About fab24hr
A day in the life of a fab engineer
fab24hr is a small 3D game you play in the browser. You are a process engineer in a wafer fab, eight months into the job, looking after an etch tool called ETCH-03. At 02:47 your phone rings: the tool is down, a hot lot is stuck inside, and everyone is waiting for you to give them a time.
How to play
Nothing to install and no login. Open it in the browser on a phone or a computer. The game tells you the next step; press "Take me there" and your character walks there on its own. The person or tool you need has a "!" over it.
You don't need to know anything about semiconductors. Jargon in the dialogue has a dotted underline; tap it for a plain-English explanation.
Four shifts in a day
A wafer fab never stops. Whenever you open the game, you start in the shift for that time of day. A shift takes a few minutes; when it ends you can go straight on to the next one. Four shifts in a row make the whole day.
| When you open it | Shift | What happens |
|---|---|---|
| 00:00–05:59 | Late-night shift: "The Call" | You are at home and can't see the tool. You ask the night shift to be your eyes, then give instructions over the phone. |
| 06:00–11:59 | Morning shift: "Firefighting" | Clock in, read the handover sheet, get asked in the morning meeting when it will be fixed, find the cause, run the qual, bring the tool back. |
| 12:00–17:59 | Afternoon shift: "In a Hurry" | Halfway through lunch you are called to rework one wafer by hand. Then the incident report and the review meeting. |
| 18:00–23:59 | Evening shift: "Almost Out the Door" | Every time you reach the door someone stops you. In the end you are standing in front of the tool, looking at a yellow light. |
Who you'll meet
- Kai: the equipment engineer who fixes the tool.
- Ya-Ting: process integration, the owner of the lot.
- Yun: manufacturing, who dispatches lots and chases output.
- Chief Chen: your boss.
- Hao: night-shift manufacturing, the one who calls you in the middle of the night.
- Xiao An: the new hire, who started last week.
Common questions
Do I need to know semiconductors to play?
No. The game is made for people who have never been inside a fab. It tells you step by step who to find and where to go, and any jargon can be tapped for a plain-English explanation.
Does it cost anything? Do I need an account?
Neither. It is free, with no sign-up and no ads. If you like it, there is a link on the page to buy the author a coffee.
Does it work on a phone?
Yes, held upright. It runs in the browser on phones, tablets and computers.
Is the story real?
The tools, lot numbers, figures, procedures and people are all fictional game settings and do not represent any company's actual rules. The jargon explanations are drawn from public sources, listed at the bottom of this page.
How long does it take?
A shift takes a few minutes. Each one ends with a recap card; you can stop there or go on to the next shift. Progress is saved in your browser, so you can leave and pick it up later.
Can I share my result?
Yes. Each shift ends with a portrait recap card. On a phone you can send it straight to an Instagram Story from the share sheet, or copy the result as text to paste into Threads or anywhere else.
Does the site record my data?
Only anonymous play counts: a random id generated by your browser, plus whether you started, finished, or pressed share. No names, no cookies, no ad tracking.
Why is it called fab24hr?
"Fab" is what people call a wafer fabrication plant, and 24hr is twenty-four hours: the fab never stops, which is why someone calls you in the middle of the night.
Jargon in the game
These are the terms that come up in the game, with the same explanations you see when you tap them.
- MO
- Mis-operation: a mistake made by a person. Running the wrong recipe, picking the wrong wafers and running a lot at the wrong step all count. People in the industry also write it as Miss Operation. After an MO you have to report it, write an incident report and hold a review meeting.
- Tower light
- The stack of lights on a tool. Green light: it is running product. Yellow light: the tool is waiting for someone (idle, in a qual run, or showing a warning). Red light: it has stopped on a fault.
- Alarm and Warning
- A warning is a heads-up: the tool can still run, usually with a yellow light. An alarm means the tool has stopped itself, with a red light.
- Down and Up
- Down means the tool cannot run product. Up means it can. Down is either scheduled (maintenance) or unscheduled (a breakdown).
- Availability
- The share of the day a tool can actually be used to run product. The longer it sits down, the worse the number looks. The industry commonly sorts tool time into the six states of SEMI E10.
- OCAP
- Out-of-Control Action Plan. The procedure the people on the line follow when something goes wrong. A phone call is only needed for what the OCAP does not cover.
- On-call
- Standing by on a rotation. When a tool has trouble in the middle of the night, the night shift's first call goes to the on-call engineer.
- Handover
- The record passed between two shifts. The outgoing shift writes down what is still unfinished and passes it to the next shift.
- Hold
- Stopping a lot from going any further until someone decides what to do with it.
- Hot lot
- An urgent lot. It goes first at every step.
- Q-time
- The maximum time allowed between finishing one step and starting the next. Go over it and the wafers need rework; in bad cases they are scrap.
- PM
- Preventive Maintenance. When people in the fab say PM, they mean maintenance.
- Season
- After a chamber has been opened for cleaning or a part swap, a few throwaway wafers are run first so the chamber walls settle back into a stable state.
- Qual run
- Using test wafers to confirm that what the tool produces is within spec. For etch, the usual checks are etch rate and particle count. The tool can be released only after the qual run passes.
- Tool release
- Bringing a tool from down back to where it can run product. Equipment hands over the hardware, process confirms the results, and it only counts when both pass.
