Electrostatic control device for semiconductor process systems

Abstract

This embodiment relates to a technique for easily adjusting the static electricity level required by a substrate according to a semiconductor process by injecting static electricity onto the substrate or removing pre-formed static electricity. The static electricity control device of the semiconductor processing system according to the present embodiment is configured to inject static electricity onto a substrate disposed within a vacuum chamber or to remove static electricity formed on the substrate, and includes a charged particle generator disposed at an upper portion of the vacuum chamber and generating VUV (Vacuum Ultraviolet Ray) and generating charged particles including positive ions and electrons as a result of the VUV reacting with a process gas within the vacuum chamber; a grid disposed below the charged particle generator and having a number of holes for selectively passing types of charged particles downward according to an input voltage; a substrate support disposed below the grid, on whose upper surface the substrate is disposed, the substrate support made of a conductive material and for guiding the charged particles that have passed through the grid toward the substrate at a predetermined density according to an input bias voltage; and a static electricity control controller configured to supply a pulse-type voltage to at least one of the grid and the substrate support to control static electricity of the substrate, and the grid and the substrate support are disposed to have a distance therebetween that is within four times the free travel distance of the process gas according to environmental conditions of the vacuum chamber.

Description

[Technical Field]

[0001] This technology generally relates to a technique that allows for easy adjustment of the static electricity level required by a substrate according to the semiconductor manufacturing process by injecting static electricity onto the substrate or removing static electricity formed on the substrate. [Background technology]

[0002] Recently, there has been a trend of decreasing size and area of ​​semiconductor devices as the semiconductor industry becomes more integrated.

[0003] Consequently, the size of the patterns forming semiconductor device patterns and the thickness of the thin films have decreased, and factors that previously did not have a significant impact are emerging as important elements in semiconductor device development. One such factor is the static electricity formed on the substrate, and therefore, processes for controlling the static electricity formed on the substrate are being applied.

[0004] During semiconductor manufacturing processes such as plasma deposition, etching, or substrate cleaning, static electricity is formed on the substrate. If this voltage is excessively high, or if the static electricity discharges rapidly after charging within the substrate, phenomena such as arcing can occur, potentially causing deformation of the pattern.

[0005] Furthermore, static electricity formed on the substrate is mainly generated by electric charge during processes using deionized water, charge transfer from charged plastic materials, induction charging, or plasma.

[0006] To prevent the generation of such static electricity, positive charges (ions) or negative charges (electrons) are pre-charged (injected) into the substrate's insulating film (thin film) at a rate of several nanometers to tens of nanometers before the pattern formation process, cleaning process, or plasma treatment process. This is used to adjust fine patterns such as local pattern uniformity and local edge placement errors during the multiple patterning process, and to control (trade off) static electricity generated during other processes. This is called an electrostatic charger.

[0007] On the other hand, static electricity on the substrate is mainly generated in photoprocessing and cleaning processes that utilize rotational motion, and it is known that the most static electricity is concentrated in the center due to the difference in centrifugal force. In other words, in the photoresist coating process, the concentration of airflow in the center of the substrate is more than three times higher than in the outer edges due to the high-speed rotation of the wafer, so static electricity is formed mainly in the center where the centrifugal force is relatively weak. The static electricity caused by the strong electric field formed in the center of the substrate is charged inside the multilayer insulating film or on the wafer surface and the photoresist pattern formed on the surface.

[0008] Therefore, a method is needed to efficiently remove static electricity formed on the substrate. A device that removes static electricity that has already been generated on the substrate or that is generated during the manufacturing process is called an electrostatic discharger.

[0009] Figure 1(A) illustrates a shape in which electrostatic voltages of -50V, -30V, and -10V appear from the central part of the substrate 1 toward the outer edge.

[0010] However, as illustrated in Figure 1(A), when the substrate 1 is charged with a high voltage centered on the core, the region corresponding to the central part of the substrate in Figure 1(B) (the region where the electrostatic voltage is -50V in Figure 1(A)) can be charged not only on the surface of the substrate 1, such as the insulating P / R (Photo Resist) or oxide, but also to a certain depth D on the surface of the substrate, potentially creating a state where neutralization by ions with low kinetic energy is impossible.

[0011] Furthermore, the electrostatic voltage charged onto the substrate is subject to many variables, including the type of process, material, and pattern shape, and is generally formed between -100V and +100V.

[0012] For example, as shown in Figure 1(B), a charging voltage of 100V or less is formed on the substrate 1, such as an insulating film within a fine circuit of 10nm or less, or a pattern P having an aspect ratio of "5" or greater. However, due to the narrow width of the pattern, it is difficult to remove the static electricity accumulated inside the thin film due to the self-neutralization effect between cations and anions generated by the ionizer and the reduction of ion collisions due to the low electromotive force caused by the low voltage difference between the substrate and the ions. [Overview of the Initiative] [Problems that the invention aims to solve]

[0013] Conventionally, static electricity on substrates was removed using an ionizer. However, as illustrated in Figure 2, when static electricity is charged to the substrate at 1000V using an ionizer, the decay time to reduce this to within 100V using a soft X-ray ionizer is within 1-2 seconds. However, if the initial charging voltage is below 100V, it takes a long time to reduce the charging voltage to below that level.

[0014] Also, generally, the ion density of an ionizer is 10 6 When considering this, charging also occurs inside the silicon oxide layer beneath the PR within the substrate, and the ion density becomes 10 8 In the above cases, it is not possible to remove the static electricity formed inside the substrate 1 using a conventional ionizer.

