Chip manufacturing method and liquid ejecting head manufacturing method

A liquid ejection apparatus manufacturing method includes forming a metallic film in at least the section to be cut of a bonding surface between the flow path forming substrate (a second substrate) and the protection substrate (a first substrate); forming a first fragile section on the protection substrate by irradiating the section to be cut of the protection substrate bonded to the flow path forming substrate from the protection substrate side with a laser beam whose condensing point is focused thereon, and forming a second fragile section on the flow path forming substrate by melting the metallic film of the section to be cut; and dividing the protection substrate and the flow path forming substrate bonded to each other along the first fragile section and the second fragile section.

BACKGROUND

1. Technical Field

The present invention relates to a chip manufacturing method of separating a first substrate and a second substrate bonded to each other into chips, a liquid ejecting head manufacturing method, and a liquid ejecting apparatus manufacturing method.

2. Related Art

As a liquid ejecting head used in an ink jet printer and the like, for example, an ink jet recording head that is obtaining by laminating a nozzle plate having an nozzle opening, a flow path forming substrate provided with a vibrating plate or a piezoelectric element and a reservoir forming substrate has been known. JP-A-2008-119905 discloses a manufacturing method of dividing the flow path forming substrate and the reservoir forming substrate bonded to each other into a plurality of silicon devices with a laser beam. The manufacturing method discloses forming an elastic film made of silicon dioxide on a silicon substrate, forming an insulator film made of zirconium oxide on the elastic film, bonding the reservoir forming substrate on the insulator film in a section to be cut using an adhesive, forming a concave portion on the flow path forming substrate of the section to be cut by leaving the elastic film and the insulator film thereon, and then irradiating the reservoir forming substrate with the laser beam. In this case, a condensing point of the laser beam is focused within the reservoir forming substrate to leave a connection section on a surface layer, and therefore a fragile section having a predetermined width is formed within the reservoir forming substrate. Then, an external force is applied to the flow path forming substrate and the reservoir forming substrate, and therefore the flow path forming substrate and the reservoir forming substrate are divided into a plurality of the liquid ejecting heads along the fragile section.

The above-described flow path forming substrate is provided with a communication section configuring a portion of the reservoir. Therefore, the liquid ejecting head becomes long in the longitudinal direction of a pressure generation chamber. Therefore, it is disclosed that the size of the liquid ejecting head in the longitudinal direction of the pressure generation chamber is reduced in a way that the reservoir is formed out of the flow path forming substrate and a portion of a wall surface configuring the reservoir is configured by a side wall of the flow path forming substrate and a protection substrate (see JP-A-2011-62830).

The technique disclosed in JP-A-2008-119905 is that the elastic film made of the silicon dioxide and the insulator film made of the zirconium oxide are left in the section to be cut of the flow path forming substrate without a metallic film. The elastic film and the insulator film transmit the laser beam whose condensing point is focused on the reservoir forming substrate and thus do not become the fragile section. Therefore, when the external force is applied to the flow path forming substrate and the reservoir forming substrate, these substrates are not divided along the fragile section of the reservoir forming substrate. On the other hand, in order to remove the elastic film and the insulator film of the section to be cut, another step is required.

Even when the reservoir is formed out of the flow path forming substrate in order to reduce a size of the liquid ejecting head in the longitudinal direction of the pressure generation chamber, at least the elastic film made of the silicon dioxide is left in the section to be cut of the flow path forming substrate, which becomes an edge of the reservoir, without the metallic film. Similarly, since the elastic film through which the laser beam whose condensing point is focused on the reservoir forming substrate is transmitted does not become the fragile section, when the external force is applied to the flow path forming substrate and the protection substrate, these substrates are not divided along the fragile section of the reservoir forming substrate. In addition, the edge of the reservoir side cannot provide a lead electrode for connecting the reservoir to a drive circuit of a piezoelectric element.

The above-described problems are similarly present in various methods of separating a first substrate and a second substrate bonded to each other into chips.

SUMMARY

An advantage of some aspects of the invention is to simplify a chip manufacturing process.

According to an aspect of the invention, there is provided a chip manufacturing method of separating a first substrate and a second substrate bonded to each other into chips at a section to be cut, the method including: forming a metallic film in at least the section to be cut of a bonding surface between the first substrate and the second substrate; forming a first fragile section on the first substrate by irradiating the section to be cut of the first substrate bonded to the second substrate from the first substrate side with a laser beam whose condensing point is focused, and forming a second fragile section on the second substrate by melting the metallic film of the section to be cut; and dividing the first substrate and the second substrate bonded to each other along the first fragile section and the second fragile section.

When the section to be cut of the first substrate bonded to the second substrate is irradiated from the first substrate side with a laser beam whose condensing point is focused thereon, the first fragile section is formed on the first substrate. The section to be cut of the substrate of this stage becomes the fragile section, and the substrates are not divided from each other. In addition, even if the section to be cut of the second substrate is made of material transmitting the laser beam, the metallic film of the section to be cut is melted, and thus the second fragile section is formed on the second substrate. Therefore, even if another step such as cutting or removing the section to be cut of the second substrate is not performed, it is possible to easily divide the first substrate and the second substrate along the first fragile section and the second fragile section in the subsequent dividing. Therefore, in the aspect, it is possible to simplify the chip manufacturing step.

