CN213936147U

CN213936147U - Mechanical arm

Info

Publication number: CN213936147U
Application number: CN202022913314.4U
Authority: CN
Inventors: 袁鹏华
Original assignee: Shanghai Huali Integrated Circuit Manufacturing Co Ltd
Current assignee: Shanghai Huali Integrated Circuit Manufacturing Co Ltd
Priority date: 2020-12-08
Filing date: 2020-12-08
Publication date: 2021-08-10
Anticipated expiration: 2030-12-08

Abstract

A robot arm for picking and placing a wafer, comprising: the device comprises a cantilever, a position sensing part, a data processing module and a arm controller. The extending arm is used for bearing the wafer to be taken and placed, an alignment central point is set on the extending arm, and the extending arm is driven by the driving mechanism to move. The position sensing component is arranged at the position of the extending arm and used for measuring the position of the center of the wafer. And the position related signal of the wafer center obtained by the position sensing component is transmitted to the data processing module, and the data processing module stores the position data aligned with the central point. The arm controller includes an actuator that outputs an execution signal to the drive mechanism according to the measured position of the wafer center. Therefore, the position sensing component is positioned at the extending arm, so that the center position of the wafer can be sensed when the wafer is positioned at the extending arm, the position of the extending arm can be adjusted in time, and the subsequent movement of the extending arm is executed according to the actual center position of the wafer.

Description

Mechanical arm

Technical Field

The utility model relates to an integrated circuit manufacture equipment field, in particular to robotic arm.

Background

Integrated circuit factories require hundreds or thousands of manufacturing steps and weeks to fabricate minute electronic components and circuits on the top surface of a wafer. The wafer processing process comprises the following steps: wet cleaning, oxidation, photolithography, ion implantation, rapid annealing, etching, photoresist removal, CVD, PVD, CMP, and the like. Etching is a removal process, and dry etching or plasma etching is mostly used in the current advanced integrated circuit production. The plasma etcher generally consists of a vacuum chamber, a transfer chamber, a load/unload station, and a front end module, wherein the wafer is transferred into the vacuum chamber/cavity for a process by a robot mounted in the transfer chamber and the front end module. Because the wafer stage is placed in the vacuum chamber, the wafer is electrostatically adsorbed while helium is used to fill the wafer and the interior of the stage for temperature control, and the wafer transferred by the robot must be very precisely placed in a fixed position on the stage. Thus, plasma etchers are often equipped with additional wafer metrology systems for determining the exact position of the wafer on the robot. In the system, a plurality of groups of sensors are used, a window position needs to be reserved on an opening of a metal cavity of the equipment, electronic circuits which are easy to damage need to be arranged outside the equipment, a protruding sheet sensor needs to be additionally arranged between the cavities, and the situation that wafers are broken when a door plate between the cavities before a measurement alarm of the measurement system is obtained when the wafers protrude out of a normal position on a mechanical arm is closed is avoided.

In the prior art, a Lam research (Lam) wafer center positioning System mainly includes a Dynamic Alignment (DA) System and a Transition Navigation System (TNS).

