TWI405867B - Thin film deposition apparatus - Google Patents

Abstract

The disclosure is a plasma generating apparatus, which includes a plurality of interdigital electrodes, a RF power supply, a signal adjuster, and a plurality of the frequency oscillators. This apparatus can generate a larger area uniform plasma in the chamber, used for deposition of various optical thin films.

Description

Thin film deposition device

The present invention relates to a thin film deposition apparatus, and more particularly to a thin film deposition apparatus which produces a large-area uniform plasma using an interdigitated electrode.

In today's semiconductor process technologies, such as fabs or wafer-type solar plants, plasma enhanced chemical vapor deposition (PECVD) systems can achieve very high efficiency films on wafer level wafers. Deposition.

In addition, the conventional microcrystalline tantalum thin film solar cell is generally processed by diluting a large amount of hydrogen and decane in a plasma enhanced chemical vapor deposition process, and then forming a microcrystalline tantalum film by reaction to enhance each of them. The electrical characteristics of the project to achieve the goal of high efficiency. As the plasma frequency increases during the process, the coating rate increases. However, the increase of the frequency also means that the wavelength is shortened. When the area of the substrate to be coated increases, the electromagnetic wave transmitted on the substrate will change the electric field due to the phase change, which also affects the uniformity of the plasma and the coating. effectiveness. Today, the size of coated substrates has increased from the well-known gossip and twelve-inch wafers to a large area of one square meter or more in a thin film transistor liquid crystal display (TFT LCD) factory or a thin film solar power plant. When the glass substrate is used, the uniformity of the plasma will seriously affect the efficiency and cost of mass production. In order to solve the above problems, it is desirable to provide an electrode having a uniform plasma density to overcome the disadvantages of the prior art.

Reference is made to US Patent Publication No. 6,228,438, entitled "Plasma reactor for the treatment of large size substrates", which discloses a lens type electrode plate. The surface layout of the electrode plate is arranged in a Gaussian elliptic function distribution to match the electric field distribution on the electrode plate to produce a uniformly distributed plasma. However, the electrode structure disclosed in the case has a feeding point perpendicular to the center of the electrode plate, so that it is less effective to realize the effect of one-time multi-plate coating. Further, U.S. Patent No. 7,141,516, entitled "High frequency plasma generator and high frequency plasma generating method", which discloses an electric circuit using a ladder shape electrode A slurry-assisted vapor deposition system adopts a linear phase matching of a tubular electrode by a multi-point feeding method to achieve an electric field uniformly distributed over a large area.

However, in response to a larger area of coated substrate, the area of the electrode plate needs to be increased, so the number of feed points will also increase. In order to save costs, it is therefore necessary to propose a device that can take a smaller number of feed points and can form a large area equalizing the electric field.

For this reason, the applicant proposes a thin film deposition apparatus, which is particularly related to a plasma-assisted chemical vapor deposition apparatus using an interdigitated electrode. The thin film deposition apparatus of the invention can adopt a small number of feed points and can form a large area uniformized electric field, and has the value of improving the performance and productivity of the thin film solar battery. In addition, the present invention is incorporated by reference to U.S. Patent No. 7,141,516, entitled "High Frequency Plasma Generator and high frequency plasma generating method" and U.S. Patent No. 6,228,438. The reference is entitled "Plasma reactor for the treatment of large size substrates".

The invention provides a thin film deposition device capable of achieving a uniform electric field on an electrode, thereby improving the coating quality of the ruthenium-based film, and can be applied to a high-performance solar cell or a flat display device.

The invention provides a thin film deposition apparatus comprising: a cavity, an interdigitated electrode, a radio frequency current source, an impedance matcher, a signal adjuster, a first frequency oscillator and a second frequency oscillator. Wherein, the cavity system is grounded and has an air inlet hole and an air outlet hole for generating a plasma therein; the finger fork electrode system is disposed in the cavity and has a feed impedance for generating an electric field. Wherein the interdigitated electrode system comprises a plurality of tubular electrode sets arranged in a staggered manner, and each of the tubular electrode sets comprises a plurality of tubular electrodes and a connecting unit; the RF current source is used for providing RF current; and the impedance matching device is electrically connected. The RF current source and the fork electrode are used to match the RF current provided by the RF current source to the feed impedance of the interdigital electrode; the signal regulator is electrically connected to one end of the RF current source for adjusting the RF current The output phase of the source; the first frequency oscillator is electrically connected to the other end of the RF current source to provide a first frequency to the RF current source; and the second frequency oscillator is electrically connected to the signal regulator and the RF current source Between, to provide a second frequency to the RF current source.

