RU2205469C1 - Method for producing three-dimensional conducting structure - Google Patents

Abstract

FIELD: microelectronics; midget devices, integrated circuits, memory devices, and optical members. SUBSTANCE: method using only one mask for producing three- dimensional multilayer conducting structure involves irradiation of blank of two- or many-atom dielectrics by accelerated particle flow ensuring selective removal of nonmetal atoms from blank material through single mask that bears pattern in the form of through and blind holes of different height, this being followed by processing the blank through this mask with nonmetal ion flow to provide for recovery of insulating properties of blank material in desired areas; mask thickness should be greater than projective transit time of accelerated particles therein. EFFECT: facilitated manufacture. 7 cl, 1 dwg, 2 tbl

Description

 The invention relates to a technology for creating complex conductive structures or structures with other properties using a stream of accelerated particles and can be used in microelectronics to create ultra-miniature devices, integrated circuits, storage devices and optical elements.

 A known method of creating elements of a conductive structure on dielectric layers (see the description of the application of Germany 19503178, H 01 L 21/60, 1997). The method includes the destruction of the oxide layer on the surface of aluminum and the deposition of hardening material. For this, the reinforcing material located on the substrate is transferred by means of high-power radiation to the surface of aluminum, and before that, the oxide layer is destroyed under the action of high-power radiation and excited particles of the reinforcing material. Using a deflecting device for a beam, a layered metallized structure with the required geometry of the pattern is created on the surface to be treated. The disadvantage of this method is the inability to obtain a structure with the dimensions of individual elements of several nanometers. In addition, the use of the method is limited since it is applicable only to aluminum substrates.

 A known method of forming a pattern using an electron beam (see the description of Japanese application 6038411, H 01 L 21/302, 1994). The method consists in placing a system for focusing an electron beam in a reaction chamber, creating an atmosphere from excited reactive particles, and placing a plate to be processed on the holder. Using an electron beam that carries information associated with a particular pattern, the plate is irradiated and, as a result of a change in its substance under the influence of the electron beam and reactive particles, a specific pattern is formed on the plate. The disadvantage of this method is the complexity of its implementation, which consists in the formation in the chamber of the atmosphere of reactive particles with the same reactivity in order to ensure reproducibility of the process in all areas of the figure, which requires complex control equipment. In addition, the known method does not allow to obtain image elements that make up the picture, with dimensions of several nanometers.

 A known method of obtaining a conductive pattern of metal compounds by direct conversion of the processed material under the influence of a modulated radiation beam (see the description of US patent 5459098, H 01 L 21/306, NKI 437-173, 1995). The method includes depositing an insulating layer of metal nitride on a substrate and scanning it with a modulated laser beam. Under the influence of laser radiation, a metal nitride film decomposes into a metal component and a gaseous one. During the implementation of the method, the gas is removed, and the metal forming the conductive pattern remains on the dielectric substrate. The disadvantage of this method is the low resolution of the created pattern (conductive structure), which does not allow to obtain individual elements of the structure with a size of several nanometers.

 Closest to the claimed in its technical essence is a method of obtaining a conductive structure, known from the description to RU 2129320, H 01 L 21/263, 04/20/99 (see patent analogue US 6218278, NKI 438/597, 2001). A method of forming a conductive structure includes applying a layer of a material that is converted to a conductive material by radiation on a substrate and processing it with a modulated beam from a source of charged particles. Under the influence of accelerated particles in the processed material, selective removal of non-metal atoms occurs, which leads to the conversion of the dielectric into a metal in the treated area. The method allows to form layer by layer on a substrate and thus obtain volumetric conductive structures, individual layers of which, if necessary, can be separated by dielectric layers. In this case, the role of the substrate will be played by the previous layer with the structure (pattern) made in it (or on it).

 The disadvantage of this method is that in the manufacture of a three-dimensional (multilayer) structure for the formation of a pattern through a pattern in each of the subsequent layers, it is necessary to use separate patterns according to the number of layers. Given the small size of the structural elements, the problem of installing templates strictly in the same place (combining templates) causes certain difficulties. The template installation mechanism should ensure their positioning with an accuracy of several nanometers.

 The invention is aimed at simplifying the technology by using the same template to form the entire multi-level volumetric structure.

 This result is achieved by the fact that the method of obtaining a volumetric conductive multilevel structure is carried out by irradiating a workpiece from diatomic or polyatomic dielectrics with a stream of accelerated particles, which selectively remove non-metal atoms in the workpiece material, through one template in which the pattern is made in through and / or through holes of various depths, and subsequent processing of the workpiece through the same template with a stream of non-metal ions, ensuring the restoration of the dielectric properties of the material iala preform in the desired areas, the pattern is made with a thickness greater than the length of the projected range used therein accelerated particles.