The position of the wafer center relative to the robot center point is determined by a dynamic calibration positioning system, specifically, the wafer center is determined by a DA system as the robot is retracted from a position past an open slit valve. The DA may determine the position of the wafer center relative to the arm center when the wafer is removed from the Airlock (Airlock) 1. Once the wafer center position is determined, the robot dynamically adjusts the wafer position before placing the wafer to ensure the accuracy of the wafer position. When the wafer is placed by the arm to PM1, the arm dynamically adjusts the position of the wafer by the offset determined when the wafer is taken from Airlock 1. Typically, the maximum offset for dynamic arm adjustment is 0.2 inches, and an alarm is triggered beyond 0.2 inches. The working principle of the DA system is as follows: referring to FIG. 1A, the arm controller, through manual calibration, stores the arm elongation R, rotation θ and elevation Z values for each position of the arm. From this, the central position to which the robot arm is transferred to each position is determined. It should be noted that: the controller of the arm does not know where the wafer is located; but assume that the wafer center is at the center of the arm. There are two beam sensors on each slit valve, and the sensor beams are blocked when a wafer passes through the slit valve. The calibration value of the DA depends on the position of the beam sensor and the reference position determined by the arm. Since the initial position of the arm and the position of the beam sensor are not substantially changed, and the calibration of the DA depends on the two positions, the calibration of the DA is usually performed once. When the wafer movement is over, the controller of the arm has captured 4 positions of the wafer edge at the wafer periphery. From these 4 points, the DA will calculate the exact position of the wafer on the arm. And then calculating the offset of the wafer center. When the wafer is placed to the next position, the controller adjusts the position of the wafer through the offset and the calibration value of the next position so that the wafer placement position is more accurate. Referring to fig. 1B, 1C, and 1D, each slit valve (slot valve) has 3 pairs of beam emitting and receiving devices, of which 2 pairs are available for the DA system. Two pairs of the light beam emitting and receiving devices are used according to the size of the wafer. The Vacuum Transfer Module (VTM) has photoelectric converters to which each pair of light beam emission-reception sensors is connected by a fiber optic cable. The photoelectric converter then transmits the electrical signal to the printed circuit board through the signal line. The printed circuit board analyzes and calculates the electric signal, then sends the calculation result to a Vacuum Transfer Module (VTM), and further transmits the position result to the arm. Each interruption and connection of the signal of the light beam sensor can be converted into an electric signal by the photoelectric converter and transmitted to the arm. The sensor located on the slit valve has two functions: firstly, determining the position of a wafer, wherein a sensor is used for positioning the position of the wafer (measuring the positions of four points); second, wafer sensing, when the arm passes the slit valve, the sensor can determine whether a wafer has passed the door.

The Transfer Navigation System (TNS) is designed to measure the deviation of the wafer position after being unloaded from one of the modules (PM, LLM, etc.), and to correct the deviation before the next Module (Module) is loaded. At the same time, it is possible to investigate which step (e.g., Process, LM to TM transfer, etc.) the deviation occurs in.

Similar to the aforementioned system of LAM, the linear center-finding system (LCF) provided by AMAT (applied materials corporation) uses a light sensor mounted on the frame of a Vacuum Transfer Module (VTM) to detect the center of a wafer on the arm. The process cavity is provided with 3 sets of LCF light sensors, and the loading and unloading cavity is provided with 2 sets of LCF light sensors.

Disadvantages of prior art wafer centering systems: firstly, the central position (the position in a cavity provided with a sensor) can be calculated only by carrying and moving through an arm; secondly, when the wafer is transferred out of a cavity, the position of the wafer cannot be determined in advance; thirdly, if the wafer is greatly deviated in the cavity, the wafer is transmitted out of the cavity and is measured by the sensor to be out of the alarm range, and the fault is shut down; fourthly, the small offset of the wafer can not be corrected before the wafer is discharged from the cavity, and the transmission downtime frequency is reduced.

SUMMERY OF THE UTILITY MODEL

The utility model discloses the technical problem that needs to solve is: how to further determine the relative relationship between the wafer center and the position of the robot arm in advance to avoid the interference at the position (slotting valve) passing through the inductor in the prior art when the offset is too large, and both the sensor for monitoring and the judgment step are added, even if the equipment is stopped because of the situation.

In order to solve the technical problem, the utility model provides a robotic arm, its aim at can monitor the position that its center located when the wafer is located the robotic arm top to can put the relevant motion of confirming robotic arm according to the center, get the wafer of putting that can be fine, avoid unnecessary to shut down.

In order to achieve the above object, the utility model provides a robotic arm for get and put the wafer, robotic arm contains:

the extension arm is used for bearing a wafer to be taken and placed, an alignment central point is set on the extension arm, and the extension arm is driven by the driving mechanism to move;

the position sensing component is arranged at the extending arm and used for measuring the position of the center of the wafer;

the data processing module is used for transmitting the position related signals of the wafer center obtained by the position sensing component to the data processing module, and the data processing module stores position data aligned to the central point;

a arm controller including an actuator that outputs an execution signal to the drive mechanism according to the measured position of the wafer center.

Preferably, the protruding arm is provided with a bearing surface facing the wafer to be taken and placed;

the position perception part comprises a light generator and a photosensitive element array device, and the light generator and the photosensitive element array device are located on the bearing surface.

