JP2587945B2 - Thin film forming equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roll-to-roll sputtering apparatus for forming a thin film of a metal compound having conductivity, and more particularly to a thin film for forming an indium tin oxide thin film by a reactive sputtering method. The present invention relates to a forming apparatus.

2. Description of the Related Art In recent years, in the field of electronic components, electronic devices, and the like, a thin film of a conductor, a resistor, and other thin films has been formed on a synthetic resin film or the like (hereinafter, referred to as an adherend). It is important to form such a thin film with good reproducibility and uniform distribution characteristics in sheet resistance, and efforts have been made to improve the reliability of the forming apparatus itself.

In general, when forming an indium tin oxide thin film (hereinafter referred to as an ITO film) by a reactive sputtering method, it is known that controlling the flow rate of oxygen gas used as a reactive gas has a great effect on the sheet resistance of the film. It is also common to control the gas flow rate to make the area resistance distribution of the ITO film uniform.

FIG. 3 is a system explanatory diagram of a main part of a conventionally used thin film forming apparatus. In this figure, 1 is a target, 2 is a substrate to be adhered, 3 is a roll for resistance measurement whose surface is made of a metal material, and 6 and 6 'are oxygen gas jet tubes, which are arranged in a vacuum chamber (not shown). ing. The indium tin atoms sputtered when the adhered substrate 2 passes above the target 1, which is a cathode, form an ITO film by reaction with oxygen gas ejected from the oxygen gas ejection tubes 6 and 6 ',
It is continuously sent to the resistance measuring roll 3. When the adhered substrate 2 passes through the resistance measuring roll 3, the measured area resistance is converted into a voltage value by the arithmetic circuit device 4, and the oxygen gas ejection is controlled by controlling the gas introduction amount control device 5. The flow rate of the oxygen gas ejected from the tubes 6 and 6 'is controlled.

In order to set the partial pressure distribution of the oxygen gas in the oxygen gas ejection pipes 6 and 6 ′ so that the sheet resistance in the direction perpendicular to the transfer direction of the substrate 2 (hereinafter referred to as the substrate width direction) is uniform. Several ejection ports are provided in advance, so that the sheet resistance in the substrate width direction and the transport direction can be made uniform.

Problems to be Solved by the Invention However, there is no method other than determining the interval between the gas ejection ports provided in the oxygen gas ejection pipes 6 and 6 'by trial and error while considering the direction of the air flow, the flow velocity, stagnation, etc.
Finding the optimal conditions is not easy. Further, in the reactive sputtering method, the change in the processing pressure, the erosion state of the target surface, the degree of oxidation, and the like change every moment, and these directly affect the sheet resistance of the ITO film, and the desired sheet resistance distribution is not necessarily obtained. It is difficult to obtain an ITO coating having the same.

FIG. 4 shows the sheet resistance of any part of the ITO film continuously formed by the conventional apparatus measured along the width direction, that is,
4 shows the distribution of sheet resistance. In FIG. 4, it can be seen that the desired characteristics are not obtained because the above conditions vary. However, in transparent touch panel applications, which have been attracting attention in recent years, uniformity of the area resistance distribution characteristics has become one of the most required specifications, and in particular, the current characteristics are not satisfactory in obtaining wide products. is there.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a thin film forming apparatus capable of sufficiently coping with a change in sputtering conditions and capable of forming an ITO film having a uniform sheet resistance distribution. .

Means for Solving the Problems A thin film forming apparatus according to the present invention is a thin film forming apparatus for forming a thin film of a conductive metal compound on an adherend such as a synthetic resin film being transferred in a vacuum chamber. A rotating electrode provided in the width direction of the substrate to be rotated and rotatably contacting the substrate, a resistance measuring device for measuring the resistance of the region of the substrate to which the rotating electrode is in contact, and controlling the amount of gas introduced into the vacuum chamber. A gas introduction amount control device, a gas ejection pipe having a base end connected to the introduction amount control device and a distal end opened at the same position as the rotary electrode, and connected between the resistance measuring device and the gas introduction amount control device. And a plurality of sets each including one control unit.
Further, the control unit performs a comparison operation between a measurement value measured by the resistance measurement device and a preset reference value, and based on the calculation result, the gas ejected from the gas ejection pipe via the gas introduction amount control device. It is characterized in that the amounts are independently controlled.

The area of the transferred substrate is measured by N rotatable electrodes and a resistance measuring device which are rotatably provided, and the measured values are sent to the control unit. The control unit performs a comparison operation between a preset reference value and the measured value. Then, a signal based on the calculation result is sent to N sets of gas introduction amount control devices, and the flow rate control device independently controls the amounts of the reactive gases ejected from the N sets of reactive gas ejection pipes (for example, oxygen gas ejection pipes). To control.

In the present invention, the measuring points of the partial resistance value (including the specific resistance) of the thin film to be formed are divided into N sets of four measuring elements as one set in the substrate width direction of the adhered substrate, and provided. The flow rate of the oxygen gas spouted from the oxygen gas spouting pipe at the position corresponding to each measurement point can be controlled independently. That is, by controlling the gas introduction amount control devices at N locations so that the resistance value measured over N locations in the width direction of the adhered substrate approaches the reference value, the device can be made uniform in the width direction and the transport direction of the adhered substrate. It is. An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a main part system diagram of a thin film forming apparatus showing one embodiment of the present invention.

