KR20140038771A - Method for depositing metallic thin film on a substrate - Google Patents

Abstract

A method for depositing a metal thin film on a substrate is disclosed. The method for depositing a metal thin film on a substrate, according to the present invention, comprises the steps of mounting a substrate on a substrate mounting stand located inside a vacuum chamber; vacuuming the inside of the vacuum chamber using a vacuum pump; maintaining the internal pressure of the vacuum chamber to be constant by injecting a gas to be used into the vacuum chamber; and applying a bipolar pulsed direct current generated at a bipolar pulsed direct current generator to a magnetron sputtering deposition source mounted on the vacuum chamber.

Description

METHOD FOR DEPOSITING METALLIC THIN FILM ON A SUBSTRATE}

The present invention relates to a method for depositing a metal thin film, and more particularly, to a method for depositing a metal thin film on a plastic substrate.

In general, when depositing a metal thin film on the plastic surface, due to the hydrophobicity, which is a unique property of the plastic material, the bonding strength with the deposited metal thin film is weak, which causes a problem that the deposited film is peeled off after the thin film is deposited. Various methods have been devised and used to solve the peeling phenomenon.

That is, when the method of changing the hydrophilic surface of the plastic by oxygen or nitrogen plasma before depositing the metal thin film on the plastic surface is used, the bonding force of the metal vapor deposition film can be improved, In many cases, there has been a desire to improve the bonding strength by inserting a tie layer using a material such as nickel having excellent bonding strength between the plastic substrate material and the metal deposition film (US Patent No. US20080102305A1, “Adhesiveless Copper Clad Laminates And Method For Manufacturing Thereof”). ). However, when such an interlayer film is used, there is a difficulty such as nonuniformity in subsequent processes (etching, etc.) due to the heterogeneity of the material with the present film deposited on the upper portion of the interlayer film.

In addition, when plasma ion mixing effect by high energy ions is used by using plasma ion implantation technology as in Korean Patent No. 10-0674532, a high bonding force can be realized between the metal vapor deposition film and the plastic substrate material without insertion of the interlayer . However, in order to use this method, there is a disadvantage in that a high negative pulse voltage of several tens of kV or more is applied to the sample mounting table on which the plastic substrate is placed.

On the other hand, in the case of a HiPIMS (High Impulse Power Magnetron Sputtering) deposition method (J. Mater. Res., Vol. 27, No. 5, Mar. 14, 2012), which has been actively studied recently, It is known that the bonding strength between the deposited metal thin film and the substrate is improved by increasing the ionization rate of atoms and applying a negative voltage to the substrate to collide the ions with the thin film. However, this method is limited to the case of an electrically conductive metal substrate to apply a negative voltage to the substrate, and has a disadvantage in that it is difficult to apply when deposited on a non-conductive plastic substrate.

The present invention has been made to solve the above problems, an object of the present invention is to provide a method that can solve the peeling phenomenon of the metal thin film which is often a problem when the metal thin film is deposited on the plastic substrate.

In order to achieve the above object, a method of depositing a metal thin film on a substrate according to an embodiment of the present invention comprises the steps of mounting a substrate on a substrate mount located inside the vacuum chamber, using a vacuum pump to vacuum the inside of the vacuum chamber Injecting a gas to be used in the vacuum chamber to maintain an internal pressure at a constant pressure, and applying a bipolar pulsed DC generated by the bipolar pulsed DC power supply to the magnetron sputtering deposition source mounted to the vacuum chamber. It includes.

When a positive pulse DC power is applied to the magnetron sputtering deposition source, a discharge of the magnetron sputtering deposition source occurs by applying a negative pulse DC power, and a metal element plasma is generated on the surface of the sputtering target, and the metal The elemental plasma may collide in the direction of the substrate from the surface of the sputtering target by an electric field caused by bipolar (+) pulsed DC power.

The pressure of the gas to be used in the vacuum chamber can be maintained at 0.1mTorr ~ 5mTorr.

The operating frequency of bi-polar pulsed DC power applied to the magnetron sputtering deposition source may be 10 Hz to 10 kHz.

The negative partial pulse power density of the bipolar pulsed direct current power applied to the magnetron sputtering deposition source may be 10 W / cm ² to 10 kW / cm ² .

The negative (-) pulse width of the bi-polar pulsed DC power applied to the magnetron sputtering deposition source may be 5 μsec to 500 μsec.

The pulse voltage of the positive portion of the bipolar pulsed DC power applied to the magnetron sputtering deposition source may be + 10V to + 1000V.

The bipolar (+) pulse width of the bipolar pulsed DC power applied to the magnetron sputtering deposition source may be 5 μsec to 500 μsec.