[0015] One of the problems that this technology aims to solve is to overcome the shortcomings of the conventional technology described above. Another problem that this technology aims to solve is to provide an electrostatic control device for a semiconductor process system that can accurately and quickly inject electrostatics onto a substrate or easily remove electrostatics formed on a substrate by controlling the voltage applied to the grid and substrate support in a simple manner. [Means for solving the problem]

[0016] The electrostatic control device for a semiconductor process system according to this embodiment is an electrostatic control device for a semiconductor process system that injects electrostatics onto a substrate placed in a vacuum chamber or removes electrostatics formed on a substrate, and includes: a charged particle generation unit located on the upper side inside the vacuum chamber that generates VUV (Vacuum Ultraviolet Ray) and generates charged particles containing cations and electrons by the reaction of the VUV with the process gas inside the vacuum chamber; a grid located below the charged particle generation unit and equipped with a number of holes that selectively allow charged particles to pass to the lower side by an input voltage; a substrate support base located below the grid, on which the substrate is positioned on its upper surface, which guides the charged particles that have passed through the grid to the substrate side at a preset density by an input bias voltage; and an electrostatic control control unit that supplies a pulsed voltage to at least one of the grid and the substrate support base to adjust the electrostatics of the substrate, wherein the grid and the substrate support base are arranged to have a separation distance of no more than four times the free path distance of the process gas depending on the environmental conditions of the vacuum chamber.

[0017] In any one aspect of this embodiment, the electrostatic adjustment control unit applies a bias voltage to the substrate support base in electrostatic injection mode such that it is at least a certain level higher than the voltage applied to the grid, and applies voltages to the grid and the bias voltage applied to the substrate support base in electrostatic removal mode such that they are within a preset similar range.

[0018] In any one aspect of this embodiment, the electrostatic adjustment control unit adjusts the voltage level by adjusting the pulse period applied to the grid and the substrate support.

[0019]

[0020] In any one aspect of this embodiment, the charged particle generation unit includes one or more VUV lamps that emit VUV.

[0021]

[0022] In any one aspect of this embodiment, a beam generator that emits a linear ion beam through the side of the vacuum chamber is additionally provided below the VUV lamp to simultaneously generate charged particles from the reaction of VUV and process gas and charged particles from the reaction of the ion beam and process gas, thereby increasing the charged particle density.

[0023]

[0024] In any one aspect of this embodiment, the charged particle generation unit includes a plasma generator that generates plasma and a separation plate that allows only VUV to pass through below the plasma generator, and generates charged particles by the reaction of VUV generated by the plasma generator and process gas.

[0025]

[0026] In any one aspect of this embodiment, the plasma generator includes at least one microplasma device that generates plasma using a power source in the range of 10 - 200 W in a vacuum environment where the volume of the vacuum chamber is in the range of 500 - 1000 cc.

[0027]

[0028] In any one aspect of this embodiment, the electrostatic adjustment control unit adjusts the static electricity of the substrate by adjusting at least one of the type of process gas injected into the vacuum chamber of the microplasma device or the plasma power source.

[0029]

[0030] In any aspect of this embodiment, the plasma generator includes a number of microplasma devices, and the electrostatic control unit controls the type of process gas or plasma power supply injected into the vacuum chamber of each microplasma device to adjust the electrostatic charge of the substrate.

[0031]

[0032] In any aspect of this embodiment, the plasma generator comprises a number of microplasma devices, the separator plates are arranged in a one-to-one correspondence with each microplasma device, and the electrostatic control unit controls the electrostatic charge of the substrate by individually controlling the type of process gas or plasma power supply injected into the vacuum chamber of each microplasma device, although each separator plate includes lenses having different divergence angles.

[0033]

[0034] In any aspect of this embodiment, the grid and the substrate support are of a multi-zone type in which multiple regions are electrically isolated, and the electrostatic control unit supplies different voltage levels to each region of the grid and the substrate support individually.

[0035]

[0036] In any one aspect of this embodiment, the electrostatic control unit supplies voltage to the grid and the substrate support base so as to inject static electricity into certain parts of the substrate and remove static electricity from other parts of the substrate.

[0037]

[0038] In any aspect of this embodiment, the grid includes an upper grid and a lower grid positioned below the upper grid, and the electrostatic control unit supplies the upper grid and the lower grid with voltages of different levels from each other.

[0039]

[0040] In any one aspect of this embodiment, the diameter of the holes formed in the lower grid is set to be different from the diameter of the holes formed in the upper grid, and the electrostatic control unit applies a first level negative voltage to the lower grid to guide ions between the lower grid and the substrate through the holes in the lower grid to the upper grid side, and then applies a negative voltage greater than the first level to the upper grid to cause the ions that have flowed in through the lower grid to collide with the lower surface of the upper grid and generate secondary electrons, thereby controlling the emission of electrons of a higher density through the holes in the lower grid to the substrate side.

[0041]

[0042] In any one aspect of this embodiment, the hole opening ratio at the center of the grid is formed to be higher than that of the surrounding area.

[0043]

[0044] In either aspect of this embodiment, a distance adjustment unit is additionally provided to move the grid and the substrate support vertically within the vacuum chamber, and the electrostatic adjustment control unit controls the distance adjustment unit to change the position of at least one of the grid or the substrate support to the upper or lower side based on the process gas free path distance calculated by the environmental conditions of the vacuum chamber.

[0045]

[0046] In this embodiment, the grid surface is coated or sputtered with a film containing carbon components, including carbon nanotubes (CNTs) and glassy carbon, to prevent arc generation.

[0047]

[0048] In this embodiment, the grid surface is coated or sputtered with one of the following: silicon oxide (SiO2), aluminum oxide (Al2O3), silicon nitride (Si3N4), or an oxide-based thin film, to prevent arc generation. [Effects of the Invention]

[0049] This technology offers the advantage of accurately and rapidly injecting static electricity onto a substrate and easily removing static electricity formed on the substrate. Therefore, it is possible to minimize the defect rate in the semiconductor manufacturing process and to manufacture more reliable semiconductor devices.

[0050] [Brief explanation of the drawing]

[0051] [Figure 1] This diagram illustrates the problems with semiconductor electrostatic discharge.

[0052] [Figure 2] This diagram illustrates the static electricity removal characteristics of a gravity-fed method using an ionizer.

