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Gang lead bonding equipment, materials and technology
316
World Abstracts on Microelectronics and Reliability
outline the various activities of programming and thc contributions they make to the total cost.
The future of the microprocessor. I. M. BARRON. Microelectronics 8, (4) 32 (1978). The microprocessor is having such a dramatic effect on markets that already the pattern of future electronic systems design is becoming clear. Pro-
5. M I C R O E L E C T R O N I C S
gress in VLS1 will bring more memory on chip and a supercomponent will soon appear that is really an "qntelligent storage device" as a single unit. The effect of microprocessors on the custom-design approach to markets is likely to be so serious that national policies based on this for the surviwd or growth of their electronics industries are called in question.
DESIGN
Automated photomask inspection. DONALD B. NOVOTNY and DINO R. C1ARLO. Solid St. Technol. p. 51 (May 1978). Methods that may be suitable for automated photomask inspection for visual defects (spots, pinholes, etc.) or dimensional compliance are analyzed and discussed. The analysis of each method includes examinations of the physical principles upon which it is based and the a m o u n t of rotsalignment that can be tolerated. The size of the m i n i m u m visual defect to be detected was taken as 21m~. The methods analyzed for visual defect inspection were the opticaloverlay, the dual-beam flying-spot-scanner, the TV-microscope, and the spatial-filtering methods. For dimensional inspection, an analysis of line-edge location and operating criteria for the microdensitometer are presented. The fabrication of photomasks with intentionally introduced and controlled defects is described together with preliminary results of automated inspections of these photomasks. It was concluded that : automated inspection systems should be dedicated either to inspection for visual defects or dimensional compliance, not both ; and the dimensional tolerances on masks, both those of the feature dimensions in the die patterns as well as those in the dimensions between the dice, must be significantly smaller than the size of the m i n i m u m defect to be detected. Overview of photomask substrate flatness measurement techniques. RAYMOND E. LEINEN, 11. Solid St. Technol. p. 77 (May 1978). The continued demand by the integrated circuit industry for larger wafers and higher device densities has placed requirements on the photolithographic manufacturing system for "superflat'" substrate glass. Superflat substrates are flatter than current master grades, and are used primarily in projection printing. The accurate and consistent measurement of this glass as it relates to both the vendor/purchaser and the test/use situations is examined. This is accomplished through both specific measurement and computer generated data. The study concludes that while the industry objective of much flatter substrate glass is clearly established, the procedures and equipment used to measure this flatness have not, heretofore, been well defined.
Step-and-repeat wafer imaging. JEANNE ROUSSEL. Solid St. TeehnoL p. 67 (May 1978). A major performance factor in the step-and-repeat imaging process is illumination. A detailed description of illumination system criteria and implementation for this process is presented. A new illuminator, an extension of a proven design, makes possible exposure energy levels in excess of 300 milliwatts sq. cm of great uniformity over a 10 m m × 10 m m area. Resulting exposure times are last enough to make direct stepping on the wafer practical. Images stepped on wafers in both negative and positive photoresists will be discussed. Data obtained by photo-optical and SEM means demonstrate the potential usefulness in terms of resolution, topology, resist thickness and type, of photolithographic direct wafer exposure. Standing wave effects and negative resists exposed without nitrogen purge will be discussed.
Some considerations for projection printing with negative photoresisl. R RI:DDIll. J. DORAN aod J. OSBORNE. Solid
AND
CONSTRUCTION
St. lechnol, p, 72 (May 1978). Initial attempts at projection printing with negative photoresist very often result in lower device yields than the existing contact printing process. This article discusses a study contracted by the Signetics Corporation which identified some of the causes for depressed yields and their remedies. Upon implementation of the redefined process, the desired yield improvements with their bipolar RAM products were realized.
