Recipe DSL Reference

The APS recipe language is a line-based Domain Specific Language (DSL) for automating vacuum deposition processes. Each line contains a single command followed by its arguments, separated by whitespace. Recipes are executed sequentially from top to bottom unless redirected by flow-control constructs.

This is the same reference available from the language pane in the Recipe Editor.

Language Basics

Line Format

command arg1 arg2 ...    # optional comment

Each non-blank line is tokenized into a command (first word) followed by zero or more arguments (identifiers, numbers, or strings). Comments begin with # or // and extend to the end of the line. Blank lines and comment-only lines are ignored.

Data Types

Variables

Variables are declared with var and referenced with the $ prefix. Variable names are case-insensitive.

var flow_rate = 15
var gas Ar1
MFC $gas $flow_rate

Built-in system variables:

• $_i — current loop iteration index (0-based), set automatically inside loop blocks
• $pressure — current system pressure (read-only, from sensor provider)
• $temperature — current system temperature (read-only)
• $time — current recipe elapsed time (read-only)

Recipe Envelope

Recipes may optionally be wrapped in begin / end markers. These are silently skipped during execution and exist for visual clarity.

begin
    valve M1 open
    delay 5
    valve M1 close
end

Flow Control Commands

# Loop with variable count
var cycles = 3
loop $cycles
    MFC Ar1 15
    delay 5
    MFC Ar1 0
    delay 2
endloop

# Conditional with sensor reading
if pm < 0.05
    valve M1 open
else
    valve M1 close
endif

# Label and goto
label retry
pwait pm 0.01 60
check pm < 0.05
goto retry

Functions

Functions let you define reusable command sequences with parameters.

function purge_gas(gas, flow, time)
    MFC $gas $flow
    delay $time
    MFC $gas 0
endfunction

# Call the function
purge_gas Ar1 20 10
purge_gas N2 15 5

Variable Declaration

var target_pressure = 0.05
var gas_name Ar1
var use_bias = true

Timing Commands

delay 10                  # wait 10 seconds
pwait pm 0.05 60          # wait for pressure < 0.05, timeout 60s
pressure pl 0.01 120      # same as pwait, different sensor
check pm < 0.1            # assert pressure is below 0.1

Device Commands

Valve Control

valve M1 open
valve V6 close

MFC (Mass Flow Controller)

MFC Ar1 15
MFC Ar1 0        # shut off gas flow

Pump Control

pump TP1 on
pump TP1 off

Stage Positioning

stage VS -10

Bias / Power Supply

Shutter Control

Holder (Substrate Rotation)

Rotation

rotation on 5.0
rotation off

Compound Commands

Compound commands are higher-level operations that combine multiple device actions into a single step. They are typically defined as external worker operations loaded from a DLL at runtime.

Operator Interaction

message "Load substrate and close chamber door"
message Check water cooling flow

Command Case Sensitivity

Command names are case-insensitive: MFC, mfc, and Mfc are all equivalent. Device and sensor IDs are matched against the hardware configuration and are also generally case-insensitive. Variable names are case-insensitive.

Value Substitution

Before a command is dispatched to the hardware layer, certain keyword values are automatically substituted:

Nesting Rules

• loop, if, and function blocks can be nested up to 8 levels deep (the maximum nesting depth).
• function definitions cannot appear inside loop blocks.
• goto targets must be within the current execution scope — you cannot jump into or out of a loop, function, or conditional block.
• Each if may have at most one else branch.
• All block constructs must be properly closed: loop/endloop, if/endif, function/endfunction.

Validation

The recipe validator performs five phases of checking before execution:

1. Tokenization — ensures the text can be parsed into valid tokens.
2. Structure — verifies matched block pairs (loop/endloop, if/endif, function/endfunction), checks nesting depth, validates unique labels, and confirms goto targets exist.
3. Commands — checks that command names are recognized and have the minimum required number of arguments.
4. Variables — confirms all $variable references are either declared with var, defined as function parameters, or are known system variables.
5. Devices — verifies that device names used with hardware commands (valve, mfc, pump, stage, sensor, power) exist in the hardware configuration.

Complete Example

begin
    # Declare variables
    var base_pressure = 0.05
    var sputter_time = 30

    # Pump down
    pump TP1 on
    pwait pm $base_pressure 120

    # Gas flow
    valve M1 open
    valve V2 open
    MFC Ar1 15
    delay 10

    # Check pressure stabilized
    check pm < 0.1

    # Deposit with rotation
    rotation on 3.0
    shutter S1 open

    loop 3
        MFC Ar1 20
        delay $sputter_time
        MFC Ar1 10
        delay 5
    endloop

    # Shutdown sequence
    shutter S1 close
    rotation off
    MFC Ar1 0
    valve V2 close
    valve M1 close
    pump TP1 off

    message "Process complete - ready for unload"
end