Shutter structure with long service life in semiconductor overlay precision measurement

Abstract

The utility model discloses a long-life shutter structure in semiconductor overlay precision measurement, which comprises a shutter separation blade, a small-sized air floating platform, a voice coil motor, a magnetic railing ruler module and a proximity photoelectric switch, and is characterized in that the right end of the shutter separation blade is connected with the left end of an internal sliding block of the small-sized air floating platform; the right end of an inner sliding block of the small air floating platform is fixedly connected with the left side of a connecting plate, an air inlet pipe is fixed to the small air floating platform, the right side face of the connecting plate is fixedly connected with a rotor of the voice coil motor, and the magnetic railing ruler module is arranged below the connecting plate and the voice coil motor. The magnetic railing ruler module is located on the right side of the connecting plate, and the proximity photoelectric switch is arranged on the outer side of the magnetic railing ruler module. The long-life shutter structure in semiconductor overlay precision measurement has the advantages of simple structure, no friction and no noise, and provides necessary and enough guarantee and guarantee for long-life use of the shutter mechanism.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of semiconductor overlay precision measurement, specifically to a long service life shutter structure in semiconductor overlay precision measurement. BACKGROUND

[0002] In the field of semiconductor overlay precision measurement equipment, a shutter mechanism is specially set due to the process flow requirement, so as to purposefully control the illumination light path, thereby realizing the actual requirement of image acquisition. Since the shutter opening and closing frequency is extremely high in the actual use process of the equipment, the opening and closing frequency can reach 200,000 times per day, and the annual use amount needs to reach more than 60 million times, which puts forward a relatively strict requirement on the structural stability and service life of the shutter.

[0003] At present, the light path control shutter used by various manufacturers in the field of related semiconductor overlay precision measurement equipment is basically an independent motor control mode shutter, a mechanical shutter, or a pneumatic cylinder mode shutter. In addition to the difference in driving mode, they are basically contact type shutter mechanisms, which can generally meet the service life requirement. According to the data that can be inquired, the longest service life that can be reached by the best foreign equipment shutter mechanism (pneumatic cylinder mechanism) is 10 million times per year, which is still far from the actual requirement of 60 million times per year. At the present stage, the actual use requirement can only be solved by increasing the replacement frequency of the shutter mechanism, but this not only increases the maintenance cost of the equipment, but also brings certain instability to the equipment itself; in addition, the maintenance window time that can be given by the client is very valuable, and the replacement of such module parts requires a certain maintenance time, which compresses the time of other after-sales maintenance work. In short, it is a very inefficient and high-cost maintenance method, and there is an urgent need for a replacement solution, which needs further design and development.

[0004] In summary, the shutter mechanism in the above semiconductor overlay precision measurement equipment is basically a contact type driving method, which has problems such as friction loss, instability, short service life, and needs to be replaced and maintained before the shutter mechanism approaches the service life. This not only has high cost maintenance, but also has certain risks because of the different or changed use of the client. The above technical shortcomings cannot be solved in the short term. In order to break through the problems of short service life and instability of the shutter mechanism, a shutter mechanism with longer service life and higher stability is needed to meet the actual use requirement of the semiconductor overlay precision measurement equipment. UTILITY MODEL CONTENTS

[0005] The utility model aims at providing a long service life shutter structure in semiconductor overlay precision measurement, so as to solve the defects mentioned in the above background technology.

[0006] In order to achieve the above object, a long service life shutter structure for semiconductor overlay accuracy measurement is provided, comprising: a shutter baffle, a small air floating platform, a voice coil motor, a magnetic scale module and a proximity photoelectric switch, the right end of the shutter baffle is connected to the left end of the inner slider of the small air floating platform, the right end of the inner slider of the small air floating platform is fixedly connected to the left side of a connecting plate, an air inlet pipe is fixed on the small air floating platform, the right side of the connecting plate is fixedly connected to the rotor of the voice coil motor, the magnetic scale module is arranged below the voice coil motor of the connecting plate, the magnetic scale module is located on the right side of the connecting plate, and the proximity photoelectric switch is arranged on the outside of the magnetic scale module.

[0007] Further, the connecting plate extends downward to the front end of the magnetic scale module, and a photoelectric switch sensing sheet is fixedly installed on the right side of the connecting plate through a screw, and the photoelectric switch sensing sheet is arranged at the front end of the proximity photoelectric switch.

