JP3717414B2 - Plasma processing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plasma processing apparatus and a processing method that are effective in manufacturing semiconductors, liquid crystal display substrates, and the like.
[0002]
[Prior art]
Corresponding to the increase in the diameter of silicon wafers and the miniaturization of semiconductor devices, in the plasma process, for example, desired process processing parameters such as gas flow rate, processing pressure, plasma generation power, wafer temperature, and bias power are processed. The range of parameter combinations for which results are obtained, that is, the process window, is becoming narrower year by year.
[0003]
As a result, conditions that satisfy the desired plasma treatment cannot be obtained when the apparatus is started up or when a certain process is started up, or the initial plasma treatment does not contaminate the processing chamber even if the desired treatment result is obtained. When a shift of the apparatus state caused by the above occurs, there is a problem that the process window is off. Conversely, after the process chamber is cleaned, the process state shifts due to the inside of the process chamber being cleaned or the change of the internal surface state due to the opening of the process chamber to the atmosphere, so it is called aging. Although it is necessary to discharge the air and condition the device, this aging has become difficult year by year, and it is extremely difficult to determine whether or not to start construction after aging.
[0004]
[Problems to be solved by the invention]
In order to solve such problems, it is necessary to reliably grasp the state of the apparatus and the process. Usually, various signals during the process, for example, plasma emission and other monitors, plasma source and wafer bias are used. The current, voltage, and impedance state of the device are monitored. If these values are not within a certain range, it is determined that the state is abnormal. However, even if these signals are normal values, normal plasma processing is not guaranteed, and in many cases, it cannot be determined unless the wafer is finally processed. As the wafer diameter increases, the cost of the wafer becomes a serious problem.
[0005]
In addition, the place where an ordinary process monitor is installed is limited, and it is difficult to say that plasma information at the wafer position can be accurately measured. An object of the present invention is to provide a plasma processing apparatus capable of accurately measuring the state of plasma at a wafer position and other necessary processes and performing high-precision and stable processing.
[0006]
[Means for Solving the Problems]
The above-mentioned problem is that a plasma measurement stage head incorporating various sensors or a dedicated test wafer (plasma measurement wafer) incorporating various sensors is manually or automatically transferred to the wafer stage position. The problem is solved by managing the apparatus using the signal of the sensor. The output signal of the stage head for plasma measurement or the wafer for plasma measurement is taken out to the outside by a data communication terminal provided on the wafer stage, recorded in a data recording device, and used for device management, start-up judgment and the like.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is not limited to the field of manufacturing semiconductor devices, and can be applied to various fields such as manufacturing liquid crystal displays and various plasma surface treatments. Here, plasma etching for manufacturing semiconductor devices is used. Taking the apparatus as an example, an embodiment will be described.
[0008]
FIG. 1 shows an embodiment of the present invention. The processing chamber 1 in the figure is a vacuum vessel made of, for example, stainless steel or aluminum, and a pump 3 is connected through a butterfly valve 2 and an etching gas is introduced through a flow rate controller 6 to maintain a desired pressure. It is. A wafer stage 13 for placing the wafer 20 is installed in the processing chamber 1, and a high frequency bias is applied to the wafer 20 through the wafer stage 13.
[0009]
On the other hand, there is a plasma source 16 connected to the high frequency power source 5 at a position facing the wafer 20, ionizing the introduced etching gas, generating plasma 12, and etching the wafer 20. A feature of the present invention is that a data communication terminal 14 is provided on the wafer stage 13. The plasma measurement stage head 11 is placed on the wafer stage 13 to measure the plasma 12. The plasma measurement stage head 11 is equipped with a sensor for measuring the plasma 12 such as an ion current probe 15.
[0010]
Next, the structure of the wafer stage 13 and the plasma measurement stage head 11 will be described. FIG. 2 shows a cross-sectional view of a wafer stage 13 according to an embodiment of the present invention. Generally, in the case of a plasma etching apparatus, the wafer 20 is held on the wafer stage 13 by a technique such as mechanical clamping or electrostatic adsorption. Normally, a susceptor 21 (electrode protective cover) made of an insulator such as ceramic is provided around the wafer stage 13. Here, a data communication terminal 14 for exchanging electrical signals is provided at a position behind the susceptor 21.
[0011]
FIG. 3 shows an ion current probe array built-in plasma measurement stage head 11 for use in combination with the wafer stage 13 shown in FIG. The plasma measurement stage head 11 is placed on the wafer stage 13 instead of the susceptor 21 shown in FIG.
