Modern aspects of ensuring the security of the agro-industrial complex

The article substantiates the urgent need for the formation of import-substituting clusters in the agro-industrial complex to ensure food security. In modern reality, carrying out business activities, agro-industrial organizations are already using the advantages of integration to a certain extent, but at the same time, the key interests and guidelines of allied participants in entrepreneurial activities are insufficiently balanced. The authors have identified the methodological features of the formation of the subject of integration (agri-food polycluster formation), using the cluster tools of intersectoral reengineering. The basis for the introduction of the subjects of integration - allied participants in entrepreneurial activity - was their initial assessment and analysis of the factors and conditions of business activity, where the negative results of import substitution, which is an effective threat to food security, can be traced as much as possible. Evaluation of the target pairing through the integration of related business participants allows one to quantitatively assess the predominance of the target points of integration subjects - related business participants using information at the macro and micro levels.

Scheduling of Single-Arm Cluster Tools with Residency Time Constraints and Chamber Cleaning Operations

To ensure wafer quality, engineers have to impose wafer residency time constraints and chamber cleaning operations on cluster tools; this has been widely used in semiconductor manufacturing. Wafer residency time constraints and chamber cleaning operations make the scheduling problem of cluster tools more challenging. This work aims to solve such a scheduling problem for single-arm cluster tools and presents a novel method based on the use of virtual wafers. Under a one-cyclic schedule obtained for single-arm cluster tools without chamber cleaning requirements, virtual wafers are loaded into the tool such that when a process module (PM) processes virtual wafers, a chamber cleaning operation is performed in practice. The key to solve this scheduling problem is to find a wafer loading sequence with the highest performance in terms of cycle time. With this idea, this work constructs a genetic algorithm to search for such a solution. Since the obtained solution is a periodical wafer loading sequence based on a one-wafer cyclic schedule, it can be easily implemented. Therefore, this work has high practical value to numerous semiconductor manufacturers. Experiments were performed to show the efficiency and effectiveness of the proposed method.

Short-Term Scheduling Model of Cluster Tool in Wafer Fabrication

Since last decade, the cluster tool has been mainstream in modern semiconductor manufacturing factories. In general, the cluster tool occupies 60% to 70% of production machines for advanced technology factories. The most characteristic feature of this kind of equipment is to integrate the relevant processes into one single machine to reduce wafer transportation time and prevent wafer contaminations as well. Nevertheless, cluster tools also increase the difficulty of production planning significantly, particularly for shop floor control due to complicated machine configurations. The main objective of this study is to propose a short-term scheduling model. The noteworthy goal of scheduling is to maximize the throughput within time constraints. There are two modules included in this scheduling model—arrival time estimation and short-term scheduling. The concept of the dynamic cycle time of the product’s step is applied to estimate the arrival time of the work in process (WIP) in front of machine. Furthermore, in order to avoid violating the time constraint of the WIP, an algorithm to calculate the latest time of the WIP to process on the machine is developed. Based on the latest process time of the WIP and the combination efficiency table, the production schedule of the cluster tools can be re-arranged to fulfill the production goal. The scheduling process will be renewed every three hours to make sure of the effectiveness and good performance of the schedule.