JP4963293B2 - Reactive ion etching chamber excluding bonding including multiple processing stations - Google Patents

Description

  The present invention relates to a plasma processing chamber, and more particularly to a plasma processing chamber having two or tandem processing regions and capable of processing a minimum of two or more wafers.

  In the semiconductor chip manufacturing process, two types of semiconductor chip processing systems are generally used, and one is a system called a batch type wafer processing type. The main reason for using a batch process system is that a large number of chips or wafers can be processed simultaneously, providing higher throughput than the system. However, as the demands on the performance standards of semiconductor transistors become more and more severe, the industry already uses the second type of processing chamber, that is, a single wafer processing chamber. The main reason for developing a single wafer processing chamber is that it is easy to control the process characteristics of the wafer and the processing uniformity on the surface of the wafer.

  On the other hand, in certain application cases, we are trying to provide a single processing chamber that can process two wafers in parallel. Such applications can guarantee the benefits of single wafer processing and can process two wafers simultaneously. US Pat. No. 5,811,022 proposes a twin / tandem wafer processing chamber system, which is an inductively coupled plasma chamber characterized in that the photoresist is removed using plasma called resist ashing in the industry. Resist ashing is an oxidation reaction, and this process removes the organic resist by using oxygen. The photoresist is oxidized to a gas such as carbon monoxide, carbon dioxide and water vapor, and is drawn to the processing chamber by a vacuum pump. Therefore, in this case, the same level of uniformity as that of a precise application such as semiconductor wafer etching is not required.

  Because there is no precise requirement for resist ashing processing, the processing chamber proposed in US Pat. No. 5,811,022 includes two separate plasma generation chambers, each of which is open at the bottom, two sheets each. Are connected to the wafer processing chamber where the wafers are installed. A charged particle filter is installed between the plasma generation chamber and the wafer processing chamber to prevent charged particles from entering the wafer processing chamber, so that activated neutral particles can enter the wafer processing chamber. The photoresist can be removed from the wafer. The wafer processing chamber structure is not partitioned between two wafers and plasma is not excited on the wafer, and the use of a filter prevents charged particles from entering the wafer processing chamber, disclosed in the same patent The wafer processing chamber that is used is not used in cases where precise performance such as semiconductor wafer etching is required, and is applied only to simple ashing.

  Another tandem processing chamber structure is disclosed in US Pat. No. 5,855,681. The processing chamber proposed in US Pat. No. 5,855,681 allows two processing regions to process two wafers simultaneously, each region including a gas distribution assembly and an RF generating source, with a wafer in each processing region. Provides a plasma with a uniform density above the surface. In addition, in US Pat. No. 5,855,681, one disadvantage of the Mattson system (content of the aforementioned US Pat. No. 5,811,022) “The low uniformity of a batch processing system is that multiple wafers are in multiple stations in a single processing chamber. It is clearly pointed out that partial processing is a direct cause. In order to improve processing uniformity, the above-mentioned US Pat. No. 5,855,681 proposes that “separated processing regions are set up and at least two regions are isolated and at least two wafers can be processed simultaneously”. Has been.

  The solution in the isolation processing area can process two wafers in parallel, but causes a difficulty called chamber matching or station matching. That is, it is difficult to provide the same plasma processing conditions by controlling two regions in one chamber. For example, if the etching rate of one processing region is faster than that of an adjacent processing region, it is difficult to control the end point of the etching process. That is, if the etching end point is determined based on the faster etching rate, the wafer with the slower rate is not completely etched. On the other hand, if the end point is extended on the basis of the slower etching, the wafer in the high-rate region is over-etched and may be damaged.

  US Pat. No. 6,962,644 proposes a “processing chamber with a number of mutually separated processing regions” which improves on the tandem processing chamber described above. In US Pat. No. 6,962,644, the central pump chamber allows the two processing chambers to “communicate” with each other, but causes a problem called RF crosstalk. In a tandem processing system, changes in conditions in one processing area have a deleterious effect on processing in another processing area.

  In the tandem processing chamber described above, it is difficult to match the processing results between the two processing regions due to the isolation. The tandem processing chamber described in the aforementioned US Pat. No. 6,962,644 uses two RF generators, and the phase and frequency of the two RF generators are locked to prevent the occurrence of RF beating, The structure and arrangement of the processing chamber is further complicated. The method for generating plasma in the tandem processing chamber does not satisfy the precise standard required for manufacturing the leading-edge semiconductor device. Therefore, in the chamber chamber semiconductor industry, multiple chambers capable of high quality performance matching in each region are desirable.

  It is an object of the present invention to provide a number of wafer processing chambers for processing only one, two or many wafers simultaneously to ensure a high level of performance and each processing region within the processing chamber. All the engineering performances at are to guarantee matching to each other.