[0012]
One or two or more ion current probes 15 are provided on the surface. For example, as shown in FIG. 4, the distribution of the plasma 12 is achieved by arranging the ion current probes 15 over the entire surface by a cross or other arrangement. The characteristics can be grasped.
[0013]
For example, as shown in FIG. 5, a negative voltage can be applied to each ion current probe 15 using a DC power supply 34, and the current flowing from the plasma 12 into each ion current probe 15 at that time is A high-frequency component is cut out using a low-pass filter 30 through a data communication terminal 14 provided on the wafer stage 13, converted into a voltage by a resistor 31, and a computer 33 through an AD converter 32. Is taken in.
[0014]
One problem in the embodiment shown in FIGS. 2 to 5 is that, as shown in FIG. 6, when the number of ion current probes 15 is increased, the number of data communication terminals 14 for extracting ion current is the same. It is a point that needs to be prepared.
[0015]
For example, as in the embodiment shown in FIG. 7, by providing a circuit switching switch 40 on the plasma measurement stage head 11 side, a switch driving signal terminal 41 for driving the switch 40 and one ion current are supplied. It is only necessary to prepare a data communication terminal 14 for drawing out, and the structure of the wafer stage 13 is simplified.
[0016]
Alternatively, digital signals may be directly exchanged by incorporating an AD converter 32 on the plasma measurement stage head 11 side as in the embodiment shown in FIG.
[0017]
In the embodiments so far, the method of replacing the plasma measurement stage head 11 with the susceptor 21 has been used. In this case, in order to set the plasma measurement stage head 11, the processing chamber 1 must be opened to the atmosphere. It is difficult to apply to an actual production line. It is desirable that the plasma measurement stage head 11 can be transported and measured in the same manner as the wafer 20 that is the object to be processed.
[0018]
FIG. 9 shows an embodiment corresponding to such a request. First, the wafer stage 13 is provided with a data communication terminal 14 for exchanging electrical signals on the surface on which the wafer 20 is placed. For example, the data communication terminal 14 may be in contact with the back surface of the wafer 20 with a spring force enough to lose the weight of the wafer 20.
[0019]
The plasma measurement wafer 50 (corresponding to the plasma measurement stage head 11) has substantially the same outer diameter as that of the wafer 20 so that it can be transferred by the transfer system for the wafer 20, and has a certain thickness and weight. It is necessary to suppress.
[0020]
On the back surface of the plasma measurement wafer 50, the data communication terminal 14 is provided at the position of the data communication terminal 14 provided on the wafer stage 13, and when the plasma measurement wafer 50 is placed on the wafer stage 13. The data communication terminal 14 comes into contact with the data communication terminal 14 on the wafer stage 13 side, and electrical continuity is obtained. An ion current probe 15 for drawing ion current is provided on the surface and is electrically connected to the data communication terminal 14. Therefore, the ion current that enters from the plasma 12 is drawn out of the processing chamber 1 and can be measured, for example, by the method shown in FIG.
[0021]
In all of the embodiments shown in FIGS. 1 to 8, there is no particular problem in exchanging signals by the method shown in FIG. However, in the case where it is difficult to design a large number of data communication terminals 14 on the wafer stage 13 when trying to extract the signals of a large number of ion current probes 15 to the outside using the circuit as shown in FIG. There is. Even if there is only one data communication terminal 14, the plasma measurement wafer 50 can be easily installed and replaced by the automatic transfer system for the wafer 20. Such a method may be used.
[0022]
That is, as in the embodiment shown in FIG. 10, a plurality of plasma measurement wafers 50 with different positions of the ion current probe 15 on the surface are transferred one after another, and measurement is performed under the same conditions, whereby the distribution of the plasma 12 is known. be able to.
[0023]
Although all the embodiments so far have been shown taking the measurement of ion current as an example, the present invention is not limited to this. In the embodiment shown so far, by making the area of the ion current probe 15 smaller than that for ion measurement, it becomes possible to measure electrons, or, as in the embodiment shown in FIG. A combination with the plasma measurement stage head 11 or the plasma measurement wafer 50 corresponding to the energy measurement is also possible.
[0024]
In FIG. 11, the ion energy is measured by superposing the metal mesh 52, placing the electrode 17 for measuring the ion current underneath, and measuring the ion current flowing into the electrode 17 while changing the potential of the metal mesh 52. can do.
