JP2806303B2 - Manufacturing method of ceramic package - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a ceramic package, and more particularly to a method of manufacturing a ceramic package which is subjected to a press treatment after forming external electrodes.

[0002]

2. Description of the Related Art Quartz resonators are hermetically sealed by using hermetic terminals to produce products. In recent years, surface mount electronic components using ceramic packages have been put to practical use. FIG.
FIG. 8 and FIG. 8 show a conventional surface mount type ceramic package practically used as a crystal unit. As shown in the figure, the surface mount type ceramic package 21 is formed by sequentially laminating thick film sheets 23a, 23b and 23c to form a ceramic base body 23, on which external electrodes 25 and side electrodes 25a are provided. And an internal electrode 24 is provided on the sheet 23b. A crystal oscillator 26 is mounted on the pair of internal electrodes 24, 24 and fixed with a conductive paste. After that, the ceramic lid 28 is sealed with a sealing agent 27 such as low-melting glass or epoxy to maintain airtightness. Completed surface-mounted electronic components.

Here, a method of manufacturing a ceramic base body 23 of a ceramic package will be described with reference to FIGS.
This will be described with reference to FIG. In a film forming step a in which a ceramic material or a slurry material made of a ceramic and glass mixed material is applied to a constant thickness on a long carrier tape made of a plastic material to be in a semi-dry state, a thick ceramic raw sheet is formed. Formed and in a sheet cutting step b,
This raw sheet is cut into a rectangular shape having a predetermined size, and in the hole forming step c, as shown in FIG. 9, a large number of specified shapes, for example, a central portion are punched out of the cut ceramic raw sheet into small and large dimensions. Sheets 23b and 23c forming rectangular frames having different small and large openings and a rectangular flat sheet 2
3a is formed. In the next electrode forming step d, the sheet 23
The internal electrodes 24 are formed by screen printing on b.

In the laminating step e, the sheets 23a to 23a
A box-shaped ceramic base body 23 having a concave portion is formed by laminating several sheets, for example, 3 to 6 sheets of each sheet made of 23c as a set, and performing thermocompression bonding in a pressing step f. Note that the number of stacked sheets varies depending on the type. In the electrode forming step g, the external electrodes 25 are formed on the ceramic base body 23 by screen printing using silver / palladium to form the ceramic base 22. The side electrode 2 is provided on the ceramic base body 23.
5a is also formed. Thereafter, in the cutting step h, the ceramic bases 22 formed in large numbers are individually cut, and the degreasing step i and the firing step j are performed. The ceramic lid 28 is formed in the same manner.

[0005]

In general, silver / palladium is often used as an electrode material when an external electrode is formed on a ceramic with a non-plated product. When a surface mount type electronic component using the ceramic package 21 is mounted on a printed wiring board and immersed in a solder bath,
The external electrode 25 using palladium may be pointed out in terms of quality such as solder strength due to the heat resistance of the solder, and the problem of reliability must be solved. As a means for solving the reliability problem, it is conceivable to increase the firing temperature to densify the silver / palladium electrode.

However, the external electrode 25 made of silver / palladium formed on the ceramic base as described above has a limitation that the firing temperature cannot be raised to a certain temperature or higher due to the temperature resistance characteristics of the ceramic base. Accordingly, the present invention has been proposed in view of the above problems, and has as its object to provide a means for densifying an electrode using a silver / palladium material without increasing the firing temperature, It is an object of the present invention to provide a ceramic package having improved reliability such as solder heat resistance, even for an external electrode using palladium.

[0007]

According to the present invention, there is provided a process for forming a plurality of ceramic thick film sheets which are cut into a rectangular shape and which are pre-pressed, and a method in which external electrodes are arranged on the ceramic thick film sheets. Forming a first sheet, a second sheet provided with a rectangular through hole and an internal electrode in the thick film sheet, and a third sheet provided with a rectangular through hole in the thick film sheet; A step of forming a ceramic base body by sequentially laminating the second and third sheets and thermocompression-bonding with a press; and a step of arranging side electrodes on the ceramic base body and connecting internal and external electrodes. A manufacturing method is provided.

[0008] Further, a step of forming a plurality of ceramic thick film sheets cut into a rectangular shape and pre-pressed, a first sheet as the ceramic thick film sheet, and a rectangular sheet in the thick film sheet. A second sheet having a through hole and an internal electrode;
A step of forming a third sheet having a rectangular through hole formed in the thick film sheet, a step of sequentially laminating the respective sheets, and a thermocompression bonding by pressing to form a ceramic base body; Providing a method of manufacturing a ceramic package, the method including: arranging an electrode and an external electrode to connect the internal electrode and the external electrode.

Further, the present invention provides a method of manufacturing a ceramic package in which a side surface electrode and an external electrode are provided on a ceramic base body to connect the internal electrode and the external electrode, and then the ceramic base body is pressed again. further,
Provided is a method for manufacturing a ceramic package in which an external electrode is silver / palladium.