  Embodiments of the present invention include separate plasmas and separate RFs to provide a processing chamber that includes two processing regions or multiple tandem processing regions, with a number of different frequencies from the bottom of each processing region. Power can be fed. The processing chamber wall and the isolation wall between two adjacent processing regions are also grounded. Using frequency isolation technology, a number of different RF powers at different frequencies can be fed from the cathode without crosstalk and beating. Moreover, plasma crosstalk is prevented by using a plasma limiting ring. Furthermore, a common exhaust channel that is grounded is connected to a single vacuum pump.

  A microchannel ring structure is provided at the inlet of the exhaust channel, so that plasma can be restricted within the processing region, and plasma does not enter the exhaust channel, so that plasma crosstalk occurs between the processing regions. There is no. Although the present invention draws gas with a single vacuum pump resulting in asymmetric pumping, the microchannel serves to distribute pressure within the processing region. This ring can also prevent RF leakage between the two processing regions. The upper part of the ring becomes an insulator, and the lower part is conductive and grounded without causing plasma sputtering, so that RF leakage can be prevented.

  Since the plasma limit of the processing chamber of the present invention prevents the occurrence of RF beating, it is not necessary to lock the phase and frequency of the RF generator set in the prior art. Further, in the present invention, plasma restriction and RF separation are provided, and processing can be performed independently in each processing region, or a large number of processing regions can perform processing in parallel.

A system according to embodiments of the present invention provides a high throughput, high wafer processing accuracy and uniformity, and a versatile plasma chamber. The present invention can realize the stability and consistency of the plasma in each processing region, and the obtained processing result satisfies the high precision requirement for the advanced semiconductor processing. The present invention provides a fully isolated reactive ion etching chamber that includes a number of processing stations or regions, all of which are subjected to a number of RF powers. The present invention uses various characteristics and designs to prevent the occurrence of RF beating and RF crosstalk between two parallel processing regions. In particular, a method for performing reactive ion etching that is completely separated by feeding two different frequencies of RF from the cathode in each processing region of a parallel processing chamber was proposed for the first time by the present invention.

  FIG. 1 is a cross-sectional view of a tandem plasma processing chamber 100 according to one embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line CC of FIG. What is described here refers to the above two figures. The chamber body 105 is typically made of a conductive metal material (eg, aluminum), and the chamber body 105 includes two parallel processing regions 110 and 115. The process areas 110 and 115 are physically separated by an isolation wall 122, and the specific design details that provide a structure to balance the pressure between the two process areas 110 and 115 are described in detail below. The chamber body 105 (including the isolation wall 122) is grounded to isolate the electric field between the two processing regions 110 and 115 and prevent the occurrence of RF crosstalk.

  Processing regions 110 and 115 have fixed cathodes 120 and 125, respectively, that can support wafers 130 and 135 for engineering processing. In this embodiment, the cathodes 120 and 125 are fixed because they can be more securely grounded to the movable cathode. In this embodiment, two frequencies are fed by the cathodes 120 and 125, so it is very important to ground effectively. From this, it is considered that the fixed cathode used in this example is superior to the prior art.

  Cathodes 120 and 125 include a chuck device and can support the wafer. The chuck device may be any conventional chuck device, for example, a conventional electrostatic chuck. Cathodes 120 and 125 further include built-in electrodes and are used to radiate RF energy to the processing region. RF energy is delivered to cathodes 120 and 125 by RF conductors 140 and 145. Each RF conductor is connected to two RF generators. For example, the RF generators 152 and 154 are connected to the RF conductor 140 through the matching circuit 153, and the RF generators 156 and 158 are connected to the RF conductor 145 through the matching circuit 157. In this embodiment, the RF power is equally connected to the cathodes 120 and 125 in pairs. For example, in this embodiment, power is transported by a trident coupler, each trident coupler has three connectors (only two connectors 150 and 155 are shown in the sectional view), and 120 degrees between the three connectors. It has become.

  In this embodiment, the decoupled reactive ion etching is performed by applying RF power of two frequencies to two cathodes. In this case, if the distance between the two frequencies is sufficiently large, RF power decoupling from the two RF suppliers can be achieved. For example, if the ratio between the high frequency and the low frequency is set to be larger than at least 2, the separation between the two frequencies can be ensured. In one aspect of the invention, the low frequency is selected from a range from 500 KHz to 2.2 MHz. For example, the low frequency is set to about 2 MHz and the second frequency is set to about 27 MHz. In another example, the low frequency is set to about 2 MHz and the second frequency is set to about 60 MHz or 100 MHz.

  In this embodiment, interference between the two processing regions 110 and 115 can be prevented by performing RF tuning. Since tuning can be done quickly (eg, in less than 1 second), any change in the processing area will not negatively affect the processing of adjacent areas. In this embodiment, isolated and highly efficient matching circuits 153 and 157 are used, and each RF match connects an RF signal to cathodes 120 and 125 in processing regions 110 and 115. For this purpose, the RF match filed in previously published US patent application 2005/0133163 can be used. However, the method submitted in that patent requires the use of a filter, which increases the complexity of the RF match structure. Therefore, it is more suitable to adopt the RF match filed in the already published US patent application 2007/0030091. Patent application 2007/0030091 relates to a new design of RF match, and it is not necessary to use a filter.

