KR0165578B1 - Hollow-anode-glow discharge apparatus - Google Patents

Abstract

The vapor-deposited anode glow discharge device, which is suitable for plating and etching in the form of a two- or three-electrode reactor, has improved uniformity and efficiency and is capable of processing a low pressure substrate. In a first embodiment of the treatment of ion dominance, the apparatus is equipped with a high energy density homogenization grid with multiple, variable sized equally spaced through holes. In a second embodiment of the chemical reaction preponderant treatment, there is a high energy density homogenization grid having multiple equally spaced through holes and stepped or continuously varying non-planar profiles. In a third embodiment for low pressure ion dominant treatment or chemical reaction dominant treatment, it consists of a high energy density homogenizing grid having multiple equally sized equally spaced through holes having a width large enough to overcome the influence of dark areas. In a fourth embodiment for ion dominant treatment or chemical reaction dominant treatment, a high energy density source is provided which synergistically cooperates with multiple through holes to provide a high density of selected energy ions.

Description

[Name of invention]

Glow Discharge Substrate Surface Treatment Apparatus

Detailed description of the invention

TECHNICAL FIELD The present invention relates to the field of substrate processing, and more particularly to a new glow discharge substrate surface treatment apparatus having improved uniformity and efficiency and usable at low pressure.

In general, there are two types of substrate surface treatment apparatuses for a single substrate. In one of them, a substrate surface treatment medium such as a plasma is controllably generated by two electrodes in a biode configuration, while in another form, the substrate surface treatment medium is a triode or other three. It is controllably generated by three electrodes in an electrode configuration. In such devices one or more selected surface treatment media can react with the surface of a suitably prepared semiconductor substrate or other materials to form a desired microstructure thereon or remove from them unwanted residues remaining in one or more previous substrate processing steps. To remove it. The Wafer Etch 606/616 Model Triode Reactor, commercially available from the present application, belongs to the dipole and triode known to those skilled in the art. Substrate surface treatment media such as plasma in a bipolar tube reactor is controllably generated between two electrodes in a bipolar tube configuration, while substrate processing media such as plasma in a triode tube reactor on the one hand between the top electrode and the grid electrode. And on the other hand controllably between the grid electrode and the lower electrode.

In general, there are two types of substrate surface treatment media produced in the case of a bipolar tube or a triode, controllably generated by a single substrate substrate surface treatment reactor. In some forms of substrate processing, such as etching oxides or other materials on semiconductor wafers or other substrates, the reactors generate substrate surface treatment media composed primarily of selected ions. On the other hand, in substrate surface treatment of a type such as chlorine etching aluminum or other materials on a semiconductor wafer or other substrate, the reactors generate a substrate surface treatment medium composed primarily of certain selected species. The former form of treatment is known as ion-dominated processing and the latter form is known as chemically-dominated processing. Depending on the particular microstructures formed and the phase of the overall manufacturing process, the ionic and chemical reaction dominant treatments can control the formation (plating, growth, etc.) on the substrate surface or removal from the substrate surface (etching, etc.). Can be done.

The utility of conventional reactors in triode construction or dipole construction for ion predominance treatment and chemical reaction predominance treatment has been limited to the degree of uniformity of substrate surface treatment that can be obtained. For example, when a large number of integrated circuits are applied to ultra high density integrated circuits (VLSI) fabricated on much larger semiconductor wafers, the effective yield of the fabricated device depends on the degree of uniformity obtained by the substrate surface treatment apparatus. Increasing the diameter of the substrate to increase the yield of integrated circuit devices manufactured per unit substrate makes it more difficult to achieve uniformity across the entire substrate. Since the yield of the device is directly proportional to the degree of uniformity obtained, the technique of device design advances with the degree to which the uniformity of substrate surface treatment is improved.

The utility of conventional reactors in bipolar or tripolar configurations has been further limited by the pressure at which selected ion and chemical reaction dominance treatments can be effectively performed on semiconductor substrates or other substrates. For example, when applied to very high density integrated circuits (VLSI) where it is desirable to form much smaller microstructures, the fineness and size of detail that can be produced depends on the pressure in the reaction vessel. As the pressure at which the selected ion dominant treatment and chemical reaction dominant treatment is performed decreases, the fineness and size of the microstructures that can be produced correspondingly increases. However, below a certain pressure of about 70 Torr in a reactor having a triode configuration and about 800 Torr in a reactor having a bipolar configuration, the efficiency of a conventional substrate surface treatment apparatus is so low that substantial treatment cannot be performed. The device frozens the fineness and size of the microstructures that have been produced so far at greater or coarser than desired. Since the degree and size of the manufacturable microstructure is inversely proportional to the pressure levels in these reactors, the device design advances to the extent that voltage processing can be effectively obtained.

Accordingly, a primary object of the present invention is to improve the uniformity, efficiency and voltage operability in ion and / or chemical superiority treatment for formation and / or removal of substrates in dipole or triode or other multi-electrode configurations. It is to provide a surface treatment apparatus.

