JPH0470768B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for forming external connection electrodes of chip-type electronic components and an apparatus for carrying out the method.

(Prior Art) Typical chip-type electronic components include capacitors, resistors, and inductances.

FIG. 11 is a side view showing a typical structure of a chip type capacitor, particularly a chip type multilayer ceramic capacitor.

In this figure, a plurality of dielectric ceramic layers 2
A laminate 1 is constructed with an internal electrode 3 inserted between them, and an external connection electrode 4 connected to the internal electrode 3 of this laminate 1 is formed on an end surface of the laminate.

FIG. 12 is a side view showing a typical structure of a chip resistor.

In this figure, electrodes 6, 6 are formed on a substrate 5 made of alumina or the like, and a resistor paste made of, for example, RuO ₂ is baked between the electrodes 6, 6 to form a resistor 7. An external connection electrode 8 for electrical connection is formed.

FIG. 13 is a schematic side view showing a typical structure of a chip type inductor.

Although not shown in detail in this figure, a plurality of raw ferrite sheets with conductor patterns formed thereon are stacked up, and the conductor patterns are connected, for example, from top to bottom through through holes formed in the raw ferrite sheets, resulting in is formed with the coil 9 contained therein, integrated under pressure and fired, and an external connection electrode 11 is formed on the side surface of the obtained chip 10 so as to be electrically connected to the end of the coil 9. .

The external connection electrodes of the various chip-type electronic components described above are usually formed by applying silver paste containing glass frit or varnish by means such as coating or printing, and then baking this in air.

(Problem to be solved by the invention) However, as mentioned above, the external connection electrode
Since it is formed by baking silver paste, it is formed into a thick film. In particular, Figure 11~
In the various chip-type electronic components shown in FIG. 13, raised portions A are formed at the ends of both planes. For example, regarding the chip type capacitor shown in FIG. 11, the thickness of the chip body is 500 μm, whereas the thickness of the raised portion A of the external connection electrode is approximately 50 μm. The total is 100μm
This amounts to 20% of the thickness of the chip itself.

The following problems arise due to the formation structure of such external connection electrodes.

First, when mounting a chip-type electronic component on a printed circuit board, a vacuum chuck sucks up the chip-type electronic component, but since the external connection electrode is formed with a raised part, the top surface is not flat and the chip is This creates a gap between the mold and the electronic components, making it impossible for the vacuum chuck to suck it up.

Further, as described above, if there is a raised portion of the external connection electrode, it goes against the trend toward thinning of chip-type electronic components, and there is a problem that it becomes impossible to incorporate them into electronic devices where thickness is restricted.

Furthermore, in the case of chip-type capacitors, it may be possible to reduce the number of dielectric layers stacked only in the raised portions of external connection electrodes so as not to impede thinning of chip-type electronic components. However, this also involves the problem of a decrease in capacity.

Therefore, in order to reduce the thickness of the external connection electrode and eliminate the raised parts, it has been proposed to form the external connection electrode using thin film formation techniques such as vacuum evaporation, sputtering, and ion plating. .

JP-A-58-64017 discloses the most suitable prior art for this invention.

FIG. 14 is a side cross-sectional view showing how external connection electrodes are formed on the end face of a chip-type multilayer ceramic capacitor by sputtering.

In this figure, a laminated unit 14 is attached to a pocket 13 of a masking device 12, and in this state, it is installed in a sputtering device, and a target 15 is sputtered, sputter particles are attached to the end face of the laminated unit 14, and an electrode for external connection is formed. 16 is formed. Note that 17 and 18 are internal electrodes, respectively.

However, the external connection electrode 16 formed by such a method has the following problems.

In other words, since the external connection electrodes 16 are formed only on the end faces of the laminated unit 14, sufficient bonding strength to the laminated unit 14 cannot be obtained. Therefore, the external connection electrode 16
It is clearly stated that before forming a sputter etching process, the end surface is roughened.
Even with such treatment, sufficient bonding strength has not yet been achieved.

Therefore, it is necessary to improve the external connection electrode from a structural point of view. In other words, Figures 11 to 13
As shown in the figure, the external connection electrode should not be formed only on the end face, but should have a shape that extends from the end face and the end face to the ends of the upper and lower surfaces, that is, it has a U-shaped cross section. There is.

