Requirements for continuous improvement in performance, increasing miniaturization and density of systems are the main driver in the semiconductor industry to improve the structure of chips and develop new packaging principles. Installations that install semiconductor crystals are necessarily equipped with technical vision systems. These systems include two or more industrial video cameras. The cameras are connected to a powerful computer. Computer software recognizes the position of the crystals in the storage system, monitors and corrects the error in the position of the crystal during transfer and flip operations, recognizes the mounting point of the crystal on the substrate and determines the correctness of the operation in order to identify defects.
The article discusses a technical vision system for an automatic installation of semiconductor crystals. The requirements for cameras are justified and calculated based on the required chip positioning accuracy. A description of the applied technical vision algorithms and the final software product is given.
The article discusses the technical vision system of a machine for mounting semiconductor crystals. The disadvantage of existing systems is that the moment of installation of a semiconductor crystal on the substrate is not recorded by a camera and is in no way controlled by the operator. This makes it impossible to manually control such installations and complicates the learning process.
The authors of the article eliminated this drawback by using two non-orthogonally located cameras, the focuses of which coincide with the location of the crystal on the working tool. The resulting two images are then processed. The contours of the reference marks on the substrate, already installed elements and the mounted crystal are highlighted. After geometric transformations of the selected contours, the operator receives a real-time map of elements and can adjust the position of the chip in the horizontal plane. All operations are performed in real time. This approach has been practically tested on industrial equipment developed with the direct participation of the authors.
Increasing demands for versatility, ease of deployment and operation, increasing the degree of automation and energy saving necessitate the use of new approaches to the design of manipulators for moving goods. The weight and cost of handling equipment are significantly reduced, as is the degree of protection of more advanced structures based on flexible mechanical connections.
One of the problems of machine that arises when carrying loads, is the impact of factors, such as pendulum fluctuations of the load, compression of suspension cables. In conventional manipulators, such as cranes, this is determined by the skill of the operator. This is not possible in fully controlled non-orthogonal manipulators with multiple actuators.
To solve these problems, the authors of the article use two stereo cameras, the data from which, through mathematical transformations, is fed into the control system. Using a stereo camera is the simplest way to go from object coordinates in pixels an image, in an actual offset expressed in units of length.
Today, there are many technologies for mounting semiconductor crystals and microcircuits on substrates. Some of them require preheating the substrate, which can cause its deformation. Due to the high precision of installation, it is necessary to compensate for the thermal displacement error of the substrate and other positioning errors. To do this, reference marks are made on a heated assembly table. In addition, fiducial marks are located directly on substrates and printed circuit boards.
The main problem of introducing technical vision systems is their integration into numerical control systems of installations in order to increase the speed of technological operations. Thus, the development of real-time algorithms that determine the position of semiconductor crystals relative to the substrate, their implementation in the form of programs for specialized controllers integrated directly into CNC systems, is an urgent task.
The paper presents the implementation of a system for adjusting the position of a semiconductor crystal or microcircuit by processing a video stream from high-resolution cameras, which determines the true coordinates, position relative to the reference marks of the substrate and heating table, and outputs them directly to the CNC programmable logic controller. system. The basis of the system is the 64-bit RISC-V core.
The most technologically sophisticated equipment for the production of integrated circuits is equipment for the production of semiconductor wafers, lithography, etching and implantation. In addition to operations on photolithography and the production of semiconductor wafers, the technological chain for the production of a modern microcircuit includes cutting semiconductor wafers, mounting them on a substrate, testing, bonding and packaging. All of them require high-precision manipulation work. The creation of machines that solve such problems involves, in addition to the use of sufficiently precise mechanics, also the development of methods for recognizing objects and positioning a working tool based on video data, which will increase the accuracy of mounting crystals, the repeatability of operations and, consequently, reduce the percentage of scrap and the cost of final products. The main problem of introducing vision systems is their integration into numerical control systems of installations in order to increase the speed of technological operations. Thus, the development of real-time algorithms that determine the position of semiconductor crystals relative to the substrate, their implementation in the form of programs for specialized controllers integrated directly into CNC systems is an urgent task. The paper presents the implementation of a video stream processing system from high-resolution cameras, which determines the contours of a semiconductor crystal, its position relative to the substrate, including the rotation angle, and outputs them directly to the programmable logic controller of the CNC system. The basis for the system was a programmable logic integrated circuit Cyclone IV which implements a 64-bit RISC-V core.
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