In addition, the method of depositing a metal thin film on the substrate may further comprise the step of performing a plastic substrate treatment using a single gas of argon, oxygen, nitrogen, or a mixed gas plasma before the metal thin film deposition.

The substrate may be plastic.

The present invention has the following effects.

First, a metal thin film having excellent bonding strength can be effectively deposited on a plastic substrate. That is, by applying bi-polar high-power pulsed DC power to a magnetron sputtering evaporation source, which is commonly used as an evaporation source for depositing a metal thin film, a high-density metal By repulsing the plasma by using the positive polarity (+) pulse power applied in succession, it is possible to increase the energy of the metal ions reaching the plastic substrate to improve the bonding strength of the metal thin film deposited on the plastic substrate.

Second, when the method according to the present invention can be used to improve the bonding strength without inserting the intermediate layer, there is no problem caused by the intermediate layer in subsequent processes such as etching, and there is no need to apply a negative voltage to the substrate. There is an advantage that can be applied to non-conductive substrates such as plastic.

Third, by using the method of the present invention, it can be applied not only to the metal thin film but also thin film deposition of various materials, and also to the substrate material can be widely applied to various substrate materials including metal materials.

Fourth, when a plasma treatment using a single gas containing argon, oxygen, nitrogen or a mixture of these gases is performed before the deposition of the metal thin film, the bonding strength of the metal thin film deposited on the plastic substrate may be further improved.

1 is a structural diagram of an apparatus for depositing a metal thin film on a substrate according to an embodiment of the present invention.
2 is a conceptual diagram of a large output bi-polar pulsed direct current power applied to a magnetron sputtering deposition source of a metal thin film deposition apparatus according to an embodiment of the present invention.
FIG. 3 shows (a) a copper deposited film deposited using direct current power, (b) a copper deposited film deposited using short (negative) polar high output pulsed DC power, and (c) a bi-polar large output pulse. It is a figure which shows the bonding force test result in the case of the copper vapor deposition film deposited using DC power.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. However, it is to be understood that the present invention is not limited to the disclosed embodiments, but may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. It is intended that the disclosure of the present invention be limited only by the terms of the appended claims. Like reference numerals refer to like elements throughout the specification.

Hereinafter, a method of depositing a metal thin film on a substrate according to a preferred embodiment of the present invention will be described.

The method of depositing a metal thin film on a substrate according to the present invention comprises the steps of mounting a substrate on a substrate mount located inside the vacuum chamber, vacuuming the inside of the vacuum chamber using a vacuum pump, the gas to be used in the vacuum chamber Maintaining the internal pressure at a constant pressure, and applying a bipolar pulse DC generated in the bipolar pulsed DC power supply to the magnetron sputter deposition source mounted in the vacuum chamber.

1 is a structural schematic diagram of an apparatus for depositing a metal thin film of strong bonding strength on a plastic substrate according to the present invention. The metal thin film deposition apparatus includes a vacuum chamber (1), a bi-polar pulsed DC power supply unit (2) for generating bi-polar large output pulsed DC power, and a magnetron sputtering deposition source for metal thin film deposition ( 4), a gas flow rate adjusting device 8 for adjusting the pressure of the use gas 9 used for plasma generation, and a vacuum pump 10 for maintaining the vacuum of the vacuum chamber 1.

Reference numeral 3 designates bi-polar versus output pulse DC power generated by the bipolar pulse direct current power supply 20; numeral 5 designates a pulse plasma of a metal element generated in the magnetron sputtering deposition source 4; The plastic substrate, 11, mounted on the mounting table 7 indicates that the vacuum chamber is electrically grounded.

The principle of improving the bonding force between the metal thin film and the plastic substrate to be deposited by applying a bi-polar large output pulsed DC power to the magnetron sputtering deposition source according to the present invention is as follows.

That is, after the substrate 6 is mounted on the substrate mount 7 located in the vacuum chamber 1, the vacuum degree inside the vacuum chamber 1 is exhausted to the high vacuum region by using the vacuum pump 10. Thereafter, the use gas 9 such as argon is introduced through the gas flow rate adjusting device 8 to adjust the pressure inside the vacuum chamber to a pressure of 0.1 mTorr to 5 mTorr.

For this reason, the magnetron sputtering deposition source is difficult to operate at low pressures of less than 0.1 mTorr gas pressure inside the vacuum chamber, while at higher pressures of 5 mTorr or more, the film reaches the deposited film due to frequent collisions of ions and surrounding gas particles. This is because the energy loss of ions is very severe.

In addition, when using a process pressure of 5 mTorr, considering that the average collision distance of the ions is only about 1.6 cm, the energy of the ions incident on the deposition film is not high at a pressure of 5 mTorr or higher, it is self-explanatory You can do it.