[0025]
Although not shown in the drawings, the present invention can be combined with any physical or chemical measurement sensor such as a temperature sensor, and the plasma measurement stage head 11 or the plasma measurement equipped with these plural types of sensors. It is also possible to use a wafer 50 for use.
[0026]
Although the present invention is characterized in that the data communication terminal 14 for exchanging signals is provided on the wafer stage 13, the signal targeted by the present invention is not limited to an electrical signal. Any signal terminal equipment including signals such as light and electromagnetic waves is included in the present invention.
[0027]
FIG. 12 shows an embodiment of the present invention, in which light emitted from the plasma 12 is taken in from a lens 60 mounted on the plasma measurement stage head 11 and drawn out to the wafer stage 13 side through a light guide 61 and a collimator 64. ing. Further, by switching using the optical switch 62, it is possible to switch and monitor the light emission entering a plurality of positions. The light emission of the plasma 12 contains a lot of information of the plasma 12, and according to the present invention, the light emission of the plasma 12 entering the wafer 20 position can be analyzed.
[0028]
【The invention's effect】
As described above, according to the present invention, a wafer stage holding a workpiece is equipped with a terminal for data communication, and a sensor for knowing the plasma state is installed or transported on the wafer stage, through the terminal for data communication. By extracting the signal to the outside and obtaining data related to plasma, information necessary for various processes at the wafer position can be obtained accurately, so that it is possible to accurately determine the start of construction and management of the apparatus. In addition, there are effects of accelerating the start-up of apparatuses and processes and reducing the cost of test wafers. Furthermore, by stabilizing the state of the apparatus, it is possible to control plasma processing with high accuracy, and fine etching processing, high-quality film formation processing, surface treatment, and the like are possible.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing an embodiment of the present invention.
FIG. 3 is a sectional view showing an embodiment of the present invention.
FIG. 4 is a perspective view showing an embodiment of the present invention.
FIG. 5 is a cross-sectional view showing an embodiment of the present invention.
FIG. 6 is a cross-sectional view showing an embodiment of the present invention.
FIG. 7 is a cross-sectional view showing an embodiment of the present invention.
FIG. 8 is a cross-sectional view showing an embodiment of the present invention.
FIG. 9 is a cross-sectional view showing an embodiment of the present invention.
FIG. 10 is a perspective view showing an embodiment of the present invention.
FIG. 11 is a cross-sectional view showing an embodiment of the present invention.
FIG. 12 is a cross-sectional view showing an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Processing chamber, 2 ... Butterfly valve, 3 ... Pump, 4 ... Matching device, 5 ... High frequency power supply, 6 ... Flow controller, 7 ... High frequency power supply, 8 ... Matching device, 9 ... Pressure gauge, 10 ... Data recording device, DESCRIPTION OF SYMBOLS 11 ... Plasma measurement stage head, 12 ... Plasma, 13 ... Wafer stage, 14 ... Data communication terminal, 15 ... Ion current probe, 16 ... Plasma source, 17 ... Electrode, 20 ... Wafer, 21 ... Susceptor, 30 ... Low pass Filter, 31 ... IV converter (resistor), 32 AD converter with insulation amplifier, 33 ... Computer, 34 ... DC power supply, 40 ... Switch, 41 ... Switch drive signal terminal, 50 ... Plasma measurement wafer, 51 ... Spring 52 ... Metal mesh, 53 ... DC power source 1, 54 ... DC power source 2, 55 ... Current measuring instrument, 56 ... Ion energy analyzer, 60 ... 'S, 61 ... light guide path, 62 ... optical switch, 63 ... prisms, 64 ... collimator, 65 ... optical fiber

Claims (3)

A processing chamber, comprising: a plasma source, a data communication terminal provided on the upper surface of the perimeter of the wafer stage to be connected to the data communication terminal of the flop plasma measurement stage head together when holding the object to be treated wafers A plasma processing apparatus comprising a stage,
A data acquisition device connected to the data communication terminal of the wafer stage for acquiring data relating to the plasma state is provided outside the processing chamber,
It is not installed during normal plasma processing, but if necessary, a stage head for plasma measurement is installed on the wafer stage, and the output from the sensor installed on the stage head is processed through each data communication terminal. A plasma processing apparatus which is taken out by an external data acquisition apparatus. 2. The plasma processing apparatus according to claim 1 , wherein the data communication terminal is an electric signal terminal or an optical signal terminal . 2. The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus has a function of transporting an object to be processed, and the sensor can be transported by the transport function similarly to the object to be processed. .

Images