RU2516612C1 - Canal matrix and method of its production - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: in canal matrix in addition to plate of monocrystalline silicon of hole type with opened canals and deposited material on frontal surface of this plate intermediate dielectric layer of silicon dioxide is created and metal film is applied on the frontal surface of plate with opened canals which have specified diametrical dimension.

EFFECT: improvement of exploitation characteristics by introduction of electrodes and application of electrokinetic and electrophysiological control, which makes it possible to extend nomenclature of membrane equipment products based on biocompatible and highly technological silicon.

8 cl, 8 dwg

Description

The invention relates primarily to the field of membrane nanotechnology, the industry of nanosystems and materials, molecular biology, genetics and cytology and can be used in the production of micro- and nanofluidic filters for separation and concentration of nanomaterials, in the manufacture of biosensor devices for medical diagnostic devices.

Known channel matrix described in US patent No. 5997713, S.R. Beetz, R.W. Boerstler, J. Steinbeck, D.R. Winn, IPC C25D 5/34, 1999. The channel matrix is a hole-type single-crystal silicon wafer with open, through channels with micrometer transverse dimensions.

The disadvantage of the channel matrix is the presence of channels only in the micrometer range of transverse dimensions, which does not allow it to be used as a filtering device for nanomaterials.

A known method of manufacturing channel matrices (US patent No. 5997713, S.P. Beetz, RW Boerstler, J. Steinbeck, DR Winn, IPC C25D 5/34, 1999), including the creation of ordered spaced seed pits on the front surface of single-crystal silicon hole type , the formation of an ohmic contact on the back surface of the plate, anode etching in a solution of electrolytes containing hydrogen and fluorine ions, and opening of channels.

The main disadvantage of the described method is the fact that as a result of only anodic etching create a silicon matrix having open channels with micrometer transverse dimensions. Due to this structural factor, the filtering ability of the resulting microchannel matrices does not allow the separation and concentration of nanometer-sized substances.

Of the known channel matrices, the channel matrix described in the patent of the Russian Federation No. 2428763 "Method for obtaining the channel matrix" of the authors: Romanov S.I., Vandysheva N.V., Semenova O.I., Kosolobov S.S., IPC: H01L 21/00, B82B 3/00, published on 09/10/2011 in Bul. Number 25. The channel matrix consists of a hole-type single-crystal silicon wafer with open, through channels and a material of silicon and silicon oxides deposited on its frontal surface, which determines a given micro- and nanometer transverse size of the matrix channels.

The main disadvantage of the known matrix is the lack of a structural element that allows you to effectively manage the transport of colloidal solutions of ultradispersed substances of organic and inorganic origin when they are filtered and concentrated.

Of the known methods for manufacturing channel matrices, the closest to the claimed one is the method presented in RF patent No. 2428763 "Method for producing a channel matrix" of the authors: Romanov S.I., Vandysheva N.V., Semenova O.I., Kosolobov S.S. , IPC: H01L 21/00, B82B 3/00, published on 09/10/2011 in Bull. Number 25. According to this method, a channel matrix is obtained by creating ordered seed pits on the front surface of a hole-type single crystal silicon wafer, forming an ohmic contact on the back surface of the wafer, anodic etching in an electrolyte solution containing hydrogen and fluorine ions, opening channels and depositing materials (silicon and oxides silicon) on the front surface of the plate with open channels to obtain a given transverse size of the channels.

The main disadvantage of this method is the absence in the manufacture of a channel matrix of an operation involving the creation of an element by which the processes of filtering, concentration and detection of substances in colloidal solutions become effectively controlled. The noted drawback complicates the widespread use of channel matrices obtained by the existing method.

The technical result of the invention is to improve the operational characteristics of channel matrices by introducing a metal film into the matrix structure.

