JP4165169B2 - Manufacturing method of flake type thermistor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a flake-type thermistor used in the field of optical communications, electronic devices such as home appliances and automobiles, printed circuit boards, and the like, and a method for manufacturing the same.
[0002]
[Prior art]
Conventionally, a thermistor called a flake type is known in which electrodes are formed on the upper and lower surfaces of a wafer-like thermistor body made of a ceramic material and then diced to a desired size.
Such a flake type thermistor is described in Patent Document 1 below, for example.
[Patent Document 1]
Japanese Utility Model Publication No. 56-89189
This flake-type thermistor is used in the optical communications field by die bonding the lower surface and wire bonding the upper surface, and as a temperature sensor, the lead wire is soldered to the upper and lower electrodes and pulled out, and the thermistor portion is made of various resins. Used by molding with material. Depending on the application, it may be inserted into a metal case or a resin case.
[0004]
[Problems to be solved by the invention]
However, the following problems remain in the conventional flake type thermistor technology. That is, in recent years, improvement in reliability such as weather resistance and migration resistance has been demanded. In particular, LD (semiconductor laser) modules and the like are in a state of being hermetically sealed by filling with nitrogen, and there is a disadvantage that a change in resistance value with time is large.
Further, since the electrode is formed and diced to form a flake, the peripheral edge surface of the electrode is peeled off at the time of dicing, and solder erosion may occur from the peeled portion.
Furthermore, when used as a temperature sensor used in the field of home appliances, automobiles, etc., it may be used under high temperature and high humidity, and in the case of resin moisture absorption and thermosetting resin, resin solidification occurs. In some cases, stress is applied to the thermistor molded on the electrode to cause electrode peeling or cracking.
[0005]
The present invention has been made in view of the above-described problems, and provides a flake type thermistor that can improve weather resistance and migration resistance, and can suppress the occurrence of electrode peeling and cracks, and a method for manufacturing the same. Objective.
[0006]
[Means for Solving the Problems]
The present invention employs the following configuration in order to solve the above problems. That is, the method for manufacturing a flake-type thermistor according to the present invention manufactures a flake-type thermistor in which electrode layers are formed on the upper and lower surfaces of a plate-like thermistor body, and all sides of the plate-like thermistor body are covered with a glass layer. A method of cutting a sheet on a sheet by cutting a substrate of a ceramic body having electrode layers respectively formed on upper and lower surfaces thereof into a lattice shape in a state of being attached to an adhesive sheet; A gap forming step in which a sheet is stretched in a radial direction to form a gap between the plurality of plate-like bodies, and the inside of the gap is filled with glass paste and cured, and then cut into a lattice at the center of the gap and separated. And a glass layer forming step of forming the glass layer on all sides by heat-treating the plate-like body.
[0016]
In this method for manufacturing a flake-type thermistor, the gap between the plate-like bodies on the stretched adhesive sheet is filled with glass paste and cured, and then the separated plate-like body is cut into a lattice at the center of the gap and heat-treated. And since a glass layer is formed in all the side surfaces, a glass layer can be simultaneously and efficiently formed in all four side surfaces of many plate-shaped bodies.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a flake type thermistor and a method for producing the same according to the present invention will be described with reference to FIGS.
[0018]
As shown in FIG. 1, the flake-type thermistor 1 of this embodiment has electrode layers 3 formed on the upper and lower surfaces 2 a of the plate-like thermistor body 2, and the entire side surface 2 b of the plate-like thermistor element 2 is the glass layer 4. Covered with. For example, in the optical communication field, the flake-type thermistor 1 has one electrode layer 3 bonded to a circuit board 5 with a conductive fusion material 6 such as Au / Sn, as shown in FIG. The electrode layer 3 is electrically connected to another electrode pad or the like on the circuit board 5 by wire bonding using a gold wire 7. As another example, in the field of home appliances, automobiles, etc., as shown in FIG. 3, lead wires 8 are bonded to both electrode layers 3 of the flake type thermistor 1 with solder 9 as a temperature sensor. The entire flake type thermistor 1 is sealed with a resin 10. A case may be provided so as to cover the whole.
