JPS61263234A - Processor - Google Patents

Abstract

PURPOSE:To perform both works for cutting a circuit for countermeasuring a defect and marking an improper product sign by providing for emitting the laser light to the surface of a semiconductor wafer. CONSTITUTION:Information of improper portion on a circuit of each pellet is input to a controller 5. When the portion of the wafer 2 falls within the laser light emitting range by the operation of an X-Y table 3, the controller 5 decides whether the defect is countermeasured or marked. The light is emitted to a narrow portion to be cut on the circuit of the pellet zone to be countermeasured, while the light is emitted to a range which can be observed with bare eyes on the pellet zone impossible to be countermeasured. Then, a laser light source 10 emits a laser light through an optical fiber 9 onto the prescribed position of the wafer 2 to cut or mark the prescribed circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a technique that is effective when applied to bit relief processing on pellets and marking processing techniques for defective pellet DI areas.

[Background technology]

In the final inspection process of a semiconductor wafer used as a memory element such as a 5-RAM or a D-RAM, there is a so-called bullet inspection process in which the presence or absence of defects on circuits formed in each bullet area on the wafer is inspected.

In this pellet inspection process, the circuit on the pellet is inspected by a tester, and if a defect has occurred on the circuit, it is sent to a defect relief process or a marking process.

In the defect relief process, a defective bit area is cut by irradiation with a laser beam or the like, and the defective bit area is replaced with a preset spare area called a redundant bit.

However, when there are more defects than redundant bits set in advance, it is impossible to count the defects, so the defect is treated as a pellet defect. In this case, the pellet is sent to a marking step in which marks visible to the naked eye are placed on the surface of the pellet.

Incidentally, as a marking device that performs the marking process, an ink-type marking device that applies ink to the defective portion is known.

However, it is known that in this ink-based marking device, when the ink is deposited, the ink is blown onto the non-defective parts, which may cause contamination.

Therefore, it is conceivable to perform marking by irradiating a laser beam without worrying about ink scattering. This laser-type marking device irradiates the defective portion of the pellet with a laser beam over a certain range, altering the quality of the pellet surface and marking it visually.

As mentioned above, in the pellet processing process, if a defect is found on the pellet 7) during pellet inspection, either the defect relief or marking process is required, but the equipment that performs both processes is as described above. As explained above, the inventors have discovered that since they are separate devices and both are large devices, a large space is required to install these two devices.

Furthermore, the inventors have found that there is a limit to the improvement in pellet processing efficiency because each step is performed in a separate device.

A detailed example of defect detection technology for pellets used as memory elements is given in Kogyo Kenkyukai Co., Ltd., published November 20, 1980 [Electronic Materials 198
There is a November 4th issue, VLSI Manufacturing and Testing Equipment Guidebook J, P165-Pi74.

(Objective of the Invention) The object of the present invention is to provide a processing device that can perform defect relief and marking with a single device.
The objective is to provide a technology that allows pellet processing to take place in a small amount of space.

Another object of the present invention is to provide a technique that enables efficient pellet processing work.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Summary of the invention]

A brief overview of typical inventions disclosed in this application is as follows.

In other words, a processing device that performs processing by irradiating the surface of a semiconductor wafer with a laser beam has a structure that is equipped with a mechanism that can change the irradiation area of the laser beam, thereby cutting circuits for defect relief and marking defective products. Since both marking operations can be performed with a single device, pellet processing can be performed in less space.

Moreover, the above enables efficient processing of pellets.

〔Example〕

FIG. 1 is a conceptual diagram showing a processing device that is an embodiment of the present invention.

The processing apparatus 1 of this embodiment includes an XY table 3 on which a wafer 2 as a workpiece is placed, and a laser beam emitting mechanism 4 mounted above the XY table 3.

Movement of the XY table 3 in the X-axis and Y-axis directions is electrically controlled by a control section 5.

Further, the laser beam emitting mechanism 4 can change the irradiation angle of the laser beam 6. For example, by changing the position of the irradiation lens 8 by operating a servo motor attached to the laser beam emitting mechanism 4, the laser beam 6 can be emitted onto the wafer 2. The irradiation area of the laser beam 6 can be changed.

