The Holdt Archives

​Terry Holdt was the Product/Program Manager of Microcomputers for MOS Technology from 1974-1976.  He was part of the original team of eight Motorola employees who left the Semiconductor Products Division of Motorola in 1974 where he was serving as Product Manager for MOS P/N Products, including the Motorola 6800 family of microprocessors, to pursue the goal of creating the world's first affordable microprocessor at MOS Technology. It was Holdt who one Motorola manager appealed to in an effort to prevent a brain drain of talent from the 6800 microprocessor team, showing up at his front door one night to implore him, "Please stay. If you go, everyone will go." Of course, believing in Chuck Peddle's vision regarding the untapped potential of a low-cost microprocessor⁠--the creation of which Motorola declared it was unwilling to pursue⁠--Terry went, and many others in the 6800 team did, too. The rest is history.

In a resume dating to 1976, Terry describes  the wide variety of his duties at MOS Technology, noting that he reported to the company president, John Paivinen, and had responsibility for "the overall program planning and execution of efforts surrounding the microprocessor system." He describes participating in decisions regarding "the product definition, pricing, support activities (hardware and software), customer interface, advertising, factory planning, allocation of available resources, and process development," qualifying his efforts in "process development" by noting that while it was a task he agreed to perform on an "interim basis" because "management of the process development group was lacking," the supervision of that labor force as well as "a portion of the engineering of the N Channel Silicon Gate Depletion Load 5 Volt Process" evolved into a "nearly full time job." As a result, Terry explains that while his "primary function was to manage the overall microprocessor program," his primary effort was "management and technical assistance in the process development area."

This intensive focus on process development is evident in the volume as well as technical and detailed nature of the preserved documents discovered in Terry's home in 2018. Indeed, the documents in the Holdt Archives which relate to process development⁠--primarily three binders labeled N-Channel Physical Considerations, Depletion and Ion, and Int. Doc Wafer Fab 1⁠​⁠--tell a detailed and fascinating story about the collaborative effort that resulted in the specific 019-process used to create the 6500 family of microprocessors. This effort included not only MOS Technology engineers, but engineers whose published writings were photocopied, annotated, and distributed to other engineers by Holdt⁠--writings such as Robert Crawford's Mosfet in Circuit Design, an article concerning ion implantation by John R. Edwards and George Marr of Bell Labs, and several chapters from Andy Grove's 1967 book on microprocessor production, Physics and Technology of Semiconductor Devices.  

In fact, it was the information gathering, sharing, sorting, and testing efforts⁠--so carefully conducted, then preserved, by Holdt⁠--which were to credit for the knowledge and expertise he acquired to draft his report, Some Physical Considerations on the N-Channel Silicon Gate Depletion Load "019" Process. This report synthesized that information for the benefit of both the process and design teams at MOS Technology, influencing not only the transistor layout of the 6502⁠--now hailed as a masterpiece of computer architecture⁠--but the highly technical and intricate 50-step production process (also preserved in the Holdt Archives) used by MOS Technology to produce the world's first affordable microprocessor.

Because Holdt's responsibilities at MOS Technology were so varied, the historical documents provide not only a detailed window into the process development, but also a glimpse into the workings of MOS Technology across a wide variety of other fronts as well: including P&L, sales, marketing, and the creation of instructional documents which accompanied MOS Technology products⁠--such as the KIM-1, MOS Technology's single board computer⁠--at point of purchase. Therefore, included in the Holdt Archives are not only internal documents such as notes from brainstorming sessions between MOS Technology engineers, memos relating to various production challenges, and MOS testing procedures and results, but MOS Technology documents that were either released publicly or early versions of such documents noting errata. These include letters to customers, product manuals, MOS brochures, marketing materials, catalogs of MOS products, a poster for the KIM-1 Board, order forms for MOS products, and more.

NOTES:
- Many of the documents below are partial samples only. There are also additional documents in the archives not featured below. For additional information, contact team6502.org.
- Single page documents are featured as images only. Multiple page documents are offered as PDFs. Click on image to open and view PDF.

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Microprocessor Production
Process-Related Documents

N-Channel Physical Considerations Binder

Terry Holdt's N-Channel Physical Considerations binder contains a variety of documents relating to microprocessor production, including hand written and typewritten specifications detailing a highly precise and intricate 50-step production process, a variety of articles and book chapters that were consulted and annotated to solve various production challenges, as well as a wide array of testing results. There are 10 tab dividers in the binder, labeled as noted in the accompanying, above illustration.  All documents are presented in the order in which they appear in the binder.

Tab #1: Run Sheets

Lot Summary Date for 019-H written by Terry Holdt.

Process Repeatability Study for Lot 019-H conducted by Terry Holdt.

