JPH04111727U - Stepper alignment device - Google Patents

Abstract

(57) [Summary] [Purpose] The purpose is to improve the alignment accuracy of each pattern formed on a semiconductor wafer. [Structure] An alignment mark 10 formed in advance on a semiconductor wafer W is divided into three parts, and a laser irradiation device 2 is attached to each part.
A laser device 2 consisting of a laser device 1 and a light receiving portion 22 is arranged, and the outputs detected by each laser device 2 are added in a discriminating portion 3 and compared and discriminated to accurately determine the position of the original alignment mark 10.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention is applied to semiconductor wafers during numerous processes and when forming wiring patterns, etc. The present invention relates to a device for aligning steppers for exposure, etc.

0002

[Conventional technology]

Each semiconductor pellet on a semiconductor wafer is formed by sequentially performing various treatments. There is. For example, a resist film or conductive film is applied to the entire surface and a predetermined pattern is exposed. Windows are opened and wiring is done, and these processes are repeated many times, so The accuracy of pattern formation etc. in each process, that is, the alignment accuracy of the stepper requested.

0003 In order to align such steppers, for example, as shown in Figure 4, a semiconductor A large number of identical shapes protrude on a part of the surface of the body wafer W in the initial stage when viewed from above. alignment mark 10 is formed, and this large number of alignment marks Irradiate the entire area while scanning the laser beam from the laser irradiation unit 20 at the position of the hole 10. The reflected light is detected by the light receiving unit 30 to determine the unevenness of each alignment mark 10. Then, determine the position of the alignment mark 10 and align each pattern formation. I was going.

0004

[Problem that the idea aims to solve]

However, the alignment mark 10 is irradiated with a laser beam and the reflected light is detected. For example, if aluminum, etc., which will become the electrode, is vapor-deposited over the entire surface, the alignment will be improved. It becomes difficult to cover the mark 10 uniformly, and the adhesion state is uneven in some parts. The unevenness level L cannot be detected accurately and is detected as noise N as shown in Figure 5. and determine the exact position of the alignment mark 10 on the entire semiconductor wafer. There is a problem that the alignment accuracy of each pattern formation decreases. It was.

[0005]

[Means to solve the problem]

In order to solve the above problems, the stepper alignment device of the present invention The eye of the stepper is The above alignment mark is duplicated on the alignment device of the stepper that performs alignment. Multiple laser beams are irradiated with a laser beam divided into several parts and each reflected light is detected. Compare and determine the data of the laser device and the reflected light detected by each laser device. The present invention is characterized by being provided with a discrimination section.

[0006]

[Effect]

In the stepper alignment device with the above configuration, many unevenness alignments with the same shape can be performed. The mark is divided into multiple parts and each part is irradiated with laser light using a laser device. In order to detect the reflected light, we use the reflected light data obtained for each laser device. It is possible to recognize each uneven alignment mark. obtained with each laser device. Each piece of data is sent to a discriminating unit, and each data is compared by the discriminating unit. At this time, since the alignment marks formed on the semiconductor wafer have the same shape, Therefore, the recognition of alignment marks detected by each laser device is basically the same. Therefore, even if some alignment mark irregularities are not detected, other data It is possible to estimate the entire alignment mark formed on a semiconductor wafer. This improves the accuracy of stepper alignment for exposure, etc.

[0007]

【Example】

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

[0008] FIG. 1 is a schematic diagram of a stepper alignment device according to an embodiment of the present invention. main idea The proposed stepper alignment device includes a laser irradiation device 21 that irradiates laser light and its Three sets of laser devices 2 are provided, each consisting of a light receiving section 22 that receives reflected light. The output of the user device 2 is sent to a discriminator 3 that compares and discriminates each. There is.

[0009] At the initial stage of manufacturing, a part of the semiconductor wafer W has a square shape when viewed from above. A large number of rectangular prism-like alignment marks 10 similar to conventional ones are arranged vertically and horizontally in a constant manner. has been completed. This alignment mark 10 is divided into three blocks and each A laser device 2 is arranged at.

0010 In each laser device 2, the alignment mark placed in the corresponding divided portion 10, the laser beam is scanned by the laser irradiation device 21 and reflected by the light receiving section 22. It detects light. Therefore, since the alignment marks 10 have the same shape, Therefore, the data detected in the normal state is the same for each laser device 2.

[0011] For example, the determination unit 3 to which the output of each laser device 2 is sent out is configured to The resulting outputs are added together and compared with a reference output waveform to make a determination. In the stepper alignment device having the above configuration, each laser irradiation device of each laser device 2 is 21, the corresponding divided portion of the alignment mark 10 of the semiconductor wafer W is scanned. In order to simultaneously scan and scan, and detect the reflected light with each corresponding light receiving section 22. For example, when forming an electrode made of aluminum or the like, the alignment mark 10 If some of the irregularities are filled with aluminum, for example, the output O1 as shown in Fig. 2 will be reduced. It is detected by one laser device 2. However, the light receiving section 22 of another laser device 2 detects The output data accurately detects unevenness, so each data is added up in the discrimination section 3. Then, for example, as shown in Fig. 3, a low output O2 appears in the concave part, and the overall output becomes lower. noise becomes less noticeable. Therefore, with the data shown in Figure 3, the semiconductor wafer - The unevenness of the alignment mark 10 formed on the It becomes possible to detect it better.

0012 In this way, by comparing and determining the output O2 of each laser device 2 in the determining section 3, Since the position of the alignment mark 10 can be detected accurately, the wiring pattern in each process can be accurately detected. It is possible to form a pattern by exposure, etc. with high precision without positional deviation.

[0013] Note that the laser device 2 is divided into alignment marks 10 on the semiconductor wafer W. All you have to do is place them according to the number of divided parts you have created; the more parts you have, the more accurate the positioning will be. However, considering the cost, it is sufficient to divide it into three to four parts. Also, fruit The determination unit 3 in the example added the outputs detected by each laser device 2, but the determination method For example, other means such as image processing may be used as the method.

[0014]

[Effect of the idea]

As is clear from the above explanation, in the stepper alignment device of the present invention, the semiconductor The alignment mark formed on the body wafer is divided into multiple parts and laser is applied to each part. The device emits and receives a laser beam, and the identification unit accurately marks the alignment mark. The position can now be determined, improving the alignment accuracy of the stepper used for exposure, etc. It has the effect of

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of a stepper alignment device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of noise detected by a laser device of the stepper alignment device of the present invention.

FIG. 3 is a diagram showing an example of detection by the discriminator of the present invention.

FIG. 4 is a schematic explanatory diagram of a conventional stepper alignment device.

FIG. 5 is a diagram showing an example of detection by a conventional stepper alignment device.

[Explanation of symbols]

1 Alignment mark 2 Laser device 3 Discrimination section 10 Alignment mark

Claims (1)

[Scope of utility model registration request] 1. A stepper alignment device that aligns a stepper using a large number of uneven alignment marks of the same shape formed on a semiconductor wafer, wherein the alignment mark is divided into a plurality of parts and irradiated with a laser beam. What is claimed is: 1. A stepper alignment device comprising: a plurality of laser devices that respectively detect reflected light; and a discrimination section that compares and discriminates data of the reflected light detected by each laser device.