JP2000077833A - Electrode forming method and pyroelectric infrared sensor using the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form the electrode for mounting precise part in high accuracy, to achieve the efficiency of the process and to attribute to the compact configuration and the low cost of the part. SOLUTION: A thin film electrode 12 is formed on a glass board 11. After the patterning with photolithography etching, solder paste is printed and inputted into a reflow furnace. Thus, the electrode having the excellent height and the uniform shape can be readily formed. Burr and the like are not generated in the electrode, The weak and minute part can be directly mounted. The efficiency is excellent. Furthermorer, the method is suitable for the formation of the complicated shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to sensors, oscillators, etc.
The present invention relates to a method for forming electrodes of a small electronic component and a pyroelectric infrared sensor using the same.

[0002]

2. Description of the Related Art Various methods for mounting components on a substrate have been devised and widely used. Among them, the formation of bumps on the substrate electrode is one of the key technologies in the field of semiconductors and the like.

FIG. 8 is a perspective view showing an example of a method called a face-down method. 8, 81 is a member, 82 is a member electrode, 83 is a bump, 84 is a substrate, 85
Is a wiring pattern. The member 81 has an IC or the like mounted inside, and is electrically connected to the outside by a member electrode 82. The bumps 83 are formed on the member 81 using a capillary or the like, and then leveled by a method such as pressing the bumps 83 against a flat plate to form a flat portion.

[0004] Thereafter, a conductive paste is applied to the bumps 83 and placed in alignment with the wiring pattern 85 on the substrate 84 by a mounting machine such as a flip chip bonder. Implemented. Thereafter, a resin material for sealing is applied to the electrode portions joined in some cases. In addition to this method, it is of course possible to form bumps on electrodes on the substrate side.

[0005] At the time of these mountings, the bump forming method, the shape, the shape variation, and the like greatly affect the price, external dimensions, and reliability of the product. The method of forming the bump
It covers a wide variety such as plating, vacuum deposition, printing, and wire bonding. The material is nickel, gold,
Solder and the like.

FIG. 9 is a cross-sectional view showing an example of a conventional bump forming method using wire bonding.

In FIG. 9, reference numeral 91 denotes a capillary, 92 denotes a wire, 93 denotes a substrate, 94 denotes an electrode, and 95 denotes a bump. A wire 92 made of gold or the like is passed through the inside of the capillary 91, and a substantially spherical portion is formed at the tip of the wire 92 by melting. A substantially spherical portion is pressed against the electrode 94 on the substrate 93 in the molten state of the wire tip.
Thereafter, the tip end of the wire is cooled and solidified, and pulled up while drawing an arc, whereby a bump 95 is formed on the substrate 93.

FIG. 10 is a perspective view showing an example of a conventional pyroelectric infrared sensor mounted on a stem.

In FIG. 10, reference numeral 101 denotes an element portion;
a and 102b are wires, and 103 is a stem. The element portion 101 is mounted on the center of the stem 103 by a die bonder using resin. Thereafter, the electrode part of the element part 101 and the foot for taking out output to the outside provided on the stem 103 are connected by wires 102a and 102b by a wire bonder. No bump is used for mounting the sensor and taking out the output, and a fixed portion and an output taking place are separated.

FIG. 11 is a perspective view showing details of the element portion of the pyroelectric infrared sensor shown in FIG.

In FIG. 11, reference numeral 111 denotes a substrate;
Reference numerals a and 112b denote electrode portions, 113 denotes a light receiving portion, 114 denotes an etching hole, and 115 denotes a cavity portion. The element portion is formed on the substrate 111 by using a thin film forming method such as sputtering, and a patterning technique such as photolithography and etching. The light receiving section 113 has a pyroelectric element section mainly made of PLT or the like, and a three-layer structure in which the electrode sections 112a and 112b vertically sandwich the pyroelectric element section. The entire surface is covered with a thin resin such as polyimide, and an etching hole 114 is provided in a part. The substrate 111 is brought into contact with the etching solution only in the portion of the etching hole 114,
The substrate 111 immediately below 3 is removed to form the cavity 115.