However, with the masking device shown in FIG. 14, it is impossible to form external connection electrodes that reach the upper and lower surfaces of the main body of a chip-type electronic component. Moreover, in the conventional method, it is inappropriate for a gap to exist between the pocket 13 and the laminated unit 14, and the gap between the pocket 13 and the laminated unit 14 is
The dimensional accuracy of item 4 must be improved. Also, it is clear that it is quite troublesome from the point of view of loading and unloading operations.

(Object of the Invention) Therefore, the present invention provides electrodes for external connection of chip-type electronic components such as chip-type multilayer ceramic capacitors, multilayer chip-type resistors, chip-type inductors, etc. by vacuum evaporation, sputtering, and ion spraying. An object of the present invention is to provide a method for forming an external connection electrode having a U-shaped cross section at the end of a chip-type electronic component when forming it using a thin film formation technique such as the Teing method.

Another object of the present invention is to provide a method with good workability when forming external connection electrodes on the ends of chip-type electronic components.

(Means for Solving the Problems) This invention includes vacuum evaporation, sputtering,
When forming external connection electrodes at the ends of chip-type electronic components using a thin film forming technique such as ion plating, a hexahedral chip-type electronic component 20 as shown in FIG. 2 is first targeted. This chip-type electronic component 20 has left and right side surfaces A1, A2, front and rear side surfaces B1, B2, and upper and lower main surfaces C1, C2 when viewed from the illustrated position.

First, as shown in FIG.
1a, while a conductive part 22 is formed at the right end C2R.
a, and a conductive portion 22b is formed on the right side surface A2 continuously from the conductive portion 22a.

Next, turn the chip type electronic component over, that is,
The left and right sides A1 and A2 are located in opposite positions,
Turn it over so that the upper and lower planes C1 and C2 are located at opposite positions. As shown in FIG. 4, a conductive part 22C is formed at the right end C1R of the upper plane C1, and a conductive part 21C is formed at the left end C1L, and a conductive part 21 is formed continuously from the conductive part 21C.
form b. The positional relationship in the state shown in FIG. 4 has been explained based on the positional relationship defined in the state in FIG. Therefore, please note that in FIG. 4, the vertical or horizontal positional relationship is reversed.

By going through the above steps, an external connection electrode having a U-shaped cross section is formed at the end of the chip-type electronic component.

(Effects) According to the present invention, the following various effects can be obtained.

A thin film-like external connection electrode can be formed, and unlike conventional silver baked electrodes, raised parts are not formed.

Since there is no raised part of the electrode, chip-type electronic components can be picked up by a vacuum chuck device, making it possible to automatically load printed circuit boards and improving positioning accuracy.

The thickness of the chip-type electronic component body can be increased by the thickness of the raised portion of the electrode. For example, in the case of a multilayer ceramic capacitor, the number of dielectric ceramic layers can be increased, so that the capacitance can be increased. Furthermore, the bending strength can also be increased.

Baked silver electrodes have the disadvantage of poor moisture resistance because they contain alkali metal components, which are glass frit components, but according to the present invention, electrodes can be made from electrode materials that do not contain the above-mentioned alkali metal components. Therefore, it is possible to provide a chip-type electronic component having excellent moisture resistance.

Since base metals such as nickel, chromium, copper, and aluminum can be used as electrode materials, costs can be reduced.

Compared to the case where electrodes are formed only on the end faces of a chip-type electronic component, the bonding strength is greater and it becomes possible to create a highly reliable chip-type electronic component.

It is easy to load and is highly workable and mass-producible.

(Embodiments) The present invention will be described in detail below with reference to illustrated embodiments.

FIG. 1 is a partial perspective view showing a container containing chip-type electronic components to which electrodes are adhered.

In this figure, 31 is a container, and the side wall 31
a, 31b, and a bottom surface 31c. In this case, the side wall 31b is not necessarily necessary, but it is preferable to provide it from the viewpoint of preventing the chip-type electronic component from falling and positioning the chip-type electronic component. There are openings 32 and 33 on the bottom of the container.
is formed.

