CN110416052A - Wafer holder with resonant circuit - Google Patents

Abstract

The present invention provides a wafer support seat, comprising: a plurality of electrodes and a plurality of resonant circuits electrically coupled to the respective electrodes, each resonant circuit configured to adjust an impedance at least according to a signal connected to the electrodes, thereby in a The plasma distribution corresponding to the electrode is changed during processing.

Description

Wafer holder with resonant circuit

technical field

The present invention relates to wafer supports for the manufacture of semiconductor structures, in particular wafer supports suitable for plasma processing, generally equipped with partial components of radio frequency circuits.

Background technique

Plasma processing is used in the manufacture of technologies such as integrated circuits, photomasks, plasma displays and solar energy. In the manufacture of integrated circuits, wafers are processed by plasma chambers, such as etching, chemical vapor deposition PECVD or physical vapor deposition PEPVD. For smaller integrated circuits, the control of processing parameters needs to be more precise, such as plasma energy spectrum, plasma energy radial distribution, plasma density and plasma density radial distribution. Especially the plasma density, which determines the deposition rate and etch rate of the wafer surface. The radial distribution of plasma density and the radial distribution of plasma energy affect the uniformity of deposition and etching more. A known semiconductor processing device provides an upper electrode and a lower electrode between which plasma can be generated. However, known configurations still do not easily achieve these precise controls, and even limit the degrees of freedom for plasma tuning.

Therefore, it is necessary to develop a semiconductor processing device or a radio frequency component that can provide different radio frequency control strategies to satisfy the freedom of process design.

Contents of the invention

The object of the present invention is to provide a wafer support seat, comprising: a disk body; a first electrode and a second electrode embedded in the disk body, wherein the first electrode is located in an inner diameter range of the disk body, the The second electrode is located at an outer diameter range relative to the inner diameter range of the disc body; and a first resonant circuit and a second resonant circuit are electrically coupled to the first electrode and the second electrode respectively, wherein the first resonant circuit is electrically coupled to the first electrode and the second electrode, respectively. A resonant circuit is configured to adjust a first impedance at least according to a signal from the first electrode, and the second resonant circuit is configured to adjust a second impedance at least according to a signal from the second electrode.

In a specific embodiment, the disc body has a wafer carrying surface, and a distance between the first electrode and the wafer carrying surface is smaller than a distance between the second electrode and the wafer carrying surface.

In a specific embodiment, the disc body has ten electrodes, including the first electrode and the second electrode.

In one embodiment, the wafer support further includes a power supply electrically coupled to the first electrode and configured to supply a signal for electrostatic adsorption to the first electrode.

In a specific embodiment, the wafer support seat further includes a radio frequency blocking circuit electrically connected between the first electrode and the power supply, and configured to prevent radio frequency signals related to the first electrode from being transmitted to the power supply.

In a specific embodiment, the first resonant circuit includes a variable capacitor, a first inductor, and a second inductor, wherein an upstream end of the variable capacitor is electrically coupled to the first electrode, and the variable capacitor A downstream end of the first inductor is electrically connected to an upstream end of the first inductor, and the second inductor is connected in parallel with the variable capacitor and the first inductor in series.

In a specific embodiment, the second resonant circuit includes a variable capacitor, a first inductor and a second inductor, wherein an upstream end of the variable capacitor is electrically coupled to the first electrode, and the variable capacitor A downstream end of the first inductor is electrically connected to an upstream end of the first inductor, and the second inductor is connected in parallel with the variable capacitor and the first inductor in series.

In a specific embodiment, the variable capacitor is configured to be adjusted according to a signal input to the first electrode or the second electrode, so as to change the first impedance or the second impedance.

In a specific embodiment, the radio frequency blocking circuit includes a first capacitor, a second capacitor and an inductor, an upstream end of the first capacitor is electrically coupled to the first electrode, a downstream end of the first capacitor An upstream end of the second capacitor is electrically connected, and a downstream end of the first capacitor is electrically connected with an upstream end of the inductor.

Another object of the present invention is to provide a semiconductor processing device, which is used for radio frequency processing in semiconductor manufacturing, and the device includes: a cavity; a shower assembly located on a top of the cavity and having an electrode; a radio frequency generator and a matcher, electrically coupled to the shower assembly; and the wafer support base, located below the shower assembly.

These and other features and advantages of the invention will appear in more detail in the following description of the invention and the drawings illustrating by way of the principles of the invention.

Description of drawings

The present invention can be further understood with reference to the following drawings and descriptions. Non-limiting and non-exhaustive examples are described with reference to the following drawings. The components in the drawings are not necessarily in actual size; the emphasis is on illustrating the structures and principles.

FIG. 1 shows a schematic diagram of the wafer support seat and its circuit connection of the present invention.

FIG. 2 illustrates an electrode arrangement of the wafer support of the present invention.