The technical result is achieved in that in a channel matrix consisting of hole-type single-crystal silicon wafer with open channels, deposited material on the front surface of hole-type single-crystal silicon wafer with open channels, and a dielectric layer of dioxide is created on the surface of hole-type single-crystal silicon wafer silicon, and on the front surface of a plate of single-crystal silicon of a hole type with open channels having given transverse size, a metal film is applied.

In the channel matrix, a dielectric layer of silicon dioxide is created between the deposited material and the hole-type single-crystal silicon wafer.

In the channel matrix, a dielectric film is deposited on the surface of the metal film.

The technical result is achieved by the fact that in the method of manufacturing the channel matrix, which includes creating ordered seed pits on the front surface of the hole type single crystal silicon wafer, forming an ohmic contact on the back surface of the hole type single crystal silicon wafer, anode etching in an electrolyte solution containing hydrogen and fluorine ions , opening of channels and deposition of materials on the front surface of a hole single-crystal silicon wafer type with open channels until a predetermined lateral size of the channels is obtained, and after opening the channels, high-temperature oxidation of hole-type single-crystal silicon wafers with open channels is performed in a gaseous medium, and then, on the front surface of a hole-type single-crystal silicon wafer with open channels having a predetermined transverse size, metal film deposition.

In the method, high-temperature oxidation in a gaseous medium of a hole-type single-crystal silicon wafer with open channels is performed at a temperature of 800-1000 ° C.

In the method, after the materials are deposited on the front surface of the hole-type single-crystal silicon wafer with open channels until a predetermined lateral size of the channels is obtained, the dielectric layer of silicon dioxide not covered by the deposited material is removed.

In the method, a metal film of gold or aluminum is deposited onto the front surface of a hole-type single-crystal silicon wafer with open channels having a predetermined lateral size.

In the method, a dielectric film is deposited onto a surface of a metal film.

The invention is illustrated by the following description and the accompanying figures.

Figure 1 presents the proposed design of channel matrices with a dielectric layer of silicon dioxide located both over the entire surface of the channels, figa and figb, and only under the deposited material, figv and fig.1g, as well as with a dielectric film on the surface of a metal film, figb and figg.

Figure 2 shows the manufacturing circuit of the channel matrix by the proposed method: Figure 2a is the initial plate of single-crystal silicon of the hole type, Figure 2b is the plate of single-crystal silicon with ordered seed holes on the front surface, Figure 2c is the plate of single-crystal silicon with seed holes and ohmic contact on the back surface, FIG. 2d - a plate of monocrystalline silicon with open channels, FIG. 2d - a plate of monocrystalline silicon with open channels, FIG. 2e - plas the thickness of monocrystalline silicon with open channels and a dielectric layer of silicon dioxide on the surface, FIG. 2g is a plate of monocrystalline silicon with open channels having a predetermined transverse size, FIG. 2z is a plate of monocrystalline silicon with a predetermined transverse size of channels and a metal film on the front surface, FIG. .2i - a plate of single-crystal silicon with a dielectric film on the surface of a metal film, Fig. 2k - a plate of single-crystal silicon with a given transverse size 2 a channel of the channel and a dielectric layer of silicon dioxide under the deposited material, FIG. 2 l is a plate of single crystal silicon with a predetermined lateral size of the channels, a dielectric layer of silicon dioxide under the deposited material and a metal film on the front surface, FIG. 2 m is a plate of single crystal silicon with a dielectric layer of silicon dioxide under the deposited material and the dielectric film on the surface of the metal film.

Figure 1 and figure 2 shows the elements: 1 - a plate of single-crystal silicon hole type with open channels, 2 - a dielectric layer of silicon dioxide, 3 - deposited material on the front surface of the silicon wafer with open channels, 4 - a metal film on the front surface of the plate silicon with open channels having a given transverse channel size, 5 - dielectric film on the surface of the metal film, 6 - the initial plate of single-crystal silicon of the hole type, 7 - seed pits, orderly located on the front surface of the plate, 8 - monolithic part of the plate, 9 - ohmic contact on the back surface of the plate, 10 - unopened channel, 11 - open channel, 12 - channel with a given transverse size.