Preferably, the position sensing component is arranged in at least three areas within an area covered by a radius of the wafer, centered within a range of allowable wafer center position offset with respect to the alignment center point.

Preferably, the number of the areas where the position sensing components are arranged is at least four, the wafer radius data is stored in the data processing module, the position sensing components can sense at least four positions of the edge of the wafer, the four positions adopt a three-point determined circle or a two-point radius determined circle, and the center position of the wafer is determined by combining the wafer radius data.

Preferably, the light generator is an infrared light emitting diode.

Preferably, the light-sensitive element array is used for receiving light reflected by the wafer, and the light-sensitive element array and the light generator are arranged in an overlapping mode or in parallel and adjacent mode.

Preferably, the arm controller further comprises a deviation correction controller, the arm controller stores a wafer center position deviation range about the alignment center point, the actually measured wafer center position is not within the deviation range, the deviation correction controller sends a deviation correction signal to the driving mechanism, and the driving mechanism drives the extension arm to enable the wafer center position to move to be within the deviation range relative to the alignment center point.

Preferably, the driving mechanism can realize the positioning driving of the two degrees of freedom of the extension arm on a plane parallel to the plane of the wafer, the position of the center of the wafer after measurement is a fixed point of the extension arm, and the position of the center of the wafer can also realize the movement in two directions.

Preferably, the extension arm is rotatably connected with a first connecting rod, the first connecting rod is rotatably connected with a second connecting rod, and the driving mechanism is provided with a motor for respectively driving the first connecting rod and the second connecting rod to rotate.

Preferably, the extension arm is rotatably connected to a first link on a plane parallel to the plane of the wafer, the first link is rotatably connected to a second link, the second link is connected to a third shaft, the third shaft extends in a direction parallel to the vertical axis of the plane of the wafer, and the third shaft is slidably connected to a hole in the base, and the driving mechanism includes a motor for driving the third shaft to slide.

Compared with the prior art, the utility model provides a robotic arm for get and put the wafer, robotic arm contains: the extension arm is used for bearing a wafer to be taken and placed, an alignment central point is set on the extension arm, and the extension arm is driven by the driving mechanism to move; the position sensing component is arranged at the extending arm and used for measuring the position of the center of the wafer; the data processing module is used for transmitting the position related signals of the wafer center obtained by the position sensing component to the data processing module, and the data processing module stores position data aligned to the central point; a arm controller including an actuator that outputs an execution signal to the drive mechanism according to the measured position of the wafer center. Compared with the prior art, the utility model has the beneficial technical effects of: the position sensing component is positioned at the extending arm, so that the central position of the wafer can be sensed when the wafer is positioned at the extending arm, the central position of the wafer is not required to be judged by blocking light through a light emitting receiver arranged on the gate, the position of the extending arm can be timely adjusted or the subsequent movement of the extending arm can be executed according to the actual central position of the wafer, the gate does not collide with the wafer or the wafer interferes with the gate to cause halt, and more sensors are not required to be additionally installed to monitor related faults.

Drawings

Fig. 1A is a schematic diagram of a motion relationship of a robot arm in the prior art.

FIG. 1B is a schematic diagram of a prior art robot arm moving a wafer through a slit valve and showing two pairs of light beam emitting and receiving devices.

Fig. 1C is a schematic diagram of a robot arm driving a 200mm wafer to pass through a slit valve in the prior art, in which three pairs of light beam emitting and receiving devices are arranged to work.

Fig. 1D is a schematic diagram of a robot arm driving a wafer with a size of 300mm to pass through a slit valve in the prior art, and three pairs of light beam transmitting and receiving devices are arranged in the diagram, namely, the first pair and the third pair work.

Fig. 2 is a schematic diagram of a robot according to an embodiment of the present invention, illustrating a wafer transparentization process, wherein the wafer center position is aligned to the center point position.

Fig. 3 is a schematic diagram of an embodiment of a position sensing component in a robot arm according to the present invention.

Fig. 4 is a schematic view of the wafer placed on the robot arm according to the present invention.

