JPS6172030A - Method of accelerating dissolution of resin of electronic part - Google Patents

Abstract

PURPOSE:In dissolving a resin package of electronic part in fuming nitric cid, etc., to dissolve it rapidly and cleanly without damaging the electronic part at all, by irradiating the package with laser beam. CONSTITUTION:An electronic part covered with a resin package is put in a dissolution solution such as fuming nitric acid, etc., the desired part of the package is irradiated with a laser beam emitted from a laser source through a regulating plate to adjust light flux and a lens to condense the laser beam, so that dissolution of the desired part is promoted.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for accelerating the dissolution rate when dissolving a resin package of an electronic component with a dissolving solution such as fuming nitric acid, for example in failure analysis of the electronic component. Yes [Prior art] Figure 1 shows a conventional melting method, and Figure 1 (a)
1(b) shows an IC in the process of being dissolved, and FIG. 1(b) shows an IC in which a chip appears after being dissolved. In FIG. (2) is a dissolving solution such as fuming nitric acid for dissolving electronic components fi+, +311-L beaker, (41 is a hole that has been previously drilled in a local part of the resin package, and (5) is a hole that is covered with resin. It is an IC chip.

Since the conventional melting method is carried out as shown in Figure 1), if the entire resin package melts at the same time,
There is nothing left to support the electronic component chip (5). In order to prevent this, the resin of the electronic component chip (51 parts) required for microscopic observation for failure analysis etc. is removed in advance to a depth of 51 with a drill, etc., and the resin is thinned and placed in a solution (2) of fuming nitric acid etc. It had dissolved when I put it in.

However, according to this method, electronic component chips (5
) There is a risk of damaging the tip (5) when removing the resin, and to avoid this, the cutting work must be done with great care, which rarely has the disadvantage that it takes time and effort to cut the valve barrel. .

[Summary of the invention]

This invention was made with the aim of improving these shortcomings, and proposes a method for accelerating the dissolution rate by applying convergent light from a lens to the area to be dissolved and using the thermal energy generated at that time. .

[Embodiments of the invention]

FIG. 2 is a diagram showing an embodiment of the present invention.
), using a laser beam as an example, where the diameter of the luminous flux is expressed as λ and the wavelength of the light is λ, the spread angle θ of the luminous flux is generally expressed as θmiλ/D.

Also, when this parallel ray is converged by a lens at the focal length, the spot diameter d on the focal plane is d-2fθ ・・・・・・・・・・・・・・・
...+11.

When using a laser beam, if the laser output is P, the energy density PS at the focal plane is P3 W ap/π
d2=D2P/πf2λ2 ・・・・・・・・・・・・
(2) becomes.

In this formula, the diameter of the light beam is equal to the focal length of the lens, l111f.

If the wavelength of light λ and the laser output pl are given, the energy density P
a is calculated and has a larger energy than the solar convergent light,
Moreover, this energy can be electrically controlled and localized processing can be performed.

Figure 2(b) shows an example of application to resin melting, and shows (1) to (
3) and (5) are exactly the same as in FIG.

(6) is a lens adjusted to converge the laser beam onto a local part of the electronic component to be melted +11; (7) is a laser light source.

(8) is a laser beam adjustment plate ◎ In the method for accelerating resin melting of electronic components configured as described above, it is not necessary to scrape off the electronic component (1) to be melted with a drill or the like in advance. (・It has the characteristic of being able to apply focused light to a localized area and accelerate the dissolution rate only in that area.

〔Effect of the invention〕

As described above, the method according to the present invention can quickly melt one local part without damaging the electronic component chip (5), which is required for microscopic observation for failure analysis, etc.

Can be cleaned.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conventional resin melting method, and FIG. 2 is a diagram showing a resin melting acceleration method according to the present invention. In the figure, (1) is an electronic component to be melted in a resin package. (2) is a solution of fuming nitric acid, (3) is a solution of fuming nitric acid, (4)
(5) is a hole that was previously removed using a drill etc. in the resin package.
is an electronic component chip, (6) is a converging lens, and (7) is a laser light source. (81 is a laser beam adjusting plate. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

Claims (1)

[Claims] In a method in which electronic components covered with a resin package are placed in a solution such as fuming nitric acid and the main parts of the package are dissolved, an adjustment plate that adjusts the luminous flux of the laser light generated from the laser light source, and a convergence plate for converging the laser light are used. A method for accelerating resin melting of an electronic component, characterized in that the package is irradiated through a lens to accelerate melting of the irradiated portion.