KR102308684B1 - A device for matching the impedance of the plasma apparatus and the method thereof - Google Patents

Abstract

The present invention relates to a method and device for matching a high-speed impedance that set each preset in multiple recipes or steps of various manufacturing equipment (one or more steps exist in one recipe) with a multi preset function capable of setting one or more variable starting points (plasma ignition impedance position) for each process recipe or per step, and automatically move to a preset variable starting point (plasma ignition impedance position) in accordance with changes in power consumption or changes in recipe and step, thereby being capable of providing, for each different impedance matching, a variety of optimal matching starting points (plasma ignition impedance position).

Description

A DEVICE FOR MATCHING THE IMPEDANCE OF THE PLASMA APPARATUS AND THE METHOD THEREOF

The present invention relates to an impedance matching apparatus and method, and more specifically, to a Multi Preset function capable of setting one or more variable starting points (plasma ignition impedance position) for each process recipe or step. By setting each Preset in the Recipe (there is more than one Step), it automatically moves to the preset multiple ignition position (plasma ignition impedance position) according to the change in power consumption or the change of recipe and step. The present invention relates to a high-speed impedance matching apparatus and method capable of variously providing an optimal matching starting point (plasma ignition impedance position) in each different impedance matching.

In precision device manufacturing fields such as semiconductor device manufacturing, liquid crystal display (LCD) manufacturing, and solar module manufacturing, it is common to use a process using plasma for highly integrated and precise process processing.

Each manufacturing equipment using plasma is composed of a closed chamber for process treatment, a reactive gas supply device, and a RF generator for high frequency generation, and the closed chamber ) by injecting a reactive gas and applying a high frequency to discharge plasma. When plasma is generated, the chamber becomes a dynamic load including plasma, and a reflected wave reflected from the dynamic load is generated between the RF generator and the chamber due to the dynamic load.

The reflected wave is the power generated by the high-frequency generator that is returned without being transferred to the chamber, which causes failure of the high-frequency generator, product defects, and quality degradation, and serves as a standard for evaluating the quality of plasma. Therefore, in order to obtain high quality plasma, it is necessary to quickly match the impedance so that the maximum power can be supplied to the load by minimizing the reflected wave within a short time.

As the impedance matching method, in general, a method of installing a separate impedance matching device including a variable element (variable coil or variable capacitance) between the chamber and the high frequency power supply device, and performing impedance matching by changing the frequency of the high frequency power supply device There is a way to do it. On the other hand, since the load is a dynamic load that changes with time, impedance matching must be performed to follow the movement of the load.

The automatic impedance matching device using a variable element has different matching networks according to the characteristics of the load, and at least one variable element is used in the network. Since impedance matching can be performed over a very wide range of load impedances according to the network configuration using the variable element, it shows excellent impedance matching characteristics even when the plasma state is severely changed, and the reflected wave can be implemented close to "0" have. A variable capacitor or a variable inductance is generally used as the variable element, and the variable element is controlled using a motor and is controlled to automatically follow a dynamic load through a detection circuit of a reflected wave.

However, the impedance matching speed using the variable element is on the slow side, and a matching time of several hundred milliseconds to several seconds is required depending on the driving speed of the motor that moves the variable element.

On the other hand, when impedance matching is performed by varying the frequency, the normal frequency variable range is less than 10% of the reference frequency, and the impedance range of the load capable of impedance matching is very narrow. The impedance matching range of the network having one or more variable elements has a wide area, whereas the frequency variation has a line shape rather than an area due to one variation of frequency. Therefore, impedance matching cannot be performed even with a small change in the impedance of the load, and a certain amount of reflected waves inevitably remains even after completion of the performance. On the other hand, since the impedance matching speed is fast, the matching time is very short, about a few milliseconds (mili-sec).

Recently, in order to improve productivity throughout the semiconductor manufacturing process, it is required to increase the efficiency of plasma, which requires a short impedance matching time. In particular, in the atomic layer deposition (ALD) process, plasma control for a very short time must be repeated. In addition, in recent etching processes and deposition processes, plasma efficiency is controlled by repeating deposition and etching or changing high-frequency power while maintaining high-frequency power within one recipe.