【Symbol Description】

10 semiconductor processing device 200 first resonance circuit

100 Wafer Holder 200a Variable Capacitor

101 cavity 200b first inductor

102 Sprinkler Assembly 200c Second Inductor

103 RF generator 201 Power supply

104 Matching device 202 Second resonance circuit

105 first electrode 202a variable capacitor

106 second electrode 202b first inductor

107 External heater 202c Second inductor

108 Internal heater 203 Capacitor

W wafer 204 RF blocking circuit

S1 signal 205 controller

S2 Signal 206 Low Pass Filter

S3 Open and close signal 207 RF grounding circuit

401 First electrode 208 AC signal generator

402 Second electrode 209 Solid state relay

403 Third electrode

Detailed ways

The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which certain exemplary embodiments are shown by way of illustration. However, claimed subject matter may be embodied in many different forms, and thus constructions of covered or claimed subject matter are not limited to any example embodiments disclosed in this specification; the example embodiments are merely illustrations. Likewise, the invention resides in providing a reasonably broad scope for claimed subject matter as claimed or covered. Among other things, for example, claimed subject matter may be embodied as a method, apparatus, or system. Thus, embodiments may take the form of, for example, hardware, software, firmware or any combination of these (known not to be software).

The term "in one embodiment" used in this specification does not necessarily refer to the same embodiment, and the use of "in other (some/some) embodiments" in this specification does not necessarily refer to different embodiments. It is intended, for example, that claimed subject matter includes combinations of all or some of the exemplified embodiments.

FIG. 1 shows a schematic diagram of a semiconductor processing apparatus 10 and a wafer support 100 of the present invention contained therein. In particular, the semiconductor processing device 10 is a radio frequency processing device for manufacturing semiconductors, which has radio frequency components. The radio frequency assembly includes an upper electrode (not shown) of a shower assembly 102 on the top of a cavity 101 of the semiconductor processing device 10, a plurality of lower electrodes of the wafer support seat 100, and a radio frequency generator 103 and a matching device 104. combination. Wherein, the RF generator 103 and the matcher 104 are electrically coupled to the upper electrode of the shower assembly 102 to provide RF signals. The lower electrodes are grounded through respective downstream circuits, the circuit details of which are described below. In other possible embodiments, the downstream ends of the electrodes can be additionally electrically connected to respective feedback circuits configured to feed back the radio frequency signal of the lower electrode to the radio frequency generator 103 or the matcher 104, so as to meet the requirements of each The adjustment of a radio frequency signal.

Although not specified in detail, in general, a typical chamber 101 has a chamber defined by a top, a bottom, and a wall. The top usually has a complex intake manifold, gas distribution gas, gas channels and sprinklers. In a typical configuration, the upper electrode is included in the structure of the showerhead. The top of the cavity 101 or the shower head is electrically coupled to the RF generator 103 and the matcher 104 so that the upper electrode receives a signal from the RF source.

The wafer support 100 of the present invention is typically connected to the bottom of the chamber 101 so that a wafer W can be supported at a certain height in the chamber. A plasma region may be formed between the shower assembly 102 including the upper electrode and the wafer support 100 including the lower electrode.

Although not shown, in one embodiment, the RF generator 103 may include a low-frequency RF source, a RF high-frequency source, or a combination of both, and the matchers in the matcher 104 may include low-frequency dedicated matching networks, high-frequency dedicated Matching network or a combination of both. The matching network includes one or more capacitors, inductors and some electronic components, the detailed composition of which will not be repeated here. Depending on the process, the selection of low frequency or high frequency radio frequency operation is known and will not be described here. In a known method, the radio frequency generator 103 and/or the matching unit 104 are configured to adjust the output frequency of the low frequency or high frequency radio frequency source and/or the matching network in accordance with certain feedback signals related to radio frequency. variable components, such as variable capacitors.

Like known configurations, the wafer support base 100 of the present invention also has a tray body (not numbered), which has a wafer carrying surface facing the shower assembly 102 for carrying and exposing a wafer W to be processed to the chamber. in the treatment area of the body. The disc body of the present invention has a plurality of lower electrodes for receiving radio frequency signals from upstream. In one embodiment, the lower electrode includes a first electrode 105 and a second electrode 106 . As shown in FIG. 1 , the position of the first electrode 105 is slightly higher than the position of the second electrode 106 . That is, the distance between the first electrode 105 and the wafer supporting surface is smaller than the distance between the second electrode 106 and the wafer supporting surface.

In addition, the first electrode 105 is located in an inner diameter range of the disc body, and the second electrode 106 is relatively located in an outer diameter range of the disc body. In one embodiment, the first electrode 105 can be configured as an electrode with a circular area, and the second electrode 106 can be configured as an electrode with a ring-shaped area. Accordingly, the first electrode 105 covers at least the central portion of the wafer (W), while the second electrode 106 covers the peripheral portion of the wafer (W). In addition to receiving radio frequency signals, the first electrode 105 can also be configured as an electrostatic attractor to position the wafer (W) on the carrying surface. In a specific embodiment, the inner diameter of the annular second electrode 106 is larger than the outer diameter of the wafer (W).