According to one embodiment of the ion predominance treatment with improved uniformity, the apparatus of the present invention comprises a reaction vessel; At least first and second spatially spaced electrodes disposed in said reaction vessel, said first and second spatially spaced electrodes forming a substrate surface treatment medium forming zone therebetween; A substrate holder located in the vicinity of one of the electrodes; Gas injection means for injecting a reactant forming a substrate surface treatment medium into the reaction vessel; at least one electric excitation source; A coupling coupled between the at least one electric source and the at least first and second electrodes in such a manner as to ground one of the electrodes and apply power to the other to induce a hollow-anode glow discharge at the grounded electrode. Means wherein the grounded electrode has at least first and second groups of through-holes through which the hollow-anode glow discharge occurs, wherein the first and second groups of through-holes are formed on the entire surface of the substrate. And certain other properties selected to provide substantial uniformity of substrate surface treatment over.

In an embodiment of the ion predominance treatment in which the uniformity is improved, predetermined characteristics of at least the first and second groups of through holes of the grounded electrode are selected to have different sizes.

In an embodiment for chemical reaction dominance treatment with improved uniformity, the apparatus of the present invention comprises a reaction vessel; At least first and second spatially spaced electrodes disposed within said reaction vessel, said first and second spatially spaced electrodes creating a substrate surface treatment medium forming zone therebetween; A substrate holder holding a substrate close to one of the electrodes; A gas injector for injecting reactants into the reaction vessel; An electrical source connected to the at least one of the first and second electrodes to ground and one of the electrodes and to power the other to induce a hollow-anode glow discharge at the grounded electrode. Coupling means, wherein the grounded electrode has at least one through hole through which the hollow-anode glow discharge occurs; The grounded electrode has a predetermined non-planar contour without flatness in a manner selected to provide substantial uniformity of substrate surface treatment over the entire surface of the substrate. In an embodiment of the chemical reaction predominance process in which the uniformity is improved, the predetermined non-planar contour is selected to be concave. Continuous non-planar contours, such as stepped non-planar contours rather than concave contours, can be applied without departing from the spirit of the invention.

According to one embodiment of the improved low pressure treatment for selected ion dominance and / or chemical reaction dominance, the reaction vessel of the present invention; At least first and second spatially spaced electrodes disposed within said reaction vessel, said first and second spatially spaced electrodes creating a substrate surface treatment medium forming zone therebetween; A substrate holder releasably retaining a substrate close to one of the first and second spatially spaced electrodes; A gas injector for injecting substrate surface treatment reactants into the reaction vessel; Electrical excitation department; A coupling coupled between the electroexcitation source and the first and second spatially spaced electrodes to ground one of the electrodes and power the other to induce a hollow-anode glow discharge at the grounded electrode. Means; Pressure control means for selectively setting a preselected pressure in a reaction vessel selected to less than 100 mTorr, wherein the grounded electrode is provided with a hollow-anode glow discharge having a predetermined width selected greater than 4.9 mm. It has a plurality of through holes.

According to the present invention, the through hole size of the grounded grid electrode controls the manner in which the hollow-anode glow discharge occurs within the through hole, and the substrate surface treatment at low pressure and finer details than previously thought possible. It allows the production of microstructures with size.

According to one embodiment for the treatment of ion dominance and / or chemical reaction dominance with improved low pressure and selected energy, the apparatus of the present invention comprises: a reaction vessel; A high energy source for providing ions; First and second electrodes spaced apart from each other and from said high energy source and installed in said reaction vessel, said first substrate surface treatment medium forming zone being formed between said high energy source of one of said first and second electrodes; First and second electrodes forming a second substrate surface treatment medium forming region between the first and second electrodes spaced apart; A holder for detachably holding a substrate close to one of the first and second electrodes; Electrical excitation department; One of the first and second electrodes and supplying power to the other to induce a hollow-anode glow discharge at the grounded electrode and to move ions of selected energy to the substrate, A defect means connected between the first and second electrodes, wherein the grounded electrode has a plurality of through holes through which hollow-anode glow discharges are generated, through which the first substrate surface treatment medium The high energy ions generated by the high energy source in the formation zone are in communication with the second substrate surface treatment medium formation zone, and at a given low pressure operating point, a greater proportion of the selected energy in the second substrate surface treatment medium formation zone than in normal conditions. By supplying ions having a positive effect on the hollow-anode glow discharge, thereby increasing the It provides selected energy treatments with improved efficiency at lower pressures and higher densities than would have been considered. Although embodiments of the present invention use energy sources that are magnetically augmented as high energy sources, Radio Frequency Induction (RFI) and Electron Cyclotron Resonance (ECR) or other high energy sources are seen. It can be used without departing from the spirit of the invention.

The present invention can be better understood by reference to the following drawings and exemplary and detailed description of the preferred embodiments, and the objects, configurations and effects of the present invention will become more apparent.

