JPH01218036A - Inker apparatus - Google Patents

Abstract

PURPOSE:To enhance the reliability of a P/W test and to enhance the yield of a product by a method wherein a defective chip is marked and, at the same time, it is recognized whether the chip has been marked surely, and in case the chip has not been marked, it is marked again. CONSTITUTION:A gate circuit 7 is used to irradiate a wafer 6 with a laser 2; a first electric signal M1 with an intensity value P1 of its reflected beam detected by an optical detector 4 is passed in accordance with a keying control signal from a control signal input terminal 11. A comparator 9 is used to radiate a laser beam 3 of the laser 2 toward a bad mark 5 added onto a defective chip out of chips 6a; it compares a second electric signal M2 with an intensity value P2 of its reflected beam detected by the detector 4; it outputs an instruction signal to execute a marking operation again when P1<=P2. A laser marker 1 applies a laser beam 1a onto the corresponding defective chip during an operation of a switching circuit 10, and applies the bad mark 5 again. By this setup, the reliability of a P/W test can be enhanced; the yield of a product can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inker device, and more particularly to an inker device that adds defective marks using an inker as a means for removing defective chips on a semiconductor wafer.

[Conventional technology]

Conventionally, this type of inker device, as shown in FIG.
A laser inker 1 using a laser performs a test to determine whether each chip on a semiconductor wafer 6 is good or bad (hereinafter referred to as P
This wafer prober automatically tests each chip on a semiconductor wafer using a predetermined selection program and determines whether it is good or bad. The defective chips are marked with a good cine mark by laser inker 1.
was added. The laser inker 1 is a laser light source that has enough light output to inflict scratches of arbitrary size on the surface of the semiconductor wafer 6. If the target chip is determined to be defective, the laser inker 1 emits laser light. 1
A is ejected onto the surface of the defective chip to add a defective mark 5. This defective mark 5 is used to visually select chips as good or defective.

[Problem to be solved by the invention]

The conventional inker device described above does not have a means to check for defective marks, detect omissions, and re-inker. When a defect mark is not added to a defective chip, the defective chip is determined to be a finished product in the sorting process and subsequent processes are proceeded with, resulting in a disadvantage that the yield of the product is deteriorated.

[Means to solve the problem]

The inker device of the present invention includes a laser that irradiates a chip area on a semiconductor wafer, a photodetector that detects reflected light from the semiconductor wafer surface of the light emitted from the laser, and characteristics of each of the chip areas. a gate circuit that outputs a first electrical signal obtained by irradiating a predetermined location on the surface of the semiconductor wafer with the laser and detecting the reflected light with the photodetector prior to the test; and the first electrical signal output from the gate circuit. a second electrical signal that is read from the memory circuit; a second electric signal that is generated by emitting light from the laser toward a defective mark placed on the chip area and detecting the reflected light by the photodetector; a comparator that compares the first electrical signal and outputs a re-inker instruction signal when the first electrical signal and the second electrical signal are equal and when the second electrical signal is large; and a switch circuit that receives an inker instruction signal and controls re-inkering.

〔Example〕

Next, the button of the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of a first embodiment of the present invention.

As shown in FIG. 1, a laser f2 irradiates a chip area on a semiconductor wafer 6, and a photodetector 4 detects reflected light from the surface of the semiconductor wafer 66 of the laser beam 3 emitted from the laser 2, respectively. Prior to the characteristic test of the chip 6a, a laser 2 is used to irradiate a predetermined location on the surface of the semiconductor wafer 66, and a photodetector 4 detects the reflected light. A gate circuit 7 to be passed through in response to an opening/closing control signal, a memory circuit 8 for storing an electric signal M supplied from the gate circuit 7, and a defective mark 5 added on a defective chip among the chips 6a.
A second electric signal M2 of intensity P, which is obtained by irradiating the laser beam 3 of the laser 2 toward the target and detecting the reflected light by the photodetector 4, is compared with the electric signal M read from the memory circuit 8, and P1≦
a comparator 9 that outputs a re-inker instruction signal when P;
Switch circuit 10 that operates upon receiving a re-inker instruction signal
and a laser inker 1 that emits a laser beam 1a onto a corresponding defective chip when the switch circuit 10 is activated to re-ink a defective mark.

A semiconductor wafer 6 on a stage (not shown) is scanned by moving in each direction in units of chip length, and is subjected to a P/W inspection with a wafer prober (not shown), and if the corresponding step 6a is defective, The laser beam la emitted from the laser inker 1 adds a scratch as a defective mark 5 on the chip.

The photodetector 4 is set at a position where it can detect the reflected light from the surface of the semiconductor wafer 6 of the laser light 3 emitted from the inker check laser 2.

FIG. 2 is a simplified diagram for explaining the operation of the first embodiment shown in FIG. Below, with reference to FIG. 2, the first part of FIG.
The operation of the embodiment will be explained. In step 21 of Rimyo,
Before scanning the semiconductor wafer 6 prior to the P/W test, the gate circuit 7 is opened by the opening/closing control signal from the control signal input terminal 11, and in step 22, the laser beam 3 emitted from the laser 2 is applied to the semiconductor wafer 6. An electrical signal M1 having an intensity P corresponding to the light intensity reflected by the surface and detected by the photodetector 4 is stored in the memory circuit 8. Next, in step 23, the gate circuit 7 is closed.

