JPH0242744A - Sorting of chip - Google Patents

Abstract

PURPOSE:To shorten a sorting time by installing the following: a sheet-pasting process; a characteristic-measuring process of individual elements; a store and classification process of a measured result; a scribing process of a wafer; a wafer-breaking process; a sheet-stretching process; die-mounting process. CONSTITUTION:A wafer is pasted onto the surface of a sheet where an adhesive layer has been formed on its surface and a magnetic medium layer has been formed on its rear; individual characteristics of individual elements inside the wafer are measured by using a prober or the like. A measured result is stored in the magnetic medium layer situated on the rear of the individual elements; the wafer is scribed. The scribed wafer is broken; a sheet is stretched; spaces are formed in broken parts of the wafer. A good chip is discriminated on the basis of magnetic information; it is mounted in a prescribed position of a package. Thereby, it is possible to eliminate a drawback that a sorting time becomes long by a visual inspection of a human being.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a chip sorting method.

[Conventional technology]

Next, a conventional chip sorting method will be explained in detail with reference to the drawings.

FIG. 2 is a flowchart showing an example of a conventional chip sorting method.

The chip sorting method shown in Fig. 2 consists of (A) a measurement step in which each characteristic of the elements in the wafer, which has gone through processes such as diffusion and photoetching, is measured individually using a prober, etc.;
Sll), (B) A classification step (S12) in which defective elements are marked with scratch marks (or ink markings, magnetic ink markings) and classified as good or bad (C) A scribing step (S13) in which wafers are scribed, (D) Wafers (S14); (E) A breaking step (S15) for converting the wafer into chips; (F) Expanding the sheet and breaking the wafer. The process includes the following steps: a sheet expansion step (S16) for providing intervals between portions, and (G) a die mounting step (S17) for identifying non-defective chips and mounting them at predetermined positions on the package.

FIG. 3 is a sectional view showing the shape of the chip after the braking step S15 shown in FIG. 2 is completed.

Because the chips 31 to 34 stuck to the sheet 20 are braked at a certain angle due to the nature of silicon crystal, they cannot be lifted directly upward and die-mounted. Therefore, a sheet expansion step S16 is required to expand the sheet 20 in order to set a space between the chips 31 to 34 and lift them directly above to enable die mounting.

When the sheet expansion step S16 is performed, the relative position of each chip becomes indefinite, so in the die mounting step S17, the position of the chip to be mounted must be checked using an image recognition device.

The image recognition device also checks the quality of the chip to be installed.
It is used to mount only good chips, but if the recognition rate is low, a human must visually remove defective chips before the die mounting step S17.

[Problem to be solved by the invention]

The conventional chip sorting method described above uses an optical system that mechanically moves the good chips and their positions before the die mounting process, and if the recognition rate of bad chips is low, they must be visually removed by humans. Therefore, there was a drawback that the sorting time was increased.

[Means to solve the problem]

The chip sorting method of the present invention includes: (A) a sheet pasting step of pasting a wafer on the front surface of a sheet having an adhesive layer on the front surface and a magnetic medium layer on the back surface; (B) each of the elements in the wafer; (C) A classification step of storing the measurement results in the magnetic medium layer located on the back surface of each element; (D) A scribing step of scribing the wafer; (R) a braking step of braking the scribed wafer; (F) a sheet expansion step of expanding the sheet to provide a gap between the braking portions of the wafer; and (G) determining non-defective chips based on the magnetic information and packaging them. and a die mounting process for mounting the device at a predetermined position.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a flowchart showing one embodiment of the present invention.

Step S1: A wafer is attached to the front surface of a sheet having an adhesive layer on the front surface and a magnetic medium layer on the back surface.

Step S2: Each characteristic of each element within the wafer is individually measured using a prober or the like.

Step S3: Storing the measurement results in the magnetic medium layer located on the back surface of each element.

Process S4 The wafer is scribed.

Process S5 Braking the scribed wafer.

Step S6: Expanding the sheet to provide a spacing between the braking portions of the wafer.

Step S7: A non-defective chip is determined based on the magnetic information and mounted at a predetermined position on the package.

In step S6, the sheet is expanded mainly at the breaking part of the wafer, and the sheet in the area adhering to the chip is protected by the chip and hardly expands, so the magnetic information is not destroyed.

〔Effect of the invention〕

The chip sorting method of the present invention has the effect of shortening the sorting time.

Isamu 7

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing one embodiment of the present invention, and FIG.
The figure is a flowchart showing an example of the conventional method, and FIG. 3 is a sectional view showing the shape of the chip after the braking process shown in FIG. 2 is completed. 20... Sheet, 31-34... Chip. Agent Patent Attorney Susumu Uchihara

Claims (1)

[Claims] (A) A sheet pasting step of pasting a wafer on the surface of a sheet having an adhesive layer on the front surface and a magnetic medium layer on the back surface; (B) Characteristics of each element in the wafer. (C) A classification step of storing the measurement results as magnetic information in the magnetic medium layer located on the back surface of each element; (D) A scribing step of scribing the wafer; (E) ) a braking step of braking the scribed wafer; (F) a sheet expansion step of expanding the sheet to provide a gap between the braking portions of the wafer; (G) determining non-defective chips based on the magnetic information. A die-mounting step of mounting the chip in a predetermined position of the package.