[Brief Description of Drawings]

FIG. 1 is disclosed in U.S. Patent No. 5,013,400 to Kurasaki et al., Wherein FIGS. 1 (a) and (b) show schematic diagrams of each conventional representative bipolar and triode reactors.

2 is a diagram useful in explaining the principles of the present invention.

(A)-(b) of FIG. 3 show the change of saturated ion current according to the position of reactor (Z), respectively.

(A) and (b) of FIG. 4 are a plan view and a side view, respectively, showing an embodiment of the homogenization grid for ion predominance treatment according to the present invention.

5 is a graph useful for explaining the principle of the homogenization grid for ion predominance treatment according to the present invention.

(A) and (b) of FIG. 6 are a plan view and a side view, respectively, showing another embodiment of a homogenization grid for chemical reaction dominance treatment according to the present invention.

7 is a graph useful for explaining the principle of the homogenization grid for the chemical reaction dominant treatment according to the present invention.

(A) and (b) of FIG. 8 are front and side views, respectively, showing one embodiment of an improved low pressure grid for the ionic and chemical reaction dominant treatments according to the present invention.

9 is a schematic diagram illustrating one embodiment of an improved low pressure, selected energy substrate surface treatment apparatus for ion dominance and chemical reaction dominance treatments in accordance with the present invention.

Best Mode for Implementation of the Invention

Referring to FIG. 1 (a), a typical representative bipolar tube reactor 10 is shown schematically. The reactor 10 is equipped with a reaction vessel 12 having two electrodes 14, 16 spaced apart. The upper electrode 14 is grounded, and the lower electrode 16 is coupled to the electroexcitation source (RF) 18 over a suitable circuit and on which the substrate (not shown) to be processed is detachably mounted. The appropriate arc is a variable capacitor C1 and inductor L connected between the lower electrode 16 and the electric source 18 and a variable capacitor C2 connected in parallel with the electric source 18 in FIG. Consists of.

The gas injection system 20 is connected with the reaction vessel 12 for injecting gaseous reactants into the reaction vessel 12, and the temperature control system 22 controls the temperature of the reaction vessel and the electrodes therein. It is connected to the reaction vessel 12 in order to, and the pressure control system 24 is connected to the reaction vessel 12 to control the pressure inside the reaction vessel.

Since the electrode 14 is grounded, it is at a lower potential than the powered electrode 16, so that the upper electrode 14 is an anode and the lower electrode 16 is called a cathode. A reactive ion etch (RIE) plasma, outlined in ellipse 26, is generated so as to be controllable between the anode and cathode in reaction vessel 12 in a known manner.

Referring to FIG. 1 (b), 1991, entitled Dry Etch Process For Forming Champagne Profiles, and Dry Etch Apparatus, for forming the excellent contours, which are incorporated herein by reference. A triode tube reactor 30 of the type described in U.S. Patent No. 5,013,400, issued to Kurasaki on 7 March, is schematically illustrated. The triode tube reactor includes an upper vessel 34, a ground electrode 36, and a lower electrode 38 having a reaction vessel 32 spaced apart from each other in an upper tube configuration. The upper electrode 34 and the lower electrode 38 pass through the variable capacitors C1 and C2 and follow a circuit path having an inductor L connected in series to the electric source 40 and a capacitor C connected in parallel. It is connected to an electric source 40.

A gas injection system 42 is connected to the reaction vessel 32 for controllably injecting the gaseous selected reactants into the reaction vessel 32, and the temperature control system 44 controls the temperature of the vessel and the electrodes therein. Connected to the reaction vessel 32 for control, pressure control system 46 is connected to the reaction vessel 32 to set and maintain the selected operating pressure. In a preferred embodiment, the gas injection system 42 has a gas diffuser (not shown) located between the upper electrode 34 and the grid electrode 36, wherein the injected gas is supplied with the reaction vessel 32. A plurality of through holes (not shown) are formed to flow into the inside.

In a preferred embodiment, the temperature control system 44 has a passage (not shown) in the upper electrode 34 to allow the heat transfer fluid, such as water, to circulate and control the temperature of the fluid therethrough. In the reaction vessel 32, bores (not shown) are formed to receive a resistive heating element for controlling the temperature of the reaction vessel, and the lower electrode is used to control the temperature of the lower electrode 38 itself. It is preferable to have a through hole (not shown) for enabling circulation of a heat transfer fluid such as helium (He). The lower electrode 38 also has through holes (not shown) to enable circulation of heat transfer fluid such as water to control its own temperature.

Grid electrode 36 is grounded as shown. This electrode is uniformly drilled through holes having a width of 4.9 mm or less. The electric source 4 is connected to the upper electrode 34 and the lower electrode 38 via the variable capacitors C1 and C2, which are connected between the upper electrode 34 and the grid electrode 36. Form only the plasma 48 denoted Remote, or form only the plasma denoted RIE between the grid 36 and the lower electrode 38, or between the grid 36 and the lower, as well as between the upper electrode 34 and the grid 36; It is possible to form plasmas between the electrodes 38.