According to another aspect of the invention, there is provided a liquid ejecting head manufacturing method which includes separating a flow path forming substrate having a pressure generation chamber communicating with a nozzle opening and an piezoelectric element applying pressure to the pressure generation chamber, and a protection substrate located above the piezoelectric element and bonded to the flow path forming substrate at a section to be cut, the method including: forming a metallic film in at least the section to be cut of a bonding surface between the flow path forming substrate and the protection substrate; forming a first fragile section on the protection substrate by irradiating the section to be cut of the protection substrate bonded to the flow path forming substrate from the protection substrate side with a laser beam whose condensing point is focused thereon, and forming a second fragile section on the flow path forming substrate by melting the metallic film of the section to be cut; and dividing the protection substrate and the flow path forming substrate to each other along the first fragile section and the second fragile section.

Furthermore, the invention has an aspect of a liquid ejecting apparatus manufacturing method including the above-described liquid ejecting head manufacturing method.

When the section to be cut of the protection substrate bonded to the flow path forming substrate is irradiated from the protection substrate side with a laser beam whose condensing point is focused thereon, the first fragile section is formed on the protection substrate. The section to be cut of the substrate of this stage becomes the fragile section, and the substrates are not divided from each other. In addition, even if the section to be cut of the flow path forming substrate is made of material transmitting the laser beam, the metallic film of the section to be cut is melted, and thus the second fragile section is formed on the flow path forming substrate. Therefore, even if another step such as cutting or removing the section to be cut of the flow path forming substrate is not performed, it is possible to easily divide the protection substrate and the flow path forming substrate along the first fragile section and the second fragile section in the subsequent dividing. Therefore, in the embodiment, it is possible to simplify the liquid ejecting head manufacturing step.

Herein, the metallic film may be formed on the second substrate such as the flow path forming substrate, and may be formed on the first substrate such as the protection substrate. The metallic film may be formed over the entire bonding surface of the substrate, and may be formed only a portion including the section to be cut of the bonding surface of the substrate.

There may be a bonding material of an adhesive between the first substrate and the second substrate.

According to the aspect, a vibrating plate configuring a portion of a wall surface of the pressure generation chamber may be formed on the bonding surface of the flow path forming substrate, the metallic film may be formed on the vibrating plate of the section to be cut of the flow path forming substrate, and a region of an opposite side to the vibrating plate in the section to be cut of the flow path forming substrate may be removed, and then the forming of the fragile sections may be performed. The section to be cut of the flow path forming substrate is thinned, and thus the second fragile section is formed. Therefore, it is possible to more reliably separate the substrates. In particular, when the silicon oxide layer is formed on the bonding surface of the flow path forming substrate, and the metallic film is formed on the silicon oxide layer, it is possible to divide the substrates favorably.

According to the aspect, the pressure generation chamber may be formed on a surface of the opposite side to the vibrating plate of the flow path forming substrate and the region of the opposite side to the vibrating plate in the section to be cut of the flow path forming substrate may be removed, and a protection film having liquid resistance may be formed in inner surfaces of the pressure generation chamber and the removed region, and then the forming of the fragile sections may be performed. In this case, it is possible to provide a preferred manufacturing method that suppresses an erosion of the flow path forming substrate due to the liquid.

When as material of the metallic film, at least a portion of material of a lead electrode led out from the piezoelectric element on the vibrating plate may be used, it is possible to form the metallic film of the section to be cut when forming the lead electrode, and to reduce the manufacturing cost of the liquid ejecting head. In particular, when as material of the metallic film, at least the same material as material of a close contact layer of the lead electrode may be used, it is possible to form the metallic film in a preferred a thinness.

According to the aspect, the reservoir that accommodates liquid supplied to the pressure generation chamber is outwardly attached to chips formed in the dividing. In this case, it is possible to provide a liquid ejecting head manufacturing method suitable for miniaturizing the pressure generation chamber in the longitudinal direction.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, embodiments of the invention will be described. The embodiments described below merely exemplify the invention.

1. Example of Liquid Ejecting Head Obtained from Manufacturing Method of the Invention

FIG. 1Ais a vertical cross-sectional view schematically illustrating a state in which fragile sections (W1, W2) are formed with an irradiation of a laser beam LA1.FIG. 1Bis a vertical cross-sectional view illustrating a state in which substrates (10,50) are divided along the fragile sections (W1, W2).FIG. 2is an exploded perspective view explodedly illustrating a main portion of a recording head1that is an example of a liquid ejecting head obtained from a manufacturing method of the invention for convenience.FIG. 3Ais a plan view illustrating an outline of a configuration of the recording head1.FIG. 3Bis a vertical cross-sectional view in which one segment of the recording head1is broken at a position of IIIB-IIIB ofFIG. 3A. A microstructure having a possibility to remain in a vicinity of a cutting section LN2after a division of the substrates is omitted in the drawings. D1denotes the width direction of a pressure generation chamber12. D2denotes the longitudinal direction of the pressure generation chamber12orthogonal to the width direction D1. D3denotes the thickness direction of a flow path forming substrate (a second substrate)10, a vibrating plate16, a protection substrate (a first substrate)50and the like, that is, the depth direction of the pressure generation chamber12. To easily understand, an enlargement ratio of the width direction D1and the thickness direction D3is greater than that of the longitudinal direction D2, and each of drawings may not be matched.