When infrared rays are incident on the light receiving section, the temperature of the pyroelectric element section rises and charges are generated by the pyroelectric effect. This electric charge is taken out by the upper and lower electrodes and used as an output signal. At this time, if the substrate is present immediately below the light receiving unit, the rise of the temperature of the pyroelectric element unit is hindered by the escape of heat to the substrate, and the output signal level is greatly reduced. Therefore, by hollowing just below the light receiving unit,
The sensitivity of the sensor can be improved.

[0013]

In recent years, members such as vibrators and sensor elements have become lighter and thinner and smaller, and the method of joining members when mounting, the shape of electrodes on the substrate side, and the like have been adjusted. I'm under pressure. For a wide range of applications, miniaturization, low cost, and high performance are essential, and it is necessary to conduct verification from a wide perspective in electrode formation and mounting, with this in mind. Conventional methods of providing bump electrodes on a substrate often have advantages and disadvantages.

For example, in the conventional wire bonding method, the bump shapes are easy to be uniform. However, since the work is performed for each electrode location, the work time increases in proportion to the number of bumps. And cost are determined, and are not suitable for cost reduction. In addition, since burrs are generated on the bumps, it is necessary to make the heights uniform by a labeling process.

[0015] In the method by plating or vacuum deposition, there is a problem that efficiency is poor because time is required for forming according to the thickness of the electrode. The conventional printing method can reduce the number of openings by batch processing, but has a problem in that the shape varies widely.

On the other hand, in the case of a pyroelectric infrared sensor, in the conventional mounting method, mounting by face-down is impossible because the substrate exists below the light receiving portion, and the height of the product is equivalent to the thickness of the substrate and the height of the wire. In addition, the wire is at a position higher than the light receiving section, and the Si window when enclosing the element section must be fixed at a position away from the light receiving section, and it is larger for securing the visual field. The necessity of a window has affected the product shape and material cost.

In addition, the element portion needs to be sealed from the viewpoints of ensuring performance and reliability, and in some cases, a specific gas may be sealed. It is conceivable that the performance is degraded due to the influence of gas generated over time. Therefore, in order to ensure the performance of the pyroelectric infrared sensor, and to satisfy more miniaturization and high reliability, the element part can be mounted face down without using a resin paste or the like. It is desirable.

The present invention provides a method for forming an electrode having low cost and high reliability, and using the method, a more compact,
It is an object of the present invention to provide a pyroelectric infrared sensor that achieves low cost.

[0019]

SUMMARY OF THE INVENTION In order to solve this problem, the present invention uses a glass material as a substrate material, forms a thin-film electrode by a method such as sputtering, forms an island-like electrode by etching, and then forms a screen. A solder paste is applied by a printing method, put into a reflow furnace, melted and cured to form a solder electrode (bump). Further, a through hole is formed by sandblasting directly below the solder electrode, and a conductive material is applied inside the through hole.

Further, the thin film element of the pyroelectric infrared sensor formed on the MgO substrate is formed into a foil shape by removing MgO by etching, and the electrode portion on the back surface of the element portion is directly pressed against the solder electrode to be heated and joined. , The foil-like element portion is held hollow.

Thus, a solder electrode having a height capable of holding the foil-shaped element portion in a hollow state can be efficiently and accurately formed on the substrate. Further, the output of the element portion can be efficiently taken out to the back surface of the substrate by the through hole immediately below the solder electrode. Since the element portion is in the form of a foil and is mounted face-down, it is possible to reduce the size as compared with the related art, and to suppress the escape of heat from the light receiving portion by holding in a hollow shape, without deteriorating the performance of the sensor. In addition, since it is mounted by direct bonding between metals,
This is shorter than the conventional process of fixing the element portion and conducting by a wire, and is not affected by gas due to a resin paste or the like, which is advantageous from the viewpoint of ensuring long-term performance.