 The indicated result is also achieved by the fact that protons are used as accelerated particles.

 The indicated result is also achieved by the fact that helium ions are used as accelerated particles.

 The indicated result is also achieved by the fact that hydrogen or helium atoms are used as accelerated particles.

 The indicated result is also achieved by the fact that polyatomic compounds of metals with oxygen, hydrogen, nitrogen, and fluorine are used as the workpiece material.

 The specified result is also achieved by the fact that as a metal or a semiconductor included in the polyatomic compound of the workpiece material, elements with an atomic number equal to or greater than 12 are used.

 The indicated result is also achieved by the fact that the metals included in the polyatomic compounds are magnesium, copper, aluminum, iron, tungsten, cobalt, nickel, germanium, erbium, gallium, silicon, calcium, tantalum, titanium, vanadium, and arsenic.

 The indicated result is also achieved by using a layer of workpiece material with a thickness of 2 to 150 nm.

 Performing a template with a pattern in the form of through holes or through holes, but with different depths, allows using one pattern for the manufacture of conductive patterns in different layers and / or providing interlayer connections and thereby solve the problem of combining patterns of different layers involved in the formation of the volumetric structure. In the well-known technical solutions, for this, several templates had to be used (for each of the layers its own).

 Indeed, if we take and place a plate of variable thickness between the source of accelerated particles and the material being processed, then the particle beam weakened in different ways, depending on the plate thickness, will reach the material being processed. Accordingly, this beam will penetrate to a different depth into the processed material and, accordingly, the dielectric properties of the processed material will be converted to conductive at different depths. Therefore, depending on the depth of the hole in the template, “metallization” will occur at different depths in the areas of the processed material located under these holes. Creating through holes in the template allows you to solve two problems at once. On the one hand, to provide “metallization” to a greater depth compared to what non-through holes in the template provide, and on the other hand, an ion beam will freely pass through these through holes to partially restore the dielectric properties in the areas of the processed material under these holes, which expands the formation of complex conductive structures.

 In addition, through these through holes, by varying the parameters of the conditions of irradiation with accelerated particles, it is possible to form repeatedly alternating layers of "metal - dielectric - metal - dielectric --.........".

 Naturally, in order for sections with the initial material properties to be preserved in the formed structure, it is necessary that the thickness of the template provides a complete delay in the particle flow in the required places. To do this, it must be greater than the projective path length of the accelerated particles used for the template material.

 The use of accelerated particles for irradiation of beams allows the conversion of the conductive properties of the workpiece material by transferring from a dielectric state to a metallic or more conductive one, which is a consequence of the interaction of accelerated particles with the workpiece material.

 As it was established experimentally, beams of protons, helium ions, as well as hydrogen and helium atoms can be used as accelerated particles that ensure the conversion of the conductive properties of the workpiece material.

 The workpiece material can be selected from among known dielectrics - oxides, hydrides, nitrides and fluorides of metals or semiconductors. In these materials, under the influence of accelerated particles, the chemical composition of the material changes, namely, only metal or semiconductor atoms remain in the irradiated areas of these materials due to the selective removal of non-metal atoms - oxygen, hydrogen, nitrogen or fluorine.

 Moreover, it was experimentally established that the effective removal of non-metal atoms occurs only in compounds in which there are semiconductor or metal atoms with an atomic number equal to or greater than 12.

 For each type of particle and the material they process, the processing regimes are experimentally selected — the energy of the particles in the beam, the exposure time, etc., as well as the pairs “type of particles - type of material” that provide the most efficient conversion of properties due to the selective removal of atoms of the desired type.

 When using a blank layer thickness of less than 2 nm, violations of its continuity may occur, which makes it impossible to form a bulk structure. It is impractical to produce a workpiece layer of more than 150 nm, since for the majority of materials used that transform their properties under the influence of a stream of accelerated particles, the projective path of the particles does not exceed the specified value.

 By the proposed method, it is possible to form not only conductive structures in the volume of the dielectric, but also magnetic structures in the volume of non-magnetic material or a structure of non-magnetic material in the volume of magnetic, as well as the formation of volumetric optical waveguides. In the latter case, in the volume of a transparent dielectric (most oxides are transparent at the thicknesses used in microstructures), opaque or less transparent "partitions" are formed from the material of the initial dielectric of the workpiece converted to metal.

 The essence of the proposed method is illustrated by examples of the implementation of the conductive structure and the drawing (a, b, c, d), which schematically shows the individual stages of the process.

 Example 1. In the General case, the method of manufacturing a bulk conductive structure is as follows.

 On a substrate 1, which can be made of silicon, aluminum or silicon dioxide, a layer of material of the workpiece 2 of the required thickness is applied. Oxides, hydrides, nitrides or fluorides of metals or semiconductors are used as the workpiece material.