In order to implement these new process conditions, a very fast impedance matching time is required. In addition, by setting each pre-ignition position movement in several types of recipes or steps (one or more steps exist in one recipe), change of power used or recipe and step ( A high-speed impedance matching device and method and reliable process that can automatically move to a preset multiple ignition position (plasma ignition impedance position) according to the change of step) and provide various optimal matching situations for each different impedance matching For the result, it automatically follows the ignition position even when the ignition position changes according to the change of the load, and requires constant plasma generation through rapid and constant matching.

In order to satisfy the new requirements of short matching time, constant plasma quality, and wide matching range, a new impedance matching method and impedance matching device capable of setting various impedance ignition positions in an impedance matching device using a variable network are required.

In the matching between the RF Generator and the chamber, even in the same chamber environment, different impedances may be obtained depending on the recipe or step contents (gas type, gas usage amount, chamber temperature, power size, etc.). Therefore, a difference occurs between the plasma matching impedance and the impedance of the ignition position for generating plasma.

In such a diverse impedance environment, stable and fast matching time must be implemented according to recipe or step contents (gas type, gas consumption, chamber temperature, power size, etc.) And as the processing time increases, it leads to a decrease in production.

In order to solve this problem, the load and phase variable elements (variable capacitors or variable inductances) of the automatic impedance matching device during initial matching in various impedance environments are ignited with a new plasma according to the recipe or step before applying the high frequency power. There is a need for a new impedance matching method and impedance matching device with a recipe preset with position or multi preset function and algorithm.

Recognizing that the position of the load and phase variable element (variable capacitor or variable inductance) required for ignition in impedance matching is at the plasma ignition position according to the impedance of the chamber, high-frequency power (RF Power) ), it is necessary to develop a technology to reduce the initial reflection wave and shorten the matching time by moving the load and phase variable element (variable capacitor or variable inductance) to the plasma ignition impedance position. . (Existing technology has only one preset regardless of recipes or steps of various equipment and chamber)

This function is to move the load and phase variable element (variable capacitor or variable inductance) to various plasma ignition impedance positions according to recipes or steps with electrical and communication signals from the internal software or external system of the automatic impedance matching device.

Hereinafter, this will be described in detail with reference to FIGS. 1, 2 and Table 1. As shown in FIG. 1 , in the case of a general CCP type chamber, it includes a chamber 30 , an impedance matcher 20 , and an RF power supply 10 , and the impedance within the chamber 30 is the electrode parts 42 and 44 . ) and the parasitic capacitance Cc, inductance L, and resistance R between the electrodes 42 and 44 and the chamber 30 wall.

Step 1 Step 2 Step 3 Gas A 300 sccm 900 sccm 0 Gas B 1200sccm 1200sccm 1500scm Gas C 700sccm 1000sccm 0 RF Power 900w 1500w 300 Pressure 600mTorr 600mTorr 1200mTorr Temp.

Table 1 shows one reference recipe for each step, and has various impedances depending on the environment of the chamber, such as the type of gas used, the amount of gas used, the size of RF power, and pressure. 2 shows the plasma matching positions for each step and ignition impedance positions for each step of Table 1.

Table 1 is a recipe with three steps in one recipe, and the location of the plasma impedance is different as shown in FIG. 2 according to the amount or type of gas used, RF power, pressure, etc. It can be seen that there is a difference in the ignition position due to this difference, and despite the difference in the plasma matching position, it is difficult to optimize the plasma matching, which has a difference for each step with one ignition position.

For this reason, in order to optimize each plasma matching, it is necessary to move the load and phase variable elements (variable capacitor or variable inductance) to the ignition position of each step in advance. It is impossible to satisfy

In addition, in this conventional single ignition position setting function, the variable starting point (plasma ignition impedance for each step) that can set two or more optimal ignition positions for multiple impedances according to different RF power sizes, gas types, temperature changes, etc. position), and an impedance matching device with

In particular, recent semiconductor manufacturing equipment uses various recipes (including steps) or various steps such as system semiconductor manufacturing equipment and etching process, chemical vapor deposition process, and atomic layer deposition process, so that the variable starting point (plasma ignition) of the variable element of the impedance matching device is used more and more. two or more impedance positions) are required.

