JP2001341316A - Ink jet head and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet head, and its manufacturing method, in which power loss is reduced in a power supply wiring for supplying power to a heater film and an earth wiring while enhancing the reliability of wiring. SOLUTION: A power supply wiring 15a and an earth wiring 15b connected with a heater film 17 formed on a semiconductor substrate 2 are made of copper.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet head for ejecting fine ink droplets by applying thermal energy to ink and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for colorization of hard copies for recording images of video cameras, televisions, computer graphics, and the like on paper.
Examples of the color hard copy system include a sublimation type thermal transfer system, a melt thermal transfer system, an ink jet system, an electrophotographic system, and a thermally developed silver salt system.

[0003] Among these methods, there is an ink jet method as a method for easily outputting a high quality image with a simple device. The ink jet method uses a method such as an electrostatic attraction method, a continuous vibration generation method (piezo method), or a thermal method (valve jet method) to fly small droplets of a recording liquid (ink) from a nozzle provided on an ink jet head.
The recording (printing) is performed by adhering to a recording member such as paper. Among them, the thermal method has been widely used because a color image can be easily output.

A thermal type ink jet head is
Thermal energy is applied to the ink in the ink chamber to eject the ink as fine droplets from the nozzles. When the thermal energy is applied, bubbles are generated in the ink and the force generated when the bubbles expand. In response, the ink is ejected from the nozzles.

[0005] A heat-generating resistive film made of, for example, tantalum is used as a means for giving thermal energy to the ink. The heating resistance film is formed on the semiconductor substrate,
A power supply wiring and a ground wiring (GND wiring) for supplying power to the heat-generating resistance film are also formed on the same semiconductor substrate so as to be connected to the heat-generating resistance film.

The power supply wiring is divided for each block with respect to a large number of heat-generating resistive films. The wiring width is changed according to the wiring length of the wiring corresponding to each block, and the voltage drop due to the wiring connected to each block is reduced. It is constant. That is, when the wiring length is long, the wiring width is wide, and when the wiring length is short, the wiring width is narrow. In some cases, the ground wiring is also divided corresponding to each block in correspondence with the division of the power supply wiring for each block.

[0007]

At present, the power supply wiring and the grounding wiring are made of an aluminum-based metal (specific resistance 3.0 Ω · cm).
Is formed. When the size of the ink-jet head chip is reduced in order to increase the yield from one semiconductor substrate, the area occupied by the power supply wiring and the ground wiring (wiring width) is reduced, and the resistance of the power supply wiring and the ground wiring is reduced. As a result, the power loss in these wirings increases.

When a large current of 100 mA or more flows, in a wiring made of an aluminum-based metal, aluminum atoms move due to collision with electrons, and the portion where the aluminum atoms have moved becomes a vacancy. The probability of occurrence of disconnection electromigration is also high.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an ink jet head capable of reducing power loss in a power supply wiring and a ground wiring for supplying power to a heating resistor film and improving the reliability of the wiring, and a method of manufacturing the same. The task is to provide

[0010]

In order to solve the above problems, according to the first aspect of the present invention, a semiconductor substrate is provided with a heating resistance film, and a power supply wiring and a ground wiring connected to the heating resistance film. The power supply wiring and the ground wiring are formed of copper.

According to a third aspect of the present invention, a heating resistor film is formed on a semiconductor substrate, and a power supply wiring and a ground wiring formed by connecting the heating resistor film to the same semiconductor substrate are formed of copper.

From the above, the specific resistance of copper is 1.8Ω · c
m, which is about 40% lower than that of the aluminum-based metal wiring. Furthermore, the resistance to electromigration is higher than that of aluminum-based metal wiring.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a partially broken sectional view of an ink jet head 1 according to a first embodiment of the present invention. Hereinafter, the manufacturing process will be described.

First, the silicon substrate 2 is subjected to a cleaning process,
Depositing a silicon nitride film (not shown) on the substrate 2;
Lithography and reactive ion etching are performed on the silicon nitride film so that the silicon nitride film remains only on the region where the transistor is to be formed.

