JP2000021912A - Method for unsealing resin of semiconductor package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To expose the surface of the IC chip of a semiconductor package, which is difficult to be unsealed in an electrically conducted state by etching the surface of resin with laser irradiation, dissolving a remaining resin part by fuming nitric acid, immersing it into organic solvent and removing dissolved resin. SOLUTION: A part except for the resin of a semiconductor package formed of an IC chip 1, resin 2 and copper foil 3 is covered by protection adhesive sheets 4. Then, resin 2 is removed by using CO2 laser 5 used for printing the semiconductor package. For removing resin 2 left in a recess, a sample is heated by a hot plate 8. When a temperature becomes a prescribed one, the fuming nitric acid 7 at an ordinary temperature is applied on resin 2 from a tapered syringe 6 and it is heated until resin 2 dissolves. It is quickly immersed in organic solvent 9. Thus, the strong exothermic reaction between acid and organism occurs and dissolved resin 2 and fuming nitric acid 7 on the IC chip 1 are immediately removed with the cleaning actin of organic solvent 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for unsealing a resin of a semiconductor package used for evaluation and analysis of a semiconductor device.

[0002]

2. Description of the Related Art In the evaluation and analysis of a semiconductor package, only the resin on an IC chip is exposed with an etching solution, and the analysis is performed using a liquid crystal / emission microscope or the like.

[0003]

However, in the conventional sealing resin opening method, the copper wiring is melted and disconnected at the same time as the sealing resin by the etchant, so that electrical connection with the silicon chip cannot be obtained. It had problems that could not be evaluated and analyzed.

[0004]

In order to solve the above problems, the present invention has the following arrangement. That is, the resin surface is etched by laser irradiation, and the remaining resin portion is dissolved using fuming nitric acid. And it is characterized in that it is immersed directly in an organic solvent to remove the dissolved resin.

[0005]

According to the above-described structure, an IC of a semiconductor package which has conventionally been difficult to open while maintaining electrical continuity.
The chip surface can be exposed.

[0006]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an opening procedure according to the present invention.
C chip, 2 resin, 3 copper foil, 4 adhesive protective sheet, 5 laser, 6 tapered dropper, 7 fuming nitric acid,
8 is a hot plate and 9 is an organic solvent.

First, as a sample from which resin is to be removed, an IC
A portion of the semiconductor package including the chip 1, the resin 2, and the copper foil 3 other than the resin is covered with a protective adhesive sheet 4. Then, using a CO2 laser used for printing on the semiconductor package, the light is focused on the resin surface so that the laser spot is minimized. In this state, a laser beam is scanned to remove the resin having a thickness of about several tens of microns.

Next, in order to remove the resin remaining in the concave shape, the sample is heated from 80 ° C. to 100 ° C. from below with a hot plate 8, and when the sample is stabilized at a constant temperature,
The fuming nitric acid 7 at room temperature is applied to the resin from the tapered dropper 8 and heated for about 30 seconds until the resin is dissolved.

Next, in order to completely remove the resin remaining after dissolving on the IC chip 1, the IC chip 1 is quickly immersed in a highly volatile organic solvent 9 such as acetone without passing through a washing step. When the heated fuming nitric acid 7 and the organic solvent 9 come into direct contact with each other, a strong exothermic reaction between the acid and the organic (explosive reaction) occurs. The fuming nitric acid 7 is instantly and cleanly removed. And
By peeling off the protective pressure-sensitive adhesive sheet, as shown in FIG. 2, it becomes possible to obtain a state in which electrical conduction can be obtained without melting the copper foil, and electrical analysis and the like can be performed.

[0011]

As described above, according to the present invention, only the resin can be removed from the semiconductor package.
Electrical analysis of the IC chip mounted after the resin is melted is possible.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a procedure of a resin opening method according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the present invention after opening.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... IC chip 2 ... Resin 3 ... Copper foil 4 ... Protective adhesive sheet 5 ... Laser 6 ... Tapered dropper 7 ... Fuming nitric acid 8 ... Hot plate 9 ···Organic solvent

Claims (1)

[Claims] A step of irradiating a laser to the sealing resin portion to remove the resin in a thin concave shape; a step of applying an etchant to the resin portion to remove the resin;
A method for opening a resin of a semiconductor package comprising a cleaning step.