[0022]

DETAILED DESCRIPTION OF THE INVENTION According to the first aspect of the present invention, there is provided a step of providing an island-shaped flat electrode on a glass substrate by a thin film forming method and an etching method, and applying the solder paste by a screen printing method to the flat electrode. It is an electrode forming method that has a step of coating on the top and a step of melting the solder paste by heating, and is efficient because all steps are batch processing.
In addition, even if the applied solder paste protrudes from the island electrode, it hardly exists on the glass substrate after heating and condenses on the island electrode, and the solder electrode can be formed only on the island electrode. Solder electrodes can be formed well, and in addition, the shape of the solder electrodes is almost determined by the amount of solder paste applied and the shape of the island-shaped electrodes, so that there is little variation in shape and solder electrodes of any height can be easily formed. The formed electrode has an effect such that there is no burr or the like and the bonding property with the mounting member is good even without a treatment such as labeling.

According to a second aspect of the present invention, a solder paste is applied to a larger area than the island-shaped electrode by screen printing using a mask having an opening having a larger area than the island-shaped flat electrode. 2. The electrode forming method according to claim 1, wherein the solder paste is applied more widely than the surface of the island-shaped electrode, and after the heating, all are agglomerated on the island-shaped electrode, so that the positioning at the time of printing is easy. Has an effect that a higher solder electrode can be formed since the amount of the applied electrode can be increased.

According to a third aspect of the present invention, there is provided a screen printing method for the island-shaped electrode having a substantially circular or substantially square shape, using a mask which is 1 to 1.5 times the diameter or each side dimension. 3. A method for forming an electrode according to claim 2, wherein the solder paste is applied by a method, and the diameter or side dimension of the island-shaped electrode is from 0.1 mm to 0.5 mm, and has the same function as the invention according to claim 2. In addition, it has the effect of preventing problems such as the solder electrode swelling due to excessive solder paste, protruding beyond the outer shape of the island-shaped electrode, and causing leakage with other members.

According to a fourth aspect of the present invention, a lower plane electrode of another material is provided below the uppermost plane electrode of a certain material, and the lower plane electrode has an area of the uppermost plane electrode and
The lower plane electrode has at least a larger area than the application area of the solder paste, and the lower plane electrode is made of a material having a lower wettability with the solder material than the uppermost plane electrode. The electrode forming method according to any one of claims 1 to 3, wherein, after the formation, the lower layer flat electrode other than immediately below the solder electrode portion is removed by etching.
Since the solder is agglomerated in the uppermost flat electrode, the solder electrode can be formed with high precision, and the lowermost flat electrode is removed by etching after the formation of the solder electrode, so that the surface of the glass substrate is kept in a more clean state. It has the effect of eliminating the influence on the process.

According to a fifth aspect of the present invention, there is provided the electrode forming method according to the fourth aspect, wherein chromium is used as the lower plane electrode material and copper is used as the uppermost plane electrode. It hardly exists on chromium and has the same effect as in claim 4.

According to a sixth aspect of the present invention, the thickness of the lower plane electrode provided on the plane of the glass substrate is 300 to 1500.
The electrode forming method according to claim 5, wherein the thickness of the angstrom uppermost flat electrode is 1.5 to 2.5 m.
In the process of the present invention, there is an effect that the adhesion to the glass substrate is good and the island-shaped electrode is hardly damaged by electrode erosion due to ordinary eutectic solder or the like.

The invention according to claim 7 is the electrode forming method according to claim 4, wherein titanium is used as the lower plane electrode material and palladium is used as the uppermost plane electrode. Have.

According to the present invention, the thickness of the lower flat electrode provided on the flat surface of the glass substrate is from 1500 to 250.
8. The electrode forming method according to claim 7, wherein the thickness of the top flat electrode is 0.5 to 1 μm.
It has an effect that corrosion resistance and the like are more excellent.

According to a ninth aspect of the present invention, there is provided the electrode forming method according to any one of the fourth to eighth aspects, wherein the glass substrate is heated before applying the solder paste to oxidize the surface of the lower planar electrode. This has the effect that the wettability between the flat electrode and the solder is further reduced and the effect is enhanced.