A positional relationship described herein is merely an illustration for describing the invention, and does not limit the invention. Even if a second electrode is disposed in positions other than a first electrode, for example, a lower position, a right position, a left position and the like, which is included in an aspect of the invention.

In a chip C1of the recording head1illustrated inFIG. 2, a nozzle plate70formed with a nozzle opening71, the flow path forming substrate (the second substrate)10formed with a vibrating plate16, an piezoelectric element3and a lead electrode45, and the protection substrate (the first substrate)50of the flow path forming substrate10are laminated in this order. A liquid flow path such as the pressure generation chamber12communicating with the nozzle opening71, a communication section13and an ink supply port14is formed within the flow path forming substrate10. As illustrated inFIG. 3B, a protection film80is formed on the inner surface of the liquid flow paths (12to14) in order to suppress erosion due to the liquid flowing through the liquid flow path. In the recording head1, a reservoir9accommodating the liquid to be supplied to the pressure generation chamber12is outwardly attached to the chip C1. The reservoir9is connected to the section to be cut LN2of the divided chips C1. Therefore, the liquid within the reservoir9flows into the chip C1from the outside of the pressure generation chamber in the longitudinal direction D2.

A liquid ejecting apparatus illustrated as a recording apparatus200illustrated inFIG. 10includes the liquid ejecting head as above described.

The flow path forming substrate10may be made of a silicon single crystal substrate having a relatively thick thickness such as approximately 500 to 800 μm, and having a high rigidity. In the flow path forming substrate10, segments SG1are partitioned from each other by partitions11, and long liquid flow paths (12to14) are formed for each segment SG1. The ink supply port14has a width narrower than that of the pressure generation chamber12and the communication section13. The respective liquid flow paths (12to14) are arranged in the width direction D1that is an arrangement direction of the pressure generation chamber12.

The vibrating plate16has an elastic film16aformed on a silicon substrate15, and an insulator film16bformed on the elastic film16a, and configures a portion of a wall surface of the pressure generation chamber12. The elastic film16amay be made of silicon oxide (SiOx), for example, and the insulator film16b, may be made of zirconium oxide (ZrOx), for example. The thickness of the vibrating plate16is not particularly limited as long as it has elasticity, but may be approximately 0.5 to 2 μm, for example.

The piezoelectric element3has a piezoelectric body layer30, a lower electrode (a first electrode)20disposed on the pressure generation chamber12side of the piezoelectric body layer30, and an upper electrode (a second electrode)40disposed on the other side of the piezoelectric body layer30, and applies a pressure to the pressure generation chamber12. A substantial active section4of the piezoelectric element3becomes an area in which the piezoelectric body layer30is interposed between the lower electrode20and the upper electrode40. When the piezoelectric element is a common lower electrode structure, a position of an active end of an active section4becomes a boundary position of the upper electrode40. When the piezoelectric element is a common upper electrode structure, a position of the active end of the active section4becomes a boundary position of the lower electrode20. The piezoelectric element3is provided with the lead electrode45led out in order to connect to a drive IC (a semiconductor integrated circuit)65.

The lead electrode45has a close contact layer46formed on the vibrating plate16, and a main metallic layer47formed on the close contact layer46. As constituent metal of the main metallic layer47, gold (Au), platinum (Pt), aluminum (Al), copper (Cu), mixtures thereof and the like may be used. The thickness of the main metallic layer47may be approximately, 0.5 to 1.5 μm, for example. For the close contact layer46, nickel-chromium (NixCr1-x; 0<x <1), nickel (Ni), chromium (Cr), titanium (Ti) and the like may be used. The thickness of the close contact layer46may be approximately 30 to 70 nm, for example. Of course, when a close contact force between the vibrating plate16and the metallic layer47is sufficient, it is possible to omit the close contact layer46. In addition, a layer other than layers46and47thereof may be provided on the lead electrode45. The drive IC65is electrically connected to the lead electrode45via a drive wiring66to drive the arranged piezoelectric element3. Of course, the drive circuit of the piezoelectric element3is not limited to the IC. For the drive wiring66, a conductive wire such as a bonding wire may be used.

The piezoelectric body layer30is essentially formed on the upper surface of the lower electrode20in an area corresponding to at least the pressure generation chamber12. For example, for the piezoelectric body layer30, material having a perovskite structure such as ferroelectrics such as PZT (lead zirconate titanate, Pb (Zrx, Ti1-x) O3), material obtained by adding metal oxide such as niobium oxide, nickel oxide and magnesium oxide to the ferroelectrics, non-lead-based perovskite oxide such as (Bi, Ba) (Fe, Ti) O3and material obtained by adding metal such as manganese to a B site of the non-lead based perovskite oxide may be used.

The thickness of the piezoelectric body layer30is not particularly limited, but may be approximately 0.2 to 5 μm for example.

As constituent metal of the electrodes (20,40), one or more kinds of Pt (platinum), Au, Ir (iridium), Ti (titanium) and the like may be used. The constituent metal may be in a state of compound such oxide, may be in a state which that is not compound, may be in a state of alloy, may be in a state of single metal and may contain another metal in a small molar ratio while setting the metal as a main component. The thickness of the electrodes (20,40) is not particularly limited, but may be approximately 10 to 500 nm, for example.