Tab #2: Hand Carry Spec Notes

Terry Holdt's handwritten notes describing steps 0-14 of a 50-step microprocessor production process.

Tab #3: Formal Specs

Terry Holdt's typed and handwritten notes describing steps 1-13 of 50-step microprocessor production process.

Tab #7: ATT. 4: I22 (ion)

This report, "Ion Implant Profile Calculations," was written by MOS Technology founder and President, John Paivinen. Additional copies were also found in Holdt's Depletion and Ion binder under Tab #1: "John's Writings," and in the INT. DOC Wafer Fab 1 binder under Tab #1: "MOS Tech Processing."

Tab #9: ATT. 6  019 Run Sheet

Tab #10: ATT. 7 

No additional title was given to ATT. 7 tab, however, this section consists of Lot 0H-19 test results. 

Tabs ATT. 1, ATT. 2, ATT. 3, and ATT. 5 

​Tabs ATT. 1, ATT. 2, ATT. 3, and ATT. 5 contain highly annotated photocopies of the following articles and chapters from books. Below are their titles.

ATT.1  HC1 Oxidation
ISSCC 75/Wednesday, February 12, 1975/Brandywine Ballroom/3:10-5:45
WMP6.3: High Quality Si02 for Integrated Circuits (handwritten by Holdt after title: "- Hcl")
SESSION VI/INVITED: Frontiers of Technology
Rudolph Kreiger
Bell-Northern Research, Ltd. 
Ottawa, Canada

ATT. 2  Grove
Chapters from book Physics and Technology of Semiconductor Devices by Andrew S. Grove, 1967:
- 2 Thermal Oxidation
- 3 Solid State Diffusion
- 4 Elements of Semiconductor Physics
- 6 p-n Junctions
- 9 Theory of Semiconductor Surfaces
- 10 Surface Effects on p-n Junctions
- 11 Surface Field-Effect Transistors
- 12 - Properties of the Silicon-Silicon Dioxide System

ATT. 3 Crawford
Mosfet in Circuit Design by Robert Crawford, June 1967.

​ATT. 5 Depletion Article
"Depletion-Mode IGFET Made by Deep Ion Implantation" by John R. Edwards and George Marr,  IEEE Transactions on Electron Devices (Volume: 20 , Issue: 3 , March 1973 )

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Depletion and I2 (Ion) Binder

Terry Holdt's Depletion and Ion Binder binder contains a variety of documents that show the collaborative effort of the engineers who worked on depletion and enhancement issues surrounding the production of the 6500 family of microprocessors. These documents include various handwritten notes taken by Holdt during meetings with other MOS Technology engineers such as John Paivinen and Walt Eisenhower, various technical reports written by Paivinen, pages of formulas relating to depletion and enhancement, photocopies of published articles annotated by Holdt, information on settings and other issues relating to depletion mode devices, CV Analysis test results, and more. There are 9 tab dividers in the binder, labeled as noted in the accompanying, above illustration.  All documents are presented in the order in which they appear in the binder.

TAB #1: John's Writings

NOTE: "John" refers to MOS Technology Founder and President, John Paivinen.

Notes taken by Terry Holdt during his meeting with John Paivinen and Walt Eisenhower, Oct. 10, 1974.

Notes taken by Terry Holdt during his meeting with John Paivinen, Oct. 31, 1974.

The next item in the binder is an additional copy of Paivinen's report, Ion Implant Profile Calculations which is archived under Tab #7 of the N-Channel Physical Considerations Binder above. 

This report, "Effect of Gate Oxide Thickness Variations on Implanted Enhancement and Depletion Devices" was written by John Paivinen.

This report, "Impact of Surface State Charge on Enhancement and Depletion Devices" was written by John Paivinen.

This report, "Threshold Voltage Stabilization in N-Channel Implanted Enhancement Devices" was written by John Paivinen.

This report, "Design of a P-JFet for Threshold Voltage Translation and Depletion Mode Operation" was written by John Paivinen.

This report, "An Equivalent Circuit for the P-JFet in Depletion Mode" was written by John Paivinen.

Notes taken by Terry Holdt during a February 7, 1975 meeting.

Notes taken by Terry Holdt during a March 4, 1975 meeting with John Paivinen on M reduction.

Terry Holdt's notes on Normal Distribution-Standardization

Terry Holdt's notes taken from John Paivinen Report, "Ion Implant Profile Calculations."

Chart of values of the Standard Normal Distribution Function (publication unclear).

Notes taken by Terry Holdt on "Technique Used" (October, 1974) and notes from meeting with John Paivinen, Steve Sherman, Walt Eisenhower, himself, and Ernie Helfrich (October 4, 1974).