The invention also provides a thin film deposition apparatus comprising: a cavity; an interdigital electrode; an RF current source; an impedance matching device; a signal regulator; a first frequency oscillator; and a second frequency oscillator . The cavity is grounded and has an air inlet hole and an air outlet hole for generating plasma; the finger fork electrode is disposed in the cavity for generating an electric field, and the interdigitated electrode is staggered by a plurality of tubular electrode groups The tubular electrode assembly comprises a plurality of tubular electrodes, a connecting unit, and a plurality of feeding units having a feeding impedance; a radio frequency current source for providing a radio frequency current; and an impedance matching device electrically connected to the radio frequency The current source and the plurality of feeding units are configured to match the RF current provided by the RF current source to the feeding impedance of the plurality of feeding units; the signal regulator is electrically connected to one end of the RF current source for adjusting the RF The output phase of the current source; the first frequency oscillator is electrically connected to the other end of the RF current source for providing a first frequency; the second frequency oscillator is electrically connected to the other end of the RF current source for A second frequency is provided.

According to the thin film deposition apparatus of the present invention, the enamel film required for preparing the bismuth thin film photovoltaic element (including the display and the solar cell) by using the interdigitated electrode has the following advantages: the film coating rate is increased, and a large area ruthenium film can be produced. Photoelectric components.

The above and other objects, features, and advantages of the present invention will become more apparent and understood.

While the invention may be embodied in various forms, the embodiments illustrated in the drawings It is not intended to limit the invention to the particular embodiments illustrated and/or described.

Please refer to FIG. 1a, which is a top view of a thin film deposition apparatus 100 of the present invention, which discloses a thin film deposition apparatus 100 comprising: a cavity 110; a finger electrode 120; a first frequency oscillator 150; Second frequency oscillator 160; impedance matcher 190; signal adjuster 170; RF current source 180. The cavity 110 is in a grounded state for generating plasma, and has an air inlet hole 111 and an air outlet hole 112. The thin film deposition apparatus 100 can be used for plasma processing and etching processes such as plasma assisted chemical vapor deposition, plasma assisted etching, and plasma polymerization, and is used for plasma assisted chemical vapor deposition in the embodiment of the present invention. The film process is particularly relevant for depositing tantalum films. The air inlet 111 is configured to pass at least one gas capable of generating a plasma reaction. In one embodiment, it is selected from the group consisting of hydrogen (H ₂ ) and decane (SiH ₄ ) gas to deposit amorphous silicon. a-Si), nanocrystal silicon (nc-Si) film and microcrystalline silicon (μ-Si) film. The air outlet 112 is used to connect a pump. By the pumping function of the pump, the pressure in the chamber 110 can be adjusted, and the exhaust gas after the reaction of hydrogen (H ₂ ) and decane (SiH ₄ ) gas is exhausted.

The plasma reaction is generated by applying energy to the gas in the cavity 110 to dissociate the electrons in the gas to form a dissociated gas, that is, a plasma. In the present invention, the energy is given by an electric field generated by radio frequency current. Thus, in the cavity 110, a plurality of tubular electrodes are arranged to introduce an RF current to generate an electric field. In order to achieve a large-area electric field, a plurality of tubular electrodes are implemented in the form of an interdigitated form, and a large-area electric field is generated by the coupling effect of the electric field on the electrodes.

The interdigitated electrode 120 is disposed in the cavity 110 for generating an electric field. The electric field of the interdigitated electrode 120 is generated by the introduction of a radio frequency current, wherein the interdigitated electrode 120 is composed of a plurality of tubular electrode groups staggered.

Referring now to FIG. 1b and FIG. 1c, which are respectively shown as a first tubular electrode set 130 and a second tubular electrode set 140 in the first embodiment of the present invention, wherein the first tubular electrode set 130 and the second tubular electrode are respectively The group 140 includes a plurality of tubular electrodes 121, and a first connecting unit 131 and a second connecting unit 141, respectively. The first connecting unit 131 and the second connecting unit 141 are configured to connect the plurality of tubular electrodes 121 and serve as a feeding medium for the radio frequency current. The first connecting unit 131 and the second connecting unit 141 may be disposed on either side of the cavity 110 in the present invention. In the present embodiment, the feeding of the radio frequency current is on the same side of the cavity 110, and thus the first connecting unit 131 and the second connecting unit 141 have different forms.