[0008] Further, the magnetic scale module is composed of a magnetic scale and a reading head, the magnetic scale is composed of a series of magnetic stripes, and the reading head comprises a light source, a grating and a photoelectric sensor.

[0009] Further, the small air floating platform, the magnetic scale module and the proximity photoelectric switch are fixedly installed on a supporting bottom plate, the right side of the supporting bottom plate is integrally connected to a supporting vertical plate, and the tail end of the voice coil motor is fixed on the supporting vertical plate.

[0010] Compared with the prior art, the utility model has the advantages that:

[0011] 1. The voice coil motor is used as a driving execution module, and there is no contact, friction and loss between the moving stator and the fixed stator; the small air floating platform is used as a guide and a support body of the shutter piece, and because of the action of the positive pressure gas, a 10um air film gap is formed between the air floating slider and the outer fixed body, and the slider moves without friction; the reading head of the magnetic scale and the magnetic grid are in a non-contact and lossless mode; the proximity photoelectric switch is used in a non-contact mode; and the related mechanisms are all used in a non-contact mode, so that the wear and consumption between the moving parts are avoided, the service life of the moving parts is indirectly guaranteed, and the long service life of the shutter device in the semiconductor overlay accuracy measurement equipment is achieved.

[0012] 2. The closed loop control mode is adopted, so that the running position accuracy of the shutter mechanism is effectively and accurately controlled, the use safety is effectively guaranteed, the control is adjustable, and the use is convenient.

[0013] 3. The combination of the pneumatic and electric modes is adopted to combine and design the related structures, the design structure is simple and compact, the closed loop control is adopted, and the use is convenient and efficient. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 It is a structural schematic view of the utility model.

[0015] Marked number in the drawing: 1, shutter baffle; 2, small air floating platform; 3, internal slider; 4, air inlet pipe; 5, connecting plate; 6, voice coil motor; 7, magnetic scale module; 8, proximity photoelectric switch; 9, screw; 10, photoelectric switch sensing sheet; 11, support base plate; 12, support vertical plate. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the utility model.

[0017] Please refer to Figure 1 The utility model provides a kind of shutter structure of long service life in semiconductor overlay precision measurement, comprising: shutter baffle 1, small air floating platform 2, voice coil motor 6, magnetic scale module 7 and proximity photoelectric switch 8.

[0018] The right end of the shutter baffle 1 is connected to the left end of the internal slider 3 of the small air floating platform 2, the right end of the internal slider 3 of the small air floating platform 2 is fixedly connected to the left side of a connecting plate 5, and an air inlet pipe 4 is fixed on the small air floating platform 2.The small air floating platform 2 plays a guiding role and supports the shutter piece.When the small air floating platform 2 is aerated, the movable slider in the small air floating platform 2 is pushed back and forth by the voice coil motor 6 to reciprocate.Since a 10um air film gap is formed between the air floating slider and the outer fixed body, the slider movement generates almost no friction, so its service life can be considered as infinite.

[0019] The right side of the connecting plate 5 is fixedly connected to the rotor of the voice coil motor 6.When the power supply wire (coil) of the voice coil motor 6 is placed in the magnetic field, it will be affected by the magnetic field force, thereby generating torque to drive the movement of the body, realizing the forward and backward movement of the transmission mechanism.Since the moving stator and the fixed stator of the voice coil motor 6 are non-contact, a certain driving force is generated by relying on the magnetic field, so there is no friction between the moving stator and the fixed stator, and there is no loss, so the service life can be infinite.

[0020] The magnetic scale module 7 is arranged below the voice coil motor 6, and is located on the right side of the connecting plate 5. The magnetic scale module 7 is composed of a magnetic scale and a reading head. The magnetic scale is composed of a series of magnetic stripes. The reading head includes a light source, a grating, and a photoelectric sensor. The working principle of the magnetic scale can be divided into the following steps:

[0021] 1) The light source emits light. The light source in the magnetic scale emits a beam of light, which is divided into a series of light spots by the grating;

[0022] 2) The grating scans the magnetic scale. When the target object moves, the grating scans the magnetic scale, and the light spot changes with the movement of the target object;

[0023] 3) The photoelectric sensor detects the light signal. The photoelectric sensor detects the light signal of the grating and converts the light signal into an electric signal;

[0024] 4) The electric signal is converted into a position signal. After processing by the signal processor, the electric signal is converted into a position signal of the target object. As a high-precision measuring device, the magnetic scale is mainly composed of a magnetic scale, a sensor, and a digital processor. It uses the changing magnetic field generated by the magnetic scale and the detection of the magnetic field by the sensor to measure the length. The magnetic scale has the advantages of simple structure and high durability.