This container 31 is composed of a side wall 31a, a bottom surface 31c, and openings 32 and 33 formed in the bottom surface 31c, and the area partitioned by the side wall 31a is a unit for accommodating chip-type electronic components. becomes. Therefore, a plurality of regions, that is, a plurality of units, may be used to accommodate the chip-type electronic components.

Reference numeral 20 indicates a chip-type electronic component, which corresponds to that shown in FIG. 2 and is given the same number. Therefore, the left side of the chip type electronic component is A1, the right side is A2, the front side is B1, the rear side is B2, and the top plane is C.
1. Define the lower plane as C2.

When the chip type electronic component 20 is housed in the container 31, the housing condition is as follows.

That is, the chip-type electronic component 20 is housed in a state in which the left side surface A1 is in contact with the side wall 31a of the container 31, and the lower surface C2 of the chip-type electronic component 20 is in surface contact with the bottom surface 31c of the container 31.

Therefore, when the container 31 is viewed from the back side, the left end C2L side of the lower plane C2 of the chip-type electronic component 20 is exposed through the opening 32 of the container 31, and the opening 33 of the container 31 From this, the right side C2R side of the lower plane C2 of the chip type electronic component 20 and the right side surface A2 are exposed.

Regarding the aperture 33, the width of the aperture 33 is formed to have a spatial distance D having an opening area further to the right of the right side surface A2 of the chip type electronic component 20. The spatial distance D of the opening 33 is such that the electrode forming material scattered from the electrode forming material scattering source, which will be described later, passes through the opening 33 to the chip-type electronic component 20.
It suffices if it is formed to an extent that is effective for wrapping around and adhering to the right side surface A2. According to experimental results, the spatial distance D of the opening 33 should be 0.1 mm or more.

On the back side of the container 31, a material for forming external connection electrodes, that is, an electrode forming material scattering source 51 is provided.
is installed parallel to the container 31. For example, the electrode forming material scattering source 51 is usually called an evaporation source in a vacuum evaporation method or an ion plating method.
A heater, boat, crucible, etc. is heated and the evaporated material is placed above it. Also, in the sputtering method, it is called a target.

The container 31 containing the chip-type electronic component 20 and the electrode forming material scattering source 51 are placed in a vacuum container, and the process of forming external connection electrodes is performed in a vacuum atmosphere.

Next, the external connection electrodes are connected to the chip type electronic component 20.
The process of forming this will be explained.

First, as a first step, dry plating is performed in the state shown in FIG.

When the chip-type electronic component 20 is viewed from the electrode forming material scattering source 51, the left end C2L of the lower main surface C2 is exposed from the opening 32 of the container 31. In addition, the right end C2R of the lower main surface C2 is exposed through the opening 33, and the right side surface A2 is also exposed. When particles are scattered from the electrode forming material scattering source 51 in this state, the particles adhere to the exposed left end C2L, right end C2R, and right side surface A2. At this time, the right side surface A2 of the chip-type electronic component 20 does not face the source of the electrode forming material scattering, but the scattered particles adhere to the right side surface A2 due to the flying particles from an oblique direction. Regarding other parts of the chip-type electronic component 20, the container 31 acts as a mask, and the chip-type electronic components are in close contact with each other, that is, the front and rear sides B1 and B2 are in close contact with each other, so that the scattered particles are not exposed. I don't wear it.

FIG. 6 shows this state.

Next, in the second step, the chip-type electronic component is moved in the direction of arrow a or arrow b, as shown in Figure 6.
Then, as shown in FIG.
It is housed in surface contact with 1c.

At this stage, when the container 31 is viewed from the back side, the right end C1R of the upper plane C1 is exposed from the opening 32 of the container 31. Further, the left end C1L of the upper plane C1 is exposed from the opening 33, and the left end surface A1 is also exposed. When particles are scattered from the electrode forming material scattering source 51 in this state, the particles adhere to the exposed right end C1R, left end C1L, and left side surface A1. At this time, the left side surface A1 of the chip type electronic component 20 is the electrode forming material scattering source 5.
1, but the scattered particles adhere to the left side surface A1 due to the flying particles coming from an oblique direction.
Regarding other parts of the chip-type electronic component 20, the container 31 serves as a mask, and the chip-type electronic component 20 is in close contact with each other, that is, the front and rear sides B1 and B2 are in close contact with each other, so that the scattered particles are prevented. Does not adhere.