Next, a thermal oxidation process is performed to form a thermal silicon oxide film (LOCO) serving as an element isolation region for isolating individual transistors in a region where the silicon nitride film is removed.
S (local oxidation of silicon) 3 is formed.

Next, after cleaning is performed again, gates 4a and 4b are formed in the transistor forming region, and the sources 5a and 4b are formed.
An ion implantation step and a heat treatment step for forming the 5b and the drains 6a and 6b are performed to form a MOS transistor. The gates 4a and 4b have a structure of, for example, a silicon oxide film / polysilicon / tungsten silicide in order from the lower layer. Through these steps, a driver transistor 7 having a withstand voltage of about 30 V and a 5 V operation transistor 8 a constituting the logic integrated circuit 8 are formed.
The driver transistor 7 is a power supply element that supplies power to the heating resistor film, and the logic integrated circuit 8 is a control circuit that controls the driver transistor 7.

Next, BPSG (borophos
After depositing a phosilicate glass) film 9 and performing a photolithography process, connection holes (contact holes) connected to the sources 5a, 5b and the drains 6a, 6b by reactive ion etching using a CFX-based gas. Is opened in the BPSG film 9.

After dilute hydrofluoric acid cleaning, titanium is deposited in a thickness of 20 nm and a titanium nitride barrier metal is deposited in a thickness of 50 nm by sputtering. Then, the contact hole is filled with tungsten by the CVD method, and tungsten plug 10 is formed by leaving the tungsten only in the contact hole by the etch-back method.

Next, aluminum to which 0.5% of copper is added is deposited to a thickness of 600 nm, and a photolithography step and a dry etching step are performed to form an aluminum wiring 11 connected to the tungsten plug 10. This wiring 1
1, the individual transistors (only the transistor 8a is shown in the figure) constituting the logic integrated circuit 8 are connected to form the logic integrated circuit 8, and the logic integrated circuit 8 and the driver transistor 7 for power supply are connected. Connected.

Next, a silicon oxide film (TEOS) 12 is deposited on the aluminum wiring 11 by the CVD method,
The silicon oxide film 12 is planarized by a (chemical mechanical polishing) process. Then, a photolithography step and a dry etching step are performed to open a connection hole (via hole) facing the aluminum wiring 11. Then, 10 nm of titanium and titanium nitride are sequentially deposited from the lower layer by a sputtering method, and then the via holes are filled with tungsten by a CVD method, and a tungsten plug 13 is formed by an etch-back method.

Next, C on the tungsten plug 13
After depositing a 50 nm silicon nitride film 14a by the VD method,
A silicon oxide film (TEOS) 14b is deposited, and the silicon oxide film 14b is planarized by a CMP process. And
A photolithography step and a dry etching step are performed to open a wiring groove 16 connected to the tungsten plug 13.

Next, after a tantalum film is used as a barrier metal to a volume of 50 nm by a long distance sputtering method, copper is subsequently deposited to a thickness of 100 nm by the same sputtering apparatus.

Next, the semiconductor substrate 2 is set in an electrolytic plating apparatus, and the wiring grooves 16 are filled with copper by electrolytic plating using the previously deposited copper film as a shield layer.

Then, the excess copper and the tantalum barrier metal on the silicon oxide film 14b are removed by the CMP method, so that copper embedded wirings 15a and 15b are obtained. Copper wiring 15
a is used as a power supply wiring, and the copper wiring 15b is used as a ground wiring.

Next, the semiconductor substrate 2 is placed on a sputtering apparatus, a tantalum film is deposited to a thickness of 50 to 100 nm, the tantalum film is processed by a photolithography process, and a dry etching method using a chlorine-based gas is used. A heating resistance film 17 connected to the ground wiring 15b is formed.

Next, a silicon nitride film 18 serving as a protective film is deposited on the heating resistor film 17 to a thickness of 300 nm, and a tantalum film 19 serving as a second protective film is deposited by a 200 to 300 nm sputtering method.