In order to implement these new process conditions, two or more variable starting points (plasma ignition impedance positions) of the variable element of the impedance matching device are required to be set.

The technical problem to be solved by the present invention is a multi-ignition position setting function capable of setting a variable starting point (plasma ignition impedance position) for each step in one recipe, and setting each pre-ignition position movement in several recipes of various manufacturing equipment With this possible recipe preset function, it automatically moves to a preset multiple ignition position (plasma ignition impedance position) according to a change in power consumption or a change in recipe and step, which is optimal for each different impedance matching. It is to provide a high-speed impedance matching apparatus and method that can variously provide a matching starting point (plasma ignition impedance position) of

A high-frequency power supply capable of outputting a high frequency for plasma ignition according to the present invention for solving the above technical problem; A process in which the output is provided from the high-frequency power supply device and transmitted to a load, the reflected wave transmitted from the load is sensed, and the impedance matching function is automatically performed using the variable network, and the starting position of the variable network is started before starting a new process and an automatic impedance matching device capable of moving to a pre-ignition position by a preset relative value according to a recipe or step and setting two or more ignition positions.

And in the present invention, the automatic impedance matching device comprises: a variable network circuit unit including at least one variable element; a detection circuit unit for detecting the reflected wave transmitted from the load in real time; an automatic matching unit for changing the variable network circuit unit in real time so that the reflected wave detected by the detection circuit unit approaches "0"; It is preferable to include a; multi-ignition position adjustment unit for moving the position of the variable network circuit unit to the pre-ignition position moved by a preset relative value according to the corresponding process recipe or step before starting a new process.

In addition, in the present invention, it is preferable that the multi-ignition position adjusting unit moves to the pre-ignition position moved by a preset relative value according to a process recipe or step performed by the manufacturing apparatus using the plasma.

In addition, in the present invention, the control unit includes an ignition position calculation unit having an algorithm capable of setting two or more changed plasma ignition positions of the variable network circuit unit according to a process recipe or step to newly set the position of the variable network circuit unit before starting a new process It is preferable to do

In addition, in the present invention, 1) moving the position of the variable network of the automatic impedance matching device to a first pre-ignition position set in advance according to the process to be started; 2) supplying RF power corresponding to the first pre-ignition position using a high-frequency power supply; 3) the automatic impedance matching device receives the output from the high frequency power supply device and transmits it to a load, sensing a reflected wave transmitted from the load and automatically performing an impedance matching function using the variable network; 4) confirming the recipe or step of the next process to be performed when the process is completed and the RF power is stopped; 5) before starting the next process, changing the position of the variable network to a preset second pre-ignition position according to the new process recipe or step identified in step 4);

In the present invention, in step 5), it is preferable to move to the second pre-ignition position moved by a preset relative value according to a recipe or step set by the manufacturing apparatus.

According to the ultra-high-speed impedance matching device and method of the present invention, the Multi Preset function that allows setting of two or more variable starting points (plasma ignition impedance position) for each power band used and multiple recipes or steps of various manufacturing equipment (one or more steps in one recipe) By setting each Preset in this existence), it automatically moves to the preset variable starting point (plasma ignition impedance position) according to changes in power consumption or changes in recipe and step, and the optimal matching starting point (plasma It has the advantage of providing various ignition impedance positions).

1 is a view showing a general CCP TYPE chamber, an impedance matcher, and an RF power supply.
2 is a view showing the impedance matching position and ignition position for each step of a general recipe on a Smith chart.
3 is a block diagram showing the configuration of a high-speed impedance matching device according to an embodiment of the present invention.
4 is a flowchart of an ultra-fast impedance matching method according to an embodiment of the present invention.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 3 , the ultra-high speed impedance matching device 100 according to the present embodiment may include a high frequency power supply device 110 , an automatic impedance matching device 120 , and a controller 130 .

First, the high frequency power supply 110 is a component that generates RF power and provides it to the load, that is, the chamber 101 , and it is preferable that it can supply high frequency power for plasma generation. In addition, the high-frequency power supply 110 may generally employ a commercially available product capable of amplifying function or frequency variable.