[0053] [Figure 3] This is a schematic diagram illustrating a semiconductor process system equipped with an electrostatic control device according to the first embodiment.

[0054] [Figure 4] This is a diagram illustrating the configuration of the charged particle generation unit shown in Figure 3.

[0055] [Figure 5] This diagram illustrates the multi-zone structure of the grid and substrate support base shown in Figure 3.

[0056] [Figure 6] This is a diagram illustrating the dual grid structure of the grid shown in Figure 3.

[0057] [Figure 7] Figure 3 shows experimental results of electrostatic injection and removal based on the distance between the grid and the substrate support base, as illustrated in the example.

[0058] [Figure 8] This is a diagram illustrating the operation of the electrostatic control device in the semiconductor process system shown in Figure 3. [Modes for carrying out the invention]

[0059] The embodiments and configurations illustrated in the drawings described in this invention are merely preferred embodiments of the invention and do not represent the entire technical idea of ​​the invention; therefore, the scope of the invention should not be construed as being limited by the embodiments and drawings described herein. In other words, since embodiments can be modified in various ways and can take various forms, the scope of the invention should be understood to include equivalents that can realize the technical idea. Furthermore, the purposes or effects presented in this invention do not mean that a particular embodiment must include all of them or only such effects; therefore, the scope of the invention should not be understood as being limited by them.

[0060] All terms used herein have the same meaning as those generally understood by those ordinary skill in the art to which this invention pertains, unless otherwise defined. Terms defined in commonly used dictionaries should be interpreted as having the meaning they have in the context of the relevant art, and not as having any ideal or overly formal meaning not expressly defined herein.

[0061]

[0062] Figure 3 is a schematic diagram illustrating a semiconductor process system equipped with an electrostatic control device according to the first embodiment of the present invention.

[0063] Referring to Figure 3, the semiconductor process system according to the present invention includes a charged particle generation unit 100 located on the upper side inside a vacuum chamber C in which a substrate 10 is placed, and a grid 200 and a substrate support base 300 sequentially located below the charged particle generation unit 100. The system generates charged particles in the vacuum chamber C through the charged particle generation unit 100 and includes an electrostatic adjustment control unit 400 that controls the density of charged particles released to the substrate 10 through the grid 200 by controlling the voltage applied to the grid 200 and the substrate support base 300, thereby injecting electrostatics onto the substrate 10 or removing electrostatics formed on the substrate 10.

[0064] Furthermore, the system may include a distance adjustment unit 500 that adjusts the distance between the grid 200 and the substrate support base 300 by adjusting the position of at least one of the grid 200 and the substrate support base 300 up or down under the control of the electrostatic adjustment control unit 400.

[0065] In other words, this embodiment selectively transmits charged particles generated in the vacuum chamber C through the grid 200, and applies a bias voltage to the substrate support base 300 that supports the substrate 10 to guide the charged particles that have passed through the grid 200 towards the substrate 10, thereby injecting static electricity onto the substrate 10 or neutralizing (removing) static electricity formed on the substrate 10.

[0066]

[0067] Next, we will explain this embodiment in more detail.

[0068] The vacuum chamber C is equipment for performing semiconductor processes on the substrate 10, and although not shown in the figure, it includes a vacuum forming unit for maintaining a vacuum inside the chamber and a gas supply unit for supplying gas inside the chamber.

[0069] In this case, the vacuum forming unit may include a vacuum pump for discharging material from inside the chamber to the outside, a vacuum gauge for detecting the internal vacuum level, a valve for intermittently controlling the inflow and outflow of material, and piping for connecting each component. Preferably, the vacuum forming unit sets the vacuum level inside the chamber to 10-1 ~10 -4 Maintain in Torr

[0070] The gas supply unit can supply different gases depending on the process, providing gases such as helium (He), nitrogen (N2), and argon (Ar) inside the chamber, and the gas flow rate can be set to 10 to 1000 sccm.

[0071] The charged particle generation unit 100 is a device that generates VUV (Vacuum Ultraviolet Ray) and reacts the VUV with a process gas to produce charged particles containing positive ions and electrons. The charged particle generation unit 100 includes at least one of a VUV lamp and a plasma generator, and can generate additional linear ion beams, large-area electron beams, etc., using plasma to produce charged particles containing electrons and ions.

[0072] Figure 4 illustrates the configuration of the charged particle generation unit 100.

[0073] As shown in Figure 4(A), the charged particle generation unit 100 can have a VUV lamp 110 positioned above the vacuum chamber C, and may be additionally equipped below it with a beam generator 120 that emits a large-area beam (B), i.e., an ion beam or electron beam, into the vacuum chamber C from the side of the vacuum chamber C. In this case, multiple VUV lamps 110 may be arranged. That is, the VUV lamps 110 generate and irradiate the inside of the vacuum chamber C with VUV light in the wavelength range of 110 nm to 400 nm. The VUV reacts with the process gas inside the vacuum chamber C to decompose the gas particles and generate charged particles containing positive ions and electrons.

[0074] The beam generator 120 can further increase the density of electrons and cations emitted to the grid 200 side by dissociating the process gas inside the vacuum chamber C through an ion beam or electron beam to additionally generate cations and electrons. Here, the configuration of the beam generator 120 that generates a line-shaped beam is disclosed in the inventor's patents of this application, Korean Patent Nos. 10-1911542, 10-1989847, 10-1998774 and 10-2118604, etc., and all of these are included in this application, so a detailed explanation is omitted.

[0075] Furthermore, as shown in Figure 4(B), the charged particle generation unit 100 has a plasma generator 130 positioned inside the vacuum chamber C. The plasma generator 130 can generate charged particles containing positive ions and electrons by reacting the VUV formed by the plasma with the process gas.