  FIG. 5 shows a schematic diagram of the RF matching circuit structure, which can be used in the tandem plasma processing chamber of the present invention, so the use of an electrical filter is not necessary. As shown in the figure, this embodiment has two RF inputs, which are a high frequency input unit and a low frequency input unit, respectively. The RF matching circuit has a total of three ports, two of which are input ports, ie connected to a high frequency RF generator (158) connected to a high frequency RF generator and a low frequency RF generator. A low frequency RF generator (156). Conductor (not shown) outputs multiple RF generator energy to the RF output port of the tandem plasma processing chamber. The RF matching network of the tandem plasma processing chamber is divided into a low-frequency part and a high-frequency part, and the two parts are connected to each other by a continuous contact at an output port. The high frequency unit includes a capacitor C1 ', a capacitor C2', and an inductor L 'that are grounded. The low frequency portion constitutes one end grounded through the capacitor C1, and the other end is connected to the capacitor C2. Capacitor C2 is connected in series with inductor L to the output port.

  In the low frequency part, the inductor L, the capacitor C1 and the capacitor C2 constitute a low pass filter, and in the high frequency part, the inductor L ', the capacitor C1' and the capacitor C2 'constitute a high pass filter. When the frequency of the high frequency input is much higher than the frequency of the low frequency input, that is, when the frequency of the high frequency input is at least twice that of the low frequency input (excellent is at least 10 times), the characteristics of the high pass filter And taking into account the impedance characteristics of the high-frequency input of the tandem plasma processing chamber, the high-frequency unit requires a relatively small inductance, and can realize conjugate matching between the entire matching network and the tandem plasma processing chamber. . Under certain conditions, the RF output port can be connected to the cathode of the tandem plasma processing chamber using conductive components (eg, cables) and conductive connectors without the use of physical inductors in the high frequency part. Just connect. Such conductive components replace the role of inductors. In the above design, the self-inductance of the conductive component and conductive connector is roughly equivalent to the inductor. At this time, the grounded capacitor C1 'can be replaced by a parasitic capacitor between the conductive component, the conductive connector and the ground. Since the values of the parasitic capacitors C1 'and L' are small and difficult to adjust, the high-frequency capacitor C2 'can be used as a variable capacitor in order to adjust the impedance of the entire circuit.

  The values of the capacitor and the inductor can be estimated from the frequencies of the high frequency portion and the low frequency portion. The ideal impedance can be obtained by selecting the value of the capacitor C1. As is well known, the circuit itself combined with a capacitor and an inductor has a complex impedance. Therefore, since the electric circuit component and the cable have their own impedance, RF matching is performed by selecting and adjusting the component values in the matching circuit. When the low-frequency part is connected to the low-frequency RF generator, the low-frequency impedance obtained when measuring from the output port to the low-frequency part and the low path through the return path from the output port. The impedance under the low frequency obtained when measuring up to the frequency portion is roughly conjugate matching. When the high frequency part is connected to the high frequency RF generator, the impedance under the high frequency obtained when measuring from the output port to the high frequency part and when measuring to the high frequency part via the path returning from the output port It can be said that the impedance under high frequency obtained in the above is roughly conjugate matching.

  In the RF matching network shown in FIG. 5, low frequency RF energy is output at an output port via an electric circuit including a capacitor C2 and an inductor L. The low frequency RF output is then input to a vacuum processing chamber or high frequency section through two possible passages. The high frequency part (in addition to the parasitic capacitor) includes a capacitor C2 'and an inductor L'. In this embodiment, the high frequency portion capacitor C2 'and the inductor L' are installed, so that the impedance of the high frequency portion for the low frequency RF input end is much larger than the impedance of the tandem plasma processing chamber. Thus, most of the energy of the low frequency RF generator is input to the processing chamber in vacuum. Further, by selecting an appropriate value of the capacitor C2 ', the energy input to the high frequency portion can be reduced to 2% or less.

  Similarly, high frequency RF energy reaches the output port through a circuit combined by a capacitor C2 'and an inductor L'. The high frequency RF output then enters the processing chamber in vacuum or the low frequency portion through two possible passages. The low frequency part includes a parasitic capacitor, a capacitor C2 and an inductor L, of which the inductor L and the capacitor C2 are connected in series. One end of the capacitor C1 is connected to the capacitor C2, and the other end is grounded. The placement of the circuit increases the estimated capacitor and inductor values, and by adjusting the capacitor values, the low frequency impedance for the high frequency RF input is much greater than the impedance of the tandem plasma processing chamber. Therefore, most of the energy of the high frequency RF generator is input to the processing chamber in vacuum. Furthermore, by selecting an appropriate value of the capacitor C1, the energy input to the low frequency portion can be reduced to 2% or less.