Automated equipment for 100!'~i inspection of photomasks. KI:NNEaH LEVY. Solid St. 7eetmol. p. 60 (May 1~)78). One of the major causes of loss of yield in complex large scale integrated circuits is the quality of the photomasks used to fabricate the LSI circuit. Inspection of all photomasks is necessary to insure that the final device yields meet manufacturing objectives. As circuits grow larger, there are fewer circuits per mask; therefore, statistical sampling of the photomask is not wdid and 100% inspection is required. An automatic inspection system, which can rapidly inspect photomasks for random defects, has recently been introduced to the semi-conductor industry. Automatic photomask inspection promises to increase LSI yields as mask quality will improve once the masks are inspected and the defects are identified.
Symbolic layout system speeds mask design for ICs. ROBEWr P. LARSFN. Electronics p. 125 (21) July 1978). Easily learned computer-aided design procedure allows the designer to quickly check out IC circuit geometry and device structure.
Gang lead bonding equipment, materials and technology. THOMAS L. AN(;EI wct:l SR. Solid St. Technol. p, 65 (March 1978), Early and subsequent development of automatic tape carrier bonding is discussed. Major equipment considerations include wafer b u m p plater, and inner and outer bonders. Bonding tapes are evaluated, and predictions for the fnture are made.
Automated photomask inspection. DONALD B. NOVOTNY and DINO R. CIARLO. Solid St. Teehnol. p. 59 {June 1978). Methods that may be suitable for automated photomask inspection for visual defects (spots, pinholes, etc.) or dimensional compliance are analyzed and discussed. The analysis of each method includes examinations of the physical principles upon which it is based and the amount of misalignment that can be tolerated. The size of the m i n i m u m visual defect to be detected was taken as 21~m. The methods analyzed for visual defect inspection were the optical-overlay, the dual-beam flying-spot-scanner, the TV-microscope, and the spatial-filtering methods. For dimensional inspection, an analysis of line-edge location and operating criteria for the microdensitometer are presented. The fabrication of photomasks with intentionally introduced and controlled defects is described together with preliminary results of automated inspections of these photomasks. It was concluded that automated inspection systems should be dedicated either to inspection for visual defects or dimensional compliance, not both ; and the dimensional tolerances on masks, both those of the feature dimensions in the die patterns as well as those in the dinaensions
World Abstracts on Microelectronics and Reliability
outline the various activities of programming and thc contributions they make to the total cost.
The future of the microprocessor. I. M. BARRON. Microelectronics 8, (4) 32 (1978). The microprocessor is having such a dramatic effect on markets that already the pattern of future electronic systems design is becoming clear. Pro-
5. M I C R O E L E C T R O N I C S
gress in VLS1 will bring more memory on chip and a supercomponent will soon appear that is really an "qntelligent storage device" as a single unit. The effect of microprocessors on the custom-design approach to markets is likely to be so serious that national policies based on this for the surviwd or growth of their electronics industries are called in question.
DESIGN
Automated photomask inspection. DONALD B. NOVOTNY and DINO R. C1ARLO. Solid St. Technol. p. 51 (May 1978). Methods that may be suitable for automated photomask inspection for visual defects (spots, pinholes, etc.) or dimensional compliance are analyzed and discussed. The analysis of each method includes examinations of the physical principles upon which it is based and the a m o u n t of rotsalignment that can be tolerated. The size of the m i n i m u m visual defect to be detected was taken as 21m~. The methods analyzed for visual defect inspection were the opticaloverlay, the dual-beam flying-spot-scanner, the TV-microscope, and the spatial-filtering methods. For dimensional inspection, an analysis of line-edge location and operating criteria for the microdensitometer are presented. The fabrication of photomasks with intentionally introduced and controlled defects is described together with preliminary results of automated inspections of these photomasks. It was concluded that : automated inspection systems should be dedicated either to inspection for visual defects or dimensional compliance, not both ; and the dimensional tolerances on masks, both those of the feature dimensions in the die patterns as well as those in the dimensions between the dice, must be significantly smaller than the size of the m i n i m u m defect to be detected. Overview of photomask substrate flatness measurement techniques. RAYMOND E. LEINEN, 11. Solid St. Technol. p. 77 (May 1978). The continued demand by the integrated circuit industry for larger wafers and higher device densities has placed requirements on the photolithographic manufacturing system for "superflat'" substrate glass. Superflat substrates are flatter than current master grades, and are used primarily in projection printing. The accurate and consistent measurement of this glass as it relates to both the vendor/purchaser and the test/use situations is examined. This is accomplished through both specific measurement and computer generated data. The study concludes that while the industry objective of much flatter substrate glass is clearly established, the procedures and equipment used to measure this flatness have not, heretofore, been well defined.