According to a tenth aspect of the present invention, as the solder paste material, tin: 6% by weight based on the whole of the main material is used.
The method for forming an electrode according to any one of claims 1 to 9, wherein a high-temperature solder of about 8 to 8%, 75 to 85% of lead, and 1 to 2% of silver is used. In this case, the process of the present invention can be performed without damaging the island-shaped electrode, and the use of high-temperature solder has the effect of forming a solder electrode that can withstand a higher-temperature process.

[0032] According to an eleventh aspect of the present invention, after the through hole is formed in the glass substrate, an island-shaped electrode having a larger area than the through hole is formed, and the solder paste is printed and melted by heating. 10. The electrode forming method according to any one of the items 10, wherein the solder electrode and the back surface of the glass substrate can be directly conducted through the through hole for a short distance, and if the diameter of the through hole is about 0.2 mm, the solder penetrates. There is almost no filling in the holes, and the solder electrode shape is maintained uniformly.

According to a twelfth aspect of the present invention, after a through-hole is formed in a glass substrate, an island-shaped electrode having a larger area than the through-hole is formed. The method for forming an electrode according to any one of claims 1 to 11, wherein after the material layer having wettability is simultaneously formed on the back surface and inside the through hole, solder paste printing and heat melting are performed. It has an effect that it penetrates into the through hole along the material layer and forms an alloy so that conduction can be obtained on both surfaces of the glass substrate.

According to a thirteenth aspect of the present invention, there is provided the electrode forming method according to any one of the first to tenth aspects, wherein after the island-shaped electrodes are formed, a through hole is formed in the glass substrate by sandblasting from the back surface of the island-shaped electrodes. Yes, the glass substrate, which is a brittle material, is easily processed by sand blasting, and can be processed in accordance with the position of the island-shaped electrodes, so that it is easy to visually align it. Since the diameter becomes smaller, it is difficult for the solder to flow into the through-hole during subsequent solder paste printing and heating and melting, the shape of the solder electrode is maintained, and in addition, a conductive material is injected into the through-hole from the back surface, that is, the injection side. When applying, there is an effect that the application is easier because of the inclination.

According to a fourteenth aspect of the present invention, there is provided any one of the first to tenth aspects, wherein after forming an island-shaped electrode, printing a solder paste, and heating and melting, a through hole is provided directly below the electrode by sandblasting from the opposite side. In the electrode forming method described above, since the processing rate of solder is slower than that of glass, processing is delayed at the solder portion, uniform through holes can be formed, and abrasive grains of sand blast wrap around the back surface and the solder electrode and the surroundings This has the effect of preventing damage to the glass part.

According to a fifteenth aspect of the present invention, the light-receiving element portion has a foil shape, and has an extraction electrode on the back surface on the light-receiving side. A soldering electrode formed by the method for forming an electrode is bonded to ensure mounting and conduction, and the light receiving element is a pyroelectric infrared sensor that is held in a hollow state. Since it is directly mounted on the electrodes, the overall size is reduced, and if the joints of the two electrodes are directly alloyed, there is no risk of gas generation seen in resin paste, etc. In addition, when the glass substrate is bonded to the glass substrate with a glass material, silicon, or the like during sealing, it has an effect of preventing generation of gas at the sealing portion.

FIG. 1 is a perspective view showing an example of a process for forming a pad electrode (island electrode) and a three-dimensionally formed bridge electrode (solder electrode) on a substrate.

In FIG. 1, reference numeral 11 denotes a substrate, 12 denotes a film forming unit, 13 denotes a pad electrode, 14 denotes a printing unit, and 15 denotes a bridge electrode. First, a film forming unit 12 is formed on the surface of the substrate 11 with a substantially uniform film thickness over the entire central part of the surface of the substrate 11 by a method such as sputtering. The material of the substrate 11 is glass,
For the material of the film forming unit 12, for example, Cr is firstly provided in order to secure adhesion to glass, and Cu is used in the second layer in consideration of wettability with solder or the like to be printed in a later step. Used.

