JP2004219370A - Experiment chip, and manufacturing method of experiment chip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an experiment chip using a semiconductor, particularly, an experiment chip suitable for detection using light and electrophoresis, and to provide its manufacturing method. <P>SOLUTION: A capillary channel, and a groove 22 to be used as reservoirs 12A and 12B are formed on a surface of a silicon substrate 20 by etching. A thin film layer 23 of SiO<SB>2</SB>is formed by sputtering on the surface of the substrate 20 formed with the groove 22. Thin film electrodes 14A and 14B of Au are formed in positions corresponding to bottom faces of the reservoirs 12A and 12B of the groove 22. A thin film layer 25 of SiO<SB>2</SB>is formed on a chip surface excluding openings of the reservoirs and an area 25C corresponding to an upper part of the capillary channel of the groove 22. Au thin film electrodes 15A and 15B are formed next to the reservoir openings of the chip surface. The Au thin film electrodes 14A and 15A, and 14B and 15B are connected by a bonding wire. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a reaction chip and an experimental chip for performing lab processes such as electrophoresis, chemical reaction, cell culture and separation detection on the chip.
[0002]
[Prior art]
A microchannel, a capillary channel, is formed on a flat glass chip, plastic chip, or silicon chip using photolithography, and the reaction is integrated with laboratory processes such as electrophoresis, chemical reaction, cell culture, or separation detection. Chips and experimental chips (Lab-on-a-chip, μ-TAS) are known.
[0003]
If low cost is intended for disposable use, it is preferable to use glass or plastic as the material of the chip. For example, currently, electrophoresis chips using glass or plastic (polydimethylsiloxane, polymethyl methacrylate, etc.) are mainly used.
[0004]
[Patent Document 1]
Japanese Patent No. 2937064 [Patent Document 2]
Japanese Patent No. 3077609 [Patent Document 3]
JP-A-10-10088 [Patent Document 4]
JP 2000-310614 A [Patent Document 5]
JP 2000-338085 A [Patent Document 6]
JP 2001-157855 A
[Problems to be solved by the invention]
However, when glass or plastic is used for a reaction chip / experimental chip (hereinafter simply referred to as an experimental chip), it is difficult to add a high-performance device such as a micropump using a micromachining technology. When micromachining technology is applied, silicon is preferred, but silicon is an opaque semiconductor, so DNA analysis that transmits or reflects light to the capillary to detect patterns, or electricity that requires the capillary to be an insulator It is difficult to use a silicon chip for electrophoresis.
[0006]
An object of the present invention is to provide an experimental chip using a semiconductor and a method for manufacturing the same. In particular, it is an object of the present invention to provide an experimental chip suitable for detection using light and electrophoresis, and a method for producing the same.
[0007]
[Means for Solving the Problems]
The experimental chip of the present invention is an experimental chip formed on a semiconductor substrate, and a groove formed for forming a flow path on the surface of the semiconductor substrate, and a flow path formed by coating the groove with an insulator. And an upper thin film layer made of silicon dioxide or silicon nitride which covers an upper portion of the flow path and transmits electromagnetic waves in any wavelength range from infrared to ultraviolet.
[0008]
It is preferable that the semiconductor substrate has a recess for forming a reservoir connected to the flow path on the surface of the semiconductor substrate, and that this reservoir is covered with a lower thin film layer. Preferably, a first electrode made of a thin film is formed. Thus, an experimental chip for electrophoresis can be easily obtained. From the viewpoint of the durability of the experimental chip, it is preferable that the first electrode is made of a material having corrosion resistance.
[0009]
It is preferable that a second electrode made of a conductive thin film electrically connected to the first electrode is formed at a position adjacent to the reservoir on the upper surface of the experimental chip. This makes it possible to more easily supply power to the first electrode for electrophoresis. At this time, the electrical connection between the first electrode and the second electrode is performed by, for example, a bonding wire. Alternatively, the first electrode and the second electrode are connected as, for example, a step cover electrode.
[0010]
The method of manufacturing an experimental chip according to the present invention includes a first etching step of forming a groove serving as a flow path and a recess connected to the groove and serving as a reservoir on the surface of the semiconductor substrate; A lower thin film layer forming step of forming a lower thin film layer composed of a body, a resist layer forming step of applying a resist to the entire surface on which the lower thin film layer is formed to form a flat resist layer, and corresponding to the grooves and recesses. A first resist stripping step of stripping the resist layer around it while leaving the resist layer in the region, and insulating and transmitting the electromagnetic wave in any wavelength range from infrared to ultraviolet to the entire surface after the resist stripping step An upper thin film layer forming step of forming a flat upper thin film layer made of a body, and a second etching step of etching the upper thin film layer in a region corresponding to the concave portion. When it is characterized in that a second resist removal step of removing the resist layer left in the resist stripping step.
