JPH11329916A - Method for sorting of semiconductor chip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for sorting semiconductor chips, by which acceptable chips can be sorted out from the defective ones without subjecting to marking on the elements themselves. SOLUTION: The rear surface of a wafer sheet 8 is irradiated with ultraviolet light L 8 via a mask 10, on which a distribution pattern corresponding with an array 3a of defective semiconductors based on the result of measurement of a wafer test is formed. Then, acceptable semiconductor chips 3 are picked up according to discoloration distribution on the rear surface of the wafer sheet 8 by the use of a color image recognizing device to transfer the acceptable chips to a next process, the mounting process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor chip sorting method for sorting non-defective / defective semiconductor chips held on a wafer sheet based on a measurement result of a wafer test.

[0002]

2. Description of the Related Art When a semiconductor chip is transported to a bonding process, a non-defective product of each diced semiconductor chip is used.
Conventionally, in order to select defective products, a semiconductor chip with a fail mark is determined as a defective chip in a wafer test process using a wafer prober, while a semiconductor chip without a fail mark is determined as a good chip. Only the non-defective chips are sucked and held one by one by a collet.

In general, the presence or absence of a fail mark is identified by an image recognition device, and controls the operation of picking up a semiconductor chip by the collet. Wafer testing is performed automatically by a wafer prober. The wafer prober is for testing the electrical characteristics of each semiconductor element 3 formed on the semiconductor wafer 2 on the measurement stage 1 as shown in FIG. Connect the needle (probe needle) 6
This is an apparatus that enables an electrical test of each element 3 by a tester (not shown) connected to the stylus 6 and attaches the fail mark to the surface of the element that the tester has determined to be defective. The semiconductor wafer 1 on which the wafer test has been completed is supported by a wafer ring 7 while being bonded to a wafer sheet 8 as shown in FIG. 4, and each semiconductor element 3 is separated into individual semiconductor chips in a dicing process.

[0004]

As described above, in the prior art, when selecting good or defective individual semiconductor chips 3, a fail mark directly attached to the surface of the semiconductor chip 3 is identified by an image recognition device. However, it is not possible to write the fail mark on all the semiconductor devices. That is, the droplets of the ink attached as a fail mark to the defective semiconductor element by the wafer prober may be scattered to the adjacent non-defective element, so that even the non-defective element becomes defective. Even after completion, the method described above cannot be applied to a device that is extremely sensitive to dust. Therefore, the semiconductor chip 3
However, there is a problem that good and defective products cannot be sorted out.

The present invention has been made in view of the above-described problems, and has as its object to provide a method of selecting a semiconductor chip which can select good / defective products without marking the element itself.

[0006]

In order to solve the above-mentioned problems, the present invention provides a method for manufacturing a wafer sheet through a mask which describes an array distribution pattern of good or bad semiconductor chips based on a measurement result of a wafer test. After irradiating the back surface of the wafer sheet with a light beam, good and defective semiconductor chips are selected based on the distribution of discolored portions due to the irradiation of the light beam on the back surface of the wafer sheet. As a result, it is possible to sort non-defective products and defective products without directly marking semiconductor chips.

[0007]

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

FIG. 1 shows an embodiment of the present invention. In the present embodiment, the number of semiconductor elements formed on the semiconductor wafer is set to nine for ease of explanation, but actually, it is several hundreds or more as is known.

In the wafer test process, the semiconductor chips 3 on the semiconductor wafer 2 whose electric characteristics have been measured by the wafer prober are diced and held individually on the wafer sheet 8 in a separated state. In the present embodiment, in the wafer test process,
The conventional fail mark is not attached to the semiconductor chip 3a determined to be defective, and the measurement result (either non-defective or defective) of each chip is stored in a host computer (not shown). The wafer sheet 8 is provided with an adhesive (about 10 μm) on a polyvinyl chloride film (about 70 μm).
m) is applied, and each semiconductor chip 3 is held by the adhesive.

Therefore, the measurement result of the wafer test indicates that the first chip (shown in the figure, the same applies hereinafter): non-defective product,
2nd chip (): good product, 3rd chip (): good product, 4
Chip (): defective, 5th (): good, 6
Chip (): defective, chip 7 (): good, 8
It is assumed that the chip (): non-defective product and the ninth chip (): non-defective product. That is, two of the fourth chip () and the sixth chip () are defective, and all the rest are good. Based on this, according to the arrangement of the semiconductor chips 3 on the semiconductor wafer 2, in this embodiment, openings are provided only at arrangement positions () and () of the semiconductor chips 3 a corresponding to defective products (indicated by double hatching in the figure). A mask 10 having 10a is manufactured. It should be noted that the mask 10 can be of the same type as a mask used in a semiconductor device manufacturing process such as an exposure process.