Next, a dry film 20 is formed on the tantalum film 19, the dry film 20 is opened by a photolithography process and an etching process, and an ink liquid chamber 21 is formed. The ink 22 is stored in the ink liquid chamber 21.

Next, the metal film 23 is formed on the dry film 20.
Is formed, and an opening 23 a is formed at a position corresponding to the ink liquid chamber 21.
Is formed, and this serves as a nozzle for discharging the ink 22.

The ink jet head 1 according to the present embodiment is configured as described above, and its operation will be described next.

Under the control of the logic integrated circuit 8, power is supplied from the driver transistor 7 to the heating resistor film 17 via the aluminum wiring 11, the tungsten plug 13, and the power supply wiring 15a. Thereby, the heating resistance film 17 is formed.
Generates heat, and heats the ink 22 in the ink liquid chamber 21 provided to face the ink. As a result, bubbles are generated in the ink 22, and the ink 22 receives the force generated when the bubbles expand,
Is ejected from the nozzle 23a in the form of fine droplets and adheres to a recording member such as paper.

When the supply of power to the heating resistor film 17 is stopped, the bubbles collapse, and the portion where the bubbles are formed acts to replenish the ink. Occurs. If this is repeatedly received, the heating resistor film 17 will be greatly damaged. However, the heating resistor film 17 is made up of the tantalum film 19 and the silicon nitride film 18.
And is protected from damage.

As described above, in this embodiment, since the power supply wiring 15a and the ground wiring 15b are formed of copper, the resistance is lower than that of the conventional aluminum wiring, and the power loss in these wirings can be reduced. Further, the resistance to electromigration is higher than that of the aluminum wiring, and the reliability of the wiring can be improved. Further, when the same resistance as that of the conventional aluminum wiring is to be provided, the wiring width of the copper wiring of the present embodiment can be made smaller than that of the aluminum wiring, so that the size of one chip of the ink jet head can be made smaller, and accordingly, the semiconductor The chip yield from one substrate (wafer) can also be improved.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 2 shows a partially cutaway sectional view of an inkjet head 25 according to the second embodiment. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

As in the first embodiment, a driver transistor 7 made of MOS and a logic integrated circuit 8 are formed. Then, the sources 5a of these transistors,
A contact hole connected to 5b and the drains 6a and 6b is filled with tungsten, and a tungsten plug 26 is formed by etching back, leaving tungsten only in the contact hole.

Next, CVD is performed on the tungsten plug 26.
A silicon nitride film is deposited to a thickness of 50 nm by a method, a silicon oxide film (TEOS) 29 is subsequently deposited, and the silicon oxide film 29 is planarized by a CMP process. Then, a photolithography step and a dry etching step are performed to open a wiring groove 27 a facing the tungsten plug 26.

Next, after depositing a 50 nm thick tantalum film as a barrier metal by a long distance sputtering method, 100 nm of copper is successively deposited by the same sputtering apparatus.

Next, the semiconductor substrate 2 is set in an electrolytic plating apparatus, and the wiring groove 27a is filled with copper by an electrolytic plating method using the previously deposited copper film as a shield layer.

Next, the excess copper and the tantalum barrier metal on the silicon oxide film 29 are removed by the CMP method to form a buried wiring 27 of copper. The wiring 27 connects the individual transistors constituting the logic integrated circuit 8 (only the transistor 8 a is shown in the figure) to form the logic integrated circuit 8 and forms the logic integrated circuit 8.
And the power supply driver transistor 7 are connected.

Next, after depositing a 50 nm silicon nitride film on the copper wiring 27 by the CVD method, a silicon oxide film (TEO
S) 30 is deposited, and a silicon oxide film 3 is
0 is flattened. And a photolithography process,
A connection hole (via hole) facing the copper wiring 27 is opened by performing a dry etching process.

Next, after depositing a 50 nm thick tantalum film as a barrier metal by a long-distance sputtering method, subsequently depositing 100 nm of copper by the same sputtering device, embedding copper in via holes by electrolytic plating, and excess copper by CMP. Then, tantalum is removed to form a plug 28 made of copper.

