film containing Si is formed on a surface of the discharge port by plasma polymerization and an ink supply member (not shown) is attached on the bottom side of the Si substrate 501 to complete the ink jet head.
• an ink supply member (not shown) is attached on the bottom side of the Si substrate 501 to complete the ink jet head.
• wet processes may be used to manufacture an ink jet head.
• a resist is applied as a soluble solid layer, which will become an ink liquid flow path in the end, by spin coat method.
• the resist made of polymethyl isopropenyl keton, acts as a negative resist and is patterned in a shape of the ink liquid flow path by using a photolithography technique. Subsequently, a coating resin layer is formed to form the liquid flow path or the discharge port.
• a silane coupling treatment or the like may be performed as required in order to improve adhesion.
• the coating film layer can be applied on the substrate for the ink jet head with the ink liquid flow path pattern formed by a coating method which can be selected from well-known coating methods.
• an ink liquid supply port corresponding to 513 is formed from the back side of the substrate for the ink jet head by using anisotropic etching method, sand blast method, anisotropic plasma etching method or the like.
• anisotropic etching method tetramethyl hydroxylamine (TMAH) , NaOH, KOH or the like may be used to form the ink liquid supply port.
• TMAH tetramethyl hydroxylamine
• KOH tetramethyl hydroxylamine
• the thermal action part of the ink jet head is a part which is exposed to high temperatures due to the heat generation in the heating resistor and mainly suffers cavitation impact arising from ink bubbling and contraction or a chemical action of the ink. Accordingly, the thermal action part is provided with the upper protective layer 107 for protecting the electro-thermal conversion element from this cavitation impact and the chemical action of the ink.
• the upper protective layer 107 which comes in contact with the ink is required to have film properties excellent in heat resistance, mechanical properties, chemical stability, oxidation resistance, alkali resistance and the like.
• an amorphous alloy consisting of Ta and Cr in which the content of Ta is larger than that of Cr.
• the amorphous alloy according to the present invention represents an alloy having an amorphous structure, which exhibits no peak showing the presence of a specific crystal plane (or if any, extremely low peaks) and a broad diffraction pattern in crystal structure analysis by X-ray diffraction method.
• Supposing the content of Cr in the amorphous alloy is represented by y, it is preferable that 0 at.% ⁇ y ⁇ 30 at.% is satisfied. Furthermore, it is more preferable that 0 at.% ⁇ y ⁇ 25 at.% is satisfied.
• the film thickness of this upper protective layer 107 is selected from a range of 50 nm to 500 nm, preferably 100 nm to 300 nm.
• the film stress of this upper protective layer has at least compression stress and is preferably not more than 1.0 x 10 10 dyn/cm 2 .
• the durability cannot be improved. It can be supposed that this is because an increase of the Ta component results in a decrease of the SUS component, which decreases a Cr component considered to contribute to the durability.
• the upper protective layer 107 to which the present invention is applied is amorphized by adding chemically stable Cr to the conventional Ta layer and spots where crystal interfaces exist, which become starting points of corrosive reactions, are significantly reduced, thereby improving the corrosion resistance as compared to the conventional Ta layer.
• the upper protective layer 107 to which the present invention is applied has a composition of a high Ta content
• the surface of the upper protective layer slightly corrodes to suppress the deposition of the kogation product, which allows the same degree of discharge performance as that of the conventional Ta layer to be maintained.
• Figs. 5A to 5D differences between the conventionally used Ta layer and the TaCr film according to the present invention will be described.
• Fig. 5A is an exemplary view showing the upper protective layer 107 and an interface with the ink in the case where the upper protective layer 107 is made of the conventional Ta layer.
• a kogation product 301 is deposited in the thermal action part by driving the heating resistor.
• Ta of the upper protective layer 107 makes up an oxidized film 302 by heat generated during driving. The film thickness of this oxidized film is increased as the number of driving pulses is increased, and the oxidized film is formed wholly in the film thickness direction in the end. Part of this oxidized film 302 is separated from the upper protective layer 107 together with the deposited kogation product 301 as shown in Fig. 5B.
• the deposition of the kogation product 301 is suppressed to maintain the discharge performance and the film thickness of the upper protective layer 107 is reduced.
• the oxidized film 302 in the interface with the ink is formed very thinly on a metal layer 303 as compared to that of the conventional Ta layer.