  As shown in FIGS. 1 and 2, the process gas is supplied by a common source 160. The gas supplied by the shared source 160 is distributed into each processing region by the shower heads 170 and 175, and in this embodiment, a dual zone or multiple zone shower head is used. That is, as shown in FIG. 1, the shower head 170 includes a center region 172 and an outer edge region 176, and the center region 172 and the outer edge region 176 are separated by a seal 174. The gas pipe 171 transports the gas to the central region 172, and the gas transport pipe 173 transports the gas to the outer edge region 176. The gas transport ratio between the central region and the outer edge region is controlled by a common source 160. Further, the gas composition transported by the gas pipes 171 and 173 can be controlled by the common source 160. That is, the gas transport pipes 171 and 173 can transport different gases, the same gas, or a mixed gas.

  Shower heads 170 and 175 further include built-in electrodes and constitute an RF generator and ground circuit coupled to cathodes 120 and 125, respectively.

  Also shown in FIG. 1 is a central vacuum pump 180. The vacuum pump 180 can exhaust the gas in the processing regions 110 and 115 through the exhaust port 182 of the exhaust chamber 184. The use of a single central vacuum pump 180 simplifies the structure of the entire processing chamber and allows the processing chamber to be miniaturized. Also, the common exhaust port 182 can further balance the pressures in the two process zones 110 and 115, but this design presents some problems. This will be described below based on the present embodiment.

  The processing area 110 will be described below, but this description also applies to the processing area 115. As shown in FIG. 1, since the exhaust port 182 is provided between the two processing regions 110 and 115, the exhaust port 182 is asymmetric with respect to the processing regions 110 and 115. For example, it can be easily understood that the arrow A is a passage where particles approach the exhaust port 182 along the processing region, and the arrow B is a passage where particles leave the exhaust port 182 along the processing region. Since it is longer than a, a pressure difference in the processing region 110 is generated. In order to overcome this drawback, in this embodiment, microchannel plasma limiting rings 190 and 195 are installed in each processing region 110 and 115. The restriction ring 190 is used to isolate the processing region 110 and the exhaust port 182, and draws gas from the processing region 110 while maintaining pressure equilibrium. The constraining ring 190 can be used in any ring construction filed in published US patent application 2007/0085483.

  3 and 4 show an embodiment of a restriction ring 190 that can be used in the processing chamber of FIG. Here, the number 70 is assigned. The present invention can use other types of plasma limiting devices, but will be described in more detail with respect to FIGS. As shown in FIGS. 3 and 4, the plasma limiting device is installed between the processing region 110 and the exhaust chamber 184. In the embodiment shown in FIG. 1, the upper position of the limiting ring 70 and the wafer 130 are approximately at the same height. 3 and 4, the plasma limiting ring 70 includes a grounded conductive component 71. The grounded conductive component 71 is defined by an inner peripheral edge 73 opposite the outer edge 72 and normally surrounds the inner wall 183 of the exhaust chamber 184. The grounded conductive component 71 includes a top surface 74 and a bottom surface 75 on the opposite side. As shown in the figure, some channels are installed in a predetermined manner inside a grounded conductive component 71 and extend between a bottom surface 74 and a top surface 75. The grounded conductive component 71 constitutes an electric field shield and basically suppresses RF radiation from reaching the exhaust port 182. With this method, the plasma is not likely to be excited in the exhaust port 182. Also, RF crosstalk between the two processing regions 110 and 115 can be prevented.

  The plasma limiting ring 70 further includes an electrically insulating layer 80 located (or partially covered) on the upper surface 74 of the conductive component 71 that is grounded. As shown in FIG. 4, the electrical insulating layer 80 extends radially inward so as to correspond to the outer edge portion 72. The electrical insulating layer 80 is composed of one layer (as shown in the figure) or multiple layers. Located above the electrically insulating layer 80 is a conductive support ring 90. The conductive support ring 90 has an outer peripheral portion 91 (a common surface with the outer peripheral portion 72), and further includes an inner peripheral boundary 92 that is separated by a certain space. The conductive support ring 90 and the several electrically conductive parts 95 are integrated, and the conductive parts 95 are separated from each other by a predetermined distance. In addition, since it is insulated from the grounded conductive component 71, such an electrically conductive component 95 is electrically floating from the ground when performing the process. Such an electrically conductive component 95 is represented here as a ring 96 (or conductive concentric ring) with a set of spacings. The rings 96 form a set of channels 99 that are in fluid communication with the channels 76 on the grounded conductive component 71. Channels 76 and 99 thus constitute a fluid channel, helping plasma process gas generated in process region 110 to leave process region 110 and reach exhaust port 182. In one aspect of the invention, the electrically conductive component 95 is made of a doped semiconductor material. Doping has the function of increasing the electrical conductivity of the semiconductor material.

