JPS625885A - Coating material for marking and marking method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a marking technique, particularly a technique using a laser, and relates to a technique that is effective for displaying marks on the surface of a package, for example, in the manufacture of semiconductor devices.

[Background technology]

In the manufacture of semiconductor devices, a marking method for displaying marks on the surface of semiconductor device (hereinafter referred to as IC) packages is to display marks by irradiating the surface of a resin package with a laser and burning the resin surface. A method of applying a coating material that easily absorbs laser to the surface of a package, and then irradiating the coating material with a laser to burn off a part of the coating material to expose a part of the package and display a mark. There is a way.

However, the inventor of the present invention has found that such a marking method has the following problems.

In the method of directly irradiating the package with a laser, the mark is displayed by discoloration due to burning of the resin surface and diffused reflection due to surface roughness, so the clarity is low, and it is difficult to see if the package surface was later coated with transparent resin. Sometimes the marks are hard to see.

In the method of exposing the surface of the package by irradiating the coating material with a laser, the mark is displayed by burning away the coating material with the laser, so it is necessary to precisely control the thickness of the coating material. ,
If it is too thick, the burnout will be incomplete and the image will be unclear; if it is too thin, the background will be burned out and the image will be unclear.

In addition, examples of laser marking technology include:
Published by Nikkei McGraw-Hill Co., Ltd. [Nikkei Mechanical 19
December 31, 1984 issue” December 31, 1984 issue P
There are 53 to 57.

[Purpose of the invention]

An object of the present invention is to provide a marking technique that can produce clear marks.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Summary of the invention]

A brief overview of typical inventions disclosed in this application is as follows.

In other words, after applying a marking coating material to the object to be marked, by irradiating a part of this coating material with a laser, the property of the luminous component contained in the coating material relative to light is changed and a mark is created. It is intended to be displayed.

〔Example〕

FIGS. 1(a), (b), and (c) are perspective views showing a marking method according to an embodiment of the present invention, and FIGS. 2 and 3 are enlarged partial cross-sectional views for explaining its operation. It is.

In this example, the marking method is used to display a mark on the surface of an IC resin package 1, and the package 1 is made of black non-transparent resin.
It is formed into a dual in line package (DIP) type as shown in FIG. 1(a).

The surface of the resin-molded IC package 1 is contaminated by the adhesion of a mold release agent to the mold, as well as the adhesion of dust and hand marks during handling during the manufacturing process, so it is contaminated with organic solvents such as trichlorethylene. Cleaned with cleaning agent. This cleaning improves the adhesion between the coating material and the package, which will be described later.

Subsequently, as shown in FIG. 1(b), a marking coating material 3 is applied to the surface of the package 1 as the object to be marked in an area necessary for displaying the mark.
It is applied by any suitable means such as an offset printing device 2 or the like.

In this case, the thickness of the coating material film 4 may be within the standard dimensions defined as IC, and the film thickness may be non-uniform due to uneven coating or the like. That is, since the accuracy regarding the formation of the coating material film is greatly reduced, the control of the printing device 2 and the like can be simplified and speeded up.

The marking coating material contains a modification component that changes its properties against light when irradiated with a laser, and is configured to be able to adhere to the surface of the package, so that its properties against light before modification are likely to be the same as those of the surface of the package 1. are set to be virtually identical.

The material of the component that changes its properties against light when irradiated with a laser is a particle made of a pigment of the same color as the package surrounding a pigment of a different color, and the outer shell is destroyed by the energy of the irradiated laser and the inside is A conceivable example is one in which the dye is exposed. For example, it is a material in which white, silver, yellow, gold, etc. pigments are wrapped around a black pigment.

It is desirable to configure the structure so that this deterioration component changes its color properties at temperatures above 200"C, but does not change at temperatures below 200"C.In other words, during the process of IC manufacturing, inspection, and use after mounting, the package is heated to about 200"C. This is because there is a possibility that the temperature rises to a maximum of 100 degrees, and when the temperature rises, a situation may occur in which the displayed mark relatively disappears or diminishes due to the overall deterioration of the coating material film.

Possible means for configuring the marking coating material to adhere to the package 1 include using ink as the main component of the coating material.

Further, as a means to make this coating material as similar in color as the package as possible, it is possible to use black ink as the main component.

The coating material film 4 formed on the surface of the package 1 is cured by an appropriate means such as natural drying, forced drying by heating, UV irradiation, etc.
As mentioned above, if the surface of the package 1 has been washed to improve its adhesion, the coating material film will be strongly fixed even when air-dried.