Step-and-repeat wafer imaging. JEANNE ROUSSEL. Solid St. TeehnoL p. 67 (May 1978). A major performance factor in the step-and-repeat imaging process is illumination. A detailed description of illumination system criteria and implementation for this process is presented. A new illuminator, an extension of a proven design, makes possible exposure energy levels in excess of 300 milliwatts sq. cm of great uniformity over a 10 m m × 10 m m area. Resulting exposure times are last enough to make direct stepping on the wafer practical. Images stepped on wafers in both negative and positive photoresists will be discussed. Data obtained by photo-optical and SEM means demonstrate the potential usefulness in terms of resolution, topology, resist thickness and type, of photolithographic direct wafer exposure. Standing wave effects and negative resists exposed without nitrogen purge will be discussed.
Some considerations for projection printing with negative photoresisl. R RI:DDIll. J. DORAN aod J. OSBORNE. Solid
AND
CONSTRUCTION
St. lechnol, p, 72 (May 1978). Initial attempts at projection printing with negative photoresist very often result in lower device yields than the existing contact printing process. This article discusses a study contracted by the Signetics Corporation which identified some of the causes for depressed yields and their remedies. Upon implementation of the redefined process, the desired yield improvements with their bipolar RAM products were realized.
Automated equipment for 100!'~i inspection of photomasks. KI:NNEaH LEVY. Solid St. 7eetmol. p. 60 (May 1~)78). One of the major causes of loss of yield in complex large scale integrated circuits is the quality of the photomasks used to fabricate the LSI circuit. Inspection of all photomasks is necessary to insure that the final device yields meet manufacturing objectives. As circuits grow larger, there are fewer circuits per mask; therefore, statistical sampling of the photomask is not wdid and 100% inspection is required. An automatic inspection system, which can rapidly inspect photomasks for random defects, has recently been introduced to the semi-conductor industry. Automatic photomask inspection promises to increase LSI yields as mask quality will improve once the masks are inspected and the defects are identified.
Symbolic layout system speeds mask design for ICs. ROBEWr P. LARSFN. Electronics p. 125 (21) July 1978). Easily learned computer-aided design procedure allows the designer to quickly check out IC circuit geometry and device structure.
Gang lead bonding equipment, materials and technology. THOMAS L. AN(;EI wct:l SR. Solid St. Technol. p, 65 (March 1978), Early and subsequent development of automatic tape carrier bonding is discussed. Major equipment considerations include wafer b u m p plater, and inner and outer bonders. Bonding tapes are evaluated, and predictions for the fnture are made.
Automated photomask inspection. DONALD B. NOVOTNY and DINO R. CIARLO. Solid St. Teehnol. p. 59 {June 1978). Methods that may be suitable for automated photomask inspection for visual defects (spots, pinholes, etc.) or dimensional compliance are analyzed and discussed. The analysis of each method includes examinations of the physical principles upon which it is based and the amount of misalignment that can be tolerated. The size of the m i n i m u m visual defect to be detected was taken as 21~m. The methods analyzed for visual defect inspection were the optical-overlay, the dual-beam flying-spot-scanner, the TV-microscope, and the spatial-filtering methods. For dimensional inspection, an analysis of line-edge location and operating criteria for the microdensitometer are presented. The fabrication of photomasks with intentionally introduced and controlled defects is described together with preliminary results of automated inspections of these photomasks. It was concluded that automated inspection systems should be dedicated either to inspection for visual defects or dimensional compliance, not both ; and the dimensional tolerances on masks, both those of the feature dimensions in the die patterns as well as those in the dinaensions