  As can be seen from FIG. 4, the length of any of the 99 channels is greater than the mean free path of charged particles present in the plasma in any processing region 110. Therefore, while the plasma is extracted from the processing region 110 to the exhaust chamber 184, all charged particles that have passed through all the channels 99 collide with some conductive concentric rings 96, and the charged particles enter the exhaust chamber of the plasma processing apparatus. The charge that was charged before reaching it is neutralized. In the present invention, as shown in FIGS. 3 and 4, the surface of the electrically conductive component 95 (shown here as a set of concentric rings 96 having electrical conductivity) is resistant to the plasma generated in the processing region 110. It is coated with a certain material. In one embodiment of the present invention, the material covering the surface of the electrically conductive component 95 includes Y2O3. The coating layer prevents the electrically conductive component 95 from being subjected to plasma corrosive action, so that no particles are generated. In another embodiment, the electrically conductive component 95 is an integrally formed conductive plate (not shown), and the conductive plate is provided with holes or elongated holes, and the hole or elongated hole has a structural shape. Similarly, when charged particles in the plasma pass through, the charged particles can be neutralized and only neutral particles can pass through.

  Besides this, a number of alternative implementations of the limiting device can be used. For example, the grounded conductive component 71 and the surface of the ring 96 in contact with the plasma are anodized to prevent plasma corrosion and form an electrically insulating layer (not shown). Anodization is a kind of electrolysis, and an oxidation protective film can be formed on the metal surface. Anodizing treatment is used for various purposes. For example, a hard coating layer is formed on the metal surface, or the metal is provided with electrical insulation and corrosion resistance. In another aspect of the invention, the electrically conductive component 96, the electrically conductive support ring 90 and the grounded conductive component 71 are made of aluminum, the electrical insulating layer 80 is an anodized film layer, and the conductive support ring 90 is grounded. The surface of the conductive component 71 or the grounded conductive component 71 is obtained by anodizing the surface of the conductive support ring 90. In another state of the invention, all surfaces of such a structure are anodized and the electrically conductive component 95 can be electrically floating from the ground during the process. Further, in other states of the invention, some conductive rings in the electrically conductive component may be anodized on the surface area that is facing or in contact with the plasma, further improving the corrosion resistance of the plasma. Coat Y2O3. In addition to the above-described implementation method, an electrically insulating spacer (not shown) having a similar function may be used instead of the electrically insulating layer 80. This spacer is placed between the conductive support ring 90 and the grounded conductive component 71 to help ensure that the electrically conductive component 95 is electrically floating from the ground.

  The plasma limiting ring 70 used in the plasma processing region 110 includes a grounded conductive component 71 and an electrically conductive component 95 that is electrically conductive and floats above the ground, and the plasma limiting ring 70 is electrically conductive from the ground. Form plasma shield and RF shield. That is, the conductive component 95 that is electrically floating from the ground serves as a plasma shield, preventing activated particles from passing through. The grounded conductive component 71 serves as an RF shield and prevents RF energy from passing through. The electrically conductive component 95 that is electrically floating from the ground defines a set of channels 99 through which the exhaust from the processing region 110 can be controlled. The size of the channel 99 is set so that charged particles disappear and neutral particles pass. By this method, the restriction ring 70 controls the exhaust operation from the processing region 110 to maintain a uniform pressure in the processing region 110, prevents charged particles from entering the exhaust port 182, and RF is supplied to the exhaust port. Since application to 182 is prevented, plasma is not excited at the exhaust port 182. In addition, it is possible to prevent RF crosstalk from occurring between the processing regions 110 and 115.

  Another characteristic of this embodiment is the isolation ring 132 shown in FIG. The isolation ring 132 can move in the vertical direction as shown by arrow D. In order to move the wafer 130 in and out of the processing area 110, the isolation ring 132 is moved to a high position so that the tank 134 appears. After placing the wafer 130 on the cathode, the isolation ring 132 is shifted to the low position shown in FIG. In this low position, the processing area 110 defined by the isolation ring 132 exhibits a circular object and the tank 134 “hides” behind the isolation ring 132 so that it does not come into contact with the plasma. The area that the plasma can contact is the circular boundary defined by the isolation ring 132. That is, at the low position, each isolation ring 132 defines a circular boundary for each processing region 110, 115. In this embodiment, since the isolation ring 132 is made of a dielectric material and has a thickness T, it is possible to isolate the plasma from the chamber wall surface that is grounded. That is, if the thickness T is determined by a reasonable calculation, the RF return path can be prevented from passing through the chamber wall 105 grounded from the plasma. Therefore, the RF return path can pass through the shower head 170 and return the RF to the original state using the shower head 170 as an upper electrode.

  Isolation ring 132 is also used to equalize the pressure in the chamber. FIG. 6 shows an example of installing an isolation ring. Since the processing chamber 600 in FIG. 6 is similar to that shown in FIGS. 1 and 2, a detailed description is omitted here and only the salient features shown in FIG. 6 are described. The embodiment shown in FIG. 6 relates to a pressure balancing structure that is installed between two processing zones. In this embodiment, the pressure balance structure is realized by the isolation ring 632. As shown in the figure, a channel 684 is installed on the separation wall 682. When the isolation ring 632 is shifted to a high position as indicated by arrow D, the channel 684 allows gas to freely pass between the processing regions 610 and 615. Further, pressure balancing passages 634 and 636 are further installed in the isolation ring 632. When the isolation ring is shifted to a low position, as shown in FIG. 6, pressure balancing passages 634, 636 and channel 684 form a common channel, and the pressures in processing regions 610 and 615 are fluidly connected channels 634, 684. And 636 reach equilibrium.