Tab #2: Depletion Mode Devices

2 pages of formulas (first page, except for Terry Holdt's red markings, was likely written by John Paivinen) while second page written by Terry Holdt.

"Depletion Mode IGFET Made by Deep Ion Implantation," by John Edwards and George Marr, "IEEE Transactions on Electron Devices" ( Volume: 20 , Issue: 3, March 1973 )

The following articles appear next in binder:
- Implanted Depletion Loads Boost MOS Array Performance by Robert Crawford, Electronics, April 24, 1972
- N-Channel Ion-Implanted Enhancement/Depletion MOSFET'S, by L. Forbes in the IEEE Journal of Solid State Circuits, April 1973

March 3, 1975 Terry Holdt note regarding depletion model.

The article Ion Implantation Combined with Silicon-Gate Technology, by C.C. Mai, M. Hswe, and R.B. Palmer, IEEE Transactions on Electron Devices ( Volume: 19 , Issue: 11 , Nov 1972 ) appears next in binder.

Graph from article "IEEE Transactions on Electron Devices," November 1972.

 The article Doping Profiles by MOSFET Deep Depletion C(V) by D.M. Brown, R.J. Connery, and P.V. Gray, General Electric Company, Research & Development, Schenectady, NY appears next in binder. 

Tab #3: Key Articles, Graphs

Terry Holdt's notes on implantation settings for doping device.

Terry Holdt's notes on implantation dosing Oct 23, 1974.

Graph #1 by Terry Holdt

Projected Range graphs (pages 2 and 3 in Terry Holdt's hand, the author of page 1⁠— which is dated October 1, 1974⁠—is uncertain).

Graph #2 by Terry Holdt

Graph #3 by Terry Holdt

Graph #4 by Terry Holdt

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INT. DOC. Wafer Fab 1 Binder

Terry Holdt's INT. DOC Wafer Fab 1 binder contains 7 tabs labeled as noted in the accompanying, above illustration, only a few of which contain documents (the other sections are empty). Of particular interest is the Holdt report, Some Physical Considerations on the N Channel Silicon Gate Depletion Load, found under the the tab MOS Tech Process, which is Holdt's synthesis of information gleaned from meetings, articles, and reports found in the other binders. According to Holdt, his "analysis on the 019 process is not meant to be a rigorous treatment of detailed physics of semiconductor devices, but rather is meant to be of use to the process engineer in analyzing electrical considerations affected by his process decisions and to the design engineer in analyzing process considerations that will affect his electrical parameters." All documents are presented in the order in which they appear in the binder.

Tab #1: MOS Tech Processing

Part 1 of 59 page report, "Some Physical Considerations on the N Channel Silicon Gate Depletion Load '019' Process" written by Terry Holdt. Note that 2 of the items provided as attachments to this document are John Paivinen's reports, "Ion Implant Profile Calculations" which is archived under Tab #7 of the "N-Channel Physical Considerations Binder" and "Effect of Gate Oxide Thickness Variations on Implanted Enhancement and Depletion Devices" which is archived under Tab #1: "John's Writings" of the "Depletion and Ion" binder.

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Marketing Materials

Microcomputer Development Terminal (MDT) Information Booklet

Kim-1 Marketing Poster (measures 22.5 inches X 34 inches)

Kim-1 Order Form

MOS Technology Brochure

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Consumer Instruction Manuals 
​& Letters to Customers

Dated August 1975, this first edition MOS Microcomputers Hardware Manual contains Terry Holdt's handwritten edits noting errors in the publication.

Dated August 1975, this first edition MOS Microcomputers Programming Manual contains Terry Holdt's handwritten edits noting errors in the publication.

Dated January 1976, this first edition MOS KIM-1 User Manual contains Terry Holdt's handwritten edits, noting errors in publication. As this guide is already publicly archived, only those pages noting errors are included here.

View KIM-1 (and other MOS Technology User Manuals) in their entirety here.

First letter (dated January 26, 1976) to KIM-1 customers noting errata.

Second letter (dated February 12, 1976) to KIM-1 customers noting errata.

Third letter (dated March 1, 1976) to KIM-1 customers noting errata.

April 1976 letter sent to MOS customers regarding resolution of Motorola lawsuit and announcing new microprocessors. Pinned to this letter was the MOS microcomputer catalog.

MOS Microcomputer catalog pinned to April 1976 letter to customers regarding resolution of Motorola lawsuit and announcing new microprocessors.

Feb 1976 letter sent to MOS Technology customers signed by Chuck Peddle. Attachments referenced in letter are also found in the archives.

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Miscellaneous 

6530 Kim-1 Document Part 1.

6530 Kim-1 Document Part 2.

Letter sent to Terry Holdt after resolution of Motorola lawsuit.