For the protection film80provided in the inner surface of the liquid flow paths (12to14), material having a liquid resistance may be used. The protection film80suppresses the erosion of the flow path forming substrate10due to the liquid. The thickness of the protection film80is not particularly limited, but may be approximately 30 to 70 nm, for example. It is preferable that material having an ink resistance (a kind of liquid resistance) be material having alkali-resistant material. Although it is preferable that such material be tantalum oxide (TaOx) such as tantalum pentoxide (a stoichiometric ratio Ta2O5), material oxide such as zirconium oxide (a stoichiometric ratio ZrO2) may be used according to a PH value of the ink, and material containing other materials (for example, metal oxide) in the tantalum oxide may be used. The protection film may be a single layer, and may be a laminated film such as a film obtained by laminating a tantalum oxide layer and other material layers.

The protection substrate50is bonded to the flow path forming substrate10by an adhesive55, for example. The protection substrate50is referred to as a sealing plate located above the piezoelectric element3to protect the flow path forming substrate10, particularly, the piezoelectric element on the vibrating plate16. A piezoelectric element holding section52formed in an area opposing the piezoelectric element3has a space not to hinder operation of the piezoelectric element3. For example, for the protection plate50, a silicon single crystal substrate, glass, ceramic material, metal, resin and the like may be used. When the silicon substrate is used, the silicon oxide (SiOx) layer may be formed on the surface thereof. The thickness of the protection substrate50is not particularly limited, but may be approximately 100 to 800 μm, for example. When a surface of opposite side to the bonding surface50aof the protection substrate50is mirror-finished in advance by polishing such as a dry polishing processing, laser beam LA1irradiated on the protection plate50can suppress a diffused reflection on the surface of the protection substrate50. Therefore, by mirror-finishing, it is possible to perform a processing with the laser beam LA1with high accuracy.

A nozzle plate70has a nozzle opening71bored therein, which communicates with the vicinity of an end of an opposite side to the ink supply port14of each pressure generation chamber12and is fixed to a surface of the protection film80side of the flow path forming substrate10with fixing means such as an adhesive, a heat welding film. Therefore, the pressure generation chamber12communicates with the nozzle opening71discharging the liquid. For the nozzle plate70, glass-ceramic, a silicon single-crystal substrate, stainless steel and the like may be used, and is fixed to a side of an opening surface of the flow path forming substrate10. A thickness of the nozzle plate70is not limited, but may be, approximately 0.01 to 1 nm, for example.

The reservoir9illustrated inFIGS. 2 and 3Bincludes a reservoir bottom member110, a reservoir ceiling member120, and a compliance substrate60. For the reservoir bottom member110, a silicon single crystal substrate, iron alloy containing 42% of nickel (42 alloy), may be used and configures a bottom of the reservoir9. The reservoir ceiling member120has a ceiling wall121and three side walls and is provided on the protection substrate50via the adhesive, for example. The ceiling wall121is provided with a liquid introducing hole122for introducing the liquid. The compliance substrate60is bonded to an opened side surface of the reservoir ceiling member120across the reservoir bottom member110. For a sealing film61provided on the compliance substrate60, flexible material having a low rigidity such as a polyphenylene sulfide (PPS) film) having a thickness of approximately 4 to 8 μm may be used, and seals one surface of the reservoir9. For the fixing plate62provided on the compliance substrate60, a hard material of metal such as a stainless steel (SUS) having a thickness of approximately 20 to 40 μm may be used, and an area facing the reservoir9becomes an opening63.

Of course, a structure outwardly attaching the reservoir9to the substrate is not limited to the above-described structure.

Incidentally, as in a comparative example illustrated inFIG. 11, when the protection substrate50is bonded on the vibrating plate16of the section to be cut LN1without the metallic film using the adhesive55, the laser beam LA1whose condensing point P1is focused on the protection substrate50transmits the vibrating plate16. In general, the silicon oxide configuring the elastic film16a, and the zirconium oxide configuring the insulator film16bare a transparent material, and has a property that the laser beam is transmitted therethrough. The silicon oxide and the zirconium oxide remaining at the section to be cut LN1becomes the fragile section with the laser beam LA1whose condensing point P1is focused on the protection substrate50. Therefore, when an external force such as an expanding break is applied to the flow path forming substrate10and the protection substrate50, the substrates (10,50) are not divided along the fragile section of the protection substrate50. On the other hand, another process such as breaking is required for cutting or removing the vibrating plate16of the section to be cut LN1. Even if the insulator film16bof the section to be cut LN1is removed in advance, when the protection substrate50is bonded on the silicon oxide of the section to be cut LN1without the metallic film, the silicon oxide does not become the fragile section with the laser beam LA1whose condensing point P1is focused on the protection substrate50. Therefore, the substrates (10,50) which are subjected to the external force are not divided along the fragile section of the protection plate50. In addition, it is not possible to remove the entire vibrating plate16from the beginning. This is because the flow path forming substrate10is divided from the beginning, and the divided flow path forming substrates are not retained.