In a preferred embodiment, the pressure control system 46 has a pressure controller (not shown) that receives feedback from a manometer (not shown) located within the reaction vessel 32. The pressure controller responds to a chamber setpoint pressure selected in the range of 50 mTorr to 3000 mTorr, and also includes a throttle valve and an orifice valve (not shown) connected between the reaction vessel 32 and a pump (not shown). In response to the pressure value provided by the pressure gauge, a corresponding setpoint pressure is set and maintained in the reaction vessel 32. Of course, other pressure ranges can also be provided, such as 1 Torr to 10,000 mTorr.

In one mode of operation of the triode reactor 30 of FIG. 1 (b), the RIE is grounded by grounding the grid 36 and supplying full power to only the lower electrode 38 and no power to the upper electrode 34 at all. Only the plasma 50 can be provided. The triode tube reactor 30 of FIG. 1 (b) and the dipole tube reactor 10 of FIG. 1 (a) which generate RIE plasma between the electrodes 14 and 16 are operated with the same electrode and plasma. Has a configuration. As such, when the same reaction is carried out in the bipolar tube reactor 10 and in the tripolar tube reactor 30 operating as the bipolar tube reactor, the tripolar tube reactor 30 configured like the bipolar tube reactor 10 and the bipolar tube reactor is completely unexpected. It has been known to exhibit other process characteristics. For example, SiO ₂ and C to provide silicon dioxide etch in both the bipolar tube reactor 10 of FIG. 1 (a) and the tripolar tube reactor 30 operating like the bipolar tube reactor of FIG. 1 (b). _In one exemplary etch by the process of reacting ₂ F ₆ , the etch rate of the bipolar reactor 10 is measured to decrease as the pressure in the bipolar reactor decreases, while operating like a bipolar reactor. The triode reactor 30 maintains its etch rate at a fairly high level despite the reduced pressure. At approximately 100 mTorr or less, the etch rate in the bipolar reactor is about several hundred angstroms per minute, while in a triode reactor 30 that acts like a bipolar reactor, the etch rate under a pressure of about 100 mTorr is equivalent. It maintains thousands of angstroms per minute, about 20 times better than the standard RIE rate in 10).

In addition to the unexpected difference in pressure, the uniformity seen for the same exemplary etching in the bipolar tube reactor 10 of FIG. 1 (a) is achieved even though the triode tube reactor 30 is configured and operated like a bipolar tube reactor. It was found that different from the uniformity provided by the triode tube reactor 30 of FIG. The etching rate in the bipolar tube reactor 10 of FIG. 1 (a) is very high near the center and near the center of the wafer, but is low at the edge and acts like the bipolar tube reactor of FIG. 1 (b). In (30), uniformity is kept constant throughout the substrate, and unlike the bipolar tube reactor 10 of FIG. 1 (a), there is no change in etching rate between the center and the edge.

In the present invention, differences in etching rate and uniformity dominate RIE plasma and maintain the etching rate, even at low pressures where the same RIE plasma in the bipolar reactor of FIG. It is based on the recognition that it is due to hollow-anode glow discharges occurring in the voids of the grid of the triode reactor 30 of FIG. This phenomena recognized so far enables the glow discharge device to be constructed in accordance with the present invention to increase uniformity and efficiency and to allow low pressure operation.

2 shows an arrangement 60 useful for illustrating the principles of the present invention. An electric field 66 denoted by E is formed between the lower electrode 62 which receives the power of the triode reactor 30 (FIG. 1B) and the grounded grid 64. Electrons present in the RIE plasma formation region between the two electrodes 62 and 64 and schematically represented by circles 68 and e are accelerated to the grid 64 by an electric field 66. Some electrons 68 pass through the grid 64 and collide with an inner wall that forms at least one through hole 70, and a plurality of electrons 72, denoted e for each of those electrons 68. This is caused by the secondary electron emission process. Secondary electrons 72 are then caught in at least one through hole 70 and oscillate back and forth between the facing inner walls forming the through hole.

The vibrating secondary electrons 72 collide with gas molecules present in the voids of the at least one through hole 70 to generate ions 74, which are represented by +. Avalanches and breakdowns occur in the generation of secondary electrons and ions, whereby hollow-anode glow discharges of at least one through hole having an enhanced electron density along each through hole axis. Generated within each void.

According to the present generation, a dark space sheath is formed near the periphery of each through hole 70 and has a potential indicated by dotted line 76 in the drawing and denoted by V _DS1 and in which no glow discharge occurs. The intensity of the glow discharge in each through hole 70 is related to the through hole size, and the spatial extent of the dark space shielding area 76 is related to the pressure in the corresponding through hole 70. A dark shield region having a potential of V _DS2 and no glow discharge represented by a dotted line 80 is formed around the electrode 62 which is generally supplied with a power applied by a negative DC bias voltage.

(A) to (d) of FIG. 3 show the change of saturated ion current along the vertical axis according to the Z position of the reactor on the horizontal axis, and 1.5 on the horizontal axis is the grid in the reactor for chemical reactions such as C ₂ F ₆ . Corresponding to the position, the values on the vertical axis are the values measured by the Z profilometer. As shown in graph 82 of FIG. 3 (a) showing the ion current according to the Z position for the grid without through holes, the ion current has a peak of less than 150 mA in the region below the grid.