As described above, when the pressure inside the vacuum chamber is stabilized after the introduction of the used gas, the bi-polar pulsed DC power supply 2 generated in the magnetron sputtering deposition source 4 mounted on the vacuum chamber (bi-) polar) A large output pulsed direct current power 3 is applied to operate the magnetron sputtering deposition source 4.

The bi-polar large output pulsed direct current power 3 applied to the magnetron sputtering deposition source 4 is as shown in FIG.

That is, discharge of the magnetron sputtering evaporation source 4 is caused by application of the large-output pulse DC power of negative polarity (-), and a high-density metal element plasma is generated on the surface of the sputtering target. The metal ions of the metal pulse plasma are repulsed toward the substrate from the surface of the sputtering target with high energy by an electric field caused by bipolar (+) pulsed DC power applied in succession, and collide with the high energy on the surface of the substrate.

The metal deposition film deposited at such a high energy not only improves the bonding strength with the plastic substrate but also increases the density of the deposition film, and thus helps to form a solid metal deposition film. Formation can be prevented.

The negative (-) partial power density of the bi-polar large output pulsed direct current power 3 applied to the magnetron sputtering deposition source 4 is a value of 10 W / cm ² to 10 kW / cm ² . To have. For this reason, it is difficult to generate a high-density metal plasma with high ionization rate from the magnetron sputtering deposition source 4 with a low pulse DC power of 10 W / cm ² or less, whereas it is practical to use a value of 10 kW / cm ² or more. This is because the manufacturing of the DC power supply 5 is difficult and the cooling of the magnetron deposition source 4 is not smooth.

On the other hand, the voltage of the bipolar (+) portion of the bi-polar large output pulsed direct current power 3 applied to the sputtering deposition source 4 is set to have a value of + 10V to + 1000V. For this reason, at low voltages below +10 V, the energy of the accelerated ions is too low to improve the bond strength due to ion collision, while using a high voltage above +1000 V increases the risk of arcing. Because.

It is preferable that the operating frequency of the bi-polar large output pulsed direct current power 3 applied to the magnetron sputtering deposition source 4 uses a frequency of 10 Hz to 10 kHz. For this reason, a low frequency below 10 Hz takes too much time for the deposition process, which reduces the economic value of the technique, and also makes bi-polar, high power pulses operating at high frequencies above 10 kHz. This is because the manufacturing of the DC power supply 2 is difficult.

On the other hand, in the case of the negative (-) pulse width of the bi-polar large output pulsed direct current power 3, it is preferable to use the pulse width of 5 microseconds-500 microseconds. When operating at a short pulse width of 5 μsec or less, the ionization rate is low because the generation of high density plasma is not sufficient, and when a long pulse width of 500 μsec or more is used, an arc is generated in the magnetron sputtering deposition source 4 due to the high pulse power. This is because the process is unstable with a high probability of occurrence.

In addition, even in the case of the bipolar (+) pulse width of the bi-polar large output pulse direct current power 3, it is preferable to use a pulse width of 5 mu sec to 500 mu sec. When operating with a short pulse width of 5 μsec or less, the amount of high energy ions incident on the substrate is small because there is not enough time to repel ions of the high density plasma, and magnetron sputtering deposition when using a long pulse width of 500 μsec or more This is because the process is unstable because an arc is likely to occur in the circle 4.

Technical features for depositing a metal thin film of a strong bonding strength on the plastic substrate according to the present invention are as follows.

That is, by applying a bi-polar large output pulsed direct current power to a magnetron sputtering deposition source that is commonly used as a deposition source for metal thin film deposition, a high-density metal formed when a negative (-) pulse power is applied The metal ions of the plasma are repelled by using an electric field formed by the pulse power of positive polarity (+) applied in succession to increase the energy of the metal ions reaching the plastic substrate, It is to improve the bonding strength of the deposited metal thin film.

In this method, since the bonding strength can be improved without inserting the intermediate layer, there is no problem caused by the intermediate layer in the subsequent process such as etching, and there is no need to apply a negative voltage to the substrate. There is an advantage that can be applied to the substrate.

Hereinafter, the present invention will be described in more detail through experimental examples. These experimental examples are only for illustrating the present invention, and the present invention is not limited thereto.

<Examples>

A deposition experiment for depositing a metal thin film of strong bonding strength on a plastic substrate according to the method of the present invention was carried out as follows.

In other words, polyimide tape (width 20 mm, length 100 mm), which is widely used as a flexible substrate, was used as a deposition substrate, and a magnetron sputtering deposition source for depositing copper thin films was 75 mm in diameter, 6.35 mm in thickness, and purity was 99.99. % Copper target was used. After mounting the polyimide tape substrate to the electrically-grounded substrate mount, evacuating the vacuum chamber to a vacuum of 3 x 10 ^-6 Torr, and then argon gas was introduced to make the argon pressure in the vacuum chamber 1 mTorr. Experiment.