Next, as shown in FIG. 3 , the automatic impedance matching device 120 is installed between the high frequency power supply 110 and the load, that is, the chamber 101 , and provides an output from the high frequency power supply 110 . It is a component that receives and delivers to the chamber 101 . In particular, in the present embodiment, the automatic impedance matching device 120 senses a reflected wave reflected from the load in response to the output of the high frequency power supply 110 and transmitted, and the reflected wave is "0" using a variable network. Not only can the impedance matching function be performed automatically as much as possible, but the position of the variable network is set to the pre-ignition position by a relative value calculated or set in advance according to the process to be started based on the final stop position of the variable network before starting a new process. It has a structure that can also perform the function of moving.

Therefore, in this embodiment, the automatic impedance matching device 120 is specifically, as shown in FIG. 3 , a variable network circuit unit 122 , a detection circuit unit 124 , an automatic matching unit 126 , and a multi-ignition position adjustment unit 128 . ) may be included. First, as shown in FIG. 3 , the variable network circuit unit 122 may include at least one variable element, that is, a variable coil or variable capacitance, and may include a motor capable of adjusting them. In this case, the specific configuration of the variable network circuit unit 122 may be variously changed as necessary.

Next, the detection circuit unit 124 is installed in the automatic impedance matching device 120, and is a component that detects the reflected wave transmitted from the load 101 with respect to the output of the high frequency power supply 110 in real time, In this embodiment, the detection circuit unit 124 detects the reflected wave, and the control unit 130 controls the automatic matching unit so that the reflected wave is the lowest.

Specifically, the detection circuit unit 124 detects the maximum power of the high frequency power supply 110 that can be detected as a reflected wave in real time, and provides the detected voltage and current phase to the automatic matching unit 126 .

Next, the automatic matching unit 126 is installed in the automatic impedance matching device 120, and the variable network circuit unit 122 is configured so that the reflected wave detected and provided by the detection circuit unit 124 approaches “0”. It is a component that performs an automatic matching function by changing it in real time.

Next, the multi-ignition position adjustment unit 128 controls the variable network according to the number of pre-calculated or set values according to the process recipe or step to be started based on the final stop position of the variable network circuit unit 122 before starting a new process. It is a component that sets and moves the position of the circuit part 122 to the pre-ignition position.

That is, the multi-ignition position adjustment unit 128 does not always move the variable network circuit unit 122 to a specific pre-ignition position before the start of the process, but rather the variable network circuit unit ( 122) is automatically moved.

Meanwhile, in the present embodiment, the multi-ignition position adjusting unit 128 may move to the pre-ignition position moved by a preset relative value according to a recipe or step set in the manufacturing apparatus using the plasma. That is, since the pre-ignition position is changed according to the used impedance, impedance information to be used in a subsequent process recipe or step is received in advance, and the variable network circuit unit 122 is moved to the corresponding multi pre-ignition position accordingly.

Next, as shown in FIG. 3, the control unit 130 is installed in the automatic impedance matching device 120, and the impedance matching technology using the variable network circuit unit 122 and the optimum ignition position calculation algorithm are fused. By making it possible to set two or more optimal ignition impedance positions for two or more plasma matching loads, it is a component that matches any plasma matching within a short time within a few msec to several tens of msec and performs new impedance matching so that the reflected wave is the lowest.

To this end, the high-frequency output is made in the high-frequency power supply 110 , and an automatic matching function is first performed from the specified step ignition position of the specified recipe of the variable network circuit unit 122 with respect to this output. Here, the 'ignition position' generally refers to a designated position for optimal plasma matching or a plasma ignition position.

Then, by activating the automatic matching function of the automatic matching unit 126, automatic impedance matching with respect to the real-time changing chamber impedance is controlled to be performed quickly. When the automatic matching operation is completed, the optimal matching state is maintained by using a variable element so that the reflected wave is minimized.

Upon completion of the process recipe or step, the variable network circuit unit 122 is moved to the preset plasma ignition position according to the impedance of the next process recipe or the next step to be performed. Impedance matching begins.

Therefore, the control unit 130 sets the position of the variable network circuit unit 122 before a new process starts with an algorithm capable of setting two or more different plasma ignition positions of the variable network circuit unit 122 according to a new process recipe or a new step to be performed. A multi-ignition position adjustment unit 128 is provided.