Subsequently, a plurality of pad electrodes 13 are formed in the film forming section 12 by photolithography and etching. Thereafter, a solder paste is applied on the pad electrode 13 and the printed portion 1 is formed.
4 is formed. The solder paste is applied by using a screen printing method, and the size of the opening of the print mask pattern is made larger than the size of the pad electrode 13. After that, the substrate 11 is heated by a reflow furnace or the like, the printing unit 14 is melted and cooled, and the bridge electrode 15 is formed.

Since the opening of the print mask is wider than the size of the pad electrode 13, even when a displacement or the like occurs during printing, a printed portion can be completely provided on the pad electrode. Furthermore, since the substrate material is glass, the wettability with the solder is poor and no solder electrodes are formed on the glass, and almost all the printed portions are concentrated on the pad electrodes.
Therefore, the position of the bridge electrode is determined by the position of the pad electrode irrespective of the displacement during printing or the like. In addition, if the area of the printed portion is large, it contributes to the formation of a higher bridge electrode.

A bridge electrode can be similarly formed by the following method. FIG. 2 is a perspective view showing an example of a process of forming an island-like pad electrode and a bridge electrode having a three-dimensional shape on a substrate.

In FIG. 2, 21 is a substrate, 22 is a film forming section, 23 is a pad electrode, and 24 is a bridge electrode. As in FIG. 1 described above, a film forming unit 22 is provided on a substrate 21. At this time, the film forming unit 22 is made of a material having good adhesion to the substrate 21 and poor wettability with a material to be printed in a later step;
It has a structure of two layers or more of a material having good wettability with the printing material.

For example, Cr is provided on the first layer which is in close contact with the substrate, or Cu is provided on the second layer, or Ti is provided on the first layer and Pd is provided on the second layer. Subsequently, the pad electrode 23 is formed only on the second layer by photolithography and etching.
A solder paste or the like is applied by printing on 3, and the bridge electrode 24 is formed by heating and cooling. Alternatively, before printing the solder paste, the substrate is left in the air at 100 ° C. for 30 minutes to oxidize the whole. In this case, the first layer is oxidized, and the wettability with the solder is reduced to increase the selectivity.
Layers are also oxidized. Therefore, it is preferable that the resist in the photolithography is kept covered on the second layer during the oxidation treatment, and the resist is removed after the heat oxidation. Finally, the first layer of the film forming part 22 other than immediately below the bridge electrode 24 is removed by etching.

According to this method, only the second layer is etched using the photolithographic resist.
The resist only needs to be resistant to the etching solution for the second layer, and the range of choice is widened. Further, since the wettability between the first layer and the printing material is poor, even if a substrate made of a material other than glass
Similarly to the above, a bridge electrode can be formed well. Further, the contamination of the flux or the like at the time of forming the bridge electrode can be removed at the same time as the removal of the film formation portion, and the substrate surface can be kept clean.

The material and thickness of the pad electrode used for forming these electrodes are important factors for determining the quality of the finished electrode. If the thickness is too large, the material cost and the time required for formation are increased. Conversely, if it is too thin, the pad electrode will be damaged by solder erosion, or the electrode itself will peel off. In the present embodiment, specifically, in the case of a Cr-Cu system, good results are obtained when the Cr thickness is 300 to 1500 angstroms and the Cu thickness is 1.5 to 2.5 microns. Similarly, in the case of Ti-Pd, the Ti thickness is from 1500 to 250.
0 Å, Pd thickness 0.5 to 1 micron.

However, there is an exception in high-temperature solder paste materials other than ordinary eutectic solder. For example, a lead-free and Sn-rich solder hardly eats Cu. In the case of high-temperature solder, tin: 6
Some of the compositions having a melting point of about 300 ° C. in compositions having a composition of ８8%, lead: 75-85, and silver: 1-2%, and the pad electrode had a good finish with almost no damage. Therefore, by using this material, a bridge electrode stronger than other processes can be formed.