Graphs 84, 86, and 88 of Figures 3b, c and d correspond to grids having a plurality of uniform diameter through holes of 7 mm, 11 mm and 17 mm, respectively, Saturation ion current changes as the size of the through hole passing through the grid changes. In each graph (84, 86, 88) the ion current is located at the position of the grid at the maximum value according to the applied power (see some peaks at 100W, 200W, 300W) for chemistry such as C ₂ F ₆ . Indicates a peak.

Referring to FIG. 4, number 90 is a high energy density homogenization grid for ion predominance treatment according to the present invention. In a preferred embodiment the grid 90 is installed in the triode reactor 30 of FIG. 1 (b), but the grid is installed within the bipolar reactor 10 of FIG. 1 (a) without departing from the spirit of the invention. It may be arranged in another reactor configured as a reactor of dipoles, triodes or other multiple electrodes. Wherever the grid is installed in any reactor, the grid 90 is preferably grounded and the electrode supporting the substrate is preferably powered to cause hollow-anode glow discharge in each through hole.

The grid 90 has at least first and second groups of through holes having different preselected properties in which high energy density hollow-anode glow discharges occur. By varying the size of the through-holes, the intensity of the high energy density hollow-anode glow discharge is changed (see FIG. 3), and at least the preselected different properties of the through-holes of the first and second groups are characterized by It is selected to provide substantial uniformity of processing. In a preferred embodiment the feature is selected by varying the width of at least the first and second groups of through holes 92, 94, respectively. Grid 90 having differently sized through-holes 92,94 arranged concentrically in the figure imparts substantial uniformity to the exemplary ion dominant etch and the like described in connection with FIG. Different arrangements of through holes having different sizes and more than two groups of through holes of different sizes may be applied without departing from the spirit of this invention.

Hollow-anode glow discharge in each of the several through holes of the grid 90 proceeds downwardly from the grid toward the substrate, decreases in strength, and extends closer to the mutually facing surfaces of the substrate. In order to avoid duplicating the through hole pattern on the substrate, the intrahole distance between the through holes of the same size and the interhole distance between the through holes of the different sizes are within and between groups at the surface of the substrate. It is preferably chosen to be the minimum size 98 denoted D, which causes the overlap of several hollow-anode glow discharges of the ball. In an embodiment the minimum size 98 is about 0.2 mm. However, other through hole sizes may be applied to prevent replication of the through hole pattern following the particular ion predominance treatment selected. In a preferred embodiment, the distance between the through holes of the same and different sizes is selected to be the same size to prevent duplication of the through hole pattern on the wafer or another substrate, but at least the patterns of the through holes of the first and second groups Other through hole spacing arrangements can be applied as long as they are not replicated on the substrate.

The thickness 104, denoted T of the grid 90, should not be thin enough to support hollow-anode glow discharges in several through holes and also not thick enough to dissipate them. In the examples, a thickness of 0.12 to 6.3 mm has been found to be effective, but other thicknesses may be applied without departing from the spirit of the invention. As the material of the grid 90, a material such as aluminum that is not deformed or melted may be selected.

Referring to FIG. 5, numeral 110 is a graph useful for explaining the principle of constructing a high energy density homogenization grid for ion predominance treatment and the like according to the present invention. The ion dominant treatment of the example is the etching of the semiconductor substrate by the chemical action of C ₂ F ₆ . Graph 110 shows the exponent (here etch rate) of the particular substrate surface treatment on the vertical axis according to the size of the through hole on the horizontal axis.

Graph 110 is an example of one treatment that may be applied to construct a high density uniformity grid for the ion predominance treatment according to the present invention. For a given pressure, several different grids with different uniformly sized through-holes are installed in the triode reactor of FIG. 1 (b), and the etching obtained for each grid with different through-holes of uniform size. Measure the speed. In graph 110, each etch rate is shown as data points schematically indicated by square boxes. The low pressure set point moves to the right of the graph 110 and the high pressure set point moves to the left of the graph 110. To design the uniformity grid, the contour measurer measures the uniformity of the etch rate across the substrate using a grid having a through hole of one selected size, as at the midpoint of graph 110. The desorption from the uniformity of a given etch rate is supplemented by referring to graph 110 to select the size of the through-holes that gives the desired etch rate for areas where the etch rate deviates from the uniformity. This constitutes a grid with a group of through holes of different sizes selected to provide uniformity, the measurement of the contour capacitor is performed, and the same process is repeated until substantial uniformity is achieved. Graph 110 is merely an example and the high density homogenization grid for the ion dominant treatment of the present invention is different by different control grids and design methods, and in a different direction than that described by graph 110 without departing from the spirit of the present invention. It will be appreciated that by collecting different kinds of data on size and factors, it can be designed for different ion dominant treatments.