- SPC
- Statistical Process Control. Each lot's measurements are plotted on a control chart to see whether the process is drifting.
- OOC and OOS
- OOC means outside the control limits, or breaking a run rule (for example, 8 points in a row on the same side of the center line). OOS means outside the spec. OOC is not always OOS, but both need action.
- Etch
- Using plasma to remove the unprotected material on the wafer surface and carve out the circuit pattern. ETCH-03, the tool you look after, does exactly this.
- Wafer
- A round slice of silicon. Chips are built on it layer by layer. A box holds 25.
- Recipe
- The set of settings a tool runs by: gases, pressure, power, seconds. One tool has many of them; pick the wrong one and what comes out is wrong.
- Chamber
- The sealed space inside a tool where the wafer is actually processed. A tool often has two or more chambers (Chamber A, Chamber B), and each can be taken down on its own.
- ESC
- Electrostatic chuck. It uses static electricity to clamp the wafer onto the stage.
- Reset
- Clearing the tool's error state so it can start again. Reset without fixing the cause and the same problem comes back.
- Chamber open
- Opening the chamber for repair or cleaning. Once it has been opened the conditions inside change, so it has to be pumped down, seasoned and put through a qual run again.
- Tool handback
- The equipment engineer finishes the repair and hands the tool to the process engineer to verify.
- Particle
- A tiny speck. If one lands on a wafer it causes a defect, which is why the cleanroom has to be that clean. A qual run counts how many were added.
- Line width
- How wide the etched lines are. One of the most important measurements at the etch step.
- SOP
- Standard Operating Procedure. A document that spells out how each step is done.
- Dispatch
- Deciding which lot goes on which tool first.
- He backside pressure
- Helium flows between the back of the wafer and the ESC to carry heat away from the wafer. Too much helium leaking out means the wafer is not seated firmly, and its temperature can no longer be controlled. What the tool watches is the helium flow: the higher the flow, the more is leaking.
- Rework etch
- Giving a wafer whose process was interrupted the etch time it missed. It is a kind of rework, outside the normal flow.
- Manual run
- An engineer stands at the tool and picks the wafers and the recipe by hand, bypassing the system's automatic dispatch. The operation most likely to end in an MO.
- Rework
- Doing this step again or finishing it off. A rework etch is one kind.
- Scrap
- The wafer cannot be saved and is removed from the lot.
- Disposition
- Integration goes through each wafer's record and decides whether it continues, gets rework, or is scrap.
- Move out
- The lot is finished at this step and goes on to the next one.
- Work order
- An instruction issued by the system: it fills in the wafer numbers and the recipe, so nobody has to copy them by hand.
- Incident report
- The written report after an incident. A common format is 8D: describe the problem, contain it, find the root cause, correct it, prevent it from happening again.
- Containment
- Stopping the damage first: stop the bad wafers where they are, and check whether any other lots were hit too.
- Fan-out
- Applying the countermeasure from one incident to other tools, products or sections that carry the same risk.
- Mistake-proofing
- A design that makes the wrong action impossible to carry out. Not the same thing as "reminding people to be careful".
- Move and WIP
- One wafer finishing one step counts as one move. WIP is the lots still on the line, not yet finished. The board tracks both numbers every day.
Sources
Tool states, helium backside pressure, seasoning, control-chart rules and 8D are drawn from the public sources below. The use of "MO" and the new-hire stories come from public forums (in Chinese).
- INFICON | What Do We Mean When We Refer to Tool Availability?
The six tool states of SEMI E10: productive, standby, engineering, scheduled downtime, unscheduled downtime, non-scheduled time. - US Patent US6899109B1 | Method and apparatus for reducing He backside faults
Helium is the heat-transfer medium between the wafer and the stage. When there is a gap between the two, the helium leaks out and the tool raises a He backside fault. - US Patent US6374832B2 | Waferless seasoning process
After a chamber clean the etch environment changes and the first few wafers give unstable results (first wafer effect), so a season is needed. - MetricGate | Western Electric vs Nelson Rules for SPC
Control chart run rules: 8 points in a row on the same side of the center line are flagged as abnormal (Western Electric rules). - EESemi | The 8D Process
The eight steps of 8D: form a team, describe the problem, containment, root cause, corrective action, verification, prevention, closure. - PTT Tech_Job | Discussion of MO (Miss operation)
How the industry uses "MO" for human operating errors. - Disp BBS | I caused an MO with less than a year on the job. How do I get past it?
A new hire's account of causing an MO, and a senior colleague's reply that "when a new hire makes a mistake, the system and the person training them share the responsibility". - NYCU master's thesis | Reducing the cost of handling lots on hold
Common reasons a lot is put on hold: tool faults, out of spec, engineering experiments. - NTHU master's thesis | Furnace dispatching rules under queue-time limits
The definition of Q-time, and that going over it means rework or scrap. - Micron | Shift Operations Process Technician job posting
What the job on the line involves: chasing hot lots, anticipating holds, handover, notifying other teams. - GlobalFoundries | Process engineer job posting
Module engineers watch SPC, deal with process problems and set the standard recipes. - NYCU | Introduction to semiconductor processing (lecture notes)
Why the lithography area is lit yellow, how dry etch removes material with plasma, and the basics of chemical vapor deposition.