[0019]
Next, the manufacturing method of this flake type thermistor 1 is demonstrated with reference to FIG.4 and FIG.5.
[0020]
First, as shown in FIG. 4 (a), a glass layer 4 is formed by applying and baking a glass paste on the upper and lower surfaces of a square flat plate thermistor body 2 made of ceramics by screen printing or the like. Next, the thermistor element body 2 after the glass layer 4 is formed is diced (cut) into strips to form a plurality of prismatic element bodies 11 as shown in FIG. Further, as shown in FIG. 4 (c), the glass layer 4 is formed on both side surfaces where the glass layer 4 is not formed in a state in which the glass layers 4 are overlapped with each other. Thus, a prismatic body 12 is obtained.
[0021]
Next, as shown in FIG. 5A, the prismatic body 12 of the thermistor body having the glass layer 4 formed on all sides is cut into a plurality of plate bodies 13 by cutting in a direction orthogonal to the central axis. To do. Further, as shown in FIG. 5B, a jig 14 having a plurality of recesses 14a formed on the upper surface in accordance with the plate-like body 13 is prepared, and the plate-like body 13 is arranged in the recess 14a. In this state, a conductive paste 15 such as Au or Ag paste is applied to the recesses 14a by screen printing or the like and baked (heat treatment) to form the electrode layer 3 on the surface of the plate-like body 13. Similarly, the electrode layer 3 is also formed on the back surface of the plate-like body 13.
Thus, the flake type thermistor 1 of this embodiment is produced.
[0022]
In this embodiment, since all the side surfaces of the plate-like thermistor body 2 are covered with the glass layer 4, the thermistor body material itself is not exposed, weather resistance (heat resistance, cold resistance, moisture resistance, etc.), Migration property, electrode bonding strength (wire bonding property), plating solution resistance, element body strength, and the like are improved, and solder erosion is reduced.
In particular, even when nitrogen-filled and sealed, since the glass layer 4 prevents the reaction between the thermistor body material and nitrogen, it is possible to suppress a change in resistance value with time.
Moreover, after forming the glass layer 4 on the upper and lower surfaces of the substrate SUB, the prismatic element body 11 is formed by cutting, and the glass layer 4 is also formed on another side surface in a state where the prismatic element bodies 11 are arranged by overlapping each other. 4 is formed into the prismatic body 12, so that the prismatic body 12 in which the glass layer 4 is formed on all side surfaces can be produced in a large number and efficiently.
[0023]
Further, the plate-like body 13 is arranged in the concave portion 14a of the jig 14, and in this state, the conductive paste 15 is applied in the concave portion 14a and heat-treated to form the electrode layer 3 on the surface or the back surface of the plate-like body 13. The electrode layer 3 can be simultaneously and efficiently formed on a large number of the plate-like bodies 13, and the manufacturing cost can be reduced.
[0024]
Next, a second embodiment according to the present invention will be described with reference to FIGS.
[0025]
The structure of the flake type thermistor 21 according to the second embodiment will be described together with its manufacturing process. First, as shown in FIG. 6A, the ceramic element in which the electrode layers 3 are respectively formed on the upper and lower surfaces by screen printing or the like. A body substrate SUB is prepared, and is diced (cut) into a lattice shape in a state where the substrate SUB is affixed to the adhesive sheet 22 to form a plurality of plate-like bodies 13.
[0026]
Next, as shown in FIG. 6B, the adhesive sheet 22 is expanded (stretched) in the radial direction to form a predetermined gap D between the plurality of plate-like bodies 13.
Further, as shown in FIG. 7A, the gap D is filled with a glass paste 25, and the glass paste 25 is cured to some extent.
Next, as shown in FIG. 7B, by subsequently cutting into a lattice shape at the center of the gap D and heat-treating the separated plate 13 to form a glass layer 4 on all sides. As shown in FIG. 8, the flake type thermistor 21 is manufactured.
The flake-type thermistor 21 is formed so that the glass layer 4 also covers the peripheral end surface 3a of the electrode layer 3 by the above manufacturing method.