Next, ultraviolet rays L are irradiated from the ultraviolet irradiation lamp 11 toward the back surface of the wafer sheet 8 through the mask 10. At this time, since only the regions corresponding to the fourth chip () and the sixth chip () of the mask 10 are open, the fourth chip () and the sixth chip () of the semiconductor wafer 2 are provided on the back surface of the wafer sheet 8. ), I.e., only the position of the defective semiconductor chip 3a is irradiated with the ultraviolet light L, whereby the wafer sheet 8
Discolored on the back. At this time, assuming that the original color of the wafer sheet 8 is light transparent blue, the wafer sheet 8 is deteriorated by the irradiation of the ultraviolet light L and changes color to red (see FIG. 2A and FIG. 2B. Hatched). Then, the gap between the discolored portion and the chip is determined from the back surface of the wafer sheet 8 using a color image recognition device, and the semiconductor chip 3 is transferred to the next bonding process.
The operation of the collet for transporting the semiconductor chips is controlled to supply only the good semiconductor chips 3 to the next step. Further, the defective semiconductor chip 3a is left at the same position without being picked up.

When the sorting of good and bad semiconductor chips 3 individually separated from one semiconductor wafer 2 is completed, a wafer sheet holding the next semiconductor chips to be sorted is prepared. A similar method, that is, a new mask that describes the arrangement distribution pattern (openings) of defective semiconductor chips is newly prepared, and the back surface of the wafer sheet at the arrangement position of the defective semiconductor chips is irradiated with ultraviolet light, Based on the distribution of discolored portions on the back surface of the sheet, non-defective and defective semiconductor chips are selected, and only non-defective semiconductor chips are supplied to the next step.

As described above, according to the present embodiment, a non-defective product can be obtained without attaching a fail mark to the semiconductor chip 3.
Since defective products can be sorted out, sorting work can be reliably performed even for devices that are extremely sensitive to dust even after completion. Further, conventionally, when picking up a good semiconductor chip, the outer shape of the chip, that is, the boundary between adjacent chips is recognized, but according to the present embodiment, the discolored portion on the back surface of the wafer sheet and the inter-chip Can be determined and picked up by a small gap, so that a good semiconductor chip can be picked up regardless of the stretching ratio of the wafer sheet.

Although the embodiment of the present invention has been described above, the present invention is, of course, not limited to this, and various modifications can be made based on the technical concept of the present invention.

For example, in the above-described embodiment, a mask depicting the array distribution pattern of the defective semiconductor chips 3a is manufactured. Instead, a mask depicting the array distribution pattern of the non-defective semiconductor chips 3 is manufactured. Then, the non-defective semiconductor chips 3 may be picked up based on the discolored portion on the back surface of the wafer sheet at the arrangement position of the non-defective semiconductor chips 3 irradiated with ultraviolet rays through the mask. In this case, the sorting method of the present invention can be carried out by using a conventionally used ultraviolet irradiation apparatus that irradiates ultraviolet rays for the purpose of weakening the adhesive force of the wafer sheet.

In the above embodiment, the mask 10
In manufacturing, a light-transmitting opening was formed at a position corresponding to the arrangement of non-defective or defective semiconductor chips. Instead, a non-defective or defective semiconductor chip with respect to a photosensitive transparent plate material was formed. It is considered that the same effect as in the above-described embodiment can be obtained even if only a portion other than the portion corresponding to the above arrangement is devitrified by denaturation so that light cannot be transmitted, and this is used as a mask.

[0017]

As described above, according to the method for sorting semiconductor chips of the present invention, good and defective semiconductor chips can be sorted by discoloration of the back surface of the wafer sheet. Non-defective / defective products can be reliably sorted out even for devices that cannot be directly marked.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing an entire embodiment of the present invention.

FIG. 2 is a back view of the wafer sheet for explaining the same operation, in which A shows a state before light beam irradiation, and B shows a state after light beam irradiation.

FIG. 3 is a partial cross-sectional view showing a wafer test process.

FIG. 4 is a plan view schematically showing a semiconductor wafer before dicing placed on a wafer sheet.

[Explanation of symbols]

2 ... semiconductor wafer, 3 ... good semiconductor chip, 3
a: defective semiconductor chip, 8: wafer sheet,
10 mask, 10a opening, 11 ultraviolet irradiation lamp.

Claims (4)

[Claims] 1. Based on a measurement result of a wafer test,
In a semiconductor chip selection method for selecting non-defective / defective semiconductor chips held on a wafer sheet, a mask depicting an array distribution pattern of non-defective or defective semiconductor chips based on a measurement result of the wafer test is used. After irradiating the back surface of the wafer sheet with a light beam, based on the distribution of discolored portions due to the irradiation of the light beam on the back surface of the wafer sheet,
A method for sorting semiconductor chips, wherein a defective product is sorted. 2. The mask according to claim 1, wherein an opening through which the light beam can pass is formed at a location corresponding to the arrangement of the non-defective or defective semiconductor chips based on a measurement result of the wafer test. A method for sorting semiconductor chips according to claim 1. 3. The semiconductor chip according to claim 1, wherein a distribution of the discolored portions on the back surface of the wafer sheet is identified by using an image recognition device, so that good and defective semiconductor chips are selected. The method for sorting semiconductor chips according to claim 1. 4. The method according to claim 1, wherein the light beam is ultraviolet light, and the wafer sheet is made of a polyvinyl chloride film.