[0076] Below the plasma generator 130, a VUV lamp 140 may be additionally positioned to emit VUV rays into the vacuum chamber C from the side of the vacuum chamber C. In this case, multiple VUV lamps 140 may be arranged, and as shown in Figure 4(B), they can be positioned on both sides of the vacuum chamber C.

[0077] Electrons excited by the plasma formed in the plasma generator 130 return to the bottom state and emit light to the outside with energy corresponding to the energy difference between the excited state and the bottom state. The wavelength band of the light thus formed is the ultraviolet band, which can dissociate the gas supplied by the gas supply unit to form negatively charged particles and / or positively charged particles.

[0078] The plasma generator 130 can be an inductively coupled plasma (ICP) generator or a capacitively coupled plasma (CCP) generator. The electrical signal supplied to the plasma generator 130 can be a pulse or a continuous wave (CW). For example, the ultraviolet band can be distinguished by its wavelength range into near ultraviolet (NEAR UV, 300nm~380nm), far ultraviolet (FAR UV, 200nm~300nm), and vacuum ultraviolet (VUV, 70nm~200nm), which has a shorter wavelength than the far ultraviolet band. In this invention, the plasma generation unit 130 can generate ultraviolet light in the vacuum ultraviolet (VUV) band.

[0079] The plasma generation unit 130 may consist of a microplasma source that generates plasma using a DC, RF, or pulsed power supply in the range of 10 to 200 W in an environment where the volume of the vacuum chamber is in the range of 500 to 1000 cc. The microplasma source is equipped with a separate vacuum chamber for forming the plasma and is configured to perform gas injection and gas exhaust processing, vacuum processing, and power supply processing in this vacuum chamber under the control of the electrostatic adjustment control unit 400.

[0080] At this time, the microplasma source consists of one of the following atmospheric pressure plasma devices: ICP, CCP, TCP, hollow cathode, or DBD, and generates plasma using a variety of process gases including oxygen, nitrogen, argon, and helium.

[0081] Compared to VUV lamps, which typically require a preheating time of around 30 seconds and whose light source output cannot be adjusted, microplasma sources have the advantage of a short plasma turn-on time, as the vacuum chamber volume is in the range of 500-1000cc, allowing for free plasma on / off switching and easy modification of process conditions. When using a microplasma source, it is possible to prevent degradation of thin film properties, which is often required for multilayer thin films of semiconductors, and to inject or remove static electricity onto the substrate more quickly and adaptively.

[0082] Furthermore, in the present invention, as shown in Figure 4(C), the plasma generator 130 can be configured with a plurality of microplasma sources. Figure 4(C) illustrates the first to third microplasma sources 131, 132, and 133.

[0083] In the embodiment illustrated in Figure 4(C), the first to third microplasma sources 131, 132, and 133 are each implemented on independent vacuum chambers, and the electrostatic control control unit 400 can be configured to individually control the vacuum environment, process gas type, and plasma power supply of the first to third microplasma sources 131, 132, and 133 to perform different electrostatic injection or electrostatic removal processes on different regions of the substrate 10.

[0084] In other words, if more static electricity is formed in the center of the substrate 10 compared to the periphery, the electrostatic control control unit 400 can set the pressure or power supply of the microplasma source corresponding to that location differently from the pressure or power supply of the microplasma source at other locations. This enables a more precise electrostatic control process compared to VUV lamps, where the wavelength band of the output VUV light cannot be adjusted.

[0085] Furthermore, the wavelength of VUV generated in the microplasma source varies depending on the type of process gas used. When helium gas is used as the process gas, the dominant wavelength is 58.4 nm; when oxygen gas is used as the process gas, the dominant wavelength is 130.5 nm; and when argon gas is used as the process gas, it is 104.8 nm. Therefore, the electrostatic control control unit 400 can select the desired VUV wavelength by varying or mixing the types of process gases supplied to the vacuum chambers of the first to third microplasma sources 131, 132, and 133, and through this, the electrostatic level injected onto the substrate 10 or the electrostatic level removed can be set differently for each region. For example, helium gas can be used when the band gap energy of the semiconductor thin film formed on the substrate 10 is large, and nitrogen gas can be used when the band gap energy is small.

[0086] Furthermore, the electrostatic control control unit 400 can selectively operate only the microplasma sources at positions corresponding to the areas of the substrate 10 where electrostatic control is required.

[0087] Furthermore, depending on the operating environment, including the type of substrate to be electrostatically controlled, the first to third microplasma sources 131, 132, and 133 can be implemented as different types of atmospheric pressure plasma devices utilizing ICP, CCP, TCP, hollow cathode, and DBD.

[0088] On the other hand, in order to utilize the VUV wavelengths formed by the plasma, as shown in Figure 4(B), a separation plate 150 made of MgF2glass or CaF2glass material can be placed below the plasma generator 130 to block the emission of cations, electrons, and active species generated by the plasma generator 130 to the lower side, while allowing only VUV to pass through. In this case, charged particles generated by the reaction of VUV generated by the plasma generator 130 with the process gas and charged particles generated by the reaction of VUV emitted from the VUV lamp with the process gas are generated simultaneously.

[0089] The separation plate 150 can be further equipped with an optical filter coating that selectively transmits only VUV light, causing it to emit light with a size of 10-20 mm downwards. The divergence angle of the VUV light emitted downwards can be set to a desired shape using a concave lens or a convex lens, etc. When the separation plate 150 is implemented in the embodiment illustrated in Figure 4(C), the separation plates 150 can be arranged (151, 152, 153) below the first to third microplasma sources 131, 132, and 133, respectively, and can have different divergence angles. For example, convex lenses may be provided below the first and third microplasma sources 131 and 133, and a concave lens may be provided below the second microplasma source 132. Of course, as in the embodiment illustrated in Figure 4(B), it is also possible to configure the separation plate 150 to have lenses with different divergence angles corresponding to each microplasma source.

[0090] Furthermore, a light diffuser plate (not shown) can be placed in front of the VUV lamp 140 to diffuse the VUV light into the vacuum chamber C.