Wherein, the electric fields generated by the first tubular electrode group 130 and the second tubular electrode group 140 each have an electromagnetic coupling between them, which will cause the electric field to interact, and in the vicinity of the interdigitated electrode 120 and its adjacent region Form a large area of electric field. The strength of the electric field will affect the energy obtained by the electrons entering the gas in the cavity 110, thereby affecting the uniformity of the plasma distribution. The configuration of the interdigitated electrode 120 can be applied to an atmospheric pressure chemical vapor deposition system (APCVD), a low pressure chemical vapor deposition system (LPCVD), a high density plasma chemical vapor deposition system (HDPCVD), and plasma assisted chemistry. One of a vapor deposition system (PECVD), an inductively coupled plasma ion etching system (ICP), in which the number of tubular electrodes 121 can be varied depending on the size of the substrate in the process to produce a distributed plasma of any area. In the present embodiment, the number of tubular electrodes is 12 and the substrate size is 1.4 X 1.4 m ² .

The material of the interdigitated electrode 120 is selected from the group consisting of nickel, gold, silver, titanium, copper, palladium, stainless steel, beryllium copper alloy, aluminum, coated aluminum, tantalum, quartz, tantalum carbide, tantalum nitride, carbon, aluminum nitride. , sapphire, polyimine, and one of Teflon. It should be noted that the interdigitated electrodes 120 located in different systems may also affect the quality and uniformity of the deposited film. In addition, during the process, the current feeding condition of the RF current source 180 to the interdigital electrode 120 needs to be considered. In order to avoid excessive electromagnetic wave reflection, the impedance matching device 190 is electrically connected to the interdigital electrode 120 at the same time for matching the impedance of the RF current source 180 to the feeding impedance of the interdigital electrode 120 by the impedance matching device. 190 adjusts the feed impedance of the RF current source 180 to avoid excessive reflected waves.

The RF current source 180 is electrically connected to the impedance matching device 190 to provide at least one RF current to the interdigital electrode 120, and the operating frequency ranges from 10 MHz to 1 GHz. The frequency of the RF current output by the RF current source 180 affects the gas dissociation rate in the cavity 110 and changes the film deposition rate. It should be noted that the length of the tubular electrode 121 ranges from 1/1,000 to 1/2 of the wavelength of the RF current frequency. The guiding wavelength is defined as the wavelength at which the electromagnetic wave of the specific frequency is transmitted in the cavity. In the embodiment of the present invention, the preferred length L1 of the plurality of tubular electrodes 121 is 1.4 m; the impedance of the RF current source 180 fed to the interdigital electrodes 120 is 1 to 300 ohms, and the optimum impedance is 50 ohms.

In order to form a uniform electric field, the distance between the plurality of tubular electrodes 121 should not be too far to avoid insufficient electromagnetic coupling between the adjacent tubular electrodes 121. In the embodiment of the present invention, the interval W1 of the plurality of tubular electrodes 121 is 0.04 m.

In addition, in order to achieve a uniform electric field, the voltage phase and amplitude of the plurality of tubular electrodes 121 can be adjusted. Therefore, a signal adjuster 170 having a moving phase and amplitude action is required.

The signal adjuster 170 is electrically connected to one end of the RF current source 180 for adjusting the output phase of the RF current source 180. The signal conditioner 170 is coupled to the functions of a phase shifter and a signal amplifier as is well known to those skilled in the art. The first frequency oscillator 150 is electrically connected to the other end of the RF current source 180 to provide a first frequency as a frequency of at least one output RF current of the RF current source 180. The second frequency oscillator 160 is also electrically coupled to one end of the RF current source 180 for providing the second frequency as the frequency of the at least one output RF current of the RF current source 180. The signal adjuster 170 and the first frequency oscillator 150 and the second frequency oscillator 160 can cause the RF current output by the RF current source 180 to have two different output phase/amplitude/frequency/signal shapes.

Referring now to Figure 2a, which is a relationship between the RF voltage and the phase generated by the RF current, wherein the RF voltage value changes periodically with the phase change, wherein the degree of the phase can be equivalent to the RF current passing distance. The phenomenon can be applied to analyze changes in the RF voltage value on the tubular electrode.

Referring now to FIG. 2b, when the RF currents of two sets of frequencies having a phase difference of 90 degrees are input to the adjacent tubular electrodes of the tubular electrode 121, the phase of the voltage is distributed along the tubular tubular electrode 121, and the present invention presents An approximate sinusoidal distribution curve. By observing the phase of the three points a, b, and c on the curve, it is shown that the effect of phase complementation is achieved due to the difference in the phase magnitude of the three points of voltage, so that the phase of the voltage generated along the tubular electrode 121 changes. It becomes smaller and forms a uniform coupled electric field. In the first embodiment, the first frequency of the first frequency oscillator 150 is 40.68 MHz, the second frequency of the second frequency oscillator 160 is 38 MHz, and the signal adjuster 170 moves the phase of the RF current having the second frequency. 50 degrees to 180 degrees.