In Fig.3 shows an electron microscopic image of the ordered seed pits on the front surface of a plate of single-crystal silicon hole type, in Fig.2b element 7.

Figure 4 presents electron-microscopic images of the front surface, figa, and a cross section, figb, plate of single-crystal silicon with unopened channels, on fig.2g elements 8 and 10.

Figure 5 shows the electron microscopic image of the front surface of the wafer of single-crystal silicon with open channels, in Fig.2d elements 1 and 11.

Figure 6 shows the electron microscopic images of the front surfaces of wafers of single-crystal silicon with open channels having a predetermined transverse size, in Fig.2g elements 3 and 12.

7 shows electron microscopic images of single-crystal silicon wafers with a given transverse channel size, element 12 in FIG. 2g, and a metal film on the front surface, element 4 in FIG. 1 a, FIG. 1 c, FIG. 2 c and FIG. 2 l .

On Fig presents optical images of channel matrices made by the claimed method, from the front surface, figa, and from the back surface (microchannel matrix base), figb, with elements 1, 2, 3 and 4 in accordance with designations in figure 1, figs and figl.

The essence of the invention lies in the fact that the design of the channel matrix includes additional elements that are absent in the structure of the known channel matrix, namely, a dielectric layer of silicon dioxide covering the surface of the silicon wafer with open channels (element 2 in FIG. 1) and a metal film on the front surface of the silicon wafer with a given transverse size of the channels (element 4 in FIG. 1), covered or not by a dielectric film (element 5 in FIG. 1 b and FIG. 1 d).

As a result of this technical solution, the inventive channel matrix acquires a new quality of being an active and controllable device for filtering, concentrating and detecting substances dispersed in a liquid medium through the use of an in-channel electric field. A metal film (element 4 in FIG. 1 and FIG. 2z, FIG. 2i, FIG. 2l and FIG. 2m) penetrating the channel with a predetermined lateral size (element 12 in FIG. 2g) serves as an electrode, the electric potential which creates an electric field both at the entrance to the channel and partially in the channel itself. By means of the field effect, it becomes possible to control the passage of various types of particles, differing in size and charge, through the channel matrix, which was impossible in the case of the known channel matrix.

The dielectric layer of silicon dioxide (element 2 in FIG. 1 and FIG. 2e, FIG. 2g, FIG. 2z, FIG. 2i, FIG. 2k, FIG. 2l, FIG. 2m) electrically insulates the metal film (element 4 in FIG. 1 and fig.2z, fig.2i, fig.2l and fig.2m) from the silicon wafer with open channels (element 1 in fig.1 and fig.2d, fig.2e, fig.2zh, fig.2z, fig. 2i, fig.2k, fig.2l, fig.2m). The removal of a layer of silicon dioxide with the surface of the channel matrix not covered by the deposited material (Fig. 1c, Fig. 1d and Fig. 2k) is carried out in order to use a silicon wafer with open channels (element 1 in Fig. 1 and Fig. 2e, fig. 2e, fig.2zh, fig.2z, fig.2i, fig.2k, fig.2l, fig.2m) as an additional electrode for creating an electric field inside the microchannel base of the channel matrix. The dielectric film on the surface of the metal film (element 5 in fig.1b, fig.1d and fig.2i, fig.2m) is designed to isolate the latter (element 4 in the same figures) from contact with a liquid medium.