[0027]
In the present embodiment, the gaps D of the plate-like bodies 13 on the stretched adhesive sheet 22 are filled with the glass paste 25 and cured, and then cut and separated in a lattice shape at the center of the gap D. Since the glass layer 4 is formed on all side surfaces by heat-treating, the glass layer 4 can be simultaneously and efficiently formed on all four side surfaces of the many plate-like bodies 13. Therefore, the flake type thermistor 21 can be formed efficiently and at a low manufacturing cost.
Moreover, in this flake type thermistor 21, since the glass layer 4 is formed so as to also cover the peripheral end surface of the electrode layer 3, the peripheral end surface of the electrode layer 3 is pressed by the glass layer 4 to prevent peeling.
[0028]
The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
[0029]
For example, in the above embodiment, a thermistor having only external electrodes, whereas a plurality of ceramic green sheets on which internal electrodes are printed and ceramic green sheets on which internal electrodes are not formed are stacked, pressed, and fired. The plate-type thermistor substrate may be applied to a thermistor having an internal electrode.
[0030]
【The invention's effect】
The present invention has the following effects.
According to the flake-type thermistor manufactured by the method for manufacturing a flake-type thermistor of the present invention, the entire surface of the plate-type thermistor element is covered with the glass layer, so that the thermistor element is not exposed and weather resistance. Further, migration resistance and the like can be improved, and a highly reliable flake type thermistor for optical communication field and a highly reliable temperature sensor for fields such as home appliances and automobiles can be obtained.
[0031]
According to the method for producing a flake-type thermistor of the present invention, after the inside of the plate-like body on the stretched adhesive sheet is filled with glass paste and cured, the plate is cut and separated in a lattice shape at the center of the gap Since a glass layer is formed on all sides by heat-treating the plate, a glass layer can be formed simultaneously on all four sides of a large number of plate-like bodies, resulting in a high yield and high reliability flake-type thermistor. It is done.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a flake type thermistor according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a mounting state of the flake type thermistor according to the first embodiment of the present invention in the optical communication field.
FIG. 3 is a cross-sectional view showing a state in which the flake-type thermistor according to the first embodiment of the present invention is resin-molded as a temperature sensor in the field of home appliances and automation.
FIG. 4 is a perspective view showing a method for manufacturing a flake-type thermistor in order of steps (up to glass layer formation) in the first embodiment of the present invention.
FIG. 5 is a perspective view showing a method of manufacturing a flake type thermistor in order of steps (up to electrode layer formation) in the first embodiment of the present invention.
FIG. 6 is a perspective view showing a method of manufacturing a flake type thermistor in order of steps (up to gap formation) in a second embodiment according to the present invention.
FIG. 7 is a perspective view showing a method of manufacturing a flake type thermistor in order of steps (up to cutting a glass layer) in a second embodiment according to the present invention.
FIG. 8 is a perspective view showing a flake type thermistor according to a second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 21 Flakes type | mold thermistor 2 Plate-shaped thermistor body 3 Electrode layer 3a Peripheral end surface 4 of electrode layer Glass layer 11 Square column body 12 Square column body 13 Plate body 14 Jig 14a Cavity recess 15 Conductive paste 22 Adhesive Sheet 25 Glass paste D Gap between plates

Claims (1)

  A method for producing a flake-type thermistor in which electrode layers are respectively formed on the upper and lower surfaces of a plate thermistor body, and all side surfaces of the plate thermistor body are covered with a glass layer. On-sheet cutting step of cutting the formed ceramic body substrate into a plurality of plate-like bodies by cutting them into a lattice shape in a state of being attached to the pressure-sensitive adhesive sheet, and extending the pressure-sensitive adhesive sheet in the radial direction to form a plurality of the plate-like bodies A gap forming step for forming a gap between the gaps, and the inside of the gap is filled with glass paste and cured, and then cut into a lattice shape at the center of the gap, and the separated plate-like body is heat-treated on all sides. And a glass layer forming step of forming a glass layer.

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