Referring now to FIG. 3, a thin film deposition apparatus 200 according to a second embodiment of the present invention includes a cavity 110 disclosed in the first embodiment; an impedance matching unit 190; a radio frequency current source 180; and signal adjustment. The first frequency oscillator 150; the second frequency oscillator 160, the above components are implemented in the same manner as in the first embodiment. Different from the first embodiment, the interdigitated electrode 210 in the second embodiment is composed of two sets of second tubular electrode sets 140, and thus the second connecting unit 141 is located on different faces of the cavity.

Referring now to FIG. 4, a thin film deposition apparatus 300 according to a third embodiment of the present invention includes a cavity 110 disclosed in the first embodiment; an impedance matching unit 190; a radio frequency current source 180; and signal adjustment. The first frequency oscillator 150; the second frequency oscillator 160, the above components are implemented in the same manner as in the first embodiment. Different from the first embodiment, the interdigitated electrode 310 in the third embodiment is composed of two sets of second tubular electrode sets 130, and a T-shaped connecting unit 320. The electric field generating area in the embodiment is twice as large as the electric field area in the first embodiment by the coupling between the tubular electrode 121 disposed on the T-shaped connecting unit 320 and the two sets of the second tubular electrode group 130. Therefore, the process area of the thin film deposition apparatus 300 can be effectively increased. It should be noted that the phase of the radio frequency current input to the T-type connecting unit 320 is different from the phase of the radio frequency current input to the two sets of the second tubular electrode group 130. In the present embodiment, the first frequency of the first frequency oscillator 150, the second frequency of the second frequency oscillator 160, and the phase shift of the signal adjuster 170 are the same as in the first embodiment.

Referring now to FIG. 5a, a thin film deposition apparatus 400 according to a fourth embodiment of the present invention includes a cavity 110 disclosed in the first embodiment; an impedance matching device 190; a radio frequency current source 180; and signal adjustment. The first frequency oscillator 150; the second frequency oscillator 160, the above components are implemented in the same manner as in the first embodiment. Referring now to Figure 5b, there is shown an interdigitated electrode 410 of a fourth embodiment of the present invention. Different from the first embodiment, the interdigitated electrode 410 in the fourth embodiment is composed of a plurality of tubular electrodes 121, a connecting unit 411, and a plurality of feeding units 412.

In this embodiment, the impedance matching unit 190 is coupled to the plurality of feeding units 412 for matching the RF current provided by the RF current source 180 to the feeding impedance of the plurality of feeding units 412. By increasing the number of RF current feed points, the phase distortion and attenuation caused by the input RF current flowing in the connection unit 411 can be effectively reduced. Therefore, the thin film deposition apparatus 400 in this embodiment can have better functions. It should be noted that in this embodiment, the adjacent feeding unit 412 needs to input a radio frequency current having a phase difference. The first frequency of the first frequency oscillator 150, the second frequency of the second frequency oscillator 160, and the phase shift of the signal adjuster 170 are the same as those of the first embodiment, and the number of the feeding unit 412 and the tubular electrode 121 The same, all are twelve groups.

In summary, the thin film deposition apparatus according to the present invention uses the interdigitated electrode to prepare a tantalum film required for a tantalum film photovoltaic element (including a display and a solar cell), which has the following advantages: increasing the film coating rate, and Produce large-area thin film photovoltaic components.

While the present invention has been described in its preferred embodiments, it is not intended to limit the scope of the invention, and various modifications and changes can be made without departing from the spirit and scope of the invention. As explained above, various modifications and variations can be made without departing from the spirit of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

100. . . Thin film deposition device

110. . . Cavity

111. . . Air intake

112. . . Vent

120. . . Finger fork electrode

121. . . Tubular electrode

130. . . First tubular electrode set

131. . . First connection unit

140. . . Second tubular electrode set

141. . . Second connection unit

150. . . First frequency oscillator

160. . . Second frequency oscillator

170. . . Signal conditioner

180. . . RF current source

190. . . Impedance matcher

200. . . Thin film deposition device

210. . . Finger fork electrode

300. . . Thin film deposition device

310. . . Finger fork electrode

320. . . T-connecting unit

400. . . Thin film deposition apparatus of the fourth embodiment

410. . . Finger fork electrode of the fourth embodiment

411. . . Link unit of the fourth embodiment

412. . . Feeding unit

Figure 1a shows a thin film deposition apparatus according to the present invention;

Figure 1b is shown as a first tubular electrode set;

Figure 1c is shown as a second tubular electrode set;

Figure 2a shows the relationship between RF current voltage and phase;

Figure 2b is a phase diagram showing the radio frequency current on the tubular electrode in the embodiment of the present invention;

Figure 3 is a view showing a thin film deposition apparatus according to a second embodiment of the present invention;

Figure 4 is a view showing a thin film deposition apparatus according to a third embodiment of the present invention;

Figure 5a is a view showing a thin film deposition apparatus according to a fourth embodiment of the present invention;

Fig. 5b shows an interdigitated electrode according to a fourth embodiment of the present invention.