[0011]
The method of manufacturing an experimental chip more preferably has a first electrode forming step of forming a first electrode made of a conductive thin film on the bottom surface of the concave portion covered by the lower thin film layer after the lower thin film layer forming step is completed. .
[0012]
The method of manufacturing an experimental chip may further include, after the step of forming the upper thin film layer, a second electrode forming step of forming a second electrode made of a conductive thin film at a position adjacent to the concave portion on the surface of the upper thin film layer. Is preferred. At this time, it is preferable that the method for manufacturing an experimental chip includes an electrode connecting step of connecting the first and second electrodes after the end of the second resist removing step.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of an experimental chip to which the present invention is applied will be described with reference to the drawings.
FIG. 1 is a plan view showing a schematic structure of an experimental chip of the present embodiment. FIGS. 2 to 12 are elevational sectional views of the experimental chip taken along line AA in FIG. Shown in chronological order along each stage.
[0014]
The experimental chip 10 of the present embodiment is, for example, a microchip for electrophoresis. The experimental chip 10 uses a silicon substrate as a core material, and the silicon substrate uses, for example, silicon having an orientation of “100” for anisotropic etching. As shown in FIG. 1, an experimental chip 10 composed of silicon as a substrate is formed with, for example, two reservoirs 12A and 12B having openings on the upper surface of the experimental chip 10, and each of the reservoirs 12A and 12B is a capillary. 13 communicates. Electrodes (first electrodes) 14A and 14B are provided on the bottom surfaces of the reservoirs 12A and 12B, respectively. On the upper surface of the experimental chip 10, electrodes (second electrodes) 15A and 15B are provided at positions adjacent to the reservoirs 12A and 12B, respectively. The electrode 14A and the electrode 15A are electrically connected by, for example, a bonding wire 16A. Similarly, the electrode 14B and the electrode 15B are also electrically connected by the bonding wire 16B.
[0015]
Next, a method for manufacturing the experimental chip 10 of the present embodiment will be described with reference to FIGS.
[0016]
As shown in FIG. 2, in the first step, a pattern for forming a capillary channel (fine channel forming the bottom surface and both side walls of the capillary 13) 13 </ b> C and reservoirs 12 </ b> A and 12 </ b> B is formed on the upper surface of the silicon substrate 20. Affixed as layer 21. That is, the upper surface of the silicon substrate 20 is covered with the resist layer except for a region surrounded by the circular rims of the reservoirs 12A and 12B in FIG.
[0017]
In the second step, dry or wet etching is performed on the silicon substrate 20 that has been subjected to the resist patterning in the first step, and a groove 22 corresponding to the pattern formed by the resist layer 21 is formed. FIG. 3 shows a state where the etching process is completed and the attached resist layer is peeled off. Note that the groove 22 forms the bottom and wall surfaces of the reservoirs 12A and 12B and the capillary channel 13C.
[0018]
In the third step, a thin film layer (lower thin film layer) 23 made of an insulator is formed on the upper surface of the silicon substrate 20 and the groove 22 by using sputtering or the like. Examples of the material of the thin film layer 23 include glass (for example, SiO ₂ ) and silicon nitride. FIG. 4 shows a state after the thin film layer 23 is formed.
[0019]
In the fourth step, a conventionally known lift-off process (a reverse pattern of a target pattern is formed of a metal, a photoresist, or the like on a substrate, and after depositing a target thin film, unnecessary portions are removed together with the metal and the photoresist. As shown in FIG. 5, the electrodes 14A and 14B are formed at portions corresponding to the bottom surfaces of the reservoirs 12A and 12B covered with the thin film layer 23, using a method of leaving a pattern to be formed. The electrodes 14A and 14B are formed of a conductive thin film layer, for example, a metal thin film (for example, a material having corrosion resistance of Au, Ag, or Pt is preferable), a carbon thin film, or the like. After patterning, the electrodes 14A and 14B are formed on the thin film layer 23 using, for example, an evaporation method such as sputtering or ion plating. For example, when the adhesion between the Au thin film and the SiO ₂ film is poor, a base metal film having good adhesion to the SiO ₂ film may be formed under the Au thin film. FIG. 5 shows a state in which the masking layer used for patterning has already been removed and lift-off processing has been completed.