Referring to FIG. 6, number 120 is a high density homogenization grid for chemical reaction dominance treatment according to the present invention. As in the case of the high density homogenization grid for the ion dominant treatment of the embodiment of FIG. 4, the grid 120 can be installed in any suitable two-, three-, or other multi-electrode reactor, and FIG. The triode reactor is a good example at present. Unlike the case of the high density homogenization grid for the ion domination treatment of the embodiment of FIG. 4, different through holes selected to determine the relative strength of the high density hollow-anode glow discharge and to impart substantial uniformity of the substrate surface treatment throughout the substrate surface. In the case of size, the grid 120 of the embodiment of FIG. 6 for the chemical reaction dominance treatment is selected to impart substantial uniformity of substrate surface treatment over the entire surface of the substrate being treated for the selected chemical reaction dominance treatment. In a manner without any flatness contour. According to the present invention, the local intensity of the hollow-anode glow discharge is controlled from the substrate to be treated, which makes it possible to provide substantially uniformity of substrate surface treatment for any selected chemical reaction dominant treatment by controllably changing the spacing. It is determined by the local spacing of the grid.

In an embodiment, the homogenization grid 120 is made of a member 122, such as aluminum, through which a plurality of through holes 124 of the same size are provided in a uniformly spaced relationship. In an embodiment, the predetermined non-planar contour of grid 120 is selected to be two-dimensionally continuous arcuate with a centrally located through hole farther from the substrate than a peripherally located through hole. The thickness of the grid 120 should not be so thin that the homogenizing grid 120 melts and should not be thick enough to dissipate the high energy density glow discharge. Representative values of the thickness range from 0.12 mm to 6.3 mm but other thicknesses may be applied without departing from the spirit of the invention.

For any selected chemical reaction dominant treatment, the non-planar contour is selected to provide substantial uniformity across the entire surface of the wafer for the selected chemical reaction dominant treatment. In order to determine a particular non-planar contour corresponding to the particular chemical reaction preponderance selected, the selected chemical reaction predominant treatment at a point located around the entire surface of the substrate using a planar grid mounted at a first predetermined distance from the substrate. The index of is measured. The planar grid is then remounted at some other distance from the substrate in the reactor, and the index of the selected particular chemical reaction dominance treatment at the points of the same substrate is measured. The process of remounting the planar grid with respect to the points of the same set of substrates and the process of measuring the index of the selected chemical reaction dominance treatment are repeated a predetermined number of times. Each set of exponential measurements according to the position around the same points on the substrate was parameterized by the spacing of the planar grid of a particular value from the substrate for a substantially constant exponent, the spacing giving the same exponent at each point It can be measured directly, extrapolated from the measurements, or by other calculations. This interval specifies how the non-planar contour deviates from flat to provide practical uniformity for the particular chemical reaction dominant treatment selected. Without departing from the spirit of the present invention, discontinuous (stepped) non-planar contours and continuous non-planar contours other than the concave grid 120 of this embodiment may be applied.

Referring to FIG. 7, reference numeral 130 denotes an electrode on the longitudinal axis according to the position (mm) from the substrate edge indicated on the abscissa for different uniform etch rates at different pressures, as shown by curves 132, 134 and 136. A graph showing the spacing in inches. Graph 130 was experimentally obtained on a modified bipolar tube chamber using an electrostatic chuck, where the grounded electrode is suspended from the top electrode with a Teflon baffle around the side. The particular chemical reaction predominant treatment selected was aluminum etching.

The sample used was 6 inches long aluminum containing 0.5 percent copper irradiated with strong ultraviolet light at 200 ° C. Two-dimensional graphs of the three factors indicated at three points were used to produce 18 experiments. During the experiment, it was kept constant at 50 sccm of chlorine (Cl), 15 sccm of chlorine silicon (SiCl ₄ ), 300 W, and 10 Torr of helium back pressure. The changing factors were pressure 60-120 mt, electrode spacing 0.25-1.25 inch, and ground electrode through hole size 3 / 16-5 / 8 inch. All wafers were partially etched and contour gauge measurements were performed at 14 points along the diameter of each wafer. Measurements were made before etching, after etching and after resist removal. From this data, the aluminum etch rate and resist etch rate were calculated at 14 points of each wafer. The response measured was the average of the aluminum and resist etch rates and the uniformity of the etch rates for the entire wafer. The details of uniformity were obtained by analyzing the experimental results using the response value of the etching rate at 7 points from the edge of the wafer to the center. The data obtained from this scheme was used to create curves 132, 134, 136 in FIG. 7 showing electrode spacing according to wafer position for a given velocity. The data points of each curve are shown on the figure to explain how the curve was created. These curves indicate how much spacing is needed to produce a particular etch rate at a particular location on the wafer. This curve represents the shape of the ground grid needed to yield a uniform etch rate across the entire wafer for the chemical reaction dominance treatment of the selected embodiment. Different chemical reaction preponderance treatments, different control grid design methods, and other data collection methods can be applied without departing from the spirit of the present invention.