100. . . Thin film deposition apparatus of the first embodiment

110. . . Cavity

111. . . Air intake

112. . . Vent

120. . . Finger fork electrode

121. . . Tubular electrode

150. . . First frequency oscillator

160. . . Second frequency oscillator

170. . . Signal conditioner

180. . . RF current source

190. . . Impedance matcher

Claims (15)

A thin film deposition apparatus comprising: a cavity; an interdigitated electrode disposed in the cavity, having a feed impedance for generating an electric field, the interdigitated electrode comprising a plurality of tubular electrode sets arranged in a staggered configuration And each of the tubular electrode sets includes a plurality of tubular electrodes and a connecting unit; an RF current source for providing an RF current; an impedance matching device electrically connected to the RF current source and the interdigitated electrode The signal regulator is electrically connected to the RF current source for adjusting the output phase and amplitude of the RF current source; a first frequency oscillator electrically connected to the RF current source for providing a first frequency to the RF current source; and a second frequency oscillator electrically coupled to the RF current source for providing a Two frequencies are applied to the RF current source. The thin film deposition apparatus of claim 1, wherein the material of the interdigitated electrode is selected from the group consisting of nickel, gold, silver, titanium, copper, palladium, stainless steel, beryllium copper alloy, aluminum, coated aluminum, tantalum, quartz, A group consisting of tantalum carbide, tantalum nitride, carbon, aluminum nitride, sapphire, polyimine, Teflon, and combinations thereof. The thin film deposition apparatus of claim 1, wherein the length of the tubular electrode is one thousandth to one half of a wavelength of the frequency generated by the radio frequency current. The thin film deposition apparatus of claim 1, wherein the connection unit is disposed at a periphery of the cavity. The thin film deposition apparatus of claim 1, wherein the RF current source is fed to the interdigitated electrode with an impedance of 1 to 300 ohms. The thin film deposition apparatus of claim 1, wherein the first frequency is 40.68 MHz, and the second frequency is 38 MHz. The thin film deposition apparatus of claim 1, wherein the RF current source operates at a frequency of 10 MHz to 1 GHz. A thin film deposition apparatus comprising: a cavity grounded and having an air inlet hole and an air outlet hole for generating a plasma; and an interdigitated electrode disposed in the cavity for generating an electric field The interdigitated electrode comprises a plurality of tubular electrode sets arranged in a staggered manner, and each of the tubular electrode sets comprises a plurality of tubular electrodes, a connecting unit and a plurality of feeding units, wherein each of the feeding units has a Feeding the impedance; an RF current source for providing an RF current; an impedance matching device electrically connected to the RF current source and the feeding units for matching the RF current provided by the RF current source to The feed impedance of the feed unit; a signal adjuster electrically connected to the RF current source for adjusting an output phase of the RF current source; and a first frequency oscillator electrically connected to the RF current The source is configured to provide a first frequency to the RF current source; and a second frequency oscillator is electrically coupled to the RF current source for providing a second frequency to the RF current source. The thin film deposition apparatus of claim 8, wherein the material of the interdigitated electrode is selected from the group consisting of nickel, gold, silver, titanium, copper, palladium, stainless steel, beryllium copper alloy, aluminum, coated aluminum, tantalum, quartz, A group consisting of tantalum carbide, tantalum nitride, carbon, aluminum nitride, sapphire, polyimine, Teflon, and combinations thereof. The thin film deposition apparatus of claim 8, wherein the length of the tubular electrode is one thousandth to one half of a wavelength of the frequency generated by the radio frequency current. The thin film deposition apparatus of claim 8, wherein the connection unit is disposed at a periphery of the cavity. The thin film deposition apparatus of claim 8, wherein the RF current source is fed to the interdigitated electrode with an impedance of 1 to 300 ohms. The thin film deposition apparatus of claim 8, wherein the first frequency is 40.68 MHz. The thin film deposition apparatus of claim 8, wherein the second frequency is 38 MHz. The thin film deposition apparatus of claim 8, wherein the RF current source operates at a frequency of 10 MHz to 1 GHz.