Fig. 5A and 5B are schematic views illustrating operation of an embodiment of a position sensing component in a robot arm according to the present invention, fig. 5A is a schematic view illustrating a partial enlargement, and fig. 5B is a schematic view illustrating a plane projection and a wafer transparentizing process for showing a relative position relationship.

Fig. 6 is a schematic diagram of signal connection between relevant components in the robot arm according to the present invention.

Description of reference numerals:

1 wafer

2 projecting arm

3 position sensing component

4 data processing module

5 arm controller

6 bearing surface

7 light generator

8 photosensitive element array device

9 support the bumps.

Detailed Description

The following detailed description of the embodiments of the present invention will be made with reference to the accompanying drawings.

Referring to fig. 2, the robot arm of the present invention is used for picking and placing the wafer 1. The robot arm includes: a projecting arm 2, the projecting arm 2 is used for bearing the wafer 1 to be taken and placed, the projecting arm is set with an alignment center point C₀The extension arm 2 is moved by a drive mechanism. A position sensing component 3, the position sensing component 3 is arranged at the extending arm 2, the position sensing component 3 is used for measuring the position C of the center of the wafer₁. Referring to fig. 6 in combination, the data processing module 4, the position sensing component 3 obtains the position C of the wafer center₁The related signals are transmitted to a data processing module 4, and an alignment central point C is stored in the data processing module 4₀The position data of (a). A arm controller 5, the arm controller 5 including an actuator based on the measured position C of the wafer center₁And outputting an execution signal to the driving mechanism. Accordingly, the data processing module 4 stores the machine according to the alignment center point C₀Position C at the center of the wafer is measured for an initial actuation signal of the drive mechanism with reference to a coordinate system₁Then the signal is converted into an actual execution signal by coordinate transformation, and the actual execution signal is the central position C of the wafer₁Is the execution signal of the reference point. Because the position sensing component 3 is located on the extension arm 2, the center position of the wafer can be known when the wafer is located within the measurable range of the position sensing component 3, and the wafer center position can not be determined by the light blocking of the wafer through the light emitting receiver on the slotting valve as in the prior art. In the prior art, additionallyThe transmitting and receiving holes, or the observation holes additionally arranged, or the measurement and control circuit are all arranged on the cavity, and the connection between the measurement and control circuit and the controller of the mechanical arm can cause some additional arrangement and bring about faults. The position perception part 3 of this application is located robotic arm, for its component, can be better regard robotic arm as an independent part design, has avoided the interference to the cavity.

Referring to fig. 2, the arm 2 has a carrying surface 6 facing the wafer to be picked and placed. Referring to fig. 3, the position sensing part 3 includes a light generator 7 and a light sensor arrayer 8, and the light generator 7 and the light sensor arrayer 8 are located on the bearing surface 6. As shown in FIG. 4, the light generator 7 and the photosensitive element array unit 8 are partially fitted in the projecting arm 2. The photosensitive element array 8 can sense the boundary between the light receiving area and the light non-receiving area.

As shown in fig. 2 and 3, relative to the alignment center point C₀The range of the allowable wafer center position deviation amount is used as the center, and at least three areas are provided with the position sensing parts 3 in the area covered by the radius of the wafer. The position sensing components 3 can sense at least three segments of wafer edge arc positions.

Referring to fig. 2, the number of the regions where the position sensing device 3 is disposed is at least four, the wafer radius data is stored in the data processing module, the position sensing device can sense at least four positions of the edge of the wafer, the four positions adopt a three-point determined circle or a two-point radius determined circle, and the wafer center position is determined by combining the wafer radius data. The wafer generally has a notch, if one of the areas happens to be located at the notch, the center of the wafer is determined by using three other points, each three of the four points respectively determine four circles, the four circles are compared, and if the four circles are overlapped, the point without detection is located at the notch. Also, the wafer radii may be combined to determine whether the four circles conform to the respective wafer radii. In fig. 2, four areas are shown in which elongated position sensing members are arranged.

Referring to fig. 3, the light generator 7 is an infrared light emitting diode (infrared LED).

Referring to fig. 3, the light sensor array 8 is used to receive the light reflected by the wafer, and the light sensor array 8 and the light generator 7 are disposed in an overlapping manner or in parallel and adjacent. The case of a parallel abutting arrangement is shown in fig. 3.