An oxygen gas ejection pipe 10 is installed at N places in the width direction of the substrate 2 in the vicinity of the target 1, and an equal number of gas introduction amount control devices 9 are installed outside the vacuum chamber. Reference numeral 11 denotes a resistance measuring device. The resistance measuring device 11 is located above the target 1 until the substrate 2 that has passed through is wound up.
It is provided so as not to damage the O film. Reference numeral 3 denotes a guide roll.
And plays a role of guiding the adherend 2 and bringing the rotary electrode 7 into moderate contact with the adherend 2.

The rotating electrode 7 is connected to the oxygen gas ejection tube in the width direction of the substrate.
It is arranged at the same position as 10.

The resistance measuring device 11 and the gas introduction amount control device 9 are electrically connected via a control unit 8. The control unit 8 can be composed of, for example, a microprocessor, a multiplexer and the like. That is, a closed loop is constituted by N sets each including the resistance measuring device 11, the control unit 8, the gas introduction amount control device 9, and the oxygen gas ejection pipe 10.

The operation of the thin film forming apparatus configured as described above will be described.

First, a reference resistance value (reference value) is set in the control unit 8, and then formation of an ITO film is started. When the substrate 2 on which the ITO film has been formed reaches the position of the rotating electrode 7, the resistance values at N locations are measured by the resistance measuring device 11, and the results are sent to the control unit 8 where they are compared with the reference values. The calculation is performed, and a signal is sent from the control unit 8 to the corresponding gas introduction amount control device 9 based on the calculation result, thereby determining (controlling) the introduction amount of the oxygen gas. By such a loop control, an ITO film having a uniform resistance distribution characteristic can be continuously and easily formed. Here, the installation number N of the measuring element of the rotating electrode 7 and the gas introduction amount control device, etc.
May be determined according to the width of the substrate 2. For example, when the width of the substrate 2 is 1000 mm, good results are obtained when N = 5. Thus, it is possible to flexibly cope with various substrate widths by optimizing the N number.

In addition, a transmittance measuring device (not shown) is mounted on the moving path of the adherend substrate 2.
It goes without saying that control performance is further improved by arranging N signals near the rotating electrode 7 and inputting this signal to the control unit 8. Although the rotary electrode 7 according to the present embodiment uses a contact-type means using four probes, a non-contact type rotary electrode may be used.

When an ITO film was formed on a polyester film according to the preferred embodiment of the present invention, as shown in FIG. 2, the processing pressure was 4 × 10 ^-3 Torr, and the argon gas introduction rate was 250 cc /
min, oxygen gas introduction rate 70-71cc / min, film length 5
The sheet resistance distribution over 00 m made it possible to fall within ± 3% with respect to 300Ω / □.

As described above, the apparatus of the present invention is a thin film forming apparatus for forming a thin film of a conductive metal compound on a substrate to be transferred such as a synthetic resin film in a vacuum chamber. A rotating electrode provided in the width direction of the substrate and rotatably contacting the substrate to be adhered, a resistance measuring device for measuring the resistance of the region of the substrate to be adhered to the rotating electrode, and a gas introduction amount for controlling the gas introduction amount into the vacuum chamber A control device, a gas ejection pipe having a base end connected to the introduction amount control device and a distal end opened at the same position as the rotary electrode, and a control unit connected between the resistance measurement device and the gas introduction amount control device. Are provided as one set, and
In addition, the control unit performs a comparison operation between the measured value measured by the resistance measurement device and a preset reference value, and based on the calculation result, the gas ejected from the gas ejection pipe via the gas introduction amount control device. It is characterized in that the amounts are independently controlled. Accordingly, there is an effect that the sheet resistance distribution of the conductive thin film of the substrate to be adhered is greatly improved as compared with the related art, and the sheet resistance distribution characteristics can be made uniform over a large area.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a main part of a thin film forming apparatus showing one embodiment of the present invention, and FIG. 2 shows the area resistivity of an ITO film formed according to the present invention measured along the width direction of a substrate to be coated. Graph, FIG. 3 is a system explanatory view showing a main part of a conventional thin film forming apparatus, and FIG. 4 is a graph in which the area specific resistance of the ITO film is measured along the width direction of the substrate to be coated when the conventional apparatus is used. It is. DESCRIPTION OF SYMBOLS 1 ... Target 2 ... Substrate to be attached 3 ... Roll for resistance measurement 7 ... Resistance measurement device 8 ... Control unit 9 ... Control device for gas introduction amount 10 ... Oxygen gas ejection tube

Claims (1)

(57) [Claims] 1. A thin film forming apparatus for forming a thin film of a conductive metal compound on a substrate such as a synthetic resin film being transferred in a vacuum chamber. A rotating electrode that is in rotational contact with the substrate, a resistance measuring device that measures the resistance of the adhered substrate region that the rotating electrode has contacted, a gas introduction amount control device that controls the amount of gas introduced into the vacuum chamber,
A set of a gas ejection pipe having a base end connected to the introduction amount control device and a front end opened at the same position as the rotary electrode, and a control unit connected between the resistance measurement device and the gas introduction amount control device. And the control unit performs a comparison operation between a measurement value measured by the resistance measurement device and a preset reference value, and based on the calculation result, controls the gas introduction amount control device. Characterized in that the amount of gas ejected from the gas ejection pipe via the gas ejection pipe is controlled independently of each other.