JP2003262585A - Method for manufacturing surface plasmon resonance sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems that a conventional surface plasmon resonance sensor of this type has required a light source, a spectroscope, etc., at measurements to require a relatively large size and cause a high price and required expert knowledge for measurements to lower a general-purpose property. <P>SOLUTION: This method for manufacturing a surface plasmon resonance sensor 1 comprises: a first process for forming a light receiving element 4 and a circuit part 3 on a semiconductor substrate 2; a second process for forming a plurality of LEDs 5 having different wavelengths on the substrate 2 by a MOCVD method; and a third process for making a transparent, optically reactive, thermosetting resin adhere between the LEDs 5 and the light receiving element 4 by a photolithography means, heating, melting, and setting the optically reactive, thermosetting resin in a hydrophobic liquid of the approximately same specific gravity with the surface of the semiconductor substrate directed downward, and forming a sensor part 10 at a required part. Therefore, it is possible to integrally form the sensor part on the semiconductor substrate 2 with a light source and a circuit part, to eliminate the need for external apparatuses, and to solve the problems. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a sensor capable of measuring a liquid component such as an amount of sugar contained in a liquid and a composition by bringing the liquid into contact with the liquid. And
More specifically, the present invention relates to a method for manufacturing a sensor that enables simple and rapid measurement without performing composition analysis or the like by a surface plasmon resonance action, which is an optical phenomenon. 2. Description of the Related Art FIG. 12 shows an example of the structure of a conventional surface plasmon resonance sensor 90 (hereinafter abbreviated as SPR sensor 90) of this type. A base resin 93 is formed on the substrate 91, and a core 93 made of methacrylic resin and having a substantially square cross section having a side of about 0.5 mm square is provided on the substrate 91. Further, the core 9
Gold (Au), silver (A)
g) to form a metal film 94 having a thickness of about 50 nm,
The portion of the metal film 94 is a measuring portion. In the measurement, white light from a halogen lamp 80 or the like is transmitted through the core 93 from one end, and a spectroscope 81 or the like is provided at the other end on the output side of the white light.
Equipment that can measure the wavelength component of light is installed. Then, measurement is performed by bringing a liquid to be measured into contact with the metal film 94. FIG. 13 is a graph showing the operation of the SPR sensor 90 having the above-described structure. In the figure, a curve indicated by a symbol G indicates the case where pure water is brought into contact with the metal film 94, that is, the measuring portion. The wavelength characteristic measured by the spectroscope is indicated by the symbol S in the figure, and is the wavelength characteristic S of the same spectrometer when sugar (sucrose) is added to the pure water. [0005] As described above, the SPR sensor 90 has such a characteristic that the longer the refractive index of the liquid in contact with the measuring portion, the longer the wavelength of attenuation shifts to the longer wavelength side. Can be measured easily and quickly. In the SPR sensor 90,
Because it can measure the sugar concentration (refractive index) without transmitting light directly into the liquid, it can measure even colored liquids, and can be applied to various fields such as immunoassay with blood. Is expected. However, in the above-described conventional SPR sensor 90, the portion of the SPR sensor 90 is certainly not so large, but the halogen lamp 80 as the light input section is large. It consumes electric power and generates a great deal of heat, so it must be said that it is difficult to use it in a state close to the human body. In addition, the spectroscope 81 connected to the output side is unavoidably large and expensive, and can be operated by anyone, for example, the operation is complicated and a specialist is required for handling. However, it is preferable to further reduce the size of the SPR sensor 90. That is, the conventional example is large and expensive, and has a problem in practicality. [0007] The present invention provides a method of manufacturing a surface plasmon resonance sensor as a specific means for solving the above-mentioned problems occurring in the conventional SPR sensor, wherein the manufacturing method comprises the steps of: A first step of forming an IC substrate on which a light receiving element, a sensor driving circuit, and an analysis and evaluation circuit are integrated on a semiconductor substrate of Si, GaAs, or GaAs; and a plurality of light emitting lights having different wavelengths from blue to red on the IC substrate. MOCVD part
A second step of forming by a method, an appropriate amount of a transparent photoreactive thermosetting resin is adhered between the light emitting portion and the light receiving element on the IC substrate by photolithography means, and the photoreactive thermosetting resin is The photoreactive thermosetting resin having substantially the same specific gravity is heated and melted and cured in a hydrophobic liquid with the surface of the IC substrate facing downward, and a clad and a metal thin film are formed on necessary portions. And a third step of forming a sensor portion by using the method. A method for manufacturing a surface plasmon resonance sensor, comprising: Next, the present invention will be described in detail based on an embodiment shown in the drawings. 1 to 10 show a method of manufacturing a surface plasmon resonance sensor 1 (hereinafter abbreviated as SPR sensor 1) according to the present invention in the order of steps. FIG. 1 shows the first step of the manufacturing method according to the present invention. In FIG.
This is a GaAs-based semiconductor substrate. In the present invention, first, as a first step, a circuit section 3 in which a sensor driving circuit, an analysis evaluation circuit, and the like are integrated on the semiconductor substrate 2 by using a known circuit forming technique.
And a light receiving element 4 such as a photodiode,
The semiconductor substrate 2 is formed into an IC. In the present invention, as a subsequent second step, MOCVD is performed at an appropriate position on the semiconductor substrate 2 as shown in FIG.
A plurality of LEDs 5 (light emitting diodes) or LDs (laser diodes) whose emission color ranges from blue-violet to red are formed by a method (metal organic chemical vapor deposition). FIG. 3 shows a typical 17 kinds of emission spectra SP in LEDs currently generally marketed.
It is a graph showing 1 to SP17, in which the center wavelength is partially overlapped, but the center wavelength is almost uniformly distributed in a range from a wavelength of 470 nm (blue) to a wavelength of 700 nm (red). It has become something. Therefore, an appropriate LED is selected from these 17 types of LEDs so that the distribution of the center wavelength in the measurement range as the SPR sensor 1 becomes uniform, and is formed on the semiconductor substrate 2. The sensor drive circuit inside is
For example, the circuit configuration is such that the LEDs are sequentially lit one by one in the order of shorter wavelength. In addition, the above-described sensor driving circuit is configured such that each of the LEs is operated in a state where there is no liquid contact with the measuring unit.
The lighting current is also controlled so that the same output current can be obtained in the light receiving element 4 with respect to D5. FIGS. 4 to 10 show a third step of the method for manufacturing the SPR sensor 1 according to the present invention. First, the surface of the semiconductor substrate 2 on which the circuit section 3 and the light receiving element 4 are formed is shown. A transparent resin layer 6 is formed on the transparent insulating layer 6.
Is formed (see FIG. 4). Thereafter, a reflective light-shielding layer 7 is formed by vapor deposition of aluminum or the like on portions necessary for taking in and taking out light from the semiconductor substrate 2 such as portions corresponding to the light receiving elements 4 and the LEDs 5 (FIG. 5). refer. A cladding layer 8 is formed on the upper surface on which the reflective light-shielding layer 7 is formed by using a resin having low refractive index and excellent water repellency, such as a fluorine resin. In this case, similarly to the reflective light shielding layer 7, the light receiving element 4 portion,
The cladding layer 8 is not formed in a portion where light is taken in and out of the semiconductor substrate 2 such as the LED 5 portion, and a portion where the light guide 9 and the sensor portion 10 described later are provided (see FIG. 6). ) Is the standard. In forming the reflective light-shielding layer 7 and the cladding layer 8, a photoresist film is applied to the entire surface of the semiconductor substrate 2 and the photoresist film is coated by the photolithography method or the like. The layer 8 is left in an unnecessary portion, and the reflective light-shielding layer 7 or the cladding layer 8 is formed in a state where the photoresist film is formed, and then the photoresist film is removed. It may be formed by a method or the like. After the cladding layer 8 is formed as described above, a transparent photoreactive thermosetting resin (for example, JSR) supplied on the market for forming a photoresist film is used.
A light guide substrate 9a is inserted from the light receiving element 4 to a plurality of LEDs 5 by a photolithography method or the like using (trade name: MFR-343H). At this time, since the sensor unit 10 is provided in a subsequent step, the light guide base materials 9a from the plurality of LEDs 5 are integrated into a single unit up to the position where the sensor unit 10 is provided (see FIGS. 8). FIG. 9 is a view showing the light guide 9 from the light guide base material 9a.
In the present invention, the light guide substrate 9a is immersed in the silicon oil 21 filled in the bathtub 20 with the light guide substrate 9a facing down. FIG.
0, a heater 22 is attached, and the silicone oil 21 is heated to an appropriate temperature for liquefying the light guide substrate 9a. Since the silicon oil 21 is selected to have substantially the same specific gravity as the liquefied light guide base material 9a, the light guide base material 9a may be dropped or drooped even in the liquefied state. And the shape in the liquefied state is determined solely by the surface tension of the light guide substrate 9a. Therefore, the end portion of the light guide substrate 9a has a substantially hemispherical shape, and the intermediate portion has a substantially cylindrical shape. And
If this state is maintained in the silicone oil 21 and heating is continued, the light guide base material 9a maintains the above-mentioned shape and becomes thermoset, that is, the light guide 9 according to the present invention is completed as shown in FIG. I do. Subsequently, a film 10a of gold (Au), silver (Ag) or platinum (Pt) is formed at an appropriate position on the light guide 9.
Is formed to a film thickness of 30 to 70 nm, the portion becomes the sensor section 10, and the SPR sensor 1 of the present invention is completed.
Therefore, according to the manufacturing method of the present invention, all the steps from the first step to the third step are performed by a technology for producing a semiconductor IC or the like, that is, the SPR sensor 1 can be miniaturized. It becomes. The cladding layer 7 may be provided on the surface of the light guide 9 other than the sensor section 10 (see FIG. 11). In using the SPR sensor 1 manufactured as described above, the liquid to be measured is brought into contact with the sensor unit 10 and the sensor driving circuit of the circuit unit 3 has, for example, a center wavelength which is the shortest wavelength. One of the LEDs 5 is turned on, and the output from the light receiving element 4 is read and recorded. Subsequently, the circuit section 3 switches to the LED 5 having the second shortest center wavelength to turn on the LED 5, and reads and records the output from the light receiving element 4 in this state. As described above, by sequentially switching the plurality of LEDs 5 and recording up to the output of the LED 5 having the longest wavelength, the concentration (refractive index) of the liquid can be read from those output values. The brightness of each LED 5 is adjusted by the sensor unit 1.
The LEDs 5 may be sequentially lit in a state where there is no liquid contact with 0, and the lighting current may be adjusted so that the same value is obtained in all the outputs of the light receiving elements 4.
In addition, in actual measurement, it is preferable to perform calibration by bringing pure water or the like into contact with the sensor unit 10 in advance from the viewpoint of maintaining accuracy. As described above, the SP according to the manufacturing method of the present invention is used.
In the R sensor 1, a light source (LE) is placed on a semiconductor substrate 2 having a small area.
D5) Since the sensor (sensor section 10) and the circuit section 3 having the sensor drive circuit and the analysis and evaluation circuit are formed integrally, the halogen bulb, the spectroscope, and the like required in the conventional example are unnecessary. The measurement result can be obtained by the SPR sensor 1 itself. Therefore, the whole measurement system can be miniaturized, and the operation for measurement can be greatly simplified. As described above, according to the present invention, there is provided a method of manufacturing a surface plasmon resonance sensor, the method comprising the steps of: forming a light receiving element and a sensor driving circuit on a Si or GaAs semiconductor substrate; A first step of forming an IC substrate on which an analysis and evaluation circuit is integrated; a second step of forming a plurality of light emitting portions having different wavelengths from blue to red on the IC substrate by MOCVD; An appropriate amount of a transparent photoreactive thermosetting resin is adhered between the light emitting portion and the light receiving element by photolithography, and the specific gravity of the photoreactive thermosetting resin is substantially the same as the photoreactive thermosetting resin. A third step of performing heating and melting and curing in a hydrophobic liquid with the IC substrate surface downward, and further forming a sensor portion by forming a clad and a metal thin film on necessary portions. The manufacturing method of the Mont Resonance sensor enables the sensor unit to be formed integrally with the light source, light source drive circuit, and measurement circuit on the semiconductor substrate. Light sources and spectroscopes that were conventionally required as external devices Is unnecessary, and the surface plasmon resonance sensor can be handled even without special knowledge, which is extremely effective in miniaturizing this kind of surface plasmon resonance sensor and simplifying the measurement operation. .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view showing a first step of a method for manufacturing a surface plasmon resonance sensor according to the present invention. FIG. 2 is a cross-sectional view showing a second step of the method for manufacturing the surface plasmon resonance sensor according to the present invention. FIG. 3 is a graph showing an example of a center emission wavelength of an LED formed in a second step. FIG. 4 is an explanatory view showing a step of forming a transparent insulating layer in a third step of the method for manufacturing a surface plasmon resonance sensor according to the present invention. FIG. 5 is an explanatory view showing a reflection light shielding layer forming step in the third step. FIG. 6 is an explanatory view showing a clad layer forming step in the third step. FIG. 7 is a plan view showing the state of laying the light guide substrate in the third step. FIG. 8 is a sectional view taken along line AA of FIG. 7; FIG. 9 is an explanatory view showing a light guide path forming step in the third step. FIG. 10 is an explanatory view showing a bathtub used in a step of forming a light guide path. FIG. 11 is a cross-sectional view showing a surface plasmon resonance sensor manufactured by the method for manufacturing a surface plasmon resonance sensor according to the present invention. FIG. 12 is an explanatory diagram showing a conventional example. FIG. 13 is a graph showing the operation of a surface plasmon resonance sensor. [Description of Signs] 1 ... Surface plasmon resonance sensor (SPR sensor) 2 ... Semiconductor substrate 3 ... Circuit section 4 ... Light receiving element 5 ... LED 6 ... Transparent insulating layer 7 ... Reflective light shielding layer 8 ... Cladding layer 9 Light guide 9a Light guide base material 10 Sensor part 20 Bathtub

Claims (1)

Claims 1. A method of manufacturing a surface plasmon resonance sensor, comprising: integrating a light receiving element, a sensor drive circuit, and an analysis evaluation circuit on a Si or GaAs semiconductor substrate. A first step of forming an IC substrate, and a plurality of light emitting portions having different wavelengths from blue to red on the IC substrate,
A second step of forming by a VD method, and applying an appropriate amount of a transparent photoreactive thermosetting resin between the light emitting portion and the light receiving element on the IC substrate by photolithography means; The photoreactive thermosetting resin is heated and melted and cured in a hydrophobic liquid with the surface of the IC substrate facing downward, and a clad and a metal thin film are formed on necessary portions. And a third step of forming a sensor section by performing the method.