It is needless to say that the above method can be applied to the present invention even if the film forming material and the printing material are other than those in the present embodiment, as long as they have similar properties. In addition to the two-layer film forming material, even if the structure is more complicated, such as providing Au on the surface in order to further enhance the wettability with solder, it can be carried out in the same manner as this embodiment.

By opening a through hole immediately below the electrode and extracting the electrode from the back surface of the substrate, it is possible to reduce the size of the substrate and mount it on another substrate.

FIG. 3 is a cross-sectional view showing a step of forming a through hole in a substrate immediately below an electrode. In FIG. 3, 31 is a substrate,
32 is a through hole, 33 is a pad electrode, 34 is a solder paste, and 35 is a bridge electrode. First, a through hole 32 is formed in the substrate 31. At this time, the diameter of the through-hole on one side is made smaller than the diameter of the other. Next, on the side of the narrow hole of the through hole 32,
The pad electrode 33 is formed so as to cover the entire diameter. Next, the solder paste 34 is printed and heated by a reflow furnace to obtain a bridge electrode 35. The through hole is narrow on the printing side and gradually widens toward the opposite side, the printed solder paste is difficult to contact with the inner surface of the hole, and if the inside of the through hole is also glass, poor wettability, The solder paste is almost sucked up on the pad electrode. Therefore, in this case, there is little possibility that the shape and height of the bridge electrode vary.

FIG. 4 is also a cross-sectional view showing a step of forming a through hole and an electrode in a substrate immediately below an electrode.

In FIG. 4, 41 is a substrate, 42 is a through hole, 43 is a pad electrode, 44 is a back electrode, 45 is a solder paste, and 46 is a bridge electrode. First, a through hole 42 is formed in the substrate 41, and a pad electrode 43 is formed on a narrow through side surface of the through hole 42. Then, the back electrode 44 is formed on the opposite surface.
Is formed of a material such as copper having conductivity and good wettability with a solder material by a sputtering method. In some cases, a two-layer structure of chromium-copper or the like is used in consideration of adhesion to glass. Subsequently, a solder paste 45 is printed on the pad electrode 43, and is heated and melted to form a bridge electrode 46.
In this case, the effect is that the solder paste and the back surface electrode are closely adhered inside the through hole during heating, and a part of the inside of the through hole is filled with the solder material. In addition, when the reliability of conduction is further increased, the inside of the through-hole is filled with a conductive paste or the like. However, since the inside of the through-hole is filled with the solder material, connection between the two is easy.

FIG. 5 is also a cross-sectional view showing a process of forming a through hole and an electrode in a substrate immediately below an electrode.

In FIG. 5, 51 is a substrate, 52 is a pad electrode, 53 is a back surface resist, 54 is a resist hole, 55 is a through hole, 56 is a solder paste, and 57 is a bridge electrode. A pad electrode 52 is formed on the substrate 51 by a method such as sputtering. Thereafter, a backside resist 53, which is a photosensitive resin material, is applied to the backside, and a resist hole 54 is formed immediately below the pad electrode 52 by photolithography. Thereafter, SiC abrasive grains and the like are sprayed on the back side by sandblasting. The back surface resist 53 has a smaller abrasion amount due to the abrasive spray than the glass substrate 51. Therefore, the glass substrate 51 is processed through the resist holes 54. By this method, a brittle material such as glass can be processed with high accuracy, and the shape of the through hole 55 becomes narrower from the injection side to the penetration side, so that a desired shape is automatically obtained. Thereafter, the backside resist 53 is peeled off, and a bridge electrode is similarly obtained by printing and heating the solder paste 56.

FIG. 6 is also a cross-sectional view showing a process of forming a through hole and an electrode in a substrate immediately below an electrode.

In FIG. 6, reference numeral 61 denotes a substrate; 62, a pad electrode; 63, a bridge electrode;
Is a resist hole, and 66 is a through hole. The pad electrode 62 and the bridge electrode 63 are formed on the substrate 61 by the same method as described above. Next, similarly to FIG. 5, a back surface resist 64 and a resist hole 65 are formed on the back surface, and sandblasting is performed. As a result, a through hole 66 is formed. However, since the solder material is hardly affected by processing by sand blast,
The processing is almost stopped at the bridge electrode 63.
Finally, the back surface resist 64 is peeled off to complete. According to this method, the processing of the through-hole is hindered by the bridge electrode, so that excessive processing of the substrate can be prevented, and the shape of the through-hole can be made more uniform. In addition, even after some member is mounted on the bridge electrode, the through hole can be processed.