The essence of the method of manufacturing the channel matrix is that in the manufacture of the channel matrix after anodic etching and opening the channels, an additional high-temperature oxidation operation is carried out, and then after the materials are deposited, a second additional metal film deposition operation is performed. Both of these operations were not used in the known method. After the well-known method, on the front surface of the initial wafer of single-crystal silicon of the hole type (Fig. 2a, element 6) using photolithography on a layer of silicon dioxide and chemical etching of silicon in the dielectric windows, ordered seed pits are created (Fig. 2b, element 7), an ohmic contact is formed on the back surface of a single-crystal silicon wafer (Fig.2c element 9), anodic etching of the channels (Fig.2d element 10) is performed and their opening is performed (Fig.2d element 11), a monocri plate open silicon channels are subjected to high-temperature oxidation in a gaseous medium (Fig. 2e element 2). Further, after the deposition of materials on the front surface of a single-crystal silicon wafer with open channels (FIG. 2g element 3) is performed in the known method, a metal film is deposited on this surface (FIG. 2z element 4) and, in some cases, a dielectric film ( Fig.2i and Fig.2m element 5).

High-temperature oxidation of the silicon microchannel base of the channel matrix (element 1 in FIG. 2d, FIG. 2e, FIG. 2g, FIG. 2z, FIG. 2i, FIG. 2k, FIG. 2l, FIG. 2m) at temperatures of 800-1000 ° C performed in order to reliably electrically isolate it with a dielectric layer of silicon dioxide (element 2 in fig.2e, fig.2zh, fig.2z, fig.2i, fig.2k, fig.2l, fig.2m) from the electrode (element 4 Fig.2z, Fig.2i, Fig.2l, Fig.2m) formed by the deposition of a metal film. The latter cannot be done in a known manner. At oxidation temperatures below 800 ° C, the electrical insulation is not sufficiently reliable, while at temperatures above 1000 ° C, mechanical deformation of the matrix is possible.

Removing the dielectric layer of silicon dioxide from the open (without deposited material) surface of the plate with a given transverse size of the channels (Fig.2k) is carried out in order to use, in fact, silicon itself as an additional electrode element, which is impossible to obtain in a known manner.

The deposition of metal gold films is designed to work with bioorganic substances, while aluminum films - with inorganic materials.

The deposition of a dielectric film, for example, oxides or silicon nitrides, on a metal electrode is carried out to protect it, for example, aluminum, from corrosion.

Thus, the inventive channel matrix and the method of its manufacture make it possible to create micro- and nanofluidic devices with high performance characteristics in relation to the processes of filtering, concentration and detection of substances dispersed in liquids. The basis of all this is controlled electrokinetic transport of colloidal solutions through the inventive matrix and electrophysical registration of chemical reactions in its interelectrode space.

Example 1

1. A hole-type single-crystal silicon wafer with a resistivity of 40 Ohm · cm and an orientation of (100) is subjected to thermal oxidation, photolithography on a silicon dioxide layer on the front surface, and chemical etching of silicon in dielectric windows in an aqueous solution of 20% KOH at a temperature of 60 ° C in within 1 hour. In this case, seed pyramidal pits are formed with dimensions in the base of 2.4 × 2.4 μm ² , separated by walls with a thickness of 1.6 μm (Fig.2b and Fig.3 element 7).

2. The formation of ohmic contact on the back surface of a hole-type single-crystal silicon wafer with seed pits is carried out by aluminum deposition and annealing at a temperature of 450 ° C in an argon atmosphere for 15 minutes (Fig. 2c, element 9).

3. Anode etching of the channel matrix is carried out in the mode of a regularly varying DC density in the range of 14-44 mA / cm ² in an electrolytic solution

NH ₄ F (40%): HCl (36.5%): H ₂ O: neonol = 2.5: 1: 6.5: 0.025

on an area of 0.8 cm ² for 100 minutes (fig.2g, figa and fig.4b element 10). On figb. monolithic part of a single-crystal silicon wafer is presented - element 8.

4. The opening of the channels is carried out by grinding / polishing the back surface of a single-crystal silicon wafer (Fig.2d and Fig. 5 element 1) using micropowder of synthetic diamonds mixed in a solution of glycerol and isopropyl alcohol. The result is a channel matrix with a thickness of 145 μm with a transverse size of the opened channels in the near-surface region of the frontal surface equal to ~ 2.9 μm (Fig. 2e and Fig. 5 element 11).