Thereafter, using a suitable means such as a laser irradiation device 7 as shown in FIG. 1(c), the laser 5 is irradiated onto the coating material film 4 so as to display a desired mark 6.

The laser irradiation device 7 shown in FIG. By passing through the window 10, a desired mark 6 is drawn on the marking material coating 4.

As shown in FIG. 2, when the coating material film 4 on the package 1 is irradiated with the laser 5, the altered component 4a in the coating material film 4 in the portion irradiated with the laser 5 changes its properties against light. do.

That is, as shown in FIG. 3, in the area not irradiated with the laser, the unaltered component 4a absorbs most of the non-black visible light #111, but the coating material in the area irradiated with the laser absorbs most of the non-black visible light #111. The altered component 4b in the coating 4 is altered so as to reflect visible light Ia12 of colors other than black, such as white.

For example, the energy of the laser irradiated on the altered component destroys the outer skin made of black pigment, exposing the white pigment inside, and this white pigment particularly reflects white light among the light illuminating the package 1. .

In this way, since the mark 6 is displayed due to the deterioration of the coating material film 4 itself, the coating material film 4
This means that the accuracy of the coating material film may be low because it is hardly affected by the thickness of the coating material.

〔effect〕

(1) After applying a marking coating material to the object to be marked, by irradiating the coating material film with a laser to change the properties of the altered components contained in the coating material against light and displaying a mark, Since the mark can be clearly displayed, the clear display can be maintained even if a transparent film is formed on the surface after marking.

(2) Marks are displayed when a part of the coating material itself changes in quality, so it is possible to obtain clear marks even if the thickness of the coating material is uneven, and it also improves the film formation accuracy of the coating material. Productivity can be increased by easing the

(3) By altering the quality of the coating material and marking it, there is no need to change the composition of the object to be marked, so it is possible to prevent deterioration in the quality of the object to be marked, such as its moisture resistance. .

(4) By configuring the coating material to change in quality at 200° C. or higher, it is possible to prevent the mark from disappearing accidentally after the mark is displayed.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. Nor.

For example, the coating material is not limited to the same color as the object to be marked, but may be a different color.

The photo-altering substance is not limited to being configured so that its color changes upon laser irradiation, but may also be configured so that it changes from a transparent state that transmits light to a non-transparent state that blocks light.

The means for applying the coating material is not limited to offset printing, but may also be stamp printing, screen printing, or application by spraying or brushing.

The means for drawing a desired mark by laser irradiation is not limited to the method of forming a pattern by blocking the laser beam with a mask, but also the method of drawing a mark by continuously moving a laser beam, etc. may be used. .

The material of the object to be marked is not limited to resin, and may be ceramic, glass, metal, etc.

[Application field]

The above explanation has mainly been about the application of the invention made by the present inventor to marking of engineering C packages, which is the background field of application. It can also be applied to marking equipment and other products.

[Brief explanation of drawings]

FIGS. 1(a), 1(b), and 1(e) are perspective views showing a marking method according to an embodiment of the present invention. FIGS. 2 and 3 are enlarged partial cross-sectional views for explaining the operation thereof. DESCRIPTION OF SYMBOLS 1... IC package (object to be marked) 2... Offset printing system W (applying means), 3... Coating material for marking, 4... Coating material film, 4a.
... Altered component, 4b... Altered component, 5... Laser, 6... Mark, 7... Laser irradiation device, 8...
Laser source, 9... Mask, 10... Window, 11...
Absorbed light, 12...Reflected light. Figure 1 1st room
1 Figure 0. ) 2nd period
3 diagram

Claims (1)

[Scope of Claims] 1. A coating material for marking, characterized in that it contains a modifying component that changes its properties against light upon laser irradiation, and is configured to adhere to the surface of an article. 2. The coating material for marking according to claim 1, wherein the main component has the same color as the surface of the object to be coated. 3. The coating material for marking according to claim 1, wherein the altered component is configured to change color upon laser irradiation. 4. The coating material for marking according to claim 1, wherein the altered component is configured to change from transparent to non-transparent by laser irradiation. 5. The marking coating material according to claim 1, wherein the altering component is configured to change its properties against light at temperatures of 200° C. or higher. 6. A marking coating material containing a component that changes its properties against light when irradiated with a laser is applied to the object to be marked, and then a part of this coating material is irradiated with a laser to display the mark. marking method. 7. The marking method according to claim 6, wherein the marking coating material has the same color as the object to be marked.