As illustrated inFIG. 1A, according to the manufacturing method, the metallic film48is formed on at least the section to be cut LN1of the bonding surface (at least one of10aand50a) of the substrates (10,50). When the reservoir9is outwardly attached to the substrate, an edge of the reservoir9side of the flow path forming substrate10cannot be provided with the lead electrode for connecting to the drive IC65of the piezoelectric element3. Therefore, the metallic film48is different from the lead electrode. In addition, the section to be cut LN1of the protection plate50bonded to the flow path forming substrate10is irradiated from the protection substrate50side with the laser beam LA1whose condensing point P1is focused thereon. Therefore, the first fragile section W1is formed on the protection substrate50, and the metallic film48of the section to be cut LN1is melted. The protection substrate50of this stage is connected at the fragile section W1, and is not divided. Even if the section to be cut LN1of the flow path forming substrate10is made of material which transmits the laser beam LA1, the metallic film48of the section to be cut LN1is melted. Therefore, the second fragile section W2is formed on the flow path forming substrate10. Therefore, it is possible to easily divide the substrates (50,10) along the fragile section (W1, W2) in a subsequent division step.

For example, the condensing point P1is modified such a manner that the laser beam having a wavelength showing the transmission property with respect to the protection substrate50(for example, a silicon single crystal substrate) is condensed in order to focus on the section to be cut LN1within the protection substrate50using a lens optical system, thereby forming the first fragile section W1. The wavelength showing the transmission property is a wavelength side longer than the wavelength showing an absorption property for melt cutting. Therefore, the protection substrate50is only fragile at the section to be cut LN1on irradiation of the laser beam LA1, but is not cut. The first fragile section W1means a modified area in which strength of a melted processed area crystallized after melting is fragile. The first fragile section W1may be formed to leave a surface layer of the protection substrate50(at least one of the opposite surface to the bonding surface side). In addition, if the fragile section W1is formed, when a portion of the first fragile section W1is flaked off, a particular problem does not occur.

The modification of the protection substrate50with the laser beam LA1is performed to concentrate on the condensing point P1and the vicinity thereof. As illustrated inFIG. 9, the depth of the condensing point P1is changed at the section to be cut LN1, and then the first fragile section W1may be formed by scanning the laser beam LA1a plurality of times at a predetermined speed.FIG. 9illustrates an example leaving a connection section51in the surface layer of the protection substrate50.

Herein, as illustrated inFIG. 1A, when an incident width to the protection substrate50of the laser beam LA1is W, and an incident angle of the laser beam LA1within the protection substrate50is θ, the depth Z of the condensing point P1is expressed by the following equation.
Z=W/(2×tan θ)  (1)

Therefore, by the adjustment of the incident width W in the laser beam, it is possible to adjust the depth of the condensing point P1, that is, the processing depth.

When the section to be cut LN1of the protection substrate50is irradiated from the protection substrate50side with the laser beam LA1whose condensing point P1is focused thereon, the metallic film48showing a non-transmission property with respect to the laser beam LA1is melted. Material of the metallic film48may be material showing a heat absorption property with respect to the laser beam LA1, and as a constituent metal of the main metallic layer48, nickel-chromium, nickel (Ni), chromium (Cr), titanium (Ti), gold (Au), platinum (Pt), aluminum (Al), copper (Cu), another non-transparent material, mixtures thereof and the like may be used. It is preferable that the metallic film48has a relatively thin thickness of approximately 30 to 70 nm, for example. In addition, when the metallic film48is not melted to the entire section to be cut LN1by irradiating the section to be cut LN1of the protection substrate with the laser beam whose condensing point is focused thereon, the metallic film48may be thin so that the entire section to be cut LN1may be melted. In addition, when the flow path forming substrate10is not formed with the fragile section W2to the entire section to be cut LN1by melting the metallic film48, the metallic film48may be thick so that the fragile section may be formed in the entire section to be cut LN1.

When as material of the metallic film48, the same material as that of the close contact layer46of the lead electrode such as nickel-chromium is used, it is possible to form the metallic film48in a suitable thinness, which is melted to form the second fragile section W2. In addition, when the close contact layer46is formed, it is possible to form the metallic film48of the section to be cut LN1, and to reduce the manufacturing cost of the liquid ejecting head. Of course, a layer other than a material layer of the close contact layer46may be provided on the metallic film48.

In addition, if as the material of the metallic film48, the same material as material of the main metallic layer47of the lead electrode such as gold is used, it is possible to form the metallic film48of the section to be cut LN1when the main metallic film47is formed, and to reduce the manufacturing cost of the liquid ejecting head. Of course, a layer other than a material layer of the metallic layer47such as the close contact layer46may be provided on the metallic film48.

In addition, the metallic film48may be formed separately from the formation of the close contact layer46.

The second fragile section W2is formed on the flow path forming substrate10of the section to be cut LN1by the melted metallic film W3. The second fragile section W2means an area in which the strength of a melt area solidified after the melt is fragile. It is preferable that the region of the opposite side to the bonding surface10ain the section to be cut LN1of the flow path forming substrate10is removed to form a concave portion R1, because the second fragile section W2is easily formed in the entire section to be cut LN1of the flow path forming substrate10. When the concave portion R1is formed in the section to be cut LN1and the vibrating plate16is left therein, it is possible to form the flow path forming substrate10in a suitable thinness to form the second fragile section W2in the entire section to be cut LN1. It is preferable that the concave portion R1is set to be the communication section13to the reservoir9, because the concave R1-only area is not required. In addition, if the insulator film16bis removed from the section to be cut LN1of the flow path forming substrate10and then the metallic film48is formed, it is possible to form the thin flow path forming substrate10in a further suitable thinness to form the second fragile section W2in the entire section to be cut LN1.

In addition, the adhesive55of the section to be cut LN1is modified by the melted metallic film W3, and then becomes the fragile section W4.

