JPH1066933A - Protective coating layer formation for diode element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly apply protective resin of liquid form having relatively high viscosity on the side face of a diode chip. SOLUTION: A protective resin coating layer forming device consists of first and second rollers 8, 9, a vessel 10, a roller driver 13, and a device 14 for moving a diode element 7. Protective resin of liquid form 6a is housed in the vessel 10, and a part of the second roller 9 is immersed therein. By rotating the first and second rollers 8, 9, the protective resin of liquid form 6a is stuck to the outer peripheral surface of the first and second rollers 8, 9, and the protective resin of liquid form 6a on the first roller 8 is stuck to the side face of a diode chip fixed to the diode element 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a protective coating layer such as a junction coating resin (JCR) on a coaxial diode element having a pair of rod-shaped leads.

[0002]

2. Description of the Related Art As shown in FIG. 1, a junction coating resin (JCR) is generally provided on a side surface of a diode chip 5 fixed between first and second rod-shaped leads 1 and 2 arranged coaxially with solders 3 and 4. It is known to provide a protective resin coating layer 6 referred to as). The bar-shaped leads 1 and 2 have flange-shaped heads 1b and 2b at one end of bar-shaped portions 1a and 2a extending linearly, and a diode chip 5 is arranged between the heads 1b and 2b. The diode chip 5 is a well-known device having a P-type semiconductor region, an N-type semiconductor region, an anode electrode, and a cathode electrode. The diode chip 5 has an inclined side surface for increasing the breakdown voltage, and a PN junction is exposed on the inclined side surface. ing.

[0003]

Conventionally, when forming the protective resin coating layer 6, a fluid silicone resin, for example, is potted or dropped on the side surface of the diode chip 5. However, the protective resin coating layer 6
Formed, when the diode elements were mass-produced, the thickness of the protective resin coating layer 6 varied. In particular, when a high-viscosity JCR is used, not only the variation among the diode elements becomes large, but also it is difficult to form the protective resin coating layer 6 uniformly over the entire circumference of one diode chip.

Accordingly, an object of the present invention is to provide a method capable of improving the uniformity and the productivity of a protective coating layer covering the side surface of a diode chip.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for forming a protective coating layer by attaching a liquid protective material to a side surface of a diode chip fixed between first and second rod-shaped leads. Forming a roller and a liquid protective substance supply means for supplying a liquid protective substance to an outer peripheral surface of the roller, wherein a shaft of the roller and the first
And the second rod-shaped lead is arranged so that the rollers are parallel to each other, and the liquid protective substance is attached to an outer peripheral surface of the roller by the liquid protective substance supply means, and the liquid protective substance adhered to the roller is provided. The diode chip is moved together with the first and second rod-shaped leads to a position where the side surface of the diode chip comes into contact with the diode chip, and the liquid protective material on the outer peripheral surface of the roller is transferred to the diode chip with the rotation of the roller. And forming the protective coating layer on the side surface of the diode element. Claim 2
As shown in (2), the liquid protective material supply means includes another roller for supplying the liquid protective material to the roller disposed opposite to the side surface of the diode chip, and a liquid protective member for immersing a part of the other roller. Desirably, the container contains the substance. According to a third aspect of the present invention, the roller for applying the liquid protective substance to the diode chip has a convex portion on the outer peripheral surface, and the other roller preferably has a groove on the outer peripheral surface. .

[0006]

According to the present invention, the following effects can be obtained. (A) Since the liquid protective substance is attached to the diode chip with the rotation of the roller, the uniformity of the protective coating layer can be improved as compared with the conventional potting method. (B) Since the liquid protective substance is attached to or applied to the side surface of the diode chip by the rotation of the roller, the protective coating layer can be efficiently formed.

[0007]

Next, a method of forming a protective coating layer of a diode element according to an embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the diode element 7 for forming the protective coating layer is made up of the first and second diodes as apparent from FIGS.
The diode chip 5 is fixed between the flange-shaped heads 1b and 2b of the rod-shaped leads 1 and 2 by solders 3 and 4,
As shown in FIG. 1, a protective resin layer 6 is provided on a side surface of the chip 5.

An apparatus for forming the protective resin coating layer 6 according to the present embodiment includes first and second rollers 8 and 9, a container 10 containing a liquid protective resin 6a, and first and second rollers. It comprises a roller drive 13 engaged with roller shafts 11, 12 for rotating 8, 9, and a transfer device 14 for the diode element 7.