[0091] On the other hand, the grid 200 is made of a conductive material and is composed of a plate-like structure with numerous fine holes formed therein to release charged particles flowing in from above to the bottom. Considering that the electrostatic charging voltage of the substrate 10 is always higher in the center than on the outside after the process, it is preferable that the fine hole opening ratio in the center of the grid 200 be formed to be 10% or more higher than the surrounding area. The fine holes can be circular, rhomboid, or other shapes, and their diameters can be set in the range of 1 to 10 mm.

[0092] The grid 200 selectively emits charged particles toward the substrate 10 by the voltage supplied through the electrostatic adjustment control unit 400.

[0093] Furthermore, as illustrated in Figure 5, the grid 200 can be configured as a multi-zone type in which multiple regions are electrically isolated, and each region can be individually supplied with different voltages V1, V2, and V3. In this case, considering that the electrostatic voltage is higher in the center of the substrate 10 than in the outside, the voltage supplied to the center of the grid 200 can be set even higher than that of the surrounding areas (V1>V2>V3). That is, a higher density of charged particles can be supplied to the center of the substrate 10.

[0094] The multi-zone type grid 200 is prepared by preparing circular or square graphite or metal plates with a thickness of 5 mm to 10 mm separated into multiple zones, and laminating a 50 μm to 100 μm polyimide and a 20 to 100 μm copper (Cu) film onto the metal plate or graphite. Next, the copper (Cu) film is patterned on both sides and then etched, patterning so that the metal plate or graphite is electrically separated. Then, a large number of holes with a diameter of 1 to 10 mm are formed, and the inside of the holes is plated. At this time, it is preferable that the holes have an opening ratio of 50% or more of the metal plate or graphite surface, and the inside of the holes can be treated with 20 μm electroless plating and 30 μm electrolytic plating.

[0095] Furthermore, the grid 200 can be configured to prevent arc generation by coating or sputtering a 100-1000 nm thick layer of one of the following materials on its upper surface: a film containing carbon components such as carbon, CNTs, and glassy carbon; or DLC (diamond-like carbon), silicon oxide (SiO2), aluminum oxide (Al2O3), silicon nitride (Si3N4); or an oxide-based thin film. This prevents problems such as pattern distortion, pattern shrinkage, and LER (line edge roughness) defects in the ultrafine patterns of several nanometers in size formed on the substrate 10, caused by arcs generated on the surface of the grid 200 due to partial concentration phenomena caused by ion and electron concentration phenomena on the upper surface of the grid 200.

[0096] Furthermore, the grid 200 may consist of a dual grid structure comprising an upper grid 210 and a lower grid 220, as shown in Figure 6. In this case, the upper grid 210 and the lower grid 220 receive different voltages (V) from the electrostatic control control unit 400. g1 , V g2 The upper grid 210 is provided with a voltage of, for example, 50-100V, sufficient to induce charge inside the vacuum chamber C on its own, and the lower grid 220 is provided with a voltage of 300-500V, such that it has sufficient kinetic energy to discharge the charge that has entered the grid holes into the substrate below.

[0097] In a dual grid structure, when the charge between the charged particle generation unit 100 and the grid 200 collides with the surface of the grid 200, it is guided to the grid holes by the low voltage of the upper grid 210, thus preventing phenomena such as ARC from occurring at the top of the grid. Also, a certain distance d gBy passing through the holes of the upper grid 210 and the lower grid 220 arranged so as to be separated, the charge can be more widely dispersed, and the uniformity of the charge emitted to the substrate 10 side can be enhanced.

[0098] Further, the grid 200 having a dual grid structure can be implemented such that the grid hole diameter of the lower grid 220 is set to be 10 to 20% or more smaller than the grid hole diameter of the upper grid 210, and by additionally generating secondary electrons within the grid 200, the charge density emitted to the substrate 10 side can be formed higher.

[0099] That is, the upper grid 210 serves as a cathode that emits secondary electrons, and is composed of materials such as aluminum or anodized Al, Carbon, CNT, etc. When a negative voltage of -50 to -150 V is applied to the lower grid 220 and ions formed between the lower grid 220 and the substrate 10 are provided to the upper grid 210, and a larger negative voltage, for example, a voltage of -200 to -1000 V, is applied to the upper grid 210, these ions can collide with the lower surface of the upper grid (cathode) to generate secondary electrons. Along with this, about 10 3 cm 2 of electrons formed between the lower grid 220 and the substrate 10 by VUV and the secondary electrons additionally generated inside the grid 200 are simultaneously emitted to the substrate 10 side, so that the electron density applied to the substrate 10 side becomes as high as 10 6 ~10 8 cm 2 , and as a result, the process efficiency is improved.

[0100] As shown in Figure 6(B), the lower surface of the upper grid 210 can be configured to create a rough surface, thereby broadening the direction of motion of secondary electrons and improving uniformity. Since secondary electron generation through such a dual grid structure does not generate reactive species (radicals) with chemical properties, a process that does not damage the substrate 10 is possible. In particular, since the electron beam can inject a high density of electrons into specific locations in a short time during electrostatic injection, the physical impact on the substrate 10 can be minimized.

[0101] On the other hand, the substrate support base 300 is made of a plate-like material made of a dielectric or conductive material and imparts kinetic energy to the charge emitted from the grid 200 by a bias voltage supplied from the electrostatic adjustment control unit 400 so that the charge moves toward the substrate 10 at a preset density.

[0102] In this case, the substrate support base 300 is separated into multiple regions and functions as an electrostatic adjustment control unit 400. As shown in Figure 5, when the grid 200 is divided into regions and each region receives a voltage supply individually, the substrate support base 300 is divided into the same regions as the grid 200 and can receive a bias voltage supply such that each region of the grid 200 has the same polarity and the same voltage difference. Alternatively, only the grid 200 may be separated into multiple regions, while the substrate support base 200 does not need to be separated into multiple regions. The grid 200 and the substrate support base 200 may be separated so that they have different regional configurations. If the electrostatic adjustment levels differ for each region, the voltage applied to the grid 200 and the substrate support base 300 may have different voltage differences for each region. Accordingly, electrostatic injection and electrostatic removal processes can be performed simultaneously for each different region of the substrate 10.