The tray may also contain one or more heaters, including an inner heater 107 for the central portion of the wafer and an outer heater 108 for the periphery of the wafer. The inner heater 107 and the outer heater 108 cooperate with each other according to a controller, so as to realize elastic control of the temperature of the disk surface.

The first electrode 105 and the second electrode 106 are respectively electrically coupled to the circuit of the ground terminal via a metal rod or a cable included in the support base. As shown in FIG. 1 , the first electrode 105 is electrically coupled to at least a first resonance circuit 200 and a power supply 201 for the electrostatic adsorption, and the second electrode 106 is electrically coupled to a second resonance circuit. 202. In other embodiments, the second resonant circuit 202 can be omitted, and the second electrode 106 is directly grounded to become a ground electrode.

The first resonant circuit 200 and the second resonant circuit 202 are respectively configured to change a first impedance and a second impedance according to signals received from the first electrode 105 and the second electrode 106, thereby adjusting the vicinity of the wafer carrying surface. plasma distribution. In one embodiment, the first resonant circuit 200 is electrically coupled to the first electrode 105 via a capacitor 203 . The first resonant circuit 200 may include at least one variable electronic component. For example, in one embodiment, the first resonant circuit 200 has a variable capacitor 200a, a first inductor 200b and a second inductor 200c. An upstream end of the variable capacitor 200a is electrically connected to the capacitor 203, and a downstream end of the variable capacitor 200a is electrically connected to an upstream end of the first inductor 200b. Therefore, the variable capacitor 200a and the first inductor 200b are connected in series. The second inductor 200c is connected in parallel with the series variable capacitor 200a and the first inductor 200b, and a downstream end of the first inductor 200b and the second inductor 200c is grounded. The variable capacitor 200a is configured to change the impedance of the first resonance circuit 200 according to a signal S1 received by the first resonance circuit 200, thereby adjusting the plasma distribution corresponding to the first electrode 105, that is, the area near the center of the wafer . The signal S1 is related to the RF power received by the first electrode 105 .

Claims (11)

1. A wafer support seat, characterized in that, comprising: a plate; a first electrode and a second electrode embedded in the disk, wherein the first electrode is located within an inner diameter of the disk and the second electrode is located within an outer diameter relative to the inner diameter of the disk; and a first resonant circuit and a second resonant circuit electrically coupled to the first electrode and the second electrode respectively, wherein the first resonant circuit is configured to adjust a first impedance at least according to a signal from the first electrode , the second resonant circuit is configured to adjust a second impedance at least according to a signal of the second electrode. 2. The wafer support seat as claimed in claim 1, wherein the disc body has a wafer supporting surface, and a distance between the first electrode and the wafer supporting surface is smaller than the distance between the second electrode and the wafer supporting surface. A distance between the wafer carrying surfaces. 3. The wafer support as claimed in claim 1, wherein the disk body has ten electrodes, including the first electrode and the second electrode. 4. The wafer support of claim 1, further comprising a power supply electrically coupled to the first electrode and configured to supply a signal for electrostatic adsorption to the first electrode. 5. The wafer support as claimed in claim 4, further comprising a radio frequency blocking circuit electrically connected between the first electrode and the power supply, and configured to suppress radio frequency related to the first electrode The RF signal is transmitted to the power supply. 6. The wafer support seat as claimed in claim 1, wherein the first resonant circuit comprises a variable capacitor, a first inductor and a second inductor, wherein an upstream terminal of the variable capacitor is electrically is electrically coupled to the first electrode, a downstream end of the variable capacitor is electrically connected to an upstream end of the first inductor, and the second inductor is connected in parallel with the variable capacitor and the first inductor in series. 7. The wafer support seat as claimed in claim 1, wherein the second resonant circuit comprises a variable capacitor, a first inductor and a second inductor, wherein an upstream terminal of the variable capacitor is electrically is electrically coupled to the first electrode, a downstream end of the variable capacitor is electrically connected to an upstream end of the first inductor, and the second inductor is connected in parallel with the variable capacitor and the first inductor in series. 8. The wafer support seat according to claim 7 or 8, wherein the variable capacitor is configured to be adjusted according to a signal input to the first electrode or the second electrode to change the first impedance or the Second impedance. 9. The wafer support as claimed in claim 5, wherein the radio frequency blocking circuit comprises a first capacitor, a second capacitor and an inductor, an upstream end of the first capacitor is electrically coupled to the For the first electrode, a downstream end of the first capacitor is electrically connected to an upstream end of the second capacitor, and a downstream end of the first capacitor is electrically connected to an upstream end of the inductor. 10 . The wafer support as claimed in claim 1 , wherein the second electrode is a ring-shaped electrode, and an inner diameter of the second electrode is larger than an outer diameter of the wafer. 11 . 11. A semiconductor processing device for radio frequency processing in semiconductor manufacturing, characterized in that it comprises: a cavity; a shower assembly located on a top of the cavity and having an electrode; A radio frequency generator and a matching device are electrically coupled to the shower assembly; and the wafer support seat according to claim 1 is located below the shower assembly.