FIG. 7 is a perspective view showing an example of mounting a pyroelectric infrared sensor in the form of a foil on the electrodes formed in this step.

In FIG. 7, reference numeral 71 denotes a substrate;
b is a bridge electrode, 73 is a light receiving section, and 74a and 74b are element side electrodes. The pyroelectric infrared sensor element mainly includes a light receiving portion 73 made of a pyroelectric material and element-side electrodes 74a and 74b made of platinum or the like, and has a foil shape reinforced with a polyimide resin or the like. When infrared rays are incident on the light receiving section 73 and there is a temperature change, electric charges are generated, and both element-side electrodes 7
It is output between 4a and 74b. Element-side electrodes 74a, 74
b and the bridge electrodes 72a and 72b are joined by melting and solidification of the solder, and the sensor element is held hollow. Therefore, the output from the light receiving section is taken out to the outside by the bridge electrode.

According to this configuration, since the sensor element is held in a hollow shape in the form of a foil, scattering of heat from the light receiving portion is suppressed, and high sensor sensitivity can be secured. Further, the height can be significantly reduced, which contributes to downsizing of the sensor. By providing a through hole and an electrode below the bridge electrode, the sensor output can be easily taken out on the back surface of the substrate, which contributes to the packaging of the sensor element. In addition, since a material that emits gas such as a resin is not used for bonding, a change in sensor sensitivity due to an atmosphere change can be prevented. In addition, since the substrate material is glass, it can be directly bonded to glass, silicon, or the like at the time of package production, which contributes to prevention of gas release and reduction in package cost due to integrated formation.

[0059]

As described above, according to the present invention, a plurality of solder electrodes can be easily formed integrally on a glass substrate at a high height, and subsequent direct mounting of members is easy and contributes to cost reduction. Further, by utilizing the non-wetting property of the glass and the solder material, a highly accurate solder electrode can be formed. In addition, a through hole can be easily provided in the glass substrate directly under the solder electrode by a sand blast method, and the electrode can be easily taken out to the back surface of the substrate.

A pyroelectric infrared sensor element in the form of a foil can be held and mounted in the electrode in this process in a hollow manner, so that the sensor sensitivity can be prevented from lowering and the height can be significantly reduced. In addition, since the bonding between the electrodes is a direct bonding between metals, there is little concern about outflow of gas over time, and not only can the influence on the sensor sensitivity be avoided, but also the direct bonding between the glass substrate and silicon, etc. Higher sensor sensitivity and reliability can be achieved by gas filling or the like.

[Brief description of the drawings]

FIG. 1 is a manufacturing process diagram of an electrode on a substrate according to an embodiment of the present invention.

FIG. 2 is a process chart of manufacturing an electrode on a substrate according to the embodiment.

FIG. 3 is a view showing a manufacturing process of a through hole according to the embodiment.

FIG. 4 is a view showing a manufacturing process of a through hole according to the embodiment.

FIG. 5 is a view showing a manufacturing process of a through hole in the embodiment.

FIG. 6 is a view showing a manufacturing process of a through hole according to the embodiment.

FIG. 7 is a perspective view showing a pyroelectric infrared sensor after mounting in the embodiment.

FIG. 8 is a manufacturing process diagram showing a conventional electrode forming method.

FIG. 9 is a manufacturing process diagram showing the conventional electrode forming method.

FIG. 10 is a perspective view showing a configuration of a conventional pyroelectric infrared ray.

FIG. 11 is a perspective view showing a configuration of an element portion of a conventional pyroelectric infrared sensor.