[0103] Furthermore, a rotating part 310 for rotating the substrate support base 300 may be provided on the underside of the substrate support base 300, and the rotating part 310 rotates the substrate support base 300 at 1 to 30 RPM during the electrostatic adjustment process under the control of the electrostatic adjustment control unit 400.

[0104] Furthermore, in this embodiment, it is preferable that the distance between the grid 200 and the substrate 10 be set to within four times the free path distance of the process gas due to the internal environmental conditions of the vacuum chamber C.

[0105] At this time, the process gas free path distance (λ) can be calculated by the following mathematical formula 1.

[0106]

number

[0107] Here, K is the Boltzmann constant, T is the temperature, P is the pressure, and D is the process gas particle size.

[0108] The inventor conducted an electrostatic charging experiment using a 300mm silicon wafer with a turbo vacuum pump in a chamber measuring 330mm (diameter) x 150mm (height), which is the size of a typical semiconductor manufacturing apparatus. The results showed that when the distance between the grid 200 and the substrate 10 was set to deviate by a certain amount from the free path distance (10mm) and no bias power was supplied to the substrate support base 300, the voltage of the substrate 10 after 30 seconds using a 300mm silicon.SiO2 100nm deposited wafer under process conditions of pressure 30mtorr, 5sccm, distance between substrate and grid 100mm, and grid voltage +250V was +80volts, which is significantly different from the expected voltage of -10V.

[0109] In contrast, under the same process conditions as described above, when the distance between the substrate 10 and the grid 200 was set to 10 mm, which is the free path distance due to the process gas and pressure, and a bias voltage of 200 V was supplied to the substrate 10, the voltage on the substrate 10 was induced to the target -10 V. Through this, it was confirmed that the distance between the substrate 10 and the grid 200 and the bias voltage to the substrate support base 300 are important variables for electrostatic control on the substrate 10.

[0110] Furthermore, as shown in Figure 7, it was confirmed that even when the distance between the grid 200 and the substrate 10 was increased to 40 mm, which is four times the free path distance (10 mm) due to the process gas environment, the electrostatic injection and removal efficiency remained within a certain range. In Figure 7, (A) shows the experimental results for the electrostatic injection process, measured using semilab's QC 3000e system. It was confirmed that the same electrostatic voltage was maintained on the substrate 10 up to 40 mm, which is four times the free path distance (10 mm) due to the process gas environment, under the aforementioned process gas conditions.

[0111] In Figure 7, (B) shows the experimental results for the electrostatic discharge process. The results, measured using Semilab's QC 3000e system, show that under the aforementioned process gas conditions, static electricity is removed and the electrostatic voltage converges to "0" up to a distance of 40 mm between the grid 200 and the substrate 10, which is four times the free path distance (10 mm) due to the process gas environment. However, beyond that distance, static electricity is generated again.

[0112] This confirmed that the electrostatic injection and removal efficiency, depending on the free path distance of electrons and cations, is influenced by the difference in molecular size compared to the process gas, the selective extraction of electrons or cations at the top of the grid where ions and electrons are formed due to the grid voltage, the biased electric field of the substrate support, and the rapid vacuum evacuation effect.

[0113] Meanwhile, the electrostatic control control unit 400 controls the voltage supplied to each device so that ions or electrons are supplied to the substrate 10 at the desired density, thereby injecting electrostatic charge onto the substrate or removing electrostatic charge formed on the substrate 10. When supplying power to the grid 200 and the substrate support base 300, the electrostatic control control unit 400 adjusts the power level by adjusting the pulse period.

[0114] In electrostatic injection mode, the electrostatic adjustment control unit 400 supplies voltage such that the voltage difference between the grid 200 and the substrate support base 300 is more than twice, for example, more than 2.5 times. That is, the bias voltage applied to the substrate support base 300 is set to be more than 2.5 times higher than the voltage applied to the grid 200.

[0115] Furthermore, in the static electricity removal mode, the electrostatic control control unit 400 supplies voltage such that the voltage difference between the grid 200 and the substrate support base 300 is within a preset similar range, for example, the same.

[0116] Furthermore, the electrostatic control control unit 400 supplies power such as DC, DC Pulse, Reverse Pulse, AC, or RF to the grid 200 and the substrate support base 300. When supplying voltage in pulse mode, the voltage is supplied so that the grid 200 and the substrate support base 300 are synchronized with each other, thereby increasing the efficiency of electrostatic injection and removal.

[0117] Furthermore, since the density of ions and electrons can change due to changes in gas flow rate, vacuum level, and pumping speed within the vacuum chamber C, fine adjustment of the density is not possible with a DC power supply. However, the electrostatic control control unit 400 can prevent over-schooting from occurring on the substrate 10 by adjusting the pulse on / off period or polarity of the pulsed power supply applied to the grid 200 and the substrate support base 300 to adjust the electrostatic voltage more precisely.

[0118] In other words, when a bias voltage is supplied to the substrate support base 300, charged particles that have passed through the grid 200 are accelerated toward the substrate 10 by electrical attraction, and the charged particles accelerated toward the substrate 10 either charge the substrate 10 with static electricity or neutralize the static electricity formed on the substrate 10.

[0119] When electrostatic discharge is performed using electrons, the electrons move faster than positive ions, which can cause a negative (-) overcharge phenomenon, i.e., excessive static electricity charging, on the insulating thin film on the surface of the substrate 10. Therefore, the electrostatic discharge control unit 400 can supply a bias voltage to the substrate support base 300 in a stepped manner, increasing or decreasing it.