[0010]

According to the above arrangement, the manufacturing process is such that the external electrode is formed in the electrode forming process and then the pressing process is arranged. Therefore, after forming the external electrodes on the first sheet,
By laminating and pressing in a pressing process, the external electrode layer is partially buried in the first sheet, and the external electrode becomes dense, and firing in a later process improves reliability such as solder heat resistance. I do.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.
This will be described with reference to FIG. In the figure, 1 is a ceramic package, 2 is a ceramic base on which each electrode is formed, 3 is a ceramic base body which is formed by laminating each thick film sheet and thermocompression-bonded, 4 is an internal electrode, 5 is an external electrode, and 5a is a side portion. The electrode, 6 is a crystal oscillator, 7 is a sealant, and 8 is a ceramic lid. FIG. 1 is described as a diagram common to the two embodiments.

A first embodiment will be described with reference to FIGS. 1, 3 and 5 showing the manufacturing process. The surface mount type ceramic package 1 has a first sheet 3a on which external electrodes 5 are arranged.
Then, a second sheet 3b having a rectangular through-hole and having the internal electrodes 4 disposed thereon, and a third sheet 3c having only a rectangular through-hole are sequentially laminated and thermocompression-bonded to form the ceramic base body 3. Further, the side electrodes 5a are formed on the ceramic base body 3 to form the ceramic base 2. next,
For example, a crystal oscillator 6 is mounted on a pair of internal electrodes 4 formed on the ceramic base 2 and fixed (not shown) with a conductive paste, and then a ceramic lid 8 is placed on the ceramic base 2. As described above, sealing is performed with a sealing agent 7 such as low-melting glass or epoxy resin. With this sealing, a surface-mounted electronic component that maintains airtightness is completed.

Here, a method for manufacturing a ceramic package, particularly a ceramic base, will be described. Although a description of the previous step is omitted, a film forming step A in which a ceramic material or a slurry material made of a ceramic and glass mixed material is applied to a constant thickness on a long carrier tape made of a plastic material, and a semi-dry state is formed. Then, a thick ceramic green sheet is formed (not shown). Next, in a sheet cutting step B, the sheet is cut into a rectangular shape having a predetermined size. Next, in a prepress step C, the green sheet cut into a rectangular shape having a predetermined size is preliminarily pressed.

Next, as shown in FIG. 3, in the hole forming step D, three thick film sheets are used as a set using the cut ceramic green sheets, and two of the thick film sheets are used. A central portion of the sheet is punched in small and large dimensions to form a rectangular frame having different small and large openings. In the electrode forming step E, the first sheet 3a in which the external electrodes 5 are formed by screen printing on the through-hole thick film sheet in the previous step is formed. The material of the external electrode 5 is, for example, silver / palladium. A second sheet 3b in which the internal electrodes 4 are formed by screen printing is formed on one of the two thick film sheets. The material of the internal electrode 4 is, for example, silver. The other thick film sheet becomes the third sheet 3c without any electrodes.

In the laminating step F, the first sheet 3a, the second sheet
A plurality of thick film sheets, for example, 3 to 6 thick film sheets, each of which includes a sheet 3b and a third sheet 3c, are laminated as a set,
A box-shaped ceramic base body 3 having a concave portion is formed by thermocompression bonding in the pressing step G. Note that the number of stacked thick film sheets differs depending on the type such as the shape and size.
In the electrode forming step H, the side surface electrodes 5a are formed on the ceramic base body 3 using, for example, silver / palladium. The side surface electrode 5a connects the internal electrode 4 and the external electrode 5, and forms the ceramic base 2 which is electrically connected to each other.
In the cutting step I, a large number of ceramic bases 2 are formed.
Are cut individually. Thereafter, a degreasing step J and a firing step K are performed. The description of the subsequent steps is omitted. Further, the ceramic lid 8 is formed in the same manner.

A second embodiment will be described with reference to FIGS. 1, 4 and 6 showing the manufacturing process. The surface mount type ceramic package 1 is the same as that of the first embodiment, but differs in some manufacturing steps. A first sheet 3aa and a second sheet 3bb having a rectangular through-hole and having internal electrodes 4 disposed thereon
And a third sheet 3cc having only rectangular through-holes are sequentially laminated and thermocompression-bonded to form the ceramic base body 3, but as shown in FIG. The ceramic base 2 is formed by disposing the external electrode 5a and the external electrode 5a. Next, for example, a crystal oscillator 6 is mounted on the pair of internal electrodes 4 formed on the ceramic base 2 and fixed (not shown) with a conductive paste. 8 is sealed with a sealing agent 7 such as low-melting glass or epoxy resin. With this sealing, a surface-mounted electronic component that maintains airtightness is completed.