Referring to FIG. 8, number 140 is a high energy and low pressure grid in accordance with the present invention. The grid 140 is preferably installed inside the triode reactor of FIG. 1 (b), but without departing from the spirit of the present invention, within the dipole tube reactor 10 of FIG. It may be installed in another reactor configured as another multi-electrode reactor. The grid 140 is provided with a plurality of through holes 142 having a predetermined width selected to be at least 4.9 mm, preferably 11 mm. As described above with reference to FIG. 1, the pressure in the half of a bipolar or triode configuration is less than about 100 mTorr or the bipolar tube of FIG. 1 (a) for the triode reactor 30 of FIG. When reduced to below a certain threshold of about 800 mTorr or less relative to the reactor 10, in the form, size or degree of microstructure that can be produced by conventional reactors configured as bipolar triodes or other multi-electrode reactors As the limit is reached, the processing efficiency is not valid or the processing stops completely. According to the present invention, by providing a grid 140 having a through hole having a width larger than 4.9 mm, preferably 11 mm, the conventional lower pressure limit is overcome and the degree of miniaturization that was not previously thought possible. And microstructures of size can be made. In the conventional triode reactor, the through hole widths of the grid were all less than 4.9 mm. As described above, the dark part in the grid through hole is a function of the pressure and the radiofrequency excitation applied, and increases as the pressure decreases. With respect to the through-hole size thus far, the dark portion within the through-hole has substantially eliminated or distorted the hollow-anode glow discharge of the grounded grid at the minimum pressure level so far, and thus the microstructure geometry that can be formed. Is frozen to a larger size than expected for current or future ultra high density integrated circuits (VLSI) or other applications.

According to the present invention, despite the size of the arm in the void of the grid at pressures below the minimum pressure so far, the through hole is large enough to maintain hollow-anode glow discharge in the grid 140 and thus the grid 140 The triode tube reactor of FIG. 1 (b) having the above enables substrate surface treatment at selected pressures below the conventional minimum pressure. The grid 140 according to the present invention enables substrate surface treatment in the pressure ranges that have been previously considered impossible by this method, thus producing microstructures having shapes, sizes and fineness which were previously considered impossible. To make it possible. In this embodiment of the grid 140, 11 mm wide through holes are preferred. Other through holes having a size of 4.9 mm or larger generate plasma and correspondingly result in an increase in ion density that is at least one dimension larger than previously thought possible.

Referring to FIG. 9, number 150 is another embodiment of the present invention for ion dominance and / or chemical reaction dominance treatment with selected energy at low pressure. Instead of the upper electrode 34 of the triode reactor 30 of FIG. 1 (b), a high density source 152 is provided inside the reaction vessel so as to be spaced apart from the ground grid 154, the ground grid being lower Spaced apart from the electrode 156. A first substrate surface treatment medium forming zone 158, labeled REMOTE, is provided between the high density source 152 and the grid 154, and the second substrate surface, labeled RIE, between the grid 154 and the lower electrode 156. The treatment medium forming zone 160 is provided. The high density source may be any suitable source such as a radio frequency induction (RFI) source, an electron acceleration resonance (ECR) source, a magnetic augmentation source or the like, or a spiral coplanar machine well known to those skilled in the art.

The first excitation source 162 is connected thereto to energize the high density source 152. Gas injection system 164, temperature control system 166, corresponding to 42, 44 and 46 in FIG. 1 (b). ) And the pressure control system 168 are connected to the reaction vessel in substantially the same manner as the embodiment 30 of FIG. 1 (b) and perform the same function, which are not described herein again for the sake of brevity.

The high energy density source 152 increases the efficiency of the hollow-anode glow discharge generated by the ground electrode 154. That is, the high energy ions generated by the high-energy density source 152 in the first substrate surface treatment medium formation zone 158 pass through the through hole of the grid 154 to form the second substrate surface treatment medium formation zone 160. At a given low pressure operating point to elevate the hollow-anode glow discharge within the grid 154 by providing ions with a relatively much higher proportion of selected energy than would be present in other situations within the second substrate surface treatment zone. Enhances effectively. The ions of the high energy density source 152 cooperate with the hollow-anode glow discharge of the ground electrode to provide more proportions of ions in the zone 160, which ions are controllable negative radio frequency sources. 170 may be selectively extracted by controllably applying a bias to the lower electrode. The controllable radio frequency source 170 generates a negative potential that can vary in size to extract from the upper region 158 ions of a particular energy level. For example, in polysilicon etching where it is desirable to use the minimum energy required to make anisotropic etching of the film, it is desirable to select the minimum energy ions to prevent charge accumulation and gate oxide damage, and to minimize Energy ions can be easily selected by varying the potential of radio frequency source 170 to apply a corresponding negative potential on the lower electrode that attracts the selected energy ions. Of course, other applications of the embodiment 150 may be performed without departing from the spirit of the invention.