[0120] Furthermore, the electrostatic control control unit 400, when electrostatic charge is injected, adjusts the voltage level supplied to the grid 200 or substrate support base 300 in fixed time units (several seconds) or interrupts the voltage supply to set an automatic neutralization time at fixed intervals (intervals). This prevents surface overcharging without affecting the nano-sized ultrafine patterns formed on the surface of the substrate 10.

[0121]

[0122] Next, the operation of the electrostatic control device for the semiconductor process system having the above configuration will be explained with reference to Figure 8.

[0123] First, a substrate 10 with an insulating film formed on it is placed on the upper surface of a substrate support base 300 provided inside the vacuum chamber C. At this time, the insulating film formed on the surface of the substrate 10 is made of materials such as SiO2, Si3N4, Poly-Si, or Doped oxide, and its thickness can vary from 10 nm to 200 nm, either by utilizing plasma or atomic layer deposition.

[0124] Subsequently, the electrostatic control control unit 400 uses the mathematical formula 1 to calculate the process gas free path distance corresponding to the environmental conditions of the vacuum chamber (ST100). At this time, various information including temperature, pressure, and the size of the process gas molecules for calculating the process gas free path distance can be pre-input by the administrator.

[0125] Then, the electrostatic adjustment control unit 400 controls the distance adjustment unit 500 to adjust the position of at least one of the grid 200 or the substrate support base 300 upward or downward so that the distance between the grid 200 and the substrate 10 is within four times the process gas free path distance calculated in the ST100 step (ST200).

[0126] In the aforementioned state, the electrostatic control control unit 400 sets a vacuum environment by supplying process gas to the inside of the vacuum chamber C under preset environmental conditions.

[0127] Furthermore, the electrostatic control control unit 400 generates VUV through the charged particle generation unit 100, and generates charged particles such as cations and electrons through the reaction between the VUV and the process gas. Normally, the ion density due to VUV has many variations depending on the pressure, but it is approximately 10 3 ~10 4 / cm 2 On the other hand, the electrostatic capacitance required for the substrate 10 is approximately 10 8 ~10 9 cm 2 Therefore, electrostatic injection requires a lot of processing time. By additionally using a line beam-shaped ion beam utilizing plasma, the ion density can be increased to 10 6 ~10 7 cm 2 By forming a high layer, the process time can be reduced. As shown in Figure 4(A), when a line-shaped beam is emitted from the side of the vacuum chamber C, no chemically active species (radical) are generated inside the vacuum chamber C, so it is possible to perform the electrostatic injection process without damaging the substrate 10. This not only reduces the time the VUV is in contact with the insulating film by shortening the process time, thereby reducing changes in the insulating properties of the insulating film, but also improves productivity.

[0128] In the aforementioned state, when the administrator sets the electrostatic injection mode (ST300), the electrostatic adjustment control unit 400 applies a preset voltage to the grid 200 and the substrate support base 300, but supplies a bias voltage to the substrate support base 300 that is at least twice as high as the voltage applied to the grid 200 (ST400). At this time, the voltage applied to the grid 200 is set higher than the voltage applied to the grid 200 in the electrostatic removal mode, and a pulsed voltage can be supplied to at least one of the grid 200 and the substrate support base 300.

[0129] Furthermore, at the ST300 stage, the administrator sets the electrostatic voltage to be injected into the substrate 10. The electrostatic control control unit 400 then retrieves voltage information to be supplied to the grid 200 and substrate support base 300, which has been stored in advance to correspond to the electrostatic voltage requested by the administrator, and thereby supplies the corresponding power to the grid 200 and substrate support base 300.

[0130] In other words, with the distance between the grid 200 and the substrate support base 300 positioned to be within four times the free path distance of the process gas, the charged particles generated in the charged particle generation unit 100 selectively pass through the fine holes due to the voltage of the grid 200 and move toward the substrate 10, and the high voltage applied to the substrate support base 300 causes the charged particles to be released toward the substrate 10 at a higher density.

[0131] On the other hand, when the distance between the grid 200 and the substrate support base 300 is adjusted to within four times the process gas free path distance (ST200), and the electrostatic discharge mode is set by the administrator (ST500), the electrostatic control control unit 400 applies a preset voltage to the grid 200 and the substrate support base 300, but sets the voltage applied to the grid 200 and the bias voltage applied to the substrate support base 300 to be the same or within a similar range (ST600). Here, a pulsed voltage can be supplied to at least one of the grid 200 and the substrate support base 300.

[0132] At this time, when the administrator sets the electrostatic discharge voltage for the substrate 10 in the ST500 stage, the electrostatic control control unit 400 retrieves the voltage information to be supplied to the grid 200 and substrate support base 300, which has been stored in advance to correspond to the electrostatic discharge voltage requested by the administrator, and thereby supplies the corresponding power to the grid 200 and substrate support base 300.

[0133] In other words, the removal of static electricity from the substrate surface is the same as in the electrostatic injection process, but the static electricity embedded within the multilayer film of the substrate 10 is neutralized by 100nm to 200nm VUV beams, which have greater energy than the band gap of each insulating film, passing through the multilayer film and separating the static electricity into holes and electron pairs. Meanwhile, the static electricity on the upper part of the substrate 10 is neutralized using electrons and ions formed by VUV, electron beams, and ion beams. For example, the VUV energy in the 120nm wavelength band is 10.33eV, the silicon energy is 1.1eV, and the SiO2 energy is 9 to 10eV.

[0134] On the other hand, if the grid 200 and the substrate support base 300 have a multi-zone structure in the present invention, the electrostatic control control unit 400 can supply different voltages corresponding to electrostatic injection and electrostatic removal to each region of the grid 200 and the substrate support base 300, thereby controlling the injection of electrostatic charge to a certain part of the substrate 10 and the removal of electrostatic charge to other parts of the substrate 10.