The first roller 8 has an annular convex portion 15 on its outer peripheral surface as shown in FIGS. The width of the protrusion 15 is equal to the heads 1b and 2b of the first and second rod-shaped leads 1 and 2.
Are set to be somewhat smaller than the width between them, that is, the thickness of the diode chip 5.

The second roller 9 has an annular groove 16 on the outer peripheral surface as shown in FIG. The groove 16 is formed in a V-shaped cross section, and the width of the entrance of the groove 16 is somewhat wider than the width of the convex portion 15 of the first roller 8. The second roller 9 is arranged close to the first roller 8 so that a part of the projection 15 of the first roller 8 enters the groove 16. That is, the convex portion 15 of the first roller 8 comes into contact with the liquid protective resin 6a attached to the outer peripheral surface of the second roller 9, and the liquid protective resin 6a of the second roller 9 is applied to the first roller 8. The first and second rollers 8, 9 are arranged so that they can be transferred or transferred. In FIG. 4, the outer peripheral surfaces of the first and second rollers 8 and 9 are not in direct contact with each other.

The diode element moving device 14 includes a plurality of pairs of lead supports 17 supporting the rod portions 1a, 2a of the first and second rod leads 1, 2, and the lead support 1
18 for moving the belt 7 and a belt driving device 19
Consisting of The lead support 17 is a rod-like portion 1 of the lead.
a, U-shaped recess 20 for receiving the 2a.
The belt 18 is driven intermittently or continuously by a driving device 19.

When the liquid protective resin 6a is applied to the diode chip 5 of the diode element 7, the JCR
, A part of the second roller 9 is immersed therein, and the first roller 8 is rotated counterclockwise (first direction) as shown by an arrow, The second roller 9 is rotated clockwise (second direction) as indicated by the arrow, and the diode element 7 is transferred below the first roller 8 by the moving device 14. As a result, the liquid protective resin 6a first adheres to the outer peripheral surface of the second roller 9, especially to the groove 16. Next, the liquid protective resin 6a of the second roller 8 is adhered or transferred to the outer peripheral surface of the first roller 8, especially the convex portion 15. Next, the liquid protective resin 6a on the outer peripheral surface of the first roller 8 contacts the side surface of the diode chip 5 and is transferred here. At this time, since the first roller 8 is rotating, the liquid protective resin 6a on the outer peripheral surface is stably
Supplied on the side. In this embodiment, the diode element 7
Is not particularly rotated, but since the first roller 8 rotates and supplies the liquid protective resin 6a, the liquid protective resin 6a previously attached to the side surface of the diode chip 5 is
Is pressed by the liquid protective resin 6a on the roller 8 side, and the uniform application of the liquid protective resin 6a over the entire side surface of the diode chip 5 is assisted. Even if the viscosity of the liquid protective resin 6a is relatively high, the liquid protective resin 6a has fluidity, so if the liquid protective resin 6a adheres to a part of the side surface of the diode chip 5,
Due to this flow, the entire side surface of the diode chip 5 is covered with the liquid protective resin 6a.

The liquid protective resin 6a applied to the diode chip 5 is cured by heating, for example, to obtain a protective resin coating layer 6 as shown in FIG. The hardening of the protective resin 6a is performed while transferring the diode element 7 by the transfer device 14.

As is apparent from the above, this embodiment has the following advantages. (A) Since the liquid protective resin 6a of the first roller 8 is attached to the side surface of the diode chip 5 by transfer, even if the viscosity of the liquid protective resin 6a is relatively high, the liquid protective resin 6a is applied to the side surface of the diode chip 5. The resin 6a can be applied in a state of good uniformity. (B) Since the second roller 9 and the container 10 are provided as means for supplying the liquid protective resin 6a to the first roller 8, the liquid protective resin 6a can be automatically and easily supplied. (C) Since the protective resin layer 6 is formed while transferring the diode element 7 by the transfer device 14, the protective resin layer 6 can be formed with high efficiency. (D) Since the convex portion 15 is formed on the first roller 8, the liquid protective resin 6a sticks to the convex portion 15 in a protruding manner as shown in FIG. Adheres well. (E) Since the V-shaped groove 16 corresponding to the projection 15 of the first roller 8 is formed on the second roller 9, the liquid protective resin 6a adheres well to the second roller 9, and The second roller 9 is satisfactorily supplied to the first roller 8. (C) Since the diode chip 5 is formed in a trapezoidal shape and the diode chip 5 is arranged between the heads 1b and 2b which are larger than the diameter of the portion where the PN junction of the diode chip 5 is provided, a pair of heads is provided. A recess is formed between the parts 1b and 2b. Therefore, the liquid protective resin 6a adheres favorably to the side surface of the diode chip 5.