• this oxidized film 302 is separated from the upper protective layer 107 together with the deposited kogation product 301 to suppress the deposition of the kogation product 301, which allows the discharge performance to be maintained.
• the oxidized film 302 is formed very thinly as compared to that of the conventional Ta layer, a decrease in the film thickness of the upper protective layer 107 is small, which supposedly improves the durability as compared to the conventional Ta layer.
• the upper protective layer 107 is amorphized by adding chemically stable Cr while having a proper content of Ta, which can improve the corrosion resistance while maintaining the discharge performance.
• the upper protective layer 107 has a composition of a high Ta content, a reduction in the etching rate of the upper protective layer by a chlorine gas can be suppressed to be slight as compared to the conventional Ta. Thereby, the etching quantity of the insulating protective layer is reduced and the reliability can be maintained.
• the upper protective layer 107 which can be manufactured by various film forming methods, generally, may be formed by magnetron sputtering method using a radio frequency (RF) power source or a direct current (DC) power source.
• RF radio frequency
• DC direct current
• Fig. 3 shows an overview of a sputtering apparatus for forming an upper protective layer.
• reference numeral 4001 denotes two types of targets consisting of a Ta target and a Cr target.
• Reference numeral 4002 denotes a flat magnet
• reference numeral 4011 denotes a shutter for controlling film formation on a substrate
• reference numeral 4003 denotes a substrate holder
• reference numeral 4004 denotes the substrate
• reference numeral 4006 denotes a power source connected to the target 4001 and the substrate holder 4003.
• reference numeral 4008 denotes an external heater provided in such a manner as to surround an outer peripheral wall of a film formation chamber 4009.
• the external heater 4008 is used to adjust the ambient temperature of the film formation chamber 4009.
• An internal heater 4005 for controlling the temperature of the substrate is provided on the back surface of the substrate holder 4003.
• the temperature control of the substrate 4004 is preferably performed using both internal and external heaters 4005 and 4008.
• the film formation using the apparatus of Fig. 3 is performed as follows. Firstly, air is evacuated from the film formation chamber 4009 up to 1 x 10 "5 to 1 x 10 "6 Pa using an evacuating pump 4007. Next, an argon gas is introduced from a gas introduction port 4010 to the film formation chamber 4009 via a massflow controller (not shown) . At this time, the internal heater 4005 and the external heater 4008 are adjusted so as to obtain a predetermined substrate temperature and ambient temperature. Then, power is applied to the target 4001 from the power source 4006, and sputtering discharging is performed to form a thin film on the substrate 4004 while adjusting the shutter 4011.
• the two types of targets that is the Ta target and the Cr target may be used to form a thin film by binary simultaneous sputtering method in which power is applied from two power sources connected to the respective targets.
• the power applied to the respective targets may be controlled separately.
• a plurality of alloy targets whose compositions have been adjusted in advance are prepared and each of the alloy targets is sputtered separately or two alloy targets or more are sputtered simultaneously to form a thin film with a desired composition.
• the substrate when the upper protective layer 107 is formed, the substrate is heated up to 100°C to 300°C to achieve strong film adhesion.
• a film by sputtering method capable of forming particles having comparatively large kinetic energy as describe above strong film adhesion can be achieved.
• the upper protective layer 107 made of the amorphous alloy film according to the present invention is preferably applicable whether the protective layer 106 provided under the upper protective layer 107 is thick or thin.
• Fig. 4 is an outline view showing one example of an ink jet apparatus to which the present invention may be applied.
• a recording head 2200 is mounted on a carriage 2120 engaged with a spiral groove 2121 of a lead screw 2104 which rotates in conjunction with reciprocal rotation of a driving motor 2101 via driving force transmission gears 2102 and 2103.
• the recording head 2200 is moved reciprocally in arrow directions a and b along a guide 2119 together with the carriage 2120.
• a paper pressing plate 2105 for recording paper P fed on a platen 2106 by a recording medium supply device presses the recording paper to the platen 2106 across the movement direction of the carriage 2120.
• Reference numerals 2107 and 2108 denote photo- couplers which are home position detecting means for confirming the presence of a lever 2109 in this region and switching the rotative direction of the driving motor 2101.