  Since the present invention is designed for plasma limiting and RF separation, each processing region can be processed independently, and multiple processing regions can be processed simultaneously in parallel. Multiple processing regions can also have equivalent plasma processing conditions / environments. As a result, it is possible to solve the problem of station matching in the prior art.

  FIG. 7 shows another embodiment of the present invention. A number of RF powers are applied to the two cathodes. The embodiment of FIG. 7 can be implemented with a modification of another embodiment presented by the present invention or in conjunction with other schemes not shown here. The specific embodiment presented in FIG. 7 employs the embodiment shown in FIG. 1 and uses similar numbers for similar parts. The differences are displayed based on the 700 series instead of the 100 series.

  As shown in FIG. 7, both cathodes 720 and 725 both receive three RF frequencies. Etching engineering is controlled by controlling plasma density and ion energy separately. That is, one or two frequencies control the plasma ion energy. The frequency for controlling the plasma ion energy should be selected from a low range, for example, one is selected from the range of 500 KHz to 2 MHz and the other is selected from 13 MHz (to be precise, 13.56 MHz). Such a frequency is usually called a bias frequency. The density of the plasma can be controlled through a high frequency, for example 27 MHz, 60 MHz, 100 MHz or 160 MHz, which is usually called the source frequency. A single bias frequency and a pair of source frequencies can also be used. For example, the value taken by a single bias frequency is selected from the range of 500 KHz to 2 MHz, or 13 MHz. The values taken by the pair of source frequencies are 27 MHz, 60 MHz, 100 MHz or 160 MHz.

  In a specific embodiment, bias frequencies 754 and 757 are used and set to 2 MHz or 13 MHz. Two source frequencies are applied, namely 752 and 754 to cathode 720 and 758 and 759 to cathode 725. Each source RF is set to 27MHz and 60MHz. This is because such a design is easy to control against dissociation of plasma particles.

  Another feature of the embodiment presented in FIG. 7 is switches 763 and 767. Switches 763 and 767 switch the present embodiment between a number of selectable frequencies to further control the dissociation of the plasma particles. By using switches 763 and 767, any of the previous embodiments are used in a plasma processing chamber to provide first stage operation and second stage operation. In the first stage operation, the first combination of bias frequency and source frequency is adopted, and in the second stage operation, the second combination of bias frequency and source frequency is adopted. For example, if the plasma processing chamber is engineered for the main etch stage using a low bias frequency (eg about 2 MHz) and then overetched, then to a “soft landing”, a relatively high bias frequency, eg 13 MHz, is used. Switch. On the other hand, in the processing chamber, etching is performed using a low source frequency such as 27 MHz. After the etching is completed, the wafer is transferred from the processing chamber and cleaned with a higher density plasma. Do. Higher density plasma can be obtained by using a higher source power, such as 60 MHz, 100 MHz or 160 MHz.

  FIG. 8 shows an example in which processing is performed using two bias frequencies realized based on the embodiment of the present invention. This processing is, for example, etching of a semiconductor wafer. In step 800, the source RF power is excited and ignites the plasma. The frequency of the source RF power may be any of 27 MHz, 60 MHz, 100 MHz, 160 MHz, and the like. In step 810, the first bias power is excited and applied to the processing chamber, and the dissociated ions impact the wafer (step 820). When the first step is completed, the first bias power is turned off at step 830, the second bias power is excited at step 840, and the second step 850 is performed. In this case, the first bias power can be about 2 MHz, and the second bias power can be about 13 MHz. In this case, if the bias power is 2 MHz, the source power is at least 10 times or more. On the other hand, when the bias power is set to 13 MHz, the source power will be twice or more. For example, when the bias power is 13 MHz, the source frequency may be set twice (ie, 27 MHz), five times (ie, 60 MHz), or more (100 MHz or 160 MHz).

  FIG. 9 shows an example in which processing is performed using two source frequencies realized based on the embodiment of the present invention. This processing is, for example, etching of the semiconductor wafer and subsequent in-situ cleaning. In step 900, the first source RF power is excited and ignites the plasma. The frequency of this source RF power is 27 MHz, for example. In step 910, bias power is excited and applied to the processing chamber, and the dissociated ions bombard the wafer for etching processing (step 920). When the etching step is completed, the bias power in step 930 is turned off, and the wafer is transferred from the processing chamber in step 935. Then, in step 940, the second source power is excited and cleaning is performed (step 950). In that case, the frequency of the second source power can be 60 MHz, 100 MHz, or 160 MHz.

  Finally, it should be understood that the processes and techniques described herein are essentially independent of any particular equipment, and it may use any suitable component. In addition, various types of devices can be applied based on the contents of the present invention. Manufacturing equipment can also implement the methods and processes described in this patent and is very good. Although the present invention has been described with reference to specific implementations, these are all for the purpose of illustration and are not intended to be limiting. One skilled in the art will recognize that different hardware, software and firmware combinations can be applied to the practice of the present invention. For example, software is described in various programs and command code languages, such as C / C ++, PERL, SHELL, PHP, JAVA (registered trademark), and the like.