[Explanation of symbols]

11, 21, 31, 41, 51, 61, 71, 84, 9
3 Substrate 13, 23, 33, 43, 52, 62 Pad electrode (island electrode) 15, 24, 35, 46, 57, 63, 72a, 72b
Bridge electrode (solder electrode) 32, 42, 55, 66 Through hole 73, 113 Light receiving section

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Koji Nomura 1006 Kazuma Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. F-term (reference) 2G065 AB02 BA13 BA14 DA20 5E319 AA03 AB06 AC04 AC17 BB05 CC33 CD60

Claims (15)

[Claims] 1. A step of providing an island-shaped planar electrode on a glass substrate by a thin film forming method and an etching method, a step of applying a solder paste on the planar electrode by a screen printing method, and a step of melting the solder paste by heating. An electrode forming method comprising: 2. The electrode forming method according to claim 1, wherein a mask having an opening having a larger area than the island-shaped flat electrode is used, and a solder paste is applied to a larger area than the island-shaped electrode by a screen printing method. Method. 3. An island electrode having a substantially circular or substantially square shape is coated with a solder paste by a screen printing method using a mask having a diameter or a dimension of 1 to 1.5 times each side, 3. The electrode forming method according to claim 2, wherein the diameter or side dimension of the island-shaped electrode is 0.1 mm to 0.5 mm. 4. A lower planar electrode of another material is provided below an uppermost planar electrode of a certain material, and the lower planar electrode is at least larger than an area of the uppermost planar electrode and an application area of a solder paste. The lower flat electrode has an area, and the lower flat electrode is made of a material having a lower wettability with the solder material than the uppermost flat electrode. After the solder paste is melted by heating to form the solder electrode, the solder electrode portion is etched. The electrode forming method according to any one of claims 1 to 3, wherein the lower planar electrode other than immediately below is removed. 5. Use of chromium as a lower plane electrode material,
5. The electrode forming method according to claim 4, wherein copper is used as the uppermost planar electrode. 6. The electrode forming method according to claim 5, wherein the thickness of the lower planar electrode provided on the plane of the glass substrate is 300 to 1500 angstroms, and the thickness of the uppermost planar electrode is 1.5 to 2.5 μm. 7. Titanium is used as a lower plane electrode material,
5. The electrode forming method according to claim 4, wherein palladium is used as the uppermost planar electrode. 8. The lower plane electrode provided on the glass substrate plane has a thickness of 1500 to 2500 angstroms, and the uppermost plane electrode has a thickness of 0.5 to 1 μm.
The electrode forming method according to the above. 9. The electrode forming method according to claim 4, wherein the glass substrate is heated before applying the solder paste to oxidize the surface of the lower planar electrode. 10. A solder paste material comprising 6 to 8% by weight of tin, 75 to 85% of lead, and
The electrode forming method according to any one of claims 1 to 9, wherein a high-temperature solder of silver: 1 to 2% is used. 11. The method according to claim 1, wherein after forming a through hole in the glass substrate, an island-shaped electrode having a larger area than the through hole is formed, and a solder paste is printed and heated and melted. Electrode formation method. 12. After forming a through hole in a glass substrate, an island-shaped electrode having a larger area than the through hole is formed, and a material layer having conductivity and wettability with solder is formed by a thin film forming method. The electrode forming method according to any one of claims 1 to 11, wherein the solder paste is printed and heated and melted after being simultaneously formed on the back surface and the inside of the through hole. 13. The electrode forming method according to claim 1, wherein after forming the island-shaped electrode, a through-hole is formed in the glass substrate by sandblasting from the back surface of the island-shaped electrode. 14. The electrode forming method according to claim 1, wherein after forming the island-shaped electrode, printing the solder paste, and performing heat melting, a through hole is provided directly below the electrode by sandblasting from the opposite side. 15. The light-receiving element section has a foil shape,
An extraction electrode is provided on the back surface on the light receiving side, and the extraction electrode and the solder electrode formed by the electrode forming method according to any one of claims 1 to 14 are joined to ensure mounting and conduction, and the light reception is performed. The element is a pyroelectric infrared sensor that is held hollow.