2. Example of Liquid Ejecting Head Manufacturing Method

Next, a recording head manufacturing method is illustrated with reference toFIGS. 4A to 9.FIGS. 4A to 9illustrate a vertical cross-sectional view along the recording head1A in which the detailed structure is different from that ofFIGS. 2 to 3Bin the longitudinal direction D2of the pressure generation chamber. First, the elastic film16ais integrally formed with respect to a surface of the silicon substrate15in a way that the silicon wafer of, for example, a surface orientation (110) for the flow path forming substrate10is thermally oxidized in a diffusion furnace at a temperature of approximately 1000 to 1200° C. The elastic film16ais made of silicon oxide (a stoichiometric ratio SiO2), and has a thickness of 400 to 1500 nm. Next, as illustrated inFIG. 4A, the insulator film16bis formed on the elastic film16a. For example, it is possible to form a zirconium oxide layer as the insulator film16bin a way that a zirconium (Zr) layer is formed on the elastic layer16aby a sputtering method, and then the zirconium layer is thermally oxidized in the diffusion furnace at a temperature of approximately 500 to 1200° C., for example. The insulator film16bmay have a thickness of approximately 300 to 500 nm, for example. In an example illustrated inFIG. 4A, the insulator film16bis formed and then is patterned, and the through-hole16cis in the section to be cut LN1. For example, by etching the insulator film16b, the insulator film16bof the section to be cut LN1is removed from above the elastic film16a. In addition, it is assumed that the concept of the vibrating plate16in which the metallic film48is formed on the surface thereof includes the elastic film16a, from which the insulator film16bis removed.

The above is a vibrating plate forming step S1.

Next, the lower electrode20is formed on the vibrating plate16by a sputtering method. In an example illustrated inFIG. 4B, the lower electrode20is formed and then is patterned. In addition, instead of the above-described zirconium oxide layer, or in addition to the zirconium oxide layer, a layer such as a titanium aluminum nitride (TiAlN) film, an Ir film, an iridium oxide (IrO) film and the like is formed on the vibrating plate16as the close contact layer or a diffusion preventing layer, and then the lower electrode20may be formed on the layer.

Next, the piezoelectric body layer30is formed on at least the lower electrode20by a liquid phase method such as a spin coating method, and the upper electrode40is formed on at least the piezoelectric body layer30by a sputtering method. In an example illustrated inFIG. 4B, the upper electrode40is formed, and then the piezoelectric body layer30and the upper electrode40are patterned. Therefore, the piezoelectric element3having the piezoelectric body layer30and the electrodes (20,40) is formed, and the piezoelectric actuator2having the piezoelectric element3and the vibrating plate16is formed. The above is a piezoelectric element forming step S2.

When forming the piezoelectric body layer30, the piezoelectric body layer30having peroviskite oxide is formed through, a coating step of a precursor solution in which organic material of metal configuring the above-described PZT is dispersed in a dispersion medium, a drying step at approximately 170 to 180° C., a degreasing step at approximately 300 to 400° C., and a firing step at 550 to 800° C., for example. The combination of the coating step, the dying step, the degreasing step and the firing step may be performed several times. Furthermore, in addition to the liquid phase method, the piezoelectric body layer30may be formed by the liquid phase method such as the sputtering method.

Next, as illustrated inFIG. 4C, the close contact layer46is formed on the substrate (a metallic film forming step S3). For example, the close contact layer46such as nickel-chromium may be formed over an entire surface of the substrate provided with the piezoelectric element3by the sputtering method, and may be patterned through a mask pattern made of a resist and the like. Then, it is possible to form the discontinuous metallic film48(for example, nickel-chromium layer) to the close contact layer of the lead electrode45on the elastic film16a(for example, silicon oxide layer) of the section to be cut LN1. By the metallic film forming step S3, it is possible to form the close contact layer of the lead electrode45and simultaneously the metallic layer48that is an isolating layer, and to simplify a manufacturing process and therefore to reduce the cost. Of course, independently of a formation of the close contact layer of the lead electrode45, the metallic layer48may be formed.

Next, as illustrated inFIG. 4D, the main metallic layer47is formed on the substrate (a main metallic layer forming step S4). For example, the main metallic layer47such as gold may be formed over the entire surface of the substrate by the sputtering method, and may be patterned via a mask pattern made of a resist and the like.

In addition, the electrodes (20,40), the close contact layer46and the main metallic layer47can be formed by the sputtering method such as a DC (a direct current) magnetron sputtering method. The thickness of each layer can be adjusted by changing an applied voltage and a sputtering processing time of a sputtering apparatus.

Next, as illustrated inFIG. 5A, the protection substrate50forming the piezoelectric element holding section52in advance is bonded to, for example, the bonding surface10aof the flow path forming substrate10with the adhesive55(a protection substrate bonding step S5). In an example illustrated inFIG. 5A, in the section to be cut LN1, there is the adhesive55between the metallic film48provided on the bonding surface10aand the bonding surface50aof the protection substrate50.

As illustrated inFIG. 5B, the silicon substrate15forming the elastic film16ais allowed to set to approximately 60 to 80 μm, for example. For example, in the silicon substrate15, the opposite side to the piezoelectric element3is polished until having some extent thickness and then, becomes to have a predetermined thickness by wet etching using fluoric-nitric acid (a cutting step S6). In addition, the surface of the opposite side to the vibrating plate16of the flow path forming substrate10becomes a nozzle side10b.