In the above embodiment, the hollow-anode glow discharge in the case where the grid is grounded by the application of a bias has been described. However, a voltage is applied to the grid as in the case of film removal within a range not departing from the spirit of the present invention. Hollow-cathode glow discharge may also be provided. Apparatuses of some of the above embodiments, such as the grid embodiment 90 of FIG. 4 primarily for ionic dominance treatment and the grid embodiment 120 of FIG. 6 primarily for chemical reaction dominance treatment, do not depart from the spirit of the invention. Within the reactor 150 of FIG. 9 in a manner such as to provide a high density homogenization grid 90 or 120.

Claims (10)

An ion dominant substrate surface treatment apparatus comprising: a reaction vessel; At least first and second spatially spaced electrodes disposed in said reaction vessel, said first and second spatially spaced electrodes forming a substrate surface treatment medium forming region therebetween; A substrate holder adjacent one of the electrodes; Gas injection means for injecting a reactant forming a substrate surface treatment medium into the reaction vessel; At least one electric excitation source; Coupling means connected between said at least one electrical excitation source and said at least first and second spatially spaced electrodes to induce a hollow-anode glow discharge to one of said electrodes, wherein One has at least first and second groups of through holes having certain different properties from which the hollow-anode glow discharge occurs, wherein the predetermined different properties of the through holes in the groups of through holes are the entire surface of the substrate. And to provide a substantially uniform substrate surface treatment over the substrate. 2. The apparatus of claim 1, wherein said predetermined through hole characteristics of at least first and second groups of through holes formed in one of said electrodes are selected to different sizes. 3. The method of claim 2, wherein the through holes of groups of different sized through holes prevent corresponding replicas of the through hole patterns of the through hole groups on the substrate, such that the corresponding hollow-anode glow discharges overlap in the substrate. And spatially spaced apart by a uniform preselected distance selected. A substrate surface treatment apparatus having a chemical reaction advantage, comprising: a reaction vessel; At least first and second spatially spaced electrodes disposed in said reaction vessel, said first and second spatially spaced electrodes forming a substrate surface treatment medium forming region therebetween; A substrate holder for holding a substrate adjacent one of the electrodes; A gas injector for injecting reactants into the reaction vessel; Electrical excursions; Coupling means connected between the electrical excitation source and the at least first and second spatially spaced electrodes to induce a hollow-anode glow discharge on one of the electrodes, one of the electrodes Has at least one through hole in which the hollow-anode glow discharge takes place and has a predetermined non-planar contour without flatness in a manner selected to provide a substantially uniform substrate surface treatment over the entire surface of the substrate. Substrate surface treatment apparatus. The apparatus of claim 4, wherein the predetermined non-planar contour is concave. The apparatus of claim 4, wherein the predetermined non-planar contour is continuously non-planar. The apparatus of claim 4, wherein the predetermined non-planar contour is discontinuously non-planar. A low pressure substrate processing apparatus comprising: a reaction vessel; At least first and second spatially spaced electrodes disposed within said reaction vessel and defining a substrate surface treatment medium forming zone therebetween; A substrate holder removably holding a substrate adjacent to one of the first and second spatially spaced electrodes; A gas injector for injecting substrate surface treatment reactants into the reaction vessel; Electrical excursions; Coupling means connected between the excitation source and the first and second spatially spaced electrodes to induce a hollow-anode glow discharge on one of the first and second electrodes; Pressure control means for selectively setting a predetermined pressure, one of the electrodes having at least one through hole through which the hollow-anode glow discharge takes place, the at least one through hole each being 4.9 mm A substrate processing apparatus, characterized in that it has a predetermined width selected to be larger than that. A substrate surface treatment apparatus for ion dominance and / or chemical reaction dominance of selected energy at low pressure, comprising: a reaction vessel; A high energy source for providing high energy ions; Forming a first substrate surface treatment medium between the high energy source and one of the first and second electrodes as first and second electrodes provided in the reaction vessel to be spaced apart from each other and the high energy source. First and second spatially spaced electrodes disposed to form a zone and to form a second substrate surface treatment medium forming zone between the first and second electrodes; A substrate holder removably holding a substrate adjacent to one of the first and second spatially spaced electrodes; Inducing a hollow-anode glow discharge to an electroexcitation source and one of the first and second electrodes, and selecting ions of a particular energy to migrate from the first substrate surface treatment medium formation zone to the second substrate surface treatment medium formation zone. A coupling means connected between said electrical excitation source and said first and second spatially spaced electrodes, wherein one of said first and second electrodes comprises at least one penetration through which hollow anode glow discharge occurs; And having a ball, the high energy ions generated by the high energy source in the first substrate surface treatment medium forming zone are communicated with the second substrate surface treatment medium forming zone through the through hole, and the high energy is passed through the through hole. By supplying a greater proportion of ions of a particular energy selected in the second substrate surface treatment medium forming zone than in the absence of a circle. A substrate surface treatment apparatus characterized by synergistically enhancing hollow-anode glow discharge at one of the electrodes. 10. The apparatus of claim 9, wherein said high energy source is a radio frequency disturbance source.