If the intensity of the reflected light is weak, finely adjust the position of the semiconductor wafer 6 so that the irradiation point of the laser beam 3 is on the semiconductor wafer 6.
Set it at a location with high reflectance, such as the upper aluminum wiring. The above work only needs to be performed once at Vc before the start of the P/W test.

Note that the optical output of the laser 2 is set in advance to a size that does not damage the surface of the semiconductor wafer 6 and allows sufficient reflected light to reach the photodetector 4.

Next, in step 24, each chip 6a on the semiconductor wafer 6 is tested in the normal procedure, and in step III 25, if it is a good chip, it is moved to the next chip, and if it is a defective chip, it is moved to the next chip. , in hand l1a26, a defective mark 5 is added using the laser inker 1 whose optical output has been set in advance to an extent that can add scratches to the surface of the chip 6a.

Next, in step 27, the defective mark 5 is
is irradiated and the reflected light is detected by the photodetector 4. An electric signal M having an intensity P: corresponding to the intensity of the reflected light is obtained.

It is determined that the semiconductor wafer 6 has been definitely added, and in step 29 the process proceeds to the next step 6a, and if in step 30 there is no untested chip 6a, the processing of that semiconductor wafer 6 ends. This is because if a defective mark is actually added, the laser beam 3 should be scattered by the scratch, so the intensity of the reflected light that enters the photodetector 4 at this time becomes smaller and the laser beam 3 is scattered first. This is because the intensity P of the stored electrical signal M1 is considered to be smaller.

On the other hand, when P1≦P, it indicates that the defective mark has not been definitely added, so the comparator 9 outputs a re-inker instruction signal, and the re-inker instruction signal activates the switch circuit 10. A laser inker 1 emits a laser beam 1a to re-ink a defective mark 5 on a corresponding chip 6a.

FIG. 3 is a block diagram of a second embodiment of the invention.

As shown in FIG. 3, in the second embodiment, the laser aker 12 is capable of outputting light output in two levels of strength and weakness by means of a light output switching circuit 13. It also serves as the laser 2 for inker check and the laser input power 1.

That is, when the light output is weak, the light output is equivalent to the laser inker 1 in FIG. 1, and when the light output is strong, the light output is equivalent to the laser inker 1. Further, as shown in FIG. 3, an optical output switching circuit 13 is provided between the comparator 9 and the laser inker 12 for switching between two types of optical output of the laser inker 12 as necessary.

The optical output switching circuit 13 has a switching signal input terminal 14 that controls switching from the outside.

FIG. 4 is a flow chart for explaining the operation of the second embodiment shown in FIG.

As shown in FIG. 4, steps 41 to 43 have been added to switch the optical output of the laser inker 12, and in steps 2' and 2.27 shown in FIG. The process is similar to the flowchart of FIG. 2 described above except for steps 22a and 27a, which are numbered 12.

〔Effect of the invention〕

As explained above, the inker device of the present invention adds an inker to a defective chip, and at the same time recognizes whether or not the inker has been reliably added, and re-inks if the inker is missed. The reliability of the P/W test can be improved, and therefore, the yield of products obtained by dicing the semiconductor wafer chips can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a first embodiment of the present invention, and FIG. 2 is a flowchart for explaining the operation of the first embodiment of FIG.
3 is a block diagram of the second embodiment of the present invention, FIG. 4 is a flowchart for explaining the operation of the second embodiment of FIG. 3,
FIG. 5 is a block diagram of an example of a conventional inker device. 1...Laser inker, 1a...Laser light, 2...Laser, 3...Laser light, 4-...Photodetector, 5...Failure mark, 6...Semiconductor wafer, 7...Gate circuit, 8...Memory circuit, 9...Comparator, 10... Switch circuit, 11...
・Control signal input terminal, 12... Laser inker, 13... Optical output switching circuit, 14...
Switching signal input terminal, M,, M,... Electric signal,
P1*P1...Intensity of electrical signal. Agent Patent Attorney Susumu Uchihara 5Cho7-G7 L-Sa7227-2L-Sa゛° 4 Kozai Sword Appears 1
1 41 I Wholesale Yuyo addition 1 standing system i/'bu Iy Mushiki Shiba A/
) Sumo-ri ℃ i-san Mira. M2 publication U ship P1 electrical signal error 1 ■ Fig. 2/2 L-The Saiji 1- 13 Yoneshi Hiro Kousen 1 Utsuroya 3 Fig. f

Claims (1)

[Claims] a laser that irradiates a chip area on a semiconductor wafer;
a photodetector for detecting reflected light from the semiconductor wafer surface of the light emitted from the laser; and a photodetector for detecting the reflected light from the semiconductor wafer surface by irradiating a predetermined location on the semiconductor wafer surface with the laser prior to characteristic testing of each of the chip regions. a gate circuit for extracting a first electrical signal detected by the photodetector; a memory circuit for storing the first electrical signal output from the gate circuit; A second electric signal obtained by emitting light from the laser and detecting the reflected light by the photodetector is compared with the first electric signal read from the memory circuit, and the first electric signal and the first electric signal are compared. The present invention is characterized by comprising a comparator that outputs a re-inker instruction signal when the two electric signals are equal and when the second electric signal is large, and a switch circuit that receives the re-inker instruction signal and controls the re-inker. Inker device.