Claims

1. In an electrostatic control device for a semiconductor process system that injects electrostatic charge onto a substrate placed in a vacuum chamber or removes electrostatic charge formed on a substrate, A charged particle generation unit is located on the upper side inside the vacuum chamber, and generates VUV (Vacuum Ultraviolet Ray), which reacts with the process gas inside the vacuum chamber to generate charged particles containing cations and electrons. A grid is provided below the charged particle generation unit and has numerous holes that allow charged particles to pass selectively downwards by an input voltage. A substrate support base is positioned below the grid, with the substrate positioned on its upper surface, and guides charged particles that have passed through the grid to the substrate side at a preset density by an input bias voltage, and The system includes an electrostatic adjustment control unit that supplies a pulsed voltage to at least one of the grid and the substrate support base to adjust the electrostatic charge of the substrate, An electrostatic control device for a semiconductor process system, wherein the grid and the substrate support are arranged to have a separation distance of no more than four times the free path distance of the process gas, depending on the environmental conditions of the vacuum chamber.

2. The electrostatic control control unit is The electrostatic control device for a semiconductor process system according to claim 1, wherein in electrostatic injection mode, a bias voltage applied to the substrate support is applied to be at least a certain level higher than the voltage applied to the grid, and in electrostatic removal mode, the voltage applied to the grid and the bias voltage applied to the substrate support are applied to be within a preset similar range.

3. The electrostatic control control unit is The electrostatic control device for a semiconductor process system according to claim 2, which adjusts the voltage level by adjusting the pulse period applied to the grid and substrate support base.

4. The charged particle generation unit is, An electrostatic control device for a semiconductor process system according to claim 1, comprising one or more VUV lamps that emit VUV light.

5. Below the aforementioned VUV lamp, The electrostatic control device for a semiconductor process system according to claim 4, further comprising a beam generator that emits a line-shaped ion beam through the side of a vacuum chamber, thereby simultaneously generating charged particles from the reaction of VUV with a process gas and charged particles from the reaction of an ion beam with a process gas to increase the charged particle density.

6. The electrostatic control device for a semiconductor process system according to claim 1, characterized in that the charged particle generation unit comprises a plasma generator that generates plasma and a separation plate below the plasma generator that transmits only VUV light, and charged particles are generated by the reaction of VUV light generated in the plasma generator with a process gas.

7. The electrostatic control device for a semiconductor process system according to claim 6, wherein the plasma generator includes at least one microplasma device that generates plasma using a power supply in the range of 10 to 200 W in a vacuum environment in which the volume of the vacuum chamber is in the range of 500 to 1000 cc.

8. The electrostatic control control unit is An electrostatic control device for a semiconductor process system according to claim 7, which adjusts the electrostatic charge of a substrate by adjusting at least one of the type of process gas injected into the vacuum chamber of a microplasma apparatus or the plasma power supply.

9. The aforementioned plasma generator includes a number of microplasma devices, The electrostatic control control unit adjusts the electrostatic charge of the substrate by individually controlling the type of process gas injected into the vacuum chamber of each microplasma apparatus or the plasma power supply, as described in claim 7 or claim 8.

10. The aforementioned plasma generator includes a number of microplasma devices, The separation plates are arranged so as to correspond one-to-one with each microplasma device. The electrostatic control control unit adjusts the electrostatic charge of the substrate by individually controlling the type of process gas injected into the vacuum chamber of each microplasma apparatus or the plasma power supply, The electrostatic control device for a semiconductor process system according to claim 7 or claim 8, wherein each of the separation plates is further provided with lenses having different divergence angles.

11. The electrostatic control device for a semiconductor process system according to claim 1, wherein the grid and substrate support base are of a multi-zone type in which a number of regions are electrically isolated, and the electrostatic control control unit supplies voltages of different levels individually to each region of the grid and substrate support base.

12. The electrostatic control device for a semiconductor process system according to claim 11, wherein the electrostatic control control unit supplies voltage to the grid and the substrate support base so as to inject static electricity into a certain part of the substrate and remove static electricity from other parts of the substrate.

13. The grid includes an upper grid and a lower grid positioned below the upper grid. The electrostatic control device for a semiconductor process system according to claim 1, wherein the electrostatic control control unit supplies voltages of different levels to the upper grid and the lower grid.

14. The diameter of the holes formed in the lower grid is set to be different from the diameter of the holes formed in the upper grid. The electrostatic control control unit applies a first level negative voltage to the lower grid to guide ions between the lower grid and the substrate through holes in the lower grid to the upper grid side, and then applies a negative voltage with an absolute value greater than the first level to the upper grid to cause the ions that have flowed in through the lower grid to collide with the lower surface of the upper grid and generate secondary electrons, thereby controlling the emission of electrons with a higher density than when no negative voltage with an absolute value greater than the first level is applied to the upper grid to the substrate side through holes in the lower grid, as described in claim 13.

15. The electrostatic control device for a semiconductor process system according to any one of claims 1, 11, or 13, wherein the hole aperture ratio in the center of the grid is formed to be higher than that of the surrounding area.

16. The system is further equipped with a distance adjustment unit that moves the grid and the substrate support base up and down within the vacuum chamber. The electrostatic control control unit controls a distance adjustment unit to change the position of at least one of the grid or substrate support to the upper or lower side based on the process gas free path distance calculated by the environmental conditions of the vacuum chamber, as described in claim 1.

17. The electrostatic control device for a semiconductor process system according to claim 1, wherein the surface of the grid is coated or sputtered with a film containing a carbon component, which includes at least one selected from the group consisting of carbon, CNT, and glassy carbon, in order to prevent the generation of an arc.

18. On the surface of the grid, silicon oxide (SiO ２ ), aluminum oxide (Al ２ O ３ ), silicon nitride (Si ３ N ４ The electrostatic control device for a semiconductor process system according to claim 1, wherein one of the oxide-based thin films is coated or sputtered to prevent the generation of an arc.

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