[0025] The proximity photoelectric switch 8 is arranged on the outer side of the magnetic scale module 7. The proximity photoelectric switch 8 can control the start and end positions of the shutter movement, provide the in-place and homing information of the shutter movement, ensure the accuracy and reliability of the start and end positions of the shutter structure, ensure that the voice coil motor 6 does not have problems such as flying, and indirectly ensure the overall stability and reliability of the entire shutter mechanism, providing necessary guarantees and protection for the stable operation of the shutter mechanism.

[0026] The connecting plate 5 extends downward to the front end of the magnetic scale module 7. The right side of the connecting plate 5 is fixedly installed with a photoelectric switch sensing sheet 10 through a screw 9. The photoelectric switch sensing sheet 10 is arranged at the front end of the proximity photoelectric switch 8.

[0027] The small air floating platform 2, the magnetic scale module 7, and the proximity photoelectric switch 8 are fixedly installed on a support bottom plate 11. The right side of the support bottom plate 11 is integrally connected with a support vertical plate 12. The tail end of the voice coil motor 6 is fixed to the support vertical plate 12, so that the overall structure is more compact and reasonable.

[0028] Working principle: after power on, the proximity photoelectric switch 8 is opened, the voice coil motor 6 drives the connecting plate 5 to move forward, so that the internal slider 3 of the small air floating platform 2 drives the shutter baffle 1 to move forward, the photoelectric switch sensing piece 10 is away from the proximity photoelectric switch 8, after a certain position, the magnetic grating ruler module 7 accurately measures the distance to control the voice coil motor 6 to stop accurately; when the voice coil motor 6 drives the connecting plate 5 to move backward, the internal slider 3 of the small air floating platform 2 drives the shutter baffle 1 to move backward, the photoelectric switch sensing piece 10 is close to the proximity photoelectric switch 8, when a certain position, the photoelectric switch sensing piece 10 senses the proximity photoelectric switch 8, that is, the voice coil motor 6 is controlled to stop rotating, preventing the movement distance from exceeding to cause the structure damage when returning to the original position; this is the whole process of the operation of the long service life shutter structure in the semiconductor overlay precision measurement.

[0029] Although the embodiments of the present application have been shown and described, it is to be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A long-lifetime shutter structure for semiconductor overlay accuracy measurement, comprising: The shutter baffle (1), the small air floating platform (2), the voice coil motor (6), the magnetic scale module (7) and the proximity photoelectric switch (8) are characterized in that: the right end of the shutter baffle (1) is connected with the left end of the internal slider (3) of the small air floating platform (2), the right end of the internal slider (3) of the small air floating platform (2) is fixedly connected with the left side of a connecting plate (5), an air inlet pipe (4) is fixed on the small air floating platform (2), the right side of the connecting plate (5) is fixedly connected with the rotor of the voice coil motor (6), the magnetic scale module (7) is arranged below the voice coil motor (6) of the connecting plate (5), the magnetic scale module (7) is located on the right side of the connecting plate (5), and the proximity photoelectric switch (8) is arranged on the outer side of the magnetic scale module (7).

2. The long-lifetime shutter structure for overlay measurement of a semiconductor according to claim 1, wherein: The connecting plate (5) extends downward to the front end of the magnetic scale module (7), an photoelectric switch sensing sheet (10) is fixedly installed on the right side of the connecting plate (5) through a screw, and the photoelectric switch sensing sheet (10) is arranged at the front end of the proximity photoelectric switch (8).

3. The long-lifetime shutter structure for overlay measurement of a semiconductor as claimed in claim 1, wherein: The magnetic scale module (7) is composed of a magnetic scale and a reading head, the magnetic scale is composed of a series of magnetic stripes, and the reading head comprises a light source, a grating and a photoelectric sensor.

4. The long-lifetime shutter structure for overlay measurement of a semiconductor as claimed in claim 1, wherein: The small air floating platform (2), the magnetic scale module (7) and the proximity photoelectric switch (8) are fixedly installed on a supporting bottom plate (11), the right side of the supporting bottom plate (11) is integrally connected with a supporting vertical plate (12), and the tail end of the voice coil motor (6) is fixed on the supporting vertical plate (12).

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