Hereinafter, a method of manufacturing a ceramic base according to this embodiment will be described with reference to FIGS. 4 and 6 for parts different from those of the first embodiment. Drilling process D
In the subsequent electrode forming step E1, the thick film sheet having a plate-like hole is used as the first sheet 3aa without forming the electrodes. Also,
Silver is used for one of the two thick film sheets and the internal electrode 4 is used.
To form a second sheet 3bb formed by screen printing. The other thick film sheet is the third sheet 3c without electrodes.
c. Next, in the laminating step F, the first sheet 3a
a, several thick film sheets each composed of the second sheet 3bb and the third sheet 3cc, for example, 3 to 6 thick film sheets are laminated as one set, and the concave portion is formed by the first thermocompression bonding in the pressing step G1. A ceramic base body 3 having a box shape is formed. Note that the number of stacked thick film sheets differs depending on the type such as the shape and size.

Next, in an electrode forming step H1, the external electrodes 5 and the side electrodes 5a are formed on the ceramic base body 3 by screen printing. This side electrode 5a is used as the internal electrode 4
And the external electrodes 5 are connected to each other to form a ceramic base 2 that is electrically connected to each other. The external electrode 5 and the side surface electrode 5a
Is, for example, silver / palladium. Next, a second press step G2 for the second press pressing is added. After the cutting step, a large number of formed ceramic bases 2 are individually cut and subjected to a degreasing step and a firing step.

As described above, in the two embodiments, the manufacturing process is changed to the pressing process after forming the external electrodes in the electrode forming process. Therefore, by forming an external electrode first, and then laminating and thermocompression bonding in a pressing process, as shown in a partially enlarged view of the external electrode in FIG.
When compared before and after pressing, after the pressing, the layer of the external electrode is partially embedded in the sheet (t dimension), and the external electrode is dense.

[0020]

As described above, according to the method for manufacturing a ceramic package of the present invention, after the external electrodes are formed in the electrode forming step, the manufacturing step is changed to the pressing step. Therefore, the external electrodes are formed first, and then laminated and thermocompression-bonded in a pressing process, so that the external electrode layers are partially embedded in the sheet, and the external electrodes are dense. In other words, the external electrodes can be densified without raising the firing temperature, and even with external electrodes using silver / palladium materials, ceramics with improved reliability by solving the problem of solder strength due to solder heat resistance. We can provide the package.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a ceramic package according to the present invention.

FIG. 2 is a partially enlarged view showing a state before and after pressing of an external electrode according to the present invention.

FIG. 3 is a perspective view showing a state of lamination with each sheet of Example 1 according to the present invention.

FIG. 4 is a perspective view showing a state of lamination with each sheet of Example 2 according to the present invention.

FIG. 5 is a schematic manufacturing process diagram of Example 1 according to the present invention.

FIG. 6 is a schematic manufacturing process diagram of a second embodiment according to the present invention.

FIG. 7 is a perspective view of a conventional ceramic package.

8 is a front sectional view of the ceramic package of FIG. 7 as viewed from XX.

FIG. 9 is a perspective view showing a state at the time of lamination with each conventional sheet.

FIG. 10 is a schematic view of a conventional manufacturing process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ceramic package 2 Ceramic base 3 Ceramic base main body 3a, 3aa First sheet 3b, 3bb Second sheet 3c, 3cc Third sheet 4 Internal electrode 5 External electrode 5a Side electrode 6 Crystal oscillator 7 Sealant 8 Ceramic lid

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H03H 9/02 H01L 23/12 K

Claims (4)

(57) [Claims] A step of forming a plurality of ceramic thick film sheets cut into a rectangular shape and pre-pressed, a first sheet having external electrodes disposed on the ceramic thick film sheets, and a thick film sheet. Forming a second sheet having a rectangular through hole and an internal electrode therein, and a third sheet having a rectangular through hole in the thick film sheet; and forming the first, second, and third sheets. Forming a ceramic base body by successively laminating and thermocompressing with a press, and arranging side electrodes on the ceramic base body to connect the internal electrodes and the external electrodes. . 2. A step of forming a plurality of ceramic thick-film sheets cut in a rectangular shape and pre-pressed, a first sheet as the ceramic thick-film sheet, and a rectangular sheet in the thick-film sheet. Forming a second sheet provided with the through-holes and the internal electrodes, and a third sheet having a rectangular through-hole formed in the thick film sheet. Forming a ceramic base body by performing the method, and arranging a side surface electrode and an external electrode on the ceramic base body and connecting the internal electrode and the external electrode with the side surface electrode. Manufacturing method of ceramic package. 3. The method according to claim 1, further comprising the step of arranging side electrodes and external electrodes on said ceramic base body, connecting said internal electrodes and said external electrodes, and then pressing said ceramic base body again. 3. The method for manufacturing a ceramic package according to item 2. 4. The method according to claim 1, wherein said external electrode is silver / palladium.