Load Port State Model (SEMI E87)¶

1. Overview¶

The Load Port State Model defines the operational states of each load port (carrier loading position) as specified in SEMI E87.

2. Load Port Transfer State Diagram¶

stateDiagram-v2 [*] --> OUT_OF_SERVICE OUT_OF_SERVICE --> IN_SERVICE: Service enabled IN_SERVICE --> OUT_OF_SERVICE: Service disabled state IN_SERVICE { [*] --> TRANSFER_READY TRANSFER_READY --> TRANSFER_BLOCKED: Block command TRANSFER_BLOCKED --> TRANSFER_READY: Unblock command TRANSFER_READY --> READY_TO_LOAD: Load request READY_TO_LOAD --> TRANSFER_READY: Cancel / Timeout READY_TO_LOAD --> TRANSFER_READY: Load complete TRANSFER_READY --> READY_TO_UNLOAD: Unload request READY_TO_UNLOAD --> TRANSFER_READY: Cancel / Timeout READY_TO_UNLOAD --> TRANSFER_READY: Unload complete }

3. Load Port Association State Diagram¶

stateDiagram-v2 [*] --> NOT_ASSOCIATED NOT_ASSOCIATED --> ASSOCIATED: Carrier placed & verified ASSOCIATED --> NOT_ASSOCIATED: Carrier removed

4. State Definitions¶

4.1 Transfer States¶

State	Description
OUT_OF_SERVICE	Load port disabled, no transfers allowed
IN_SERVICE	Load port enabled
TRANSFER_BLOCKED	Transfers temporarily blocked
TRANSFER_READY	Ready for load/unload operations
READY_TO_LOAD	Waiting for carrier to be loaded
READY_TO_UNLOAD	Waiting for carrier to be unloaded

4.2 Association States¶

State	Description
NOT_ASSOCIATED	No carrier associated with load port
ASSOCIATED	Carrier is associated with load port

5. Transition Table¶

#	From State	Trigger	To State	Action
1	OUT_OF_SERVICE	Enable command	IN_SERVICE / TRANSFER_READY	Initialize LP
2	IN_SERVICE	Disable command	OUT_OF_SERVICE	Reject operations
3	TRANSFER_READY	Block transfer	TRANSFER_BLOCKED	Block transfers
4	TRANSFER_BLOCKED	Unblock transfer	TRANSFER_READY	Allow transfers
5	TRANSFER_READY	Load request	READY_TO_LOAD	Signal AMHS
6	READY_TO_LOAD	Carrier arrives	TRANSFER_READY	Process carrier
7	READY_TO_LOAD	Timeout/Cancel	TRANSFER_READY	Cancel request
8	TRANSFER_READY	Unload request	READY_TO_UNLOAD	Signal AMHS
9	READY_TO_UNLOAD	Carrