JPH06181031A - Manufacture of metal foil made part of probe - Google Patents

Abstract

PURPOSE:To stabilize the detection of tunnel current, to improve the performance of AFM operation and at the same time facilitate handling and the like, at a low price, by making metal foil of specific mum in each of thickness and length into cantilever-like parts of a probe and fixing a metallic block thereto. CONSTITUTION:A bonding agent 2 is applied to a ceramic substrate 1 and then is semi-dried, and platinum foil 3 of several mum in thickness is overlapped thereupon and pressed from top and bottoms with metal plates 4 to be made flat, and then photoresist is applied to the upper surface of the foil 3. Next, a plurality of patterns are exposed to light and then developed to form a masking layer 5, and after platinum foil 3a is formed by etching, the substrate 1 is cut. Successively, the foil 3a and a metal block 7 are soldered together, and then a layer 2a of a bonding agent is dissolved in an organic solvent 9 to separate the foil 3a from a substrate 1a and the foil 3a is drawn up to clean up the solvent 9 with substitution of alcohol and then the foil 3a is dried for completion, thereby making it feasible to stably detect tunnel current and to improve the performance of AFM operation, so that the parts of a probe which facilitate handling and the like may be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an atomic force microscope (hereinafter, simply referred to as AFM) and a tunnel microscope (simply, ST).
Scanning microscope and scanning tunneling spectroscope (hereinafter referred to as STS)
The present invention relates to a method for manufacturing a probe component, which is produced by processing a metal foil used in.

[0002]

2. Description of the Related Art An AFM brings a cantilever-shaped probe component close to a sample up to a minute distance, detects an atomic force acting between the probe component and the sample as displacement of the probe component, and detects the probe component. By scanning the surface of the sample, the shape of the sample and the physical properties of the surface are measured.

In the STM, a metal probe part is brought close to a sample to the extent that a tunnel current flows, and a voltage is applied between the two so that the tunnel current flowing at that time becomes constant. The shape of the sample surface is detected from the change in the control signal when the probe part is scanned while controlling.

Using such an STM, the STS holds a scanning system at each measurement point at the time of measurement, and also holds a drive voltage of an actuator for controlling the distance between the probe part and the sample. The tunneling spectroscopy is performed by changing the voltage applied between the probe part and the sample and temporarily measuring the change in the current with the controls temporarily suspended.

Simultaneous measurement of AFM and STM or AFM
In order to perform simultaneous measurement of STS and STS, it is necessary to use a conductive cantilever-shaped probe component. Further, in order to perform measurement with good resolution, it is necessary to make the shape of the probe component small, and it is desirable that the length is 200 μm or less, the thickness is several μm, and the width is 20 μm or less. Further, in order to stably detect the tunnel current, as the probe component material, a platinum-based metal material with a proven track record in STM is desirable.

Conventionally, as such a probe part, as shown in FIG.
There was something like that. (A) The probe part shown in the figure is formed by cutting a ribbon-shaped tungsten or platinum foil with a nipper or the like and sharpening the tip by electrolytic polishing. (B) In the probe part shown in the figure, a conductive metal material such as stainless steel foil is formed on the cantilever portion having the shape shown in the figure by using photo-etching or the like, and the conductive tip ( For example, diamond is ion-implanted to have conductivity) and is bonded and bonded with a conductive adhesive. (C) The probe part shown in the figure
The surface of a cantilever-shaped probe part formed in the shape shown in the figure by micromachining of silicon nitride is thinly coated with platinum by sputtering or the like.

[0007]

However, in the production of the probe component obtained by processing the metal foil shown in the above-mentioned prior art, the probe component shown in FIG.
Width 400-700 μm, thickness 20-50 μm, length 60
The size limit was 0 to 800 μm. Further, it is difficult to obtain stable characteristics from the processing method, and this probe component cannot be accurately measured because it is used while being inclined with respect to the sample. The probe part shown in (b) has a high resonance frequency in order to reduce the effect of vibration as a probe, and the cantilever part should have a small spring constant so that it can detect even a small force. However, because of the structure in which the cantilever portion and the diamond tip are bonded together, it is difficult to manufacture a small-sized one and sufficient characteristics cannot be obtained. Further, since the weight of the conductive chip and the weight of the adhesive become heavy, the mechanical resonance frequency becomes low. The probe part shown in (c) can be made small in dimension, but there is a problem that platinum is easily peeled off during measurement because the adhesion strength of the coated platinum is weak. Furthermore, it is convenient to fix it to a block made of metal or the like in order to handle the probe part made of thin metal foil, but to fix the metal foil with a thickness of several μm without wrinkles or scratches. It is very difficult, and the thickness of the metal foil is a few
There is also a problem that the thickness becomes thicker than 0 μm.

The present invention has been made in view of the above problems of the prior art, and an object thereof is to process a thin metal foil having a thickness of several μm into a cantilever-shaped probe part having a length of 200 μm or less. By fixing a metal block to this, it is possible to realize a probe part made of metal foil that can detect tunnel current stably, has good AFM operating performance, and is easy to handle and handle at low cost. It is in.

[0009]

A first structure of the present invention for solving the above-mentioned problems is to bring a cantilever-shaped probe part close to a sample up to a minute distance, and to provide a space between the probe part and the sample. Detecting the atomic force or magnetic force acting on the displacement of the probe component, by scanning the probe component on the sample surface, while measuring the shape and physical properties of the sample, The probe component is conductive, and the electrical characteristics of the sample are also measured by detecting a current flowing between the probe component and the sample when an arbitrary potential is applied to the probe component and the sample. A method for manufacturing the above-mentioned probe component, which is obtained by processing a metal foil used in a probe scanning microscope, wherein the probe component is an adhesive coating for applying an adhesive to a substrate such as a ceramic having a flat surface. Process,
By a metal foil bonding step of flatly laminating a thin metal foil having a thickness of several μm or less on this adhesive, and applying a photoresist on the metal foil, exposing and developing a plurality of desired patterns. A masking layer forming step of forming a desired masking layer, an etching step of etching and processing a plurality of the metal foils into a desired shape, and a metal block fixing of fixing the etched metal foils to a metal block. It is characterized in that it is manufactured by a step and an adhesive agent peeling step of melting the adhesive agent between the ceramic substrate and the metal foil with an organic solvent and peeling the probe component. In the second configuration, in the metal foil laminating step, after the metal foil is laminated on the ceramic substrate via the adhesive, the metal foil is pressed from above and below by a metal plate having a good flatness and the metal It is characterized by including a step of flattening the foil.
In the third configuration, in the etching step, after removing unnecessary portions of the metal foil and the masking layer by dry etching, the metal foil is slightly etched by 1 μm or less to flatten the surface of the metal foil. It is characterized by including a step of improving the degree and gloss. In a fourth configuration, in the fixing step of the metal block, the metal block is preliminarily plated with gold, low-temperature solder having a melting point of 80 ° C. to 200 ° C. is pre-soldered on the metal block, and a plurality of the metal blocks are etched. Cut the metal foil parts one by one, position the metal block on the metal foil at a predetermined position,
The method is characterized by including a step of gradually heating the metal block and the metal foil component by pressing at about 0.5 to 1 kg, then rapidly heating for a short time by a pulse heat reflow method, and then cooling. The fifth configuration uses a polyamide adhesive as the adhesive in the adhesive applying step, uses N-methyl-2pyrrolidone as an organic solvent in the adhesive removing step, and soaks in the organic solvent for several hours. It is characterized by including a step of stacking and spontaneously peeling. The sixth configuration is
The metal block fixing step is characterized in that the metal block and the metal foil are fixed using an epoxy adhesive that does not melt in the organic solvent N-methyl-2pyrrolidone used in the adhesive peeling step. And In addition, the seventh configuration includes a gold coating step of thinly coating gold on the metal foil after the metal foil overlapping step, and the thickness of the masking layer is adjusted to a thickness where the gold remains by etching. It is characterized by doing so. Also,
An eighth configuration is characterized in that the width of the metal block is slightly larger than the width of the metal foil.

[0010]

According to the present invention, a substrate such as a ceramic is coated with an adhesive, a metal foil is adhered thereto, a photoresist is coated thereon, a photomask is used for exposure, a masking layer is formed, and the metal foil is dry-etched. A plurality of pieces are processed, a metal block is fixed to a metal foil, and an adhesive is melted with an organic solvent to manufacture a probe part. Therefore,
A thin metal foil with a thickness of several μm can be finely processed to a length of 200 μm or less, a tunnel current can be stably detected, and handling such as handling is easy, and a large number of probe parts can be manufactured at once and at low cost.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a manufacturing process diagram showing an embodiment of a method of manufacturing a probe component in which a metal foil of the present invention is processed. The steps will be sequentially described. (A) Adhesive application step: After applying the polyamide-based adhesive 2 to the ceramic substrate 1, it is heat dried to evaporate the solvent contained in the adhesive 2 and bring it to a semi-dried state. (B) Metal foil stacking step: A platinum foil 3 having a thickness of several μm is stacked on the adhesive 2. This is pressed from above and below by a metal plate 4 (or a glass plate) having good flatness to spread the platinum foil 3 evenly and improve flatness. The adhesive 2 is cured by heating as it is. (C) Masking layer formation: A photoresist is applied by spin coating to an appropriate thickness on the platinum foil 3 which has been subjected to deburring and surface treatment such as degreasing. A photomask on which a plurality of desired shapes are formed is brought into close contact, exposed and developed to form a masking layer 5. (D) Etching step: The platinum foil 3 is processed by dry etching to form a plurality of platinum foils 3a having a desired shape. At this time, the masking layer 5 is also etched at the same time, but the thickness of the masking layer 5 is set so that the masking layer 5 remains until the etching of the platinum foil 3 is completed. When the thickness of the platinum foil 3 is T _pt , the etching rate is E _pt, and the etching rate of the masking layer 5 is E _m , the thickness T _m of the masking layer 5 is calculated by the following equation. After the T _m ≧ T _pt × E _m / E _pt masking layer 5 is removed, etching is further performed for a short time, and the surface of the platinum foil 3a is slightly processed to 1 μm or less to smooth the surface of the platinum foil 3a. Gives luster. This is necessary to form a good reflecting surface because the platinum foil surface becomes a reflecting surface when the displacement of the probe part is detected by the optical displacement sensor in the AFM. (E) Cutting process: Substrate 1 on which a plurality of platinum foils 3a are formed
Cut one by one. This is necessary to stabilize the soldering conditions and to facilitate the peeling work. (F) Metal block fixing step: A low melting point solder having a melting point of 80 ° C. to 200 ° C. is preliminarily soldered (solder layer 8) to the metal block 7 which is gold-plated (gold plated layer 6) in advance. Position this on the required position of the platinum foil 3a, and from the top about 0.5 ~
Press at about 1 kg. This is heated by a pulse heat reflow method or the like to melt the solder and cool it to fix the platinum foil 3a and the metal block 7 to each other. If the heating and cooling conditions are not proper, the platinum foil 3a will be wrinkled and cannot be used as a probe part. In this case, the platinum foil 3a is not wrinkled by soldering under the temperature conditions shown in FIG.
Gradually raise the work below the melting point of the solder and hold it for a while,
The temperature rises above the melting point rapidly. Place the work on the one with poor heat conduction and let it cool down. Depending on this temperature condition, platinum foil 3
It is possible to solder the platinum foil 3a and the metal block 7 without causing wrinkles on a. (G) Adhesive peeling step: The soldered platinum foil 3a and metal block 7 is immersed in the organic solvent 9 and left for several hours to dissolve the layer of the adhesive 2a, and the platinum foil 3a and the ceramic. The substrate 1a is separated. The platinum foil 3a is naturally peeled off so as not to be deformed or scratched. As the organic solvent 9, N-methyl-2pyrrolidone is used in order to easily dissolve the polyamide adhesive. (H) Completion: The platinum foil probe part is pulled out from the organic solvent 9, and if necessary, the residual organic solvent 9 is washed by alcohol replacement. Dry the solvent to complete.

In the probe component thus manufactured, the adhesive 2 is applied to the ceramic substrate 1 and the platinum foil 3 is applied.
Are adhered, coated with a photoresist, exposed with a photomask to form a masking layer 5, a plurality of platinum foils 3a are processed by dry etching, and a metal block 7 is fixed to the platinum foil 3a by soldering. Solvent 9
Then, the adhesive 2a is melted to produce a probe part. Therefore, the thin platinum foil 3 with a thickness of several μm is
It is possible to manufacture a large number of probe parts that can be finely processed to m or less, stably detect a tunnel current, and are easy to handle such as handling at a time. Further, in the metal foil bonding step shown in (b), the platinum foil 3 is superposed on the ceramic substrate 1 via the adhesive 2 and is pressed by the metal plate 4 having good flatness from above and below, so that the platinum foil 3 is flattened. You can Also,
(D) In the etching step shown in the figure, unnecessary portions of the platinum foil 3 and the masking layer 5 are removed by dry etching,
Furthermore, since the platinum foil 3a is slightly etched by 1 μm or less, the flatness and gloss of the surface of the platinum foil 3a can be improved.
Further, in the metal block fixing step shown in (f), the metal block 7 is plated with gold 6 and the low melting point solder is used as the preliminary solder 8
Preliminarily, positioning is performed on the platinum foil 3a cut one by one, and pressed from the top at about 0.5 to 1 kg, the metal block 7 and the platinum foil 3a are gradually heated and then rapidly heated to a temperature equal to or higher than the melting point of the solder, and gradually. Since it is cooled to 1, the wrinkles do not occur on the platinum foil 3a. Further, in the adhesive peeling step shown in (g), by infiltrating and dissolving the polyamide-based adhesive 2a in N-methyl-2pyrrolidone, which is the organic solvent 9, and peeling it naturally,
It is possible to manufacture a probe part that is free from deformation and scratches. Therefore, when incorporated in the AFM and displacement is detected by the optical displacement sensor, it is possible to manufacture a probe part having good light reflection characteristics.

FIG. 3 is a manufacturing process diagram showing another embodiment of the method for manufacturing a probe component in which a metal foil is processed according to the present invention. Figure 3
In the manufacturing process drawing of, the adhesive 10 is used as the process of fixing the metal block to the platinum foil. In FIG.
The steps from the adhesive application step in (a) to the cutting step in (e) are the same as the manufacturing steps in FIG. (F) In the metal block fixing step in the figure, the metal block 7 subjected to surface treatment
Then, an appropriate amount of the epoxy adhesive 10 that does not melt in N-methyl-2pyrrolidone, which is the organic solvent 9 used in the adhesive peeling step shown in FIG. The surface treatment of the metal block 7 is
Inexpensive surface treatment other than gold plating is sufficient. The amount of the adhesive 10 is set so as not to stick out from the platinum foil 3a and the metal block 7. The metal block 7 is positioned at a desired position on the platinum foil 3a, pressed from above, and temporarily dried by a pulse heat reflow method or the like. After that, the main drying is performed at about 100 ° C. to fix. The steps from the adhesive peeling step of (g) to the completion of (h) are the same as the manufacturing steps of FIG. 1.

In this case, since the method of fixing the metal block 7 to the platinum foil 3a uses the epoxy adhesive 10 that does not melt in the organic solvent 9, N-methyl-2pyrrolidone, the curing temperature of the adhesive 10 is Since the curing time can be lengthened at about 100 ° C., when the platinum foil 3a is not wrinkled and incorporated in the AFM and displacement is detected by an optical displacement sensor, it is possible to manufacture a probe part having good light reflection characteristics.

Next, in the AFM, an optical displacement sensor is often used to detect the displacement of the cantilever. The upper surface of the cantilever serves as a reflecting surface, and FIG. 4 shows the manufacturing process in the case of coating with gold to increase the reflectance. In the metal foil bonding step shown in (b), after the platinum foil 3 has been bonded, a gold coating step (b-1) in which gold is thinly coated 11 by plating or vapor deposition is provided. Other steps are the same as those in FIG. In this case, platinum foil 3
After being bonded to the ceramic substrate 1, a thin coating 11 of gold having a high reflectance is used, the thickness of the masking layer 5 is adjusted, and the gold coating surface is slightly processed by etching to improve the flatness and gloss. When the displacement is detected by the optical displacement sensor built in, it is possible to manufacture a probe part having good light reflection characteristics.

Next, the width of the platinum foil 3a is changed to the metal block 7
If the width of the platinum foil 3a is greater than or equal to the width of the platinum foil 3a, the platinum foil 3a protrudes from the metal block 7. Therefore, when the platinum foil probe component is handled with tweezers or the like after being fixed, there is a risk that the portion of the platinum foil 3a may be damaged. Therefore, as shown in FIG. 5, by making the width of the metal block 7a larger than the width of the platinum foil 3a, the platinum foil 3a will not be hit when it is handled with tweezers, and the platinum foil 3a will not be damaged.

In the above embodiment, the metal foil is not limited to the platinum foil, and may be any material that can be processed into a thin foil such as gold, tungsten or stainless steel.

[0018]

As described above in detail with reference to the embodiments, according to the present invention, a thin metal foil having a thickness of several μm is processed into a cantilever-shaped probe component having a length of 200 μm or less, By fixing a metallic block to this, the tunnel current can be detected stably, and the AFM operation performance is good.
In addition, it is possible to realize a probe component that is processed from a metal foil that is easy to handle and is inexpensive.

[Brief description of drawings]

FIG. 1 is a manufacturing process diagram showing an example of a method of manufacturing a probe component in which a metal foil of the present invention is processed.

FIG. 2 is a diagram showing temperature conditions when soldering a platinum foil.

FIG. 3 is a manufacturing process chart showing another embodiment of the method for manufacturing a probe component in which the metal foil of the present invention is processed.

FIG. 4 is a manufacturing process chart showing another embodiment of the method for manufacturing a probe component in which the metal foil of the present invention is processed.

FIG. 5 is a view showing another embodiment of the probe component in which the metal foil of the present invention is processed.

FIG. 6 is a conventional example of a probe component.

[Explanation of symbols]

 1, 1a Ceramic substrate 2, 2a, 10 Adhesive 3, 3a Platinum foil 4 Metal plate 5 Masking layer 6 Gold plating layer 7, 7a Metal block 8 Solder layer 9 Organic solvent 11, 11a Gold coating layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Oya 2-932 Nakamachi, Musashino City, Tokyo Yokogawa Electric Co., Ltd. (72) Tomoaki Nanko 2-932 Nakamachi, Musashino City, Tokyo Horizontal Within Kawa Denki Co., Ltd.

Claims (8)

[Claims] 1. A cantilever-shaped probe component is brought close to a sample up to a minute distance, and atomic force or magnetic force acting between the probe component and the sample is detected as a displacement of the probe component. By scanning the probe surface on the sample surface, the shape of the sample, the physical properties of the surface, and the like are measured, and the probe component is electrically conductive. The probe component processed with a metal foil used in a probe scanning microscope or the like for measuring the electrical characteristics of the sample by detecting a current flowing between the probe component and the sample when an electric potential is applied. In this probe component, an adhesive applying step of applying an adhesive to a substrate such as a ceramic having a flat surface, and a thin metal foil having a thickness of several μm or less are flattened on the adhesive. And the metal foil bonding process Masking layer forming step of forming a desired masking layer by applying a photoresist on the metal foil, exposing and developing a plurality of desired patterns, and etching the metal foil into a desired shape. An etching step of processing a plurality of pieces, a metal block fixing step of fixing the etched metal foil to a metal block, and the probe by melting the adhesive between the ceramic substrate and the metal foil with an organic solvent. An adhesive peeling step of peeling a component, and a method of manufacturing a probe component made by processing a metal foil, characterized by being manufactured by: 2. The method for manufacturing a probe component, which is produced by processing a metal foil according to claim 1, wherein the metal foil bonding step comprises stacking the metal foil on the ceramic substrate via the adhesive and then applying the metal foil. A method of manufacturing a probe component processed with a metal foil, comprising the step of pressing the metal foil from above and below with a metal plate having good flatness to flatten the metal foil. 3. The method of manufacturing a probe component processed with a metal foil according to claim 1, wherein in the etching step, after removing unnecessary portions of the metal foil and the masking layer by dry etching, the metal foil is removed. 1. A method of manufacturing a probe part processed from a metal foil, comprising the step of improving the flatness and gloss of the surface of the metal foil by slightly etching the metal foil by 1 μm or less. 4. The method for manufacturing a probe component, which is produced by processing a metal foil according to claim 1, wherein, in the step of fixing the metal block, the metal block is preliminarily plated with gold, and the melting point is 80 ° C. to 200 ° C. Is pre-soldered to the metal block, the plurality of etched metal foil parts are cut one by one, the metal block is positioned at a predetermined position on the metal foil, and pressed with about 0.5 to 1 kg. A method of manufacturing a probe component processed with a metal foil, comprising the steps of gradually heating the metal block and the metal foil component, followed by rapid heating for a short time by a pulse heat reflow method and cooling. 5. The method for manufacturing a probe component processed with a metal foil according to claim 1, wherein a polyamide adhesive is used as the adhesive in the adhesive applying step, and N is used as an organic solvent in the adhesive removing step. A method for producing a probe part, which is a processed metal foil, comprising a step of dipping methyl-2pyrrolidone in the organic solvent for several hours to spontaneously peel it off. 6. The method for manufacturing a probe component processed with the metal foil according to claim 1, wherein the metal block fixing step is N-methyl-2pyrrolidone which is the organic solvent used in the adhesive peeling step. A method of manufacturing a probe component processed with a metal foil, characterized in that the metal block and the metal foil are fixed to each other using an epoxy adhesive that does not melt. 7. A method of manufacturing a probe component, which is produced by processing a metal foil according to claim 1, further comprising a gold coating step of thinly coating gold on the metal foil after the metal foil stacking step, A method for manufacturing a probe component processed from a metal foil, characterized in that the thickness of the masking layer is adjusted by etching to a thickness at which the gold remains. 8. The method for manufacturing a probe component, which is produced by processing a metal foil according to claim 1, wherein the width of the metal block is slightly larger than the width of the metal foil. Manufacturing method of the probe parts.