Referring to fig. 4, the light generator 7 and the photo sensor array device 8 are embedded in the arm 2, and the arm 2 further has a wafer support bump 9. The wafer 1 abuts against the support bumps 9 while being transferred by the robot arm. Referring to fig. 5A, light emitted from the light generator 7 is reflected by the bottom of the wafer 1 and received by the side of the carrying surface 6, while light emitted from the light generator 7 without being blocked by the wafer 1 is not reflected, so that an area receiving light and an area not receiving light on the photo sensor array device 8 are formed, and the boundary between the two areas is the edge of the wafer. Accordingly, the wafer center position can be determined.

The arm controller also comprises a deviation correction controller, and the arm controller stores the wafer center position deviation range relative to the alignment center point. The maximum allowable offset may be limited by the position of the center of the wafer, whether the center of gravity is stable or not, the support point on the robot arm, and the like. Actual measured wafer center position C₁If the wafer is not in the offset range, the deviation correction controller sends a deviation correction signal to the driving mechanism, and the driving mechanism drives the extension arm 2 to enable the center position of the wafer to move to be in the offset range relative to the alignment center point. Therefore, the deviation from the wafer center to the relative alignment center can be within the allowable range as soon as possible. Although it is possible to avoid the situation of interference with the gate due to too large deviation by calibrating the relevant transportation track according to the actual center of the wafer, if the deviation between the wafer center and the alignment center is further adjusted in advance, the risk of tipping and the like during transportation can be avoided.

On the plane parallel to the plane of the wafer, the driving mechanism can realize the positioning drive of two degrees of freedom of the extending arm, and the position C of the center of the wafer is measured₁A fixed point of the cantilever 2, a position C of the center of the wafer₁Movement in both directions can also be achieved. Measured wafer center position (or measured recalibration)The wafer center position measured again later) and the wafer abuts against the cantilever arm 2 in the wafer support bump 9, which may be regarded as a rigid body in kinematics and may be regarded as a rigid body at this point. The rigid body is driven by a driving mechanism, and the position C of the center of the wafer is fixed on the point₁The motion track of the system is required to be carried out according to a set track in each transmission.

The extension arm is rotatably connected with a first connecting rod, the first connecting rod is rotatably connected with a second connecting rod, and the driving mechanism is provided with a motor which respectively drives the first connecting rod and the second connecting rod to rotate. Accordingly, the position C of the wafer center can be realized₁Movement in two directions in a plane.

On the plane parallel to the plane of the wafer, the extension arm is rotatably connected with a first connecting rod, the first connecting rod is rotatably connected with a second connecting rod, the second connecting rod is connected with a third shaft, the third shaft extends along the direction in the direction parallel to the vertical axis of the plane of the wafer, the third shaft is slidably connected with a hole in the machine base, and the driving mechanism comprises a motor for driving the third shaft to slide. Hereby, movement in the vertical direction shown in fig. 3 is enabled.

The third shaft may also be rotatable about the axis of the bore. The rotation of the third shaft about the axis can also be superimposed to produce an effect on the movement in both directions of the plane.

The above is that the utility model provides a robotic arm primary structure's component part and connected mode.

The wafer is placed on the electrostatic chuck, the ejector pin mechanism is arranged in the electrostatic chuck to support and separate the wafer from the surface of the electrostatic chuck, the extending arm of the mechanical arm can be inserted into the lower portion of the wafer, if the center of the wafer is not located in a deviation range of an alignment center, a deviation rectification signal is sent out, the center position of the wafer is located in the deviation range, at the moment, the third shaft of the mechanical arm is driven to move upwards until the wafer supports the salient point 9 to abut against the wafer, and the wafer further moves upwards, so that the wafer is separated from the ejector pin mechanism on the electrostatic chuck. The driving mechanism of the mechanical arm drives the extending arm to convey the wafer to the next module according to an execution signal generated by the motion track set by the measured central position of the wafer.

For further understanding of the robot arm provided by the present invention, the main usage thereof will now be described in detail.

Firstly, the mechanical arm enters a film taking position to take the film.