5. High-temperature oxidation of a single-crystal silicon wafer with open channels is carried out at 1000 ° C in H ₂ O vapors for 1 hour. The result is a dielectric layer of silicon dioxide with a thickness of 100-120 nm.

6. Plasma-chemical deposition of silicon on the front surface of the channel matrix (Fig.6a element 3) is carried out from the interelectrode radio frequency glow discharge of a gas mixture of monosilane SiH ₄ and argon at a frequency of 40 MHz, pressure ~ 0.2 mm Hg at a temperature of 250 ° C for 60 minutes. Receive channels with an average transverse size equal to ~ 2.6 μm (fig.2g and figa element 12).

7. The deposition of a metal film of gold with a thickness of ~ 100 nm is performed in an average vacuum of ~ 5 · 10 ^-6 mm RT.article. by thermal evaporation of metal from a tungsten boat (fig.2z and figa element 4).

The result is a channel matrix with the structure shown in figa and Fig, with a transverse channel size of 2.6 μm. On figa shows a channel with a given transverse size - element 12, and Fig.8 (optical image of the channel matrix) shows the elements: 1 - a plate of single-crystal silicon hole type with open channels, 2 - a dielectric layer of silicon dioxide, 3 - deposited material on the front surface of a single-crystal silicon wafer with open channels, 4 - a metal film on the front surface of a single-crystal silicon wafer with open channels having a predetermined lateral size of the channels.

Example 2

1. A hole-type single-crystal silicon wafer with a resistivity of 40 Ohm · cm and an orientation of (100) is subjected to thermal oxidation, photolithography on a silicon dioxide layer on the front surface, and chemical etching of silicon in dielectric windows in an aqueous solution of 20% KOH at a temperature of 60 ° C in within 1 hour. In this case, seed pyramidal pits are formed with dimensions in the base of 2.4 × 2.4 μm ² , separated by walls with a thickness of 1.6 μm (Fig.2b and Fig.3 element 7).

2. The formation of ohmic contact on the back surface of a hole-type single-crystal silicon wafer with seed pits is carried out by aluminum deposition and annealing at a temperature of 450 ° C in an argon atmosphere for 15 minutes (Fig. 2c, element 9).

3. Anode etching of the channel matrix is carried out in the mode of a regularly varying DC density in the range of 28-44 mA / cm ² in an electrolytic solution

NH ₄ F (40%): HCl (36.5%): H ₂ O: neonol = 2.5: 1: 6.5: 0.025

on an area of 0.8 cm ² for 40 minutes (fig.2g, figa and fig.4 element 10). On figb. Shows the monolithic part of the plate of single-crystal silicon - element 8.

4. The opening of the channels is carried out by grinding / polishing the back surface of a single-crystal silicon wafer (Fig.2d and Fig. 5 element 1) using micropowder of synthetic diamonds mixed in a solution of glycerol and isopropyl alcohol. As a result, a channel matrix with a thickness of 75 μm is obtained with a transverse size of the opened channels in the near-surface region of the frontal surface equal to ~ 1.9-3.1 μm (Fig. 2e and Fig. 5 element 11).

5. High-temperature oxidation of a single-crystal silicon wafer with open channels is carried out at 1000 ° C in H ₂ O vapors for 1 hour. The result is a dielectric layer of silicon dioxide with a thickness of 100-120 nm.

6. Plasma-chemical deposition of silicon on the front surface of the channel matrix (Fig.6b element 3) is carried out from the interelectrode radio frequency glow discharge of a gas mixture of monosilane SiH ₄ and argon at a frequency of 40 MHz, pressure ~ 0.2 mm Hg at a temperature of 250 ° C for 60 minutes. The transverse size of the channels is obtained in the range of 1.6-2.8 μm (Fig.2g and Fig.6b element 12).