[0020]
In the fifth step, resist layers 24a and 24b are formed on the entire upper surface of the silicon substrate 20 on which the thin film layer 23 and the electrodes 14A and 14B are formed, and masking (not shown) shaped like a groove 22 is formed thereon. ) Is applied and exposed. FIG. 6 shows a case where a positive resist is used for the resist layers 24a and 24b. The resist layer 24a shows a region which is not exposed by masking, and corresponds to the groove 22. The resist layer 24b indicates a region to be exposed, and corresponds to a region outside the groove 22.
[0021]
In the sixth step, a developing process using a developing solution or the like is performed, and as shown in FIG. 7, an image corresponding to the groove 22 is formed at a position corresponding to the groove 22 on the upper surface of the silicon substrate 20 by the resist layer 24a. It is formed.
[0022]
In the seventh step, as in the third step, an infrared ray is formed on the upper surface of the silicon substrate 20 on which the resist layer 24a corresponding to the thin film layer 23, the electrodes 14A and 14B, and the groove 22 is formed. , A thin film layer (upper thin film layer) 25 that transmits visible light, ultraviolet light, and the like and is an insulator. Examples of the material of the thin film layer 25 include glass (for example, SiO ₂ ) and silicon nitride. FIG. 8 shows a state after the thin film layer 25 is formed. Note that, for forming the thin film layer 25, for example, CVD (Chemical Vapor Deposition) is used.
[0023]
In the eighth step, as in the fourth step, as shown in FIG. 9, electrodes 15A and 15B are formed on the uppermost surface of the silicon substrate 20 covered with the thin film layer 25. The electrodes 15A and 15B are made of a conductive thin film layer, for example, a metal thin film (for example, Au, Ag, Pt, Al, Cu), carbon, or a conductive resin. After patterning, the electrodes 15A and 15B are formed on the thin film layer 25 using, for example, an evaporation method such as sputtering or ion plating. FIG. 9 shows a state in which the masking layer used for patterning has already been removed.
[0024]
In the ninth step, as shown in FIG. 10, openings of the reservoirs 12A and 12B (see FIG. 11) are formed in the thin film layer 25. That is, masking (patterning) is performed by the resist layer 26 except for the positions corresponding to the circular openings of the reservoirs 12A and 12B, and thereafter, the circular openings are formed at positions corresponding to the reservoirs 12A and 12B of the thin film layer 25 by performing dry etching. 27A and 27B are formed. At this time, the thin film layer 25C on the capillary channel 13C is left to form the capillary 13.
[0025]
In the tenth step, the resist layer 26 and the resist layer 24a used for the masking in the ninth step are peeled off, and the silicon substrate 20 is in a state shown in FIG.
[0026]
In the eleventh step, as shown in FIG. 12, a lead wire (bonding wire) 16A is formed between the electrode 14A and the electrode 15A by bonding, and similarly, a lead is formed between the electrode 14B and the electrode 15B by bonding. Line 16B is formed. Thus, the experimental chip 10 which is the electrophoresis microchip in the present embodiment is completed.
[0027]
As described above, according to the present embodiment, a microchip for electrophoresis can be formed on a semiconductor substrate. That is, since the capillary formed on the semiconductor substrate is surrounded by the thin film layer made of an insulator, it can be used for electrophoresis. Further, since the upper surface of the capillary is formed from a material that transmits visible light, infrared light, or ultraviolet light, the capillary can be irradiated with light and the reflected light can be detected to detect the electrophoresis pattern.
[0028]
In addition, since the experimental chip of this embodiment is formed using a semiconductor substrate, it is possible to easily form nanofabrication, nanodevices, and the like on the experimental chip by using micromachining technology in a semiconductor manufacturing process. Thus, integration with a micropump, a valve, or another semiconductor circuit can be easily performed. Furthermore, since the experimental chip of the present embodiment can be mass-produced using a semiconductor wafer, the manufacturing cost can be significantly reduced.
[0029]
Next, a modification of the present embodiment will be described with reference to FIG. In the above embodiment, the electrodes 14A and 15A and the electrodes 14B and 15B are connected by bonding using lead wires. However, in a modified example, the electrodes 14A and 14B and the electrodes 15A and 15B are connected to the step cover electrode 28A. , 28B. In this modification, the same effect as in the above embodiment can be obtained.
[0030]
In this embodiment and its modifications, the electrodes for electrophoresis are provided in the reservoir, and the electrodes for connection are provided on the upper surface of the chip. However, the electrodes can be inserted directly into the reservoir from the outside and used. . In this case, it is not necessary to provide electrodes on the experimental chip.
[0031]
The experimental chip of the present embodiment includes only one flow path (capillary channel) and two reservoirs disposed at both ends of the flow path. However, a plurality of flow paths may be provided or the flow path may be branched. And the number of reservoirs may be three or more.