[0015]

[Modifications] The present invention is not limited to the above-described embodiment, and for example, the following modifications are possible. (1) As shown by a dotted line in FIG. 3, a motor M for rotating the diode element 7 is provided, and the liquid protective resin 6a of the first roller 8 is supplied to the side surface of the diode chip 5 while rotating the diode element 7. be able to. (2) The first and second rollers 8 and 9 can be configured to be in rolling contact with each other, one of the rollers is driven to rotate, and the other is driven to rotate. (3) The diode chip 5 can be a stacked diode chip in which a plurality of diode chips are stacked.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a diode element.

FIG. 2 is a front view schematically showing a protective resin layer forming apparatus according to an embodiment of the present invention.

FIG. 3 is a side view showing a part of line AA of the protective resin layer forming apparatus of FIG. 2;

FIG. 4 is a sectional view showing first and second rollers of FIG. 2;

[Explanation of symbols]

 1, 2 bar-shaped lead 5 diode chip 6a liquid protective resin

[Procedure amendment]

[Submission date] November 22, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

As is apparent from the above, this embodiment has the following advantages. (A) Since the liquid protective resin 6a of the first roller 8 is attached to the side surface of the diode chip 5 by transfer, even if the viscosity of the liquid protective resin 6a is relatively high, the liquid protective resin 6a is applied to the side surface of the diode chip 5. The resin 6a can be applied in a state of good uniformity. (B) Since the second roller 9 and the container 10 are provided as means for supplying the liquid protective resin 6a to the first roller 8, the liquid protective resin 6a can be automatically and easily supplied. (C) Since the protective resin layer 6 is formed while transferring the diode element 7 by the transfer device 14, the protective resin layer 6 can be formed with high efficiency. (D) Since the convex portion 15 is formed on the first roller 8, the liquid protective resin 6a sticks to the convex portion 15 in a protruding manner as shown in FIG. Adheres well. (E) Since the V-shaped groove 16 corresponding to the projection 15 of the first roller 8 is formed on the second roller 9, the liquid protective resin 6a adheres well to the second roller 9, and The second roller 9 is satisfactorily supplied to the first roller 8. (F) Since the diode chip 5 is formed in a trapezoidal shape and the diode chip 5 is disposed between the heads 1b and 2b which are larger than the diameter of the portion where the PN junction of the diode chip 5 is provided, a pair of heads is provided. A recess is formed between the parts 1b and 2b. Therefore, the liquid protective resin 6a adheres favorably to the side surface of the diode chip 5.

Claims (3)

[Claims] 1. A method for forming a protective coating layer by attaching a liquid protective material to a side surface of a diode chip fixed between first and second rod-shaped leads, comprising: a roller and an outer peripheral surface of the roller; A liquid protection substance supply means for supplying a liquid protection substance; and arranging the roller so that the axis of the roller and the first and second rod-shaped leads are parallel to each other. The liquid protective substance is attached by the liquid protective substance supply means, and the diode chip is moved together with the first and second rod-shaped leads to a position where the side surface of the diode chip contacts the liquid protective substance attached to the roller. Then, the liquid protective material on the outer peripheral surface of the roller is attached to the side surface of the diode chip with the rotation of the roller, thereby forming the protective coating layer. Protective coating layer forming method of the diode device characterized Rukoto. 2. The liquid protective substance supply means includes: another roller which is in rolling contact with or comes close to the outer peripheral surface of the roller; and a liquid protective material into which a lower part including a part of the outer peripheral surface of the another roller is immersed. The method for forming a protective coating layer on a diode element according to claim 1, comprising a container housed therein. 3. A roller for attaching a liquid protective substance to a side surface of the diode chip has an annular convex portion on its outer peripheral surface, and the another roller has an annular groove at a position corresponding to the convex portion. 3. The method according to claim 2, wherein the protective coating layer is formed on the diode element.