Method and device for forming external electrodes in electronic chip component

Abstract

A method and device for forming external electrodes on opposing surfaces of an electronic chip. A plurality of chips are arrayed on a plate and held at a first end faces by a silicon rubber provided on the plate. The plate is brought close to a coating bed so that second end faces of the chips are immersed in an electrically conductive paste formed on the coating bed. The second end faces of the chips are coated with the conductive paste which forms first electrodes after drying step. Subsequently, the plate is inverted and brought toward a sheet with a foamable and releasable adhesive layer for allowing the chips to be pressed against the foamable and releasable adhesive and held thereby. The chips are transferred from the plate to the sheet. Next, second electrodes are formed on the first end faces. After the first and second end faces are formed with electrodes, the sheet is heated, causing the foamable and releasable adhesive in the sheet to foam and lose its adhesive strength to remove the components from the sheet by their own weight.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is an explanatory diagram illustrating a device for forming an external electrode for electronic chip components according to a first embodiment of the present invention;

FIG. 2 is a flowchart illustrating steps in a method for forming external electrodes according to the first embodiment;

FIG. 3 is a cross-sectional view showing chips disposed in an alignment block of the external electrode forming device of the first embodiment;

FIG. 4 is a plan view of the alignment block;

FIG. 5( a) through 5(c) are cross-sectional views illustrating a step for supplying and fixing a chip in the method of forming external electrodes, and FIG. 5(a) shows a state where a plate held parallel to a bed is brought near the same;

FIG. 5( b) shows a state where a silicon rubber is pressed against a first end face of a chip;

FIG. 5( c) shows a state where the chip and the plate are separated relative to the bed;

FIG. 6( a) through 6(c) are explanatory diagrams illustrating a step for applying a first electrode in the method of forming external electrodes and FIG. 6(a) shows a state where the chip held on the plate is brought relatively near an electrically conductive paste;

FIG. 6( b) shows a state where a second end face is immersed into the electrically conductive paste;

FIG. 6( c) shows a state where the chip is removed from the electrically conductive paste;

FIG. 7 is an explanatory diagram illustrating a radiation drying method employed in the method of forming external electrodes according to the first embodiment;

FIG. 8 is an explanatory diagram illustrating a convection drying method employed in the method of forming external electrodes according to the first embodiment;

FIG. 9( a) through 9(c) are explanatory diagrams illustrating a chip transfer step in the method of forming external electrodes, and FIG. 9(a) shows a state where a sheet and the plate holding the chip are brought into relative proximity of each other;

FIG. 9( b) shows a state where the chip is pressed against the sheet;

FIG. 9( c) shows a state where the plate and the sheet are relatively moved away from each other;

FIG. 10 is a flowchart illustrating steps in the chip transfer step according to the first embodiment;

FIG. 11 is an explanatory diagram illustrating the chip transfer step according to the first embodiment;

FIG. 12( a) through 12(c) are explanatory diagrams illustrating a step for applying a second electrode in the method of forming external electrodes, and FIG. 12(a) shows a state where the chip held by the sheet and a coating bed are brought toward each other;

FIG. 12( b) shows a state where the chip is pressed against the coating bed;

FIG. 12( c) shows a state where a second electrode is formed on the chip;

FIG. 13 is an explanatory diagram illustrating a chip discharge step in the method of forming external electrodes according to the first embodiment;

FIG. 14 is an explanatory diagram illustrating the foaming state of thermally foamable and releasable adhesive in the method of forming external electrodes according to the first embodiment;

FIG. 15 is an explanatory diagram illustrating the chip transfer method in the method of forming external electrodes according to a modification to the first embodiment; and,

FIG. 16 is an explanatory diagram showing a device of an external electrode forming device according to a second embodiment of the present invention.

Claims

1. A method for forming external electrodes on a chip element having a first end face and a second end face on opposing ends to produce an electronic chip component, the method comprising: a first fixing step for fixing the first end face to a first adhesive member;a first electrode applying step for applying an electrode material to the second end face of while the chip element is fixed to the first adhesive member;a first drying step for drying the electrode material applied in the first electrode applying step to produce a first external electrode;a second fixing step for transferring the chip element from the first adhesive member to a second adhesive member and fixing the first external electrode side of the chip element to the second adhesive member;a second electrode applying step for applying an electrode material to the first end face while the chip element is fixed to the second adhesive member;a second drying step for drying the electrode material applied in the second electrode applying step to produce a second external electrode; anda separating step for separating the chip element from the second adhesive member without application of external mechanical force to the chip element.

2. The method as claimed in claim 1, wherein the second adhesive member has an upper temperature limit lower than that of the first adhesive member.

3. The method as claimed in claim 1, wherein the second adhesive member has an adhesive power stronger than that of the first adhesive member in the second fixing step.

4. The method as claimed in claim 3, wherein in the second fixing step, the chip element is transferred from the first adhesive member to the second adhesive member by pulling the chip element away from the first adhesive member while the first electrode is in adhesive contact with the second adhesive member.

5. The method as claimed in claim 1, wherein the second adhesive member is formed of a thermally foamable adhesive agent.

6. The method as claimed in claim 5, wherein the second adhesive member reduces its adhesive power upon foaming of the adhesive member by heat application during the separation step.

7. The method as claimed in claim 1, wherein the second adhesive member is made from a material plastically deformable in the second fixing step.

8. A device for forming external electrodes on a chip element having a first end face and a second end face on opposing ends to produce an electronic chip component, the device comprising: a first conveying unit provided with a first adhesive member;a first fixing unit configured to fix the first end face to the first adhesive member;a first electrode applying unit configured to apply an electrode material onto the second end face while the first end face is fixed to the first adhesive member;a first drying unit configured to dry the electrode material formed on the second end face to produce a first external electrode;a second conveying unit provided with a second adhesive member;a second fixing unit configured to transfer the chip elements from the first adhesive member to the second adhesive member and fix the first external electrode side of the chip element to the second adhesive member;a second electrode applying unit configured to apply an electrode material to the first end face while the chip element is fixed to the second adhesive member;a second drying unit configured to dry the electrode material applied in the second electrode to produce a second external electrode; anda separating unit configured to separate the chip element from the second adhesive member without application of external mechanical force to the chip element.

9. The device as claimed in claim 8, wherein the second adhesive member has an upper temperature limit lower than that of the first adhesive member.

10. The device as claimed in claim 8, wherein the second adhesive member has an adhesive power stronger than that of the first adhesive member at the second fixing unit.

11. The device as claimed in claim 10, wherein the second fixing unit comprises a pulling unit that pulls the chip element away from the first adhesive member while the first electrode is in adhesive contact with the second adhesive member for transferring the chip element from the first adhesive member to the second adhesive member.

12. The device as claimed in claim 8, wherein the second adhesive member is formed of a thermally foamable adhesive agent.

13. The device as claimed in claim 12, wherein the separating unit comprises a heater, and wherein the second adhesive member is made from a material capable of reducing its adhesive power upon foaming of the adhesive member by heat application by the heater.

14. The device as claimed in claim 8, wherein the second adhesive member is made from a material plastically deformable in the second fixing unit.