Data processing: financial – business practice – management – or co – Automated electrical financial or business practice or... – Inventory management
Reexamination Certificate
1999-01-07
2001-05-29
Trammell, James P. (Department: 2764)
Data processing: financial, business practice, management, or co
Automated electrical financial or business practice or...
Inventory management
C705S002000, C705S014270, C700S099000
Reexamination Certificate
active
06240398
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to manufacturing techniques and, more specifically, to a method and system for optimally classifying subassembly components for use in the manufacture of opto-electronic devices.
BACKGROUND OF THE INVENTION
A critical factor in determining whether semiconductor equipment will meet required technical and performance specifications, as well as pricing and manufacturing yields, is the manufacturing process. The more efficient a semiconductor manufacturing process is, the greater the likelihood that such equipment can be delivered on time, at cost and within specification. Because component selection and classification is an important step in the semiconductor manufacturing, process, any improvement in the component selection process will increase manufacturing efficiency.
The growth in optical communications equipment has increased the demand for optical semiconductor devices. Accordingly, optical semiconductor manufacturers have developed manufacturing procedures which minimize both the number of components and the number of steps required in automated manufacture. One automated manufacturing process includes a state-of-the-art packaging and testing (PAT) platform for the manufacture of analog, digital and electro absorptive modulated OSAs. That process utilizes single optical subassemblies (OSAs) each comprising a semiconductor laser, a spherical lens, and a photo detector mounted on a substrate.
An OSA embodies the major functional component of an optical semiconductor device. Each OSA has a set of unique electrical and optical parameters which fit into one or more predetermined classifications. Upon receiving an order for a particular optical semiconductor device, the PAT platform selects a pre-classified OSA which meets or matches the required specifications from the OSA buffer inventory and sends the OSA to the PAT platform. The PAT platform packages the OSA using a gantry-type robotic bonder which is well known in the art, along with other necessary components, into the specified body, which is then hermetically sealed. The result is an optical semiconductor device which meets customer specification.
OSAs are produced in code families, i.e., they are produced in bulk quantities having broad functional homogenous characteristics, e.g., digital, analog, electro absorptive modulated OSAs, etc. But, because the exact electrical and optical specifications of an OSA within the same code family vary during manufacture and, therefore, can not be predetermined, homogenous families of OSAs are produced in heterogeneous mixtures in terms of electrical and optical specifications, e.g., wavelength, voltage/current measurements, etc. Furthermore, collections of OSAs are stored on waffle packs. Efficient operation of a bonding machine requires that these waffle packs contain substantially homogenous OSAs (in term of optical and electrical specifications) when used in packaging specified opto-electronic devices. Thus, it is desirable that OSAs be pre-classified, sorted, and stored in the buffer inventory in “pure packs,” i.e., waffle packs of a single, known OSA type.
Often, however, the set of parameters which electrically, optically and physically characterize an OSA may qualify for several different classifications within a particular family of devices. In other words, an OSA, because it meets and operates within a range of electrical and optical characteristics, can be used to make various optical semiconductors devices that match various electrical and optical specifications. Nevertheless, each OSA can be stored as only one pure pack classification in the OSA buffer. Therefore, once a classification is finally selected, that classification governs the use and selection of that type of OSA in a finished optical device.
The manufacture of OSAs is a relatively costly process and it is preferable to avoid holding a large inventory of OSAs for an extended period of time. This is especially true in the case of those OSAs that have a range of optical and electrical specifications, and which are highly desired and yet are rarely produced due to variances and unpredictabilities in the OSA manufacturing process.
Additionally, many manufacturing platforms, including the PAT platform, classify a given OSA in a multiplicity of classifications, up to 300 in number in some families of devices. The efficient, unassisted manual classification of OSAs is time consuming and complex and unlikely to result in a classification which sorts and stores OSAs with regard to both actual and anticipated customer demand, as well as the peculiarities and unpredictability of the optical subassembly manufacturing process, in order to avoid inventory stockpiling.
Accordingly, what is needed in the art and has heretofore been unavailable is an automated classification sorting and storage system for OSAs which accounts for both actual and anticipated customer demand as well as the peculiarities and unpredictability of the optical subassembly manufacturing process in order to avoid inventory stockpiling.
SUMMARY OF THE INVENTION
In accordance with one aspect of the invention, a method for assigning a final classification to a device having parameters which satisfy a set of qualifying classifications includes the steps of obtaining an inventory count for each classification of device included in the set of qualifying classifications, comparing the inventory count for each such classification to a safety stock number, and assigning a final classification to the device from among the classifications which have an inventory count less than the safety stock number. In the preferred embodiment, the inventive method enables subassemblies to be automatically and finally classified with respect to projected or future demands on inventory. That is, the method better ensures that a predetermined minimum stock level is maintained for one or more classifications of devices stored in inventory.
In another aspect of the invention, the comparison and assignment are made with respect to a present demand for product. The method in accordance with that aspect of the invention includes the steps of obtaining an inventory count for each classification of device included in the set of qualifying classifications, comparing the inventory count for each such classification to a present demand, and assigning a final classification to the device from among the classifications which have an inventory count less than the present demand.
In either of these first two aspects of the invention, the final classification is made with respect to at cast one predetermined criterion. However, further criteria can be used.
In a particularly preferred arrangement in accordance with another aspect of the invention, each classification of device has an assigned a restock-priority level, and the final classification assignment step is performed not only with respect to safety stock levels and/or present demand, but with further regard to the restock-priority level of each device classification. The restock-priority level is preferably based on the difficulty of manufacturing an OSA fitting a particular code or classification. Thus, the assigning step in this preferred arrangement may first determine that there is an insufficient quantity in stock of devices that correspond to one or more of the qualifying classifications of the device presently being assigned a final classification, and for those inadequately stocked classifications, the one selected will have the highest priority. Likewise, the restock-priority assignment information can be used to arbitrate between two or more qualifying classifications for which the current inventory is inadequate to satisfy a present demand for product.
A method in accordance with another aspect of the invention includes the steps of obtaining restock-priority assignment data associated with at least the classifications included in a set of qualifying classifications of a given device, and automatically assigning a final classification to that device based on th
Allen Aristotle B.
Doran Patrick J.
Kern Daniel
Darby & Darby
Lucent Technologies - Inc.
Trammell James P.
Young John Leonard
LandOfFree
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