FIG. 8 shows the state after this process.

As shown in FIG. 4, the chip-type electronic component that has gone through the first and second steps has an external connection that is connected to the end surface of the chip-type electronic component and the flat end that is continuous to this end surface, that is, the external connection that has a U-shaped cross section. electrodes are now formed.

In the embodiment described above, the electrode forming material scattering source 51 was arranged parallel to the container 31, but the electrode forming material scattering source 51 was placed in the container 31 so as to diagonally face the right side A2 or the left side A1 of the chip type electronic component 20. The scattering source 51 of the electrode forming material may be arranged diagonally to the scattering source 51, or downward to the right in the state shown in FIG.
may be arranged diagonally with respect to the container 31, or upwardly to the right in the state shown in FIG. According to this, the right side surface A2 or the left side surface A of the chip type electronic component 20
The scattered particles from the electrode-forming material scattering source 51 are reliably and efficiently attached to the electrode-forming material scattering source 51, and the formation of the external connection electrode can be further facilitated.

Next, other embodiments of the invention will be described.

FIG. 9 shows a side sectional view of this embodiment, and the major difference from the previous embodiment is that the top surface of the container 31 is covered with a lid 41.
Although not shown, a container-shaped container may be used instead of the lid. The lid 41 is provided with openings 42 and 43, respectively, and have sizes corresponding to the holes 32 and 33 of the container 31 shown in FIG. 5, respectively. That is, the aperture 42 has a size corresponding to the aperture 32, and the aperture 43 has a size corresponding to the aperture 33.

Although the lid 41 does not perform its function in the first step in the above-described embodiment, it is useful in the second step when forming a part of the external connection electrode on a chip-type electronic component. 41 constitutes a part of the container.

Note that the same numbers are given to parts that overlap with those in the previous embodiment, and detailed explanations are omitted.

First, in the state shown in FIG. 9, electrode forming material is scattered from an electrode forming material scattering source (not shown), and an external connection electrode is scattered on the left end C2L, right end C2R, and right side surface A2 of the chip-type electronic component 20. A conductive part constituting the part is formed. The steps up to this point are the same as the first step in the previous embodiment.

Next, in the second step, from the state shown in FIG. 9, the container 31 is turned over as shown by arrow C or arrow d, with the lid 41 still on. Next, the right side surface A2 of the chip type electronic component 20 is brought into contact with the side wall 31a. In this state, when viewed from the back side of the lid 41, that is, from the electrode forming material scattering source, the right end C1R of the upper plane C1 of the chip-type electronic component 20 is seen from the opening 42.
is exposed. Also, from the opening 43 to the upper plane C1
The left end C1L of is exposed and the left side A
1 is exposed. In this state, the electrode forming material is scattered from an electrode forming material scattering source (not shown), and the right end C1R and the left end C1 of the chip type electronic component 20 are
A conductive portion constituting a part of the external connection electrode is formed on L and the left side A1.

When this second step is completed, an external connection electrode having a U-shaped cross section is formed at the end of the chip-type electronic component.

Therefore, in this embodiment, it is no longer necessary to turn over the individual chip-type electronic components as in the previous embodiment, and the container 31 is turned over with the lid 41 closed, and the right side A2 of the chip-type electronic component 20 is placed on the side wall 31a. By arranging them so that they come into contact with each other, the second stage process described above can be carried out.

Although FIGS. 5 and 9 show that one chip type electronic component 20 is housed in the area partitioned by the side wall 31a, as shown in FIG. Of course, it can be implemented with the electronic components 20 juxtaposed.

Further, in the later embodiments, as in the previous embodiment, the container 31 may be arranged diagonally with respect to the electrode forming material scattering source, or the electrode forming material scattering source may be arranged diagonally with respect to the container 31. When forming a conductive part on the side surface of a chip-type electronic component,
The scattered particles may be attached to this side surface reliably and efficiently.