Thereafter, the power supply wiring 15a connected to the copper plug 28 and the like are formed by the same method as in the first embodiment, and the ink jet head 25 is obtained.

In this embodiment, copper wiring 27 between the transistors constituting the logic integrated circuit 8, between the logic integrated circuit 8 and the driver transistor 7, and further between the driver transistor 7 and the power supply wiring 15a, 28. Thereby, in addition to the same effects as those of the first embodiment, the operation of the logic integrated circuit 8 can be speeded up.

Although the embodiments of the present invention have been described above, the present invention is, of course, not limited to these embodiments.
Various modifications are possible based on the technical idea of the present invention.

In the second embodiment, the wiring of the logic integrated circuit 8 has a single-layer structure of the wiring 27. However, as in the ink-jet head 31 shown in FIG. It may be. The wiring 32 is also made of copper. Further, the power supply wiring 15a and the ground wiring 1
5b may also have a multilayer structure.

In each of the above embodiments, the heating resistor film 17 is made of a tantalum film. However, the invention is not limited to this. For example, a heating resistor material such as a compound of tantalum and aluminum or titanium nitride may be used.

[0047]

As described above, according to the first or third aspect of the present invention, it is possible to reduce the power loss in the power supply wiring and the ground wiring which are connected to the heating resistor film and supply power thereto. At the same time, the reliability of the wiring can be improved.

According to the second or fourth aspect, the power loss of the power supply wiring and the grounding wiring can be reduced and the reliability can be improved, and the electric power for supplying power to the heating resistor film connected to the power supply wiring can be achieved. Processing operations of the supply element and a control circuit for controlling the power supply element can be accelerated.

[Brief description of the drawings]

FIG. 1 is a partially cutaway sectional view of an ink jet head according to a first embodiment of the present invention.

FIG. 2 is a partially cutaway sectional view of an inkjet head according to a second embodiment of the present invention.

FIG. 3 is a partially cutaway sectional view of an ink jet head according to a modification.

[Explanation of symbols]

1 ... inkjet head, 2 ... semiconductor substrate, 7 ...
... power supply element, 8 ... control circuit, 15a ... power supply wiring, 15b ... ground wiring, 17 ... heating resistor film, 21 ...
... Ink liquid chamber, 22 ... Ink, 23a ... Nozzle, 2
5. Inkjet head,

Claims (4)

[Claims] A semiconductor substrate having a heating resistor film, a power supply wiring and a ground wiring connected to the heating resistor film, and an ink liquid chamber provided to face the heating resistor film; A nozzle is formed in the chamber, the heating resistor film generates heat by electric power supplied through the power supply wiring, and heats the ink in the ink liquid chamber,
An ink jet head for ejecting the ink in the form of fine droplets from the nozzle, wherein the power supply wiring and the ground wiring are formed of copper. 2. A power supply element for supplying power to the heating resistor film, and a control circuit for controlling the power supply element are formed on the semiconductor substrate, and the control circuit and the power supply element 2. The ink jet head according to claim 1, wherein at least one of the wiring and the wiring between the power supply element and the power supply wiring are formed of copper. 3. 3. A step of forming a heating resistor film on a semiconductor substrate; and forming a power supply wiring and a ground wiring for supplying power to the heating resistor film by connecting the heating resistor film to the heating resistor film. Forming an ink liquid chamber in which the ink heated by the heat generated by the heat-generating resistive film is stored, facing the heat-generating resistive film; and forming a nozzle in the ink liquid chamber for ejecting the ink in the form of fine droplets. And forming the power supply wiring and the ground wiring with copper. 4. A step of forming, on the semiconductor substrate, a power supply element for supplying power to the heating resistor film and a control circuit for controlling the power supply element; Forming a wiring between the power supply element and the power supply wiring; and forming a wiring between the power supply element and the power supply wiring; and forming a wiring between the control circuit and the power supply element and the power supply element. 4. The method according to claim 3, wherein at least one of the power supply wiring and the wiring is formed of copper.