What has been described above is merely a detailed description and drawings of the best embodiment of the present invention, and the features of the present invention are not limited thereto and do not limit the present invention. The entire scope of the present invention is in accordance with the above claims, is consistent with the embodiment similar to the gist of the present invention, and falls within the scope of the present invention. All modifications and alterations within the scope of this patent by those skilled in the art are included within the scope of the above claims.

1 is a schematic cross-sectional view showing a tandem plasma processing chamber according to an embodiment of the present invention. The cross-sectional schematic in CC line of FIG. Sectional drawing which shows the Example of the plasma limiting apparatus in this invention. FIG. 4 is a sectional view of the plasma restriction device shown in FIG. The schematic of the RF matching circuit structure of this invention. The pressure balance structure used between the two processing regions shown in the examples. A number of RF frequencies applied to the two cathodes shown in the embodiments of the present invention. The example which processed using two bias frequencies implement | achieved based on the Example of this invention. The example which processed using two source frequencies implement | achieved based on the Example of this invention.

Explanation of symbols

100, 600, 700 Tandem plasma processing chamber 105, 705 Chamber body 110, 115, 710, 715 Processing region 120, 125, 720, 725 Cathode 122, 722 Separation wall 130, 135, 730, 735 Wafer 132 Isolation ring 134 Tank 140,145,740,745 RF conductor 150,155,750,755 Connector 152,154 RF generator 153,157,753,757 Matching circuit 156,158 RF generator 160,760 Shared source 170,175,770,775 Shower heads 171 and 771 Gas transport pipes 172 and 772 Central areas 173 and 773 Gas transport pipes 174 and 774 Seals 176 and 776 Peripheral areas 180 and 780 Central vacuum pumps 182 and 782 Exhaust ports 183 and 783 Inner walls 184 84 Exhaust chamber 70, 190, 195, 790, 795 Limiting device 751, 752, 758, 759 Source frequency 754, 756 Bias frequency 763, 767 Changeover switch 71 Conductive component 72 Outer edge 73 Internal peripheral edge 74 Upper surface 75 Bottom surface 76 Channel 80 Electrically insulating layer 90 Electrically conductive support ring 91 Outer edge 92 Internal peripheral boundary 95 Electrically conductive component 96 Electrically conductive ring 98,99 Channel 610,615 Processing region 632 Isolation ring 634,636 Pressure balancing passage 682 Separation wall 684 Channel
T thickness

Claims (18)