 Then a layer of the workpiece material is irradiated with a beam of accelerated particles, which are used as protons, hydrogen atoms, helium atoms and ions. Irradiation can be carried out through a template 3 with a given pattern, applied directly to the workpiece, in which through and / or through holes are made of various depths.

 Under the influence of a stream of 4 accelerated particles in the material being processed, its initial dielectric properties in the irradiated sections 5 are converted to conductive ones due to the selective removal of non-metal atoms. In this case, depending on the depth of the hole, the conversion of these properties takes place at different depths in the workpiece material (Fig. "C"). Then, after irradiation with accelerated particles, the workpiece is processed through the same template with a stream of ions, which ensures the restoration of removed atoms, as a result of which the dielectric properties are restored in the sites treated with ions (Fig. “C”). Moreover, not only ions of distant atoms, but also ions of a different kind can be used as such ions. For example, when processing a workpiece made of aluminum hydride or copper hydride or gallium hydride under the influence of a stream of accelerated particles, hydrogen atoms will be removed, and the dielectric properties in the required areas can be restored by exposing the workpiece to a stream of oxygen ions, and in particular cases even it is enough to remove the workpiece from the vacuum unit and leave it in the air without removing the template. With a sufficiently high chemical activity of the metal of the workpiece, this will already be enough to restore the dielectric properties. For example, aluminum is very rapidly oxidized by atmospheric oxygen, turning into alumina having dielectric properties. After completion of the formation process, the template 4 is removed in a known manner (chemical etching, reactive etching, mechanical removal, etc.) (see Fig. "D"). Thus, using a single template, a three-dimensional conductive multilevel structure can be formed.

Example 2. The method was implemented according to the general scheme using protons as particles for irradiating the workpiece material. For its implementation, in the vacuum chamber of the technological installation, several substrates of monocrystalline silicon with a size of 5 • 5 • 0.4 mm are installed on a substrate holder, on which a layer of the workpiece material of the required thickness is applied. The vacuum chamber was first pumped out by a forevacuum and turbomolecular pump, and then by an ion pump to a pressure of 10 ^-9 torr. As a source of protons, any of a number of known ones can be used, for example, high-frequency. A template was installed in the path of the ion beam, made of known resistes using the known technology, 0.3 μm thick and 50 • 50 mm in size, with rows of holes of various depths of 100 nm in diameter and through-cuts in the form of lines 100 nm wide and 3 mm long, made in it and a distance between them of 300 nm. In another case, a mask made using well-known technologies (for example, photolithography or electronic lithography) was used as such a template. After pumping, the proton source was switched on and its operating mode was established, which provided the conversion of the optical properties of the workpiece material. The modes for each type of material and the thickness of the workpiece were selected experimentally, some of the parameters that ensure the achievement of the result are shown in table 1.

 After processing of the workpiece with protons was completed, it was treated with a stream of ions, which ensured the restoration of the removed atoms. In most cases, a beam of oxygen ions was used for this, and sometimes nitrogen ions or fluorine ions were used.

 Example 3. The method was carried out as described in example 2, but using helium ions (and the corresponding ion source). Some parameters of the implementation of the method are shown in table 2.

 Example 4. The method was carried out as described in example 2, but for irradiation, beams of accelerated hydrogen or helium atoms were used, which were obtained by neutralizing beams of accelerated ions (protons and helium ions) using electrons.

 Technological process parameters for hydrogen atoms and helium atoms are similar to the conditions given in tables 1 and 2, because atomic beams were obtained by neutralizing electron beams of helium and hydrogen ions.

Claims (7)

 1. A method of obtaining a volumetric conductive multilevel structure by irradiating a preform from diatomic or polyatomic dielectrics with a stream of accelerated particles, which selectively remove non-metal atoms in the workpiece material through one template in which a pattern is made in the form of through and through holes of various depths and subsequent processing of the workpiece through the same template, the flow of non-metal ions, ensuring the restoration of the dielectric properties of the workpiece material in the required areas, while the template is made they are revealed with a thickness exceeding the projective path length of the used accelerated particles in it.  2. The method according to p. 1, characterized in that protons are used as accelerated particles.  3. The method according to claim 1, characterized in that helium ions are used as accelerated particles.  4. The method according to p. 1, characterized in that the accelerated particles use atoms of hydrogen or helium.  5. The method according to p. 1, characterized in that as the material of the workpiece using polyatomic compounds of metals with oxygen, hydrogen, nitrogen, fluorine.  6. The method according to p. 5, characterized in that as the metal or semiconductor included in the polyatomic compound of the workpiece material, elements with an atomic number equal to or greater than 12 are used.  7. The method according to p. 1, characterized in that they use a layer of workpiece material with a thickness of 2 to 150 nm.

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