7. The deposition of a metal film of aluminum with a thickness of ~ 150 nm is performed in an average vacuum of ~ 5 · 10 ^-6 mm RT.article. method of thermal evaporation of metal from a tungsten boat (fig.2z and figb element 4).

The result is a channel matrix with the structure shown in figb and Fig, with a transverse channel size of 1.6-2.8 microns.

Fig. 7b shows a channel with a given transverse size - element 12, and Fig. 8 (optical image of a channel matrix) shows the elements: 1 - hole-type single-crystal silicon wafer with open channels, 2 - dielectric layer of silicon dioxide, 3 - deposited material on the front surface of a single-crystal silicon wafer with open channels, 4 - a metal film on the front surface of a single-crystal silicon wafer with open channels having a predetermined lateral size of the channels.

In the manufacture of a channel matrix, high-temperature oxidation of a silicon wafer with open channels is also carried out at temperatures of 800 ° C and 900 ° C.

The channel matrix made by the proposed method has the design of a monolithic connection of the nanochannel part with a supporting microchannel base and ordered channels of a given transverse size (profile channels) in a monolithic silicon wafer. Typical structural characteristics of the channel matrix are as follows:

the thickness of the nanochannel part of the matrix is 1-6 μm,

the thickness of the microchannel part of the matrix is 50-250 microns,

preset transverse channel size 10 nm-3 μm,

ordered channels with a surface density of (3-6) · 10 ⁶ cm ^-2 .

Using the proposed channel matrix and its manufacturing method provides the following advantages compared to the known channel matrix and its manufacturing method:

improvement of operational characteristics due to the introduction of a metal film into the matrix structure,

expanding the range of membrane technology products in the production of micro- and nanofluidic systems, biosensor devices, medical diagnostic devices through the use of controlled electrokinetic filters and electrophysical detection methods based on high-tech and biocompatible single-crystal silicon.

Claims (8)

1. The channel matrix, consisting of a hole-type single crystal silicon wafer with open channels, deposited material on the front surface of a hole-type single-crystal silicon wafer with open channels, characterized in that a dielectric layer of silicon dioxide is created on the surface of a hole-type single crystal silicon wafer with open channels, and on the front surface of a wafer of single-crystal silicon of a hole type with open channels having a given transverse size, esena metal film. 2. The channel matrix according to claim 1, characterized in that the dielectric layer of silicon dioxide is created between the deposited material and the hole-type single-crystal silicon wafer. 3. The channel matrix according to claim 1 or claim 2, characterized in that a dielectric film is applied to the surface of the metal film. 4. A method of manufacturing a channel matrix, which includes creating ordered seed pits on the front surface of a hole-type single crystal silicon wafer, forming an ohmic contact on the back surface of a hole-type single-crystal silicon wafer, anodic etching in an electrolyte solution containing hydrogen and fluorine ions, opening the channels and deposition materials on the front surface of a hole-type single-crystal silicon wafer with open channels to obtain the transverse size of the channels, characterized in that after opening the channels, high-temperature oxidation of hole-type single-crystal silicon wafers with open channels is performed in a gaseous medium, and then a metal film is deposited on the front surface of hole-type single-crystal silicon wafers with open channels having a given transverse size . 5. The method according to claim 4, characterized in that the high-temperature oxidation of the plate of single-crystal silicon hole type with open channels is performed at a temperature of 800-1000 ° C. 6. The method according to claim 4, characterized in that after the materials are deposited on the front surface of the hole type monocrystalline silicon wafer with open channels until a predetermined lateral size of the channels is obtained, the dielectric layer of silicon dioxide not covered by the deposited material is removed. 7. The method according to claim 4, characterized in that the deposition of metal films of gold or aluminum is carried out on the front surface of a hole-type single crystal silicon wafer with open channels having a predetermined lateral size. 8. The method according to claim 4 or claim 6, characterized in that the dielectric film is deposited on the surface of the metal film.

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