While repeatedly performing the above operation, matching starts at the optimal plasma ignition position at any impedance to generate stable plasma through fast matching with a low initial reflection wave.

Hereinafter, a method of performing impedance matching using the automatic impedance matching apparatus 100 having such a structure will be described in detail.

As shown in FIG. 4 , the impedance matching method according to the present embodiment starts with the step ( S100 ) of moving the variable network circuit unit 122 to the first pre-ignition position. The first pre-ignition position may be a position preset to a predetermined plasma ignition position according to the characteristics of the chamber and a recipe step, or may be a position determined according to a process to be newly performed.

Next, as shown in FIG. 4 , a step ( S200 ) of providing high-frequency power from the RF power source 110 is performed. Here, the high frequency power refers to a high frequency power value specified in a process recipe to be performed by the load 101 . In this step (S200), the RF power set by first turning on the high-frequency power supply 110 is supplied to the load 101 through the automatic impedance matching device 120 .

Next, as shown in FIG. 4 , a step ( S300 ) of sensing a reflected wave transmitted from the load and automatically performing an impedance matching function using the variable network circuit unit 122 is performed. This step (S300) may be performed in various ways, for example, as shown in FIG. 4 , it may be performed by moving the variable network circuit unit 122 and finding a time point at which matching is completed.

Next, as shown in FIG. 4, when the process is completed and the RF power is stopped, a step (S400) of confirming the recipe of the process to be performed next is performed. This process recipe or step may be provided by the system or may be provided by the control unit 130 . The preset second pre-ignition position is determined by the process recipe or step provided in this way.

Next, as shown in FIG. 4 , a step ( S500 ) of determining to move to the second pre-ignition position based on the process recipe or step confirmed in the previous step ( S400 ) is performed. This step (S500) is performed automatically and quickly because it is moved to a new second pre-ignition position stored in the multi-ignition position adjustment unit set in advance based on a process recipe or step to be performed later.

The moved second pre-ignition position becomes a starting point for performing optimal impedance matching when the next RF power is supplied.

100: ultra-fast impedance matching device according to an embodiment of the present invention
101: chamber 110: high frequency power supply device
120: automatic impedance matching device 130: control unit
140: antenna 1: substrate

Claims (6)

a high frequency power supply capable of outputting a high frequency for plasma ignition;
A process in which the output is provided from the high-frequency power supply device and transmitted to a load, the reflected wave transmitted from the load is sensed, and the impedance matching function is automatically performed using the variable network, and the starting position of the variable network is started before starting a new process An automatic impedance matching device capable of moving to a pre-ignition position by a preset relative value according to a recipe or a step and setting two or more ignition positions; According to claim 1, wherein the automatic impedance matching device,
a variable network circuit unit including at least one variable element;
a detection circuit unit for detecting the reflected wave transmitted from the load in real time;
an automatic matching unit for changing the variable network circuit unit in real time so that the reflected wave detected by the detection circuit unit approaches "0";
and a multi-ignition position adjusting unit for moving the position of the variable network circuit unit to a pre-ignition position moved by a preset relative value according to a corresponding process recipe or step before starting a new process. The method of claim 2, wherein the multi-ignition position adjustment unit,
High-speed impedance matching apparatus, characterized in that the movement is moved to the pre-ignition position moved by a preset relative value according to a process recipe or step carried out by the manufacturing apparatus using the plasma. The method of claim 2, wherein the multi-ignition position adjustment unit,
High-speed impedance matching comprising an ignition position calculation unit having an algorithm capable of setting two or more changed plasma ignition positions of the variable network circuit unit according to a process recipe or step to newly change the position of the variable network circuit unit before starting a new process Device. 1) moving the position of the variable network of the automatic impedance matching device to a first pre-ignition position preset according to the process to be started;
2) supplying RF power corresponding to the first pre-ignition position using a high-frequency power supply;
3) the automatic impedance matching device receives the output from the high frequency power supply device and transmits it to a load, sensing a reflected wave transmitted from the load and automatically performing an impedance matching function using the variable network;
4) confirming the recipe or step of the next process to be performed when the process is completed and the RF power is stopped;
5) before starting the next process, changing the position of the variable network to a preset second pre-ignition position according to the new process recipe or step identified in step 4). delete

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