It has at least two plasma processing regions, and can process at least two wafers individually or simultaneously. A cathode is installed at the bottom of each processing region, an anode is installed at the top of the processing region, and an exhaust passage is provided. A vacuum pump coupled to at least one exhaust passage and at least two RF matching circuits, each positioned near the cathode and having at least two plasma restrictions to prevent plasma from entering the exhaust channel from the processing region Including equipment,
In addition, it includes at least two movable insulating isolation rings, each isolation ring limiting the perimeter of each processing area when each isolation ring is installed in any processing area and adjusted to a low position, and each isolation ring Including at least one pressure balancing passage;
Installing a grounded chamber wall, and providing an isolation ring with a thickness sufficient to shield the grounded chamber wall from RF energy;
The two treatment regions include a separating wall that separates the pressure balancing channel, and when the separating ring is set to a low position, the pressure balancing channel and the pressure balancing passage are connected,
Each RF matching circuit couples at least one first frequency and one second frequency to any cathode, of which the first frequency is higher than the second frequency.   The plasma processing chamber according to claim 1, wherein each plasma limiting device includes a plasma shield and an RF shield.   The plasma processing chamber according to claim 2, wherein the plasma shield includes a conductive component that is electrically floating from the ground, and the RF shield includes a conductive component that is grounded.   The processing chamber of claim 1, further comprising a number of RF conductors, each RF conductor coupling RF energy from one of the RF matching circuits to a corresponding cathode, wherein the RF energy is uniform. A plasma processing chamber characterized in that each RF conductor is provided with several uniformly distributed branches for coupling to the cathode. 5. The processing chamber according to claim 4, wherein each RF matching circuit includes an output used in combination with the high frequency input and the low frequency input, and the high frequency matching circuit is coupled between the output used in combination with the high frequency input. A low frequency matching circuit is coupled between the input and the output used together, the high frequency matching circuit exhibits a high impedance to the second and fourth RF frequencies, and the low frequency matching circuit is coupled to the first and third RF frequencies. A plasma processing chamber characterized by exhibiting high impedance.   6. The processing chamber according to claim 5, wherein the first RF frequency is selected from about 27 MHz, about 60 MHz, or about 100 MHz.   6. A plasma processing chamber according to claim 5, wherein the second RF frequency is selected from a range of about 500 KHz to 2.2 MHz.   The plasma processing chamber of claim 1, wherein each RF matching circuit further couples a third RF frequency to a corresponding cathode.   9. A processing chamber according to claim 8, further comprising several changeover switches, each changeover switch being used to perform a changeover operation between the first, second and third RF frequencies. Plasma processing chamber. A tandem plasma etching processing chamber, the first processing region and the second processing region, an isolation wall for separating the first processing region and the second processing region;
An exhaust chamber in fluid communication with the first treatment region and the second treatment region;
Used to prevent plasma from entering the exhaust chamber from the first processing region, and a first plasma restriction device located near the first cathode, and prevents plasma from entering the exhaust chamber from the second processing region. A second plasma limiting device located near the second cathode, and
A first movable insulating isolation ring located in the first processing region and a second movable insulating isolation ring located in the second processing region;
The exhaust chamber includes a single exhaust port and is grounded, and a conductive chamber;
A vacuum pump connected to the exhaust port;
A first fixed cathode fixed to the bottom of the first processing region and including an electrostatic chuck for supporting the wafer;
A first showerhead fixed to the top of the first treatment region and including a first electrode;
A second fixed cathode fixed to the bottom of the second processing region and including an electrostatic chuck for supporting the wafer;
A second showerhead fixed to the top of the second processing region and including a second electrode;
A common gas source for supplying processing gas to the first gas shower head and the second gas shower head;
A first RF matching circuit that simultaneously couples at least one low frequency RF frequency and one high frequency RF frequency to the first cathode;
A second RF matching circuit for simultaneously coupling at least one low frequency RF frequency and one high frequency RF frequency to the second cathode,
The first and second movable isolation rings each have a certain thickness, shield the grounded chamber wall from RF energy,
The first and second movable isolation rings each include at least one pressure balancing passage;
The first and second movable insulating isolation rings are used to place the wafer when adjusted to a high position, and used to process the wafer when adjusted to a low position.
When the isolation wall includes a pressure balancing channel, and the first and second movable insulating isolation rings are adjusted to a low position, the pressure balancing channel and the pressure balancing passage on the first and second movable insulating isolation rings are connected. ,
A tandem plasma processing chamber characterized in that the magnitude of the high frequency RF frequency is at least twice that of the low frequency RF frequency.   11. The tandem plasma etching chamber according to claim 10, wherein the first and second plasma restriction devices include a plasma shield and an RF shield. 12. The tandem plasma etching chamber according to claim 11 , wherein the plasma shield includes a conductive component that is electrically floating from the ground, and the RF shield includes a conductive component that is grounded. A tandem plasma etching chamber.   11. The tandem plasma etching chamber according to claim 10, wherein the low frequency RF frequency range is about 500 KHz to 2.2 MHz, and the high frequency RF frequency is selected from about 27 MHz, about 60 MHz, or about 100 MHz. A tandem plasma etching chamber. A tandem type plasma etching chamber according to claim 10, comprising a second changeover switch connected to the first changeover switch and the second RF matching circuit is further connected to the first RF matching circuit, a first Each of the second changeover switches selects the low-frequency RF frequency from two low-frequency RF frequencies, and selects the high-frequency RF frequency from two high-frequency RF frequencies. Plasma etching chamber.   The tandem plasma etching processing chamber according to claim 10, wherein processing can be performed independently for the other processing region in any of the first processing region and the second processing region. A tandem plasma etching chamber. A reactive ion etching process chamber excluding bonding, a conductive process chamber having a number of processing regions;
An isolation wall for separating multiple treatment areas;
A number of plasma restriction devices located near each cathode to prevent plasma from entering the exhaust chamber from the processing region;
Including
Each processing region includes one movable insulating isolation ring, each insulating isolation ring includes at least one pressure balancing passage, and limits the peripheral boundary of the corresponding processing region when each insulating isolation ring is positioned low. Fluidly connected to the pressure balancing passage and pressure balancing channel;
Each insulating isolation ring has a constant thickness, and the grounded chamber wall is shielded from RF energy;
The isolation wall is provided with a fluid channel for maintaining pressure balance in the multiple processing regions, and further includes an exhaust chamber that is fluidly connected to at least one of the multiple processing regions, and is electrically conductive. A processing chamber,
At least one vacuum pump connected to the exhaust port;
A number of cathodes fixed to the bottom of each processing region and including a chuck device for supporting the wafer;
A number of showerheads fixed on top of each processing area and including one electrode;
A common gas source for supplying processing gas to the multiple showerheads;
Reactive ion etching chamber excluding coupling, characterized in that it is a number of RF matching circuits , each coupling at least one low frequency RF frequency and high frequency RF frequency to the corresponding cathode simultaneously.   17. The reactive ion etching chamber excluding the coupling according to claim 16, wherein each plasma limiting device includes a plasma shield and an RF shield.   18. A reactive ion etching chamber excluding bonding according to claim 17, wherein the plasma shield includes a component that is electrically floating from a conductive ground, and the RF shield includes a conductive component that is grounded. Reactive ion etching processing chamber excluding bonds characterized by that.