In addition, in the processing apparatus 1 of this embodiment, the irradiation range of the laser beam 6 may be changed on the wafer 2 from about 2 μm to about 300 μm in diameter.

In other words, when cutting a circuit when repairing a defect, it is necessary to irradiate a small diameter range of about 2 μm in order not to affect other good circuit parts, whereas when marking, it is necessary to irradiate the area with the naked eye. This is because it is necessary to irradiate in a diameter range of approximately 300 μm.

The laser beam emitting mechanism 4 is connected to the laser light source 1 as a laser oscillator via an optical fiber cable 9.
0, and the light emission timing of the laser light source 10 is electrically controlled by the control unit 5.

Next, the operation of this embodiment will be explained.

First, when each pellet section on the surface of the wafer 2 is inspected by a tester (not shown), information regarding the defective location on the circuit of each pellet, that is, information such as the coordinate position of the defective location and the size of the defective location, is transmitted to the control unit 5. is input.

Next, when the inspected wafer 2 is placed on the XY table 3, the processing apparatus 1 starts pellet processing for each pellet section of the wafer 2.

First, when the wafer 2 is stopped at a predetermined position by the operation of the XY table 3 and the corresponding spot is within the range of the laser beam emitting mechanism 4, it is determined in the control unit 5 whether to perform defect relief or marking. , a control signal based on this determination is sent to the laser beam emitting mechanism 4.

In the laser beam emitting mechanism 4, the servo motor 7 is operated by the control signal, and the position of the lens is set. That is, the pellet section for which defect relief is to be performed is set to a state in which the cut portion on the circuit can be irradiated with a narrow irradiation range, for example, about 2 μm in diameter, that is, an irradiation state with the laser beam 6a.

On the other hand, for pellet sections where defect repair is not possible, a diameter 30
A state in which irradiation is possible at approximately 0 μm, that is, laser beam 6b
The irradiation state is set by

Next, the laser light source 10 is
emits light, and a laser beam is emitted from the laser beam emitting mechanism 4 via the optical fiber cable 9 to a predetermined portion 1 on the wafer 2.
is irradiated to cut or mark a predetermined portion of the circuit.

The wafer 2 that has undergone the above steps is divided into pellets, defective pellets with the markings are removed, and only good pellets are subjected to a sealing step and supplied as semiconductor devices.

In this way, according to this embodiment, by having a structure in which the irradiation area of the laser beam 6 can be changed, it is possible to perform both the work of cutting a circuit for defect relief and marking a defective item with a single device. can. Therefore, a processing device that can be used for multiple purposes can be installed in a small space, and pellet processing can be performed efficiently.

〔effect〕

(1) Regarding processing equipment that performs processing by irradiating the surface of semiconductor wafers with laser beams, the structure is equipped with a mechanism that allows the irradiation area of the laser beam to be changed. It becomes possible to perform both tasks of marking landmarks with a single device.

(2) According to (11) above, defect relief and marking steps can be performed with a single device, so pellet processing can be performed in a small space.

(3) By marking with a laser beam, it is possible to omit the ink baking process, etc.
It is possible to realize a reduction in processing time.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. Nor.

For example, in the embodiment, the case where the laser light source was provided separately from the laser beam emitting mechanism was explained.
The present invention is not limited to this, and the laser light source and laser beam emitting mechanism may be integrated.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram showing a processing device according to a first embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Processing device, 2... Wafer, 3... XY table, 4... Laser beam emitting mechanism, 5... Control unit, 6... Laser beam, 7... Servo motor, 8...
...Irradiation lens, 9...Optical fiber cable, 10
...Laser light source.

Claims (1)

[Scope of Claims] 1. A processing device that performs processing by irradiating the surface of a semiconductor wafer with a laser beam, the processing device comprising a mechanism that can change the irradiation area of the laser beam. 2. The processing apparatus according to claim 1, wherein the change in the irradiation area is automatically controlled based on wafer defect information.