Secondly, the position of the edge point of the wafer is measured by utilizing the position sensing component.

Thirdly, calculating and selecting the effective position of the edge point of the wafer, and calculating the central position of the wafer.

Fourthly, comparing with the position of the alignment central point set by the extension arm, whether the wafer central position is in the deviation range or not is judged, if not, the deviation correcting signal adjusts the position of the extension arm of the mechanical arm to the position that the wafer central position is in the deviation range, and in the adjusting process, the wafer central position is static relative to the wafer taking position, but the position of the alignment central point relative to the extension arm is moving.

Fifthly, according to the central position of the wafer (offset compensation is performed aiming at the position of the alignment central point), the driving mechanism moves according to the set movement track of the central position of the wafer, and the wafer is conveyed to the next position.

Therefore, the utility model discloses the technological effect that can reach lies in: the number of system installation inductors is reduced; no opening is made in the metal cavity of the device (for housing the inductor); no wiring needs to be arranged outside the equipment; a protruding sheet sensor is not additionally arranged between the cavities (the protruding sheet sensor is used for preventing the wafer from protruding out of the gate due to the excessive deviation of the wafer position, and the wafer is clamped and broken when the gate is closed); the wafer is prevented from being damaged due to the fact that the wafer protrudes out of a normal position on the manipulator and is stopped by an alarm or interfered and cannot be closed through a gate or a door plate; before the mechanical arm carries the wafer to move, whether the center position of the wafer is within the deviation range allowed by the alignment center can be determined, the mechanical arm can be carried to perform deviation rectifying movement before carrying, the relevant wafer taking position can be adjusted, and risks of tipping, clamping and the like in the wafer carrying process are avoided.

The above-mentioned embodiments and the accompanying drawings are only illustrative for explaining the technical solution and the technical effects of the present invention, and are not intended to limit the present invention. It is to be understood that modifications and variations may be made in the above-described embodiments by those skilled in the art without departing from the spirit and scope of the present invention as defined by the appended claims.

Claims

1. A robot arm for picking and placing a wafer, the robot arm comprising:

2. A robot arm according to claim 1,

the extending arm is provided with a bearing surface facing the wafer to be taken and placed;

3. The robot arm of claim 2, wherein the position sensing component is disposed in at least three areas within an area covered by a radius of a wafer centered within an allowable wafer center position offset amount with respect to the alignment center point.

4. The robot arm of claim 3, wherein the number of the areas where the position sensing components are arranged is at least four, the wafer radius data is stored in the data processing module, the position sensing components can sense at least four positions of the edge of the wafer, the four positions adopt a three-point determined circle or a two-point radius determined circle, and the wafer center position is determined by combining the wafer radius data.

5. The robot arm of claim 2, wherein the light generator is an infrared light emitting diode.

6. The robot arm of claim 2, wherein the light sensor array is configured to receive light reflected from the wafer, and the light sensor array is disposed in an overlapping or parallel adjacent arrangement with the light generator.

7. The robot of claim 1, further comprising a de-skew controller, wherein the wafer center position offset range is stored in the arm controller, and the actual wafer center position is not within the offset range, and the de-skew controller sends a de-skew signal to the driving mechanism, and the driving mechanism drives the extension arm to move the wafer center position to be within the offset range relative to the alignment center point.

8. The robot arm of claim 1, wherein the drive mechanism is capable of positioning and driving the cantilever in two degrees of freedom in a plane parallel to the plane of the wafer, and wherein the measured position of the center of the wafer is a fixed point of the cantilever and the position of the center of the wafer is capable of movement in two directions.

9. The robotic arm as claimed in claim 1, wherein the extension arm is pivotally connected to a first link, the first link is pivotally connected to a second link, and the drive mechanism has a motor for driving the first link and the second link to rotate, respectively.

10. A robot as claimed in claim 1, wherein the arm is pivotally connected to a first link on a plane parallel to the plane of the wafer, the first link is pivotally connected to a second link, the second link is connected to a third shaft, the third shaft extends in a direction parallel to the vertical axis of the plane of the wafer and is slidably connected to a hole in the housing, and the drive mechanism comprises a motor for driving the third shaft to slide.