• Reference numeral 2110 denotes a member supporting a cap member 2111 for capping the entire recording head 2200
• reference numeral 2112 denotes sucking means for sucking the inside of the cap member 2111, by which suction recovery of the recording head 2200 is performed via a cap opening 2113.
• Reference numeral 2114 denotes a cleaning blade
• reference numeral 2115 denotes a moving member " enabling this blade to move in the anteroposterior direction. These are supported by a body supporting plate 2116. It is understood that as the cleaning blade 2114, a well-known cleaning blade as well as this embodiment can be applied to this apparatus .
• reference numeral 2117 denotes a lever for starting suction for suction recovery which moves with the movement of a cam 2118 engaged with the carriage 2120, and thereby the movement of a driving force from the driving motor 2101 is controlled by publicly known transmission means such as clutch changeover.
• a recording control unit (not shown) for sending a signal to a heating portion provided in the recording head 2200 or controlling driving of the above-mentioned mechanisms is arranged on the side of a body of the recording apparatus.
• the ink jet recording apparatus 2100 constituted as described above performs recording with respect to the recording paper P fed on the platen 2106 by the recording medium supply device while moving the recording head 2200 reciprocally across the entire width of the recording paper P, and since the recording head 2200 is manufactured in the above-mentioned manner, the apparatus can achieve high-precision, high-speed recording.
• the present invention will be described in more detail referring to film formation examples of the upper protective layer and examples of the ink jet head using the upper protective layer made of this alloy film or the like. However, the present invention does not be limited by such examples .
• a Ta film was formed in the film formation example 1, a crystallized TaCr film in the film formation example 2, and TaCr films of amorphous structure in the film formation examples 3 to 6, with a film thickness of 200 nm on the thermal oxidized film of the silicon wafer.
• the Ta target and a Ta 18 Fe 61 Cr 15 Ni 6 target were used and power applied to the respective targets were set as Table 1 to obtain a film formation example 7 of amorphous structure. Furthermore, the Cr target and the Ta 18 Fe 61 Cr 15 Ni 6 target were used and power applied to the respective targets were set as Table 1 to obtain a film formation example 8 of amorphous structure.
• the film stress of the respective samples was determined based on the amounts of substrate deformation before and after film formation. As a result, a tendency was observed that as Cr composition is higher, film stress changed from compression stress to tensile stress, and film adhesion was reduced. By making the film stress have at least compression stress and setting it to 1.0 x 10 10 dyn/cm 2 or less, similarly strong film adhesion could be obtained.
• an Si substrate or an Si substrate with a driving IC embedded was used as a sample substrate to be evaluated with respect to ink discharge properties according to the present invention.
• an Si substrate or an Si substrate with a driving IC embedded was used.
• Si0 2 with a thickness of 1.2 ⁇ m was formed by sputtering method, CVD method or the like. Then, a heating resistor 104 represented in a composition formula of Ta 40 Si 21 N 39 with a thickness of 50 nm was formed by reactive sputtering method using a Ta-Si target. At this time, the substrate temperature was
• An Al film was formed with a thickness of 200 nm as metal wiring 105.
• the upper protective layer 107 may be patterned by wet etching using hydrofluoric acid instead of dry etching to manufacture a substrate for an ink jet head.
• the ink jet head was manufactured using the substrate for ink jet manufactured in either method. Then, discharge properties were evaluated using this ink jet head mounted on such an ink jet recording apparatus as shown in Fig. 4.
• V th represents a bubbling threshold voltage at which the ink is discharged.
• Example 1 Although the discharge speed was measured after applying the driving signal of 1 x 10 8 pulses, no sufficiently major decrease could be observed to affect ink discharge properties.
• TaCr films having different compositions were formed with a thickness of 230 nm using a similar method to that of Example 1 to be evaluated with respect to ink discharge properties. The results are shown in Table 2. (Comparative Examples 1 to 3)
• Example 2 Ink discharge properties were evaluated using a similar method to that of Example 1. As comparative examples, a Ta film, a Ta 40 Cr 60 film, and a Ta 28 Fe 52 Cr 15 Ni 5 film each having a thickness of 230 nm were evaluated. The results are shown in Table 2.