Next, as illustrated inFIG. 6A, the nozzle side10bof the silicon substrate15is subjected to anisotropic etching (wet etching) with an alkaline solution containing a KOH aqueous solution via the mask, and forms the pressure generation chamber12, the ink supply port14, and the concave portion R1(a flow path forming step S7). For example, when the mask film such as silicon nitride (a stoichiometric ratio Si3N4) is formed on the nozzle side10bof the silicon substrate15, a mask opening corresponding to the pressure generation chamber12and the concave portion R1is formed by patterning, and etching is performed through a mask film having the mask opening, the liquid flow path (12,14) and the concave portion R1are formed. Then, the mask film may be removed by etching. The concave portion R1is a removed region of the opposite side to the vibrating plate16in the section to be cut LN1of the flow path forming substrate10, and is a region to become the communication section13to the reservoir9.

In addition, the liquid flow path may be formed before forming the piezoelectric element3.

Next, as illustrated inFIG. 6B, the protection film80is formed in the inner surface of the liquid flow path (12,14) and the concave portion R1(a protection film forming step S8). For example, when the above-described tantalum oxide is deposited on the flow path forming substrate10from the nozzle side10bby a chemical vapor deposition method, the protection film80can be formed over the entire surface of the nozzle side10b, including the inner surface of the liquid flow paths (12,14) and the concave portion R1.

Next, as illustrated inFIG. 7A, the first fragile section W1is formed in the protection substrate50in a way that the section to be cut LN1of the protection substrate50is irradiated from the protection substrate50side with the laser beam LA1whose condensing point P1is focused thereon, and simultaneously the second fragile section W2is formed in the flow path forming substrate10by the melt of the metallic film48of the section of to be cut LN1(a fragile section forming step S9). As illustrated inFIG. 9, the first fragile section W1is formed by scanning the laser beam LA1a plurality of times along the thickness direction D3while changing the depth of the condensing point P1at the section to be cut LN1. As described above, the first fragile section W1is a modification area in which the strength is fragile, and thus the protection substrate50is connected at the first fragile section W1, but is not divided. By the melted metallic film W3, the adhesive55of the section to be cut LN1becomes the fragile section W4.

Next, as illustrated inFIG. 7B, the bonded substrates (50,10) are divided along the fragile sections (W1, W2) by an expanding break (a division step S10). In a case of the expanding break, for example, an adhesive tape for a dicing is pasted to one surface of the substrate, and an external force extending the adhesive tape vertically and horizontally is applied to the substrate, thereby cutting the section to be cut LN1. Therefore, the substrates are separated to a plurality of chips C1at the section to be cut LN1.

Next, as illustratedFIGS. 8A and 8B, the main metallic layer47(lead electrode45) of each of the chips C1and the drive IC65are connected to each other by the drive wiring66, the nozzle plate70having the nozzle opening71is bonded to a surface of the pressure generation chamber12side of each of the chips C1, and the reservoir9is outwardly attached to the section to be cut LN2(a reservoir forming step S11). In order to firmly fix the nozzle plate70of the opening side to the flow path forming substrate10, an adhesive, a thermal welding film and the like can be used. The reservoir9is formed by bonding the reservoir bottom member110, the reservoir ceiling member120having the liquid introducing hole122, and the compliance substrate60on which the sealing film61and the fixing plate62are laminated, to the chips C1in which the nozzle plate70is bonded. The divided concave portion R1functions as the communication section13of the reservoir9. In order to firmly fix the reservoir bottom member110to the surface of the opposite side to the pressure generation chamber12of the nozzle plate70, the adhesive, the thermal welding film and the like can be used. In order to firmly fix the reservoir ceiling member120to the surface of the opposite side to the bonding surface50aof the protection substrate50, the adhesive, the thermal welding film and the like can be used. In order to firmly fix the compliance substrate60to these members (110,120), the adhesive, the thermal welding film and the like can be used.

Therefore, the recording head1A is manufactured.

The recording head1A receives ink from the liquid introducing hole122connected to external ink supply means (not illustrated), and the inner surface thereof is filled with the ink until the ink reaches the nozzle opening71from the reservoir9. When the voltage is applied between the lower electrode20and the upper electrode40for each pressure generation chamber12according to a recording signal from the drive IC65, ink droplets are discharged from the nozzle opening71by deforming the piezoelectric layer30, the lower electrode20and the vibrating plate16.

As one example, the following sample was prepared.

The elastic film16amade of the silicon oxide (a stoichiometric ratio SiO2) was formed on a surface of the silicon single crystal substrate for the flow path forming substrate of the surface orientation (110) according to the above-described manufacturing method. The insulator film16bmade of the zirconium oxide (a stoichiometric ratio ZrO2), which has the through-hole16c, the piezoelectric element3having the piezoelectric body layer30made of the PTZ, the close contact layer46(containing the metallic film48) made of nickel-chromium, and the main metallic layer47made of gold were formed on the elastic film. The nickel-chromium layer was set to be a thickness in which the flow path forming substrate10of the section to be cut LN1is modified to the fragile section (W2) using the melt occurring with irradiating the laser beam LA1. The silicon oxide layer was formed on the surface of the silicon single crystal substrate for the protection substrate of the surface orientation (110), the piezoelectric element holding section52was formed on the substrate, and thus the flow path forming substrate10and the protection substrate50were bonded to each other using the adhesive55. The liquid flow path (12,14) and the concave portion R1were formed on the nozzle side10bof the flow path forming substrate10after bonding, and the protection film80made of tantalum oxide (a stoichiometric ratio Ta2O5) was formed over the entire surface of the nozzle side10b. The section to be cut LN1of the protection substrate50is irradiated from the protection substrate50side with the laser beam LA1having a silicon permeability, whose condensing point P1is focused thereon and thus the first fragile section W1was formed on silicon of the protection substrate50.