[0032]
Further, in the present embodiment, the formation of the thin-film electrode performed in the fourth step may be performed after the third step of the present embodiment is completed. This may be performed after the seventh step of the present embodiment is completed. For example, each electrode may be formed between the tenth step and the eleventh step in the present embodiment.
[0033]
【The invention's effect】
As described above, according to the present invention, an experimental chip using a semiconductor and a method for manufacturing the same are provided.
[Brief description of the drawings]
FIG. 1 is a plan view showing a schematic structure of an experimental chip in an embodiment in which the present invention is applied to an experimental chip for electrophoresis.
FIG. 2 is a vertical sectional view taken along the line AA of FIG. 1 in a first step of the experimental chip of the present embodiment.
FIG. 3 is an elevational sectional view along a line AA in a second step of the experimental chip.
FIG. 4 is an elevational sectional view of the experimental chip taken along line AA in a third step.
FIG. 5 is a vertical sectional view taken along line AA in a fourth step of the experimental chip.
FIG. 6 is an elevational sectional view along a line AA in a fifth step of the experimental chip.
FIG. 7 is an elevational sectional view along a line AA in a sixth step of the experimental chip.
FIG. 8 is an elevational sectional view of the experimental chip taken along line AA in a seventh step.
FIG. 9 is an elevational sectional view of the experimental chip taken along line AA in an eighth step.
FIG. 10 is an elevational sectional view taken along line AA of a ninth step of the experimental chip.
FIG. 11 is an elevational sectional view of the experimental chip taken along line AA in a tenth step.
FIG. 12 is an elevational sectional view of the experimental chip taken along line AA in an eleventh step.
FIG. 13 is a sectional view of a modified example of the experimental chip shown in FIGS. 1 to 12 taken along line AA when completed.
[Explanation of symbols]
10 Experimental chip 12A, 12B Reservoir 13 Capillary 13C Capillary channel 14A, 14B, 15A, 15B Electrode 20 Silicon substrate 22 Groove 23 Thin film layer (lower thin film layer)
25 Thin film layer (upper thin film layer)

Claims (11)

An experimental chip formed on a semiconductor substrate,
A groove formed to form a flow path on the surface of the semiconductor substrate,
A lower thin film layer covering the groove with an insulator to form the flow path;
An experimental chip, comprising: an upper thin film layer made of silicon dioxide or silicon nitride that covers an upper part of the flow path and transmits electromagnetic waves in any wavelength range from infrared to ultraviolet. The experimental chip according to claim 1, further comprising a concave portion for forming a reservoir connected to the flow channel on a surface of the semiconductor substrate, wherein the reservoir is covered with the lower thin film layer. The experimental chip according to claim 2, wherein a first electrode made of a conductive thin film is formed on the lower thin film layer on the bottom surface of the reservoir. The experimental chip according to claim 3, wherein the first electrode is made of a material having corrosion resistance. 4. The second electrode according to claim 3, wherein a second electrode made of a conductive thin film electrically connected to the first electrode is formed at a position adjacent to the reservoir on an upper surface of the experimental chip. 5. Experimental chip. The experimental chip according to claim 5, wherein the first electrode and the second electrode are electrically connected by a bonding wire. The experimental chip according to claim 5, wherein the first electrode and the second electrode are connected as a step cover electrode. A first etching step of forming a groove serving as a flow path and a concave portion serving as a reservoir connected to the groove on the surface of the semiconductor substrate;
A lower thin film layer forming step of forming a lower thin film layer made of an insulator on the surface of the semiconductor substrate on which the groove and the concave portion are formed;
A resist layer forming step of applying a resist on the entire surface on which the lower thin film layer is formed to form a flat resist layer,
A first resist stripping step of stripping the resist layer around it, leaving the resist layer in an area corresponding to the groove and the concave portion,
An upper thin film layer forming step of forming a flat upper thin film layer made of an insulator by transmitting electromagnetic waves in any wavelength range from infrared rays to ultraviolet rays over the entire surface after the resist stripping step,
A second etching step of etching the upper thin film layer in a region corresponding to the concave portion;
A second resist stripping step of stripping the resist layer left in the resist stripping step. A first electrode forming step of forming a first electrode made of a conductive thin film on a bottom surface of the concave portion covered with the lower thin film layer after the lower thin film layer forming step is completed. 9. The method for producing an experimental chip according to item 8. After the step of forming the upper thin film layer, a second electrode forming step of forming a second electrode made of a conductive thin film at a position adjacent to the recess on the surface of the upper thin film layer is provided. Item 10. The method for producing an experimental chip according to Item 9. The method according to claim 10, further comprising an electrode connecting step of connecting the first and second electrodes after the second resist removing step is completed.

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