Operation | System Hardware | System Performance
Features | Sample Defects
MIDAS Technology--Operation
MIDAS Vision Systems perform 100% inspection of printed designs at tolerances selected by an operator. The following is a description of the methodology used by MIDAS: |
Look and Learn
MIDAS Systems use a "look and learn" approach for automatic self-programming from a "Golden Sample" or ideal print pattern. The Golden Sample may be selected from a production lot, representative artwork, or a digital representation of the desired pattern. Users are simply required to enter desired inspection tolerances on a global or regional basis. MIDAS then rapidly creates an inspection template reflecting these tolerances. This template is used as a reference to verify acceptable quality of subsequent samples. |
 Template Tolerances
The MIDAS Vision System allows for template tolerances to be operator selected. These tolerances are optimized to detect all errors while minimizing the potential for "false alarms". Tolerance settings for inner and outer line widths are set globally or regionally as required for any conductor pattern. Excess and void defect levels are set independently from line tolerances, and are used to detect islands of defects inside or outside a conductor pattern. These defects are identified by a count of the offending pixels in a given region. This feature is used to detect contamination of the open substrate area or to detect a gauze effect of incomplete printing patterns.
In addition to global settings, arbitrary windows can be input throughout the pattern to create tighter or looser inspection parameters. An option for "don't care" regions is also available. |
 Pattern Registration
The first step in a MIDAS inspection is a 3-point auto-registration procedure. This provides measurement and verification (and alarming) of overall pattern registration, and corrects for allowable X,Y, and rotational offsets from the golden template. The registration reference may be specified as a part edge, or a substrate fiducial. |
Template Matching Inspection
The MIDAS image processor compares inspection samples to the "Golden Sample" template stored in memory. Template Matching systems recognize two types of defect conditions; absence of a conductor where it is required (void), and presence of a conductor where it is forbidden (excess.) Typical defects found with this technique area: shorts, opens, pattern misalignments, voids, neckdowns, and missing or misshapen vias. etc. |
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MIDAS Technology--System Hardware
The MIDAS system utilizes a CCD
Line Scan Type sensor coupled with a proprietary lighting system to capture the substrate image. This image is sent to a proprietary ultra-high-speed, processor, which is used for high-speed image manipulation and comparison. Finally, a host PC is used to provide an operator interface and to allow networking with various plant systems. Blocks within the basic system architecture may be modified to meet the needs of specific customer requirements (i.e.: manual vs. automated operation, inspection resolution, required scan rate, etc.)
In order to capture the substrate image with a line scan style
sensor, it is necessary to effect motion between the two components. MIDAS uses two approaches to achieve this requirement:
- A stationary camera with an incorporated XY
table to move the substrate
under the camera is utilized in
engineering systems
- In-line style systems utilize a stationary or single motion axis camera as required to capture images of substrates as they move under the inspection station on an existing production line conveyor
or scanning table
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MIDAS Technology--System Performance
Overall MIDAS System inspection speed is a function of both image acquisition rate, and template comparison processing speed (defect detection capability does not change.) MIDAS In-line system installations often include modifications from standard system designs. Any of the following system parameters may be modified to meet application requirements:
- Number of
sensors/Image processor
-
Number of pixel elements per
sensor (2,048 or 4,096 elements)
- Pixel
resolution, 25.4µm
to 1.0µm variable under software
control
- Image Processor Speed
-
Substrate Scan Speed
MIDAS Systems are configurable to address the inspection requirements of a wide range of microelectronics applications. See our Features page and our Sample defects page for more information.
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