In addition, as one comparative example, a sample of a structure illustrated inFIG. 11was manufactured. In a case of the sample of the comparative example, in the section to be cut LN1, the protection substrate50is bonded on the zirconium oxide layer of the section to be cut LN1using the adhesive55without the metallic film.

For each sample, a cross-section of the substrate was observed. It was confirmed that in a case of the sample of the comparative example in which the metallic film is not formed on the bonding surface, the fragile section is not formed on the silicon oxide layer and the zirconium oxide layer in the section to be cut LN1of the flow path forming substrate10. The adhesive55of the section to be cut LN1did not become the fragile section. On the other hand, it was confirmed that in a case of the sample of the example forming the metallic film on the bonding surface, nickel-chromium of the section to be cut LN1is melted, and the silicon oxide, the zirconium oxide, and the tantalum oxide in the section to be cut LN1of the flow path forming substrate10are modified (the second fragile section W2is formed). It was confirmed that the adhesive55of the section to be cut LN1is modified (the fragile W4is formed).

In addition, for each sample, it was an attempt that an adhesive tape for dicing is pasted to one surface of the substrate, and the adhesive tape is extended vertically and horizontally, thereby dividing the substrates. In the comparative example, the chips which are not divided at the section to be cut LN1occurred. On the other hand, the sample of the example was easily divided into a plurality chips at the section to be cut LN1.

From the above, in the manufacturing method, even if the section to be cut of the flow path forming substrate is made of material transmitting the laser beam, the metallic film of the section to be cut is melted, therefore, it is possible to form the second fragile section on the flow path forming substrate. Therefore, in the subsequent dividing step, it is possible to easily divide the protection substrate and the flow path forming substrate along the first fragile section and the second fragile section. Therefore, the manufacturing method does not require another step of cutting or removing the vibrating plate of the section to be cut, and it is possible to simplify the manufacturing process of the liquid ejecting head. Such effects are obtained similarly even with respect to various methods that separate the bonding body of the first substrate illustrated in the protection substrate and the second substrate illustrated in the flow path forming substrate.

FIG. 10illustrates an appearance of the ink jet recording apparatus (a liquid ejecting apparatus)200having the above-described recording head1(including1A). When the recording head1is incorporated into the recording head units211and212, it is possible to manufacture the recording apparatus200having improved durability. In the recording apparatus200illustrated inFIG. 10, the recording head1is provided for each of the recording head units211and212, and ink cartridges221and222that are external ink supply means are provided to be attachable and detachable. A carriage203on which the recording head units211and212are mounted is provided to be movable reciprocally along the carriage shaft205attached to an apparatus body204. When a drive force of a drive motor206is transported to the carriage203via a plurality of gears (not illustrated) and a timing belt207, the carriage203moves along the carriage shaft205. A recording sheet290fed by a paper feed roller and the like (not illustrated) is transported on a platen208, and printing is performed by the ink which is discharged from the recording head1supplied from the ink cartridges221and222.

4. Application and Others

In the invention, various modification examples may be considered.

A sequence of the above-described manufacturing process can be appropriately modified. For example, in the vibrating plate forming step S1, it is possible that the vibrating plate16is formed, the metallic plate48is formed, and then the piezoelectric element3is formed.

In the above described embodiment, an individual piezoelectric element is provided for each pressure generation chamber, but it is possible to dispose a common piezoelectric body in a plurality of pressure generation chambers, and provide the individual electrode for each piezoelectric pressure chamber.

In the above embodiment, although an upper side of the piezoelectric element is covered with the piezoelectric element holding section, it is possible to open the upper side of the piezoelectric element to an atmosphere.

The liquid discharged from the liquid ejecting head may be material capable of being discharging the liquid ejecting head, and includes fluid such as a solution in which a dye is dissolved, and a sol in which solid particles such as a pigment and metallic particles are dispersed in a dispersion medium. Such a liquid includes ink, a liquid crystal and the like. The liquid ejecting head can be mounted on a color filter manufacturing apparatus such as a liquid crystal display, an electrode manufacturing apparatus such as an organic EL display, a biochip manufacturing apparatus in addition to the image recording apparatus such as a printer.

In addition, even in a manufacturing method which does not have constituent elements according to dependent claims, but has only constituent elements according to independent claims, the above-described basic actions and effects are obtained.

As described above, according to the invention, it is possible to provide a technology which allows the chip manufacturing process to simplify.

In addition, a configuration in which configurations disclosed in the above-described embodiments and modification examples are substituted or combined each other, and a configuration in which configurations disclosed in the related art, the above-described embodiments and modification examples are substituted or combined can be realized. The invention includes these configurations.

The entire disclosure of Japanese Patent Application No. 2012-098104, filed Apr. 23, 2012, is expressly incorporated by reference herein.