In the later embodiment, the left end C2 of the lower main surface C2 of the chip type electronic component 20 in the state shown in FIG.
After forming a conductive part constituting a part of the external connection electrode on L, right end C2R and right side A2,
As shown by the dashed line in FIG. 9, the chip type electronic component 20 is moved to the right and the right side surface A2 is brought into contact with the side wall 31a of the container 31.
By depositing scattered particles from an electrode forming material scattering source (not shown) disposed above the lid 41
Chip type electronic component 2 is inserted through the openings 42 and 43 of
A conductive portion can be formed on the right end C1R, left end C1L, and left side surface A1 of the upper main surface C1 of 0. As a result, an external connection electrode having a U-shaped cross section is formed at the end of the chip-type electronic component.

In this case, the chip type electronic component 20 and the lid 41
Of course, measures must be taken to prevent gaps from forming between the two. External connection electrodes include base metals such as nickel, chromium, copper, and aluminum, but also nickel oxide, tin oxide, manganese oxide, iron oxide, cobalt oxide, nickel nitride, and nickel oxide (first layer). It may also be made of nickel nitride (second layer). If the latter electrode material is used, for example, in a chip-type multilayer ceramic capacitor, there is an effect that the insulation resistance does not deteriorate at high temperatures.

[Brief explanation of the drawing]

FIG. 1 is a partial perspective view showing a state in which chip-type electronic components are housed in a container in carrying out the present invention. FIG. 2 is a perspective view showing symbols for specifying the positions of the main surface and side surfaces of the chip-type electronic component. 3 and 4 are side views showing the process of forming external connection electrodes on a chip type electronic component. FIGS. 5 and 6 are side sectional views for explaining a mode in which a part of an external connection electrode is formed on a chip type electronic component. FIGS. 7 and 8 are side sectional views for explaining the manner in which other parts of the external connection electrodes are formed on the chip type electronic component. Figure 9 ~ 1st
FIG. 0 is a side sectional view illustrating another embodiment of forming external connection electrodes on a chip type electronic component. 11th
Figures 1 to 13 are side views showing typical chip-type electronic components. This is an example of a chip type inductor. FIG. 14 corresponds to the prior art of the present invention and is a side sectional view showing a state in which external connection electrodes are formed on the end face of a chip-type multilayer ceramic capacitor by sputtering. 20 is a chip type electronic component, 31 is a container, 31a
is a side wall, 31c is a bottom surface, 32 and 33 are openings, 5
1 is an electrode forming material scattering source.

Claims (1)

[Scope of Claims] 1. When forming an external connection electrode having a U-shaped cross section at the end of a chip-type electronic component by a thin film forming technique using a vacuum evaporation method, an ion plating method, or a sputtering method, One end of one main surface of the chip-type electronic component is placed so that the main surface faces the electrode forming material scattering source, and as a first step, the electrode forming material is scattered from the electrode forming material scattering source through a mask. A conductive part is formed on the part and one side surface continuous to this one end, and a conductive part is formed on the other end of one main surface of the chip-type electronic component, and then the other main surface of the chip-type electronic component is By facing the electrode forming material scattering source and scattering the electrode forming material from the electrode forming material scattering source through a mask as a second step, one end of the other main surface of the chip type electronic component and this one side are scattered. A conductive part is formed on one side surface continuous to the end, and a conductive part is formed on the other end of the other main surface of the chip-type electronic component, resulting in a U-shaped cross section at the end of the chip-type electronic component. 1. A method for forming an external connection electrode for a chip-type electronic component, the method comprising forming an external connection electrode for a chip type electronic component. 2. The mask has a bottom surface in which a first opening and a second opening are formed, and a side wall, and the first step and the second step are performed on the bottom surface of the container. and the side wall as a mask, and in the first step, the other side of one main surface of the chip-type electronic component is brought into contact with the side wall of the container, while the electrode forming material formed on the bottom surface of the container is One end of one main surface of the chip-type electronic component and one side surface continuous to this one end are exposed through the first opening and the second opening, and one main surface of the chip-type electronic component is exposed through the first opening and the second opening. The second step is carried out with the other end of the chip-shaped electronic component being brought into contact with the side wall of the container, while the other end of the chip-shaped electronic component is brought into contact with the side wall of the container, and the container is The other end of the other main surface of the chip-type electronic component and the other side surface that is continuous with this other end are exposed through the first hole and the second hole formed in the bottom surface of the chip-type electronic component. 2. A method for forming an external connection electrode for a chip-type electronic component according to claim 1, wherein the method is carried out with one end of the other main surface of the electronic component exposed.