(B) deposition using a (negative) polarity vs. output pulse DC power, (c) deposition of a bi-polar versus output pulse on a copper magnetron sputter deposition source, The bonding force of the copper vapor deposition film in the case of vapor deposition using DC power was tested.

The DC power used in the experiment (a) used a voltage of -450V, a current of 480 mA and an average power of 216 W. In the case of the experiment (b), the monopolar (negative) large output pulsed DC power was used at a frequency of 180 Hz. , Pulse width 70 usec, negative pulse DC voltage -950 V, pulse DC current 90 A, pulse DC power 85 kW, average power 228 W were used. The large output pulsed DC power has a frequency of 180 Hz, a negative pulsed DC pulse width of 70 usec, a negative pulsed DC voltage of -950 V, and a negative pulsed DC current of 90 A, negative ( A negative pulse DC power of 85 kW and a negative pulse DC power of 228 W were used.The positive pulse DC voltage applied to the negative pulse DC was +300 V and positive ( The pulse direct current pulse width of +) used a value of 100 usec.

The copper deposition layer deposited on the polyimide tape substrate was similarly deposited at a thickness of 4000 Å. In order to determine the bonding strength of the deposited copper layer, the copper deposition layer was divided into small pieces of 4 mm × 4 mm as shown in FIG. The experiment was carried out by adhering the mid tape.

As can be clearly seen from the experimental results shown in FIG. 3, in the case of the (a) substrate deposited by using DC power, most of the deposited copper thin films were peeled off, while the negative In the case of the (b) substrate, the bonding strength of the deposited copper thin film was improved as compared with the case of the (a) substrate, but it can be seen that a considerable portion is peeled off.

However, in the case of (c) the substrate using the bi-polar large output pulsed direct current power according to the present invention, the deposited copper thin film was not peeled at all, and thus the bonding force between the deposited copper thin film and the polyimide substrate It can be seen that this is very excellent.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, You will understand.

It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be interpreted as being included in the scope of the present invention .

1: vacuum chamber, 2: bi-polar pulsed DC power supply, 3: bi-polar pulsed DC, 4: magnetron sputter deposition source, 5: metal element plasma, 6: substrate, 7: substrate mount , 8: gas flow control device, 9: used gas, 10: vacuum pump, 11: vacuum chamber ground

Claims (10)

Mounting the substrate on a substrate mount located inside the vacuum chamber;
Vacuuming the inside of the vacuum chamber using a vacuum pump;
Introducing a gas to be used in the vacuum chamber to maintain an internal pressure at a constant pressure; And
And applying the bipolar pulsed DC generated by the bipolar pulsed DC power supply to the magnetron sputtering deposition source mounted to the vacuum chamber.
A method of depositing a metal thin film on a substrate. The method according to claim 1,
When bipolar pulsed DC power is applied to the magnetron sputtering deposition source, discharge of the magnetron sputtering deposition source occurs by applying a negative pulse DC power, and a metal element plasma is generated on the surface of the sputtering target, and the metal An element plasma is a method of depositing a thin metal film on a substrate, characterized in that the impingement in the direction of the substrate on the surface of the sputtering target by an electric field by a positive polarity (+) pulsed direct current applied. The method according to claim 1,
And a pressure of the gas to be used in the vacuum chamber is maintained at 0.1 mTorr to 5 mTorr. The method according to claim 1,
A method of depositing a thin metal film on a substrate, characterized in that the operating frequency of the bi-polar pulsed DC power applied to the magnetron sputtering deposition source is 10 Hz to 10 kHz. The method according to claim 1,
The negative (-) partial pulse power density of the bi-polar pulsed DC power applied to the magnetron sputtering deposition source is 10 W / cm ² to 10 kW / cm ² . How to deposit. The method according to claim 1,
And a negative pulse width of a bipolar pulsed direct current applied to the magnetron sputtering deposition source is 5 μsec to 500 μsec. The method according to claim 1,
And a pulse voltage of a bipolar (+) portion of bipolar pulsed direct current power applied to the magnetron sputtering deposition source is + 10V to + 1000V. The method according to claim 1,
The bipolar (+) pulse width of the bi-polar pulsed DC power applied to the magnetron sputtering deposition source is a method of depositing a metal thin film on a substrate, characterized in that 5μsec to 500μsec. The method according to claim 1,
A method of depositing a metal thin film on a substrate further comprising performing a plastic substrate treatment using a single gas of argon, oxygen, nitrogen or a mixed gas plasma thereof prior to metal thin film deposition. The method according to claim 1,
And the substrate is made of plastic.

Images