• Example 4 A discharge durability test was conducted using a similar ink jet head to that of Example 1. In this test, service life was detected when the jet was continued at a driving frequency of 5 kHz with a pulse width set to 1 ⁇ sec until the ink jet recording head was disabled to jet ink. At this time, the driving voltage V op was V th x 1.15. In addition, an ink containing about 4% of a bivalent metal with a nitric acid group, Ca(N0 3 ) 2 • 4H 2 0 was used. The results are shown in Table 3. As shown in Table 3, even when the driving signal was continuously applied up to 1.0 x 10 9 pulses to continuously jet the ink, stable jet was possible. (Examples 5 and 6)
• Ink jet heads were prepared in a similar method to that of Example 4 except that a Ta 74 Cr 26 film (in Example 5) and a Ta 70 Cr 30 film (in Example 6) were formed as the upper protective layers 107, respectively. Jet proof-tests were conducted in a similar method to that of Example 4 using these ink jet heads. The results are shown in Table 3. (Comparative Examples 4 and 5) Ink jet heads were prepared in a similar method to that of Example 4 except that a Ta film (in Comparative Example 4) and a film (in Comparative Example 5) were formed as the upper protective layers 107, respectively. Jet proof-tests were conducted in a similar method to that of Example 4 using these ink jet heads. The results are shown in Table 3.
• FIG. 6A shows an initial state of Example 4 and Comparative Example 4
• reference numeral 401 denotes a layer corresponding to the upper protective layer 107 which is the Ta 78 Cr 22 film in Example 4 and the Ta film in Comparative Example 4.
• Fig. 6B is an exemplary cross-sectional view after the discharge durability test was conducted until the driving signal of 1.0 x 10 9 pulses was applied to the heating resistor of the ink jet head of Example 4, and reference numeral 402 denotes an oxidized film formed on the upper protective layer 107.
• 6C is an exemplary cross-sectional view of the unbroken heating resistor when the part of the heating resistors of the ink jet head of Comparative Example 4 were broken before reaching the application of the driving signal of 4 x 10 8 pulses, and reference numeral 403 denotes an oxidized film formed on the upper protective layer 107. From these results, in Comparative Example 4, it was observed that most of Ta on the thermal action part was oxidized as shown in the oxidized film 403 and there existed regions which were locally depressed deeply in the oxidized film. It can be supposed that in the broken heating resistor of Comparative Example 4, this corrosion reached the heating resistive layer 104, which caused breaking.
• Example 4 the extremely thin oxidized film 402 was formed on the upper protective layer 107 (401) on the thermal action 108.
• the thickness was about 10 nm.
• the entire film thickness was slightly decreased to about 190 nm, most of the film remained in a metal state. As a result, it can be supposed that favorable discharge properties were maintained while maintaining durability in spite of the generation of the kogation product by a structure in which such an oxidized film 402 was formed.
• the upper protective layer of the substrate for ink jet used in the above-mentioned experiments brings about an exceptional effect.
• the results are shown in Fig. 7.
• Fig. 7 shows that in the case where the dry etching was performed using the Cl 2 gas, the etching rate depends on the content of Ta and is decreased with a decrease of the content of Ta.
• a reliability test was conducted in order to evaluate reliability of the protective layer after the upper protective layer 107 was subjected to dry etching.
• Figs. 8A to 8E are exemplary cross-sectional views of a substrate for ink jet.
• the reference numeral 106 denotes the insulating protective layer
• the reference numeral 107 denotes the upper protective layer
• reference numeral 521 denotes a heater substrate including the silicon substrate 101, the heat accumulating layer 102, the interlayer film 103, the heating resistive layer 104, and the metal wiring 105.
• Reference numeral 522 abstractly illustrates the thermal part 108 formed of the heating resistor layer 104 and the metal wiring 105 with such a constitution as shown in Fig. 1.
• reference numeral 523 denotes a resist
• Example 7 The reliability tests were conducted in a similar method to that of Example 7. As comparative examples, a Ta film, a Ta 40 Cr 60 film, a Ta 28 Fe 52 Cr 15 Ni 5 film, and a Ta 17 Fe 54 Cr 25 Ni 4 film were evaluated. The results are shown in Table 4.
• the reliability of the insulating protective layer can be maintained even in a region having a low content of Ta by making the TaCr film thinner or by selectively changing a base material to a proper one, it is preferable that the content of Cr is 30 at.% or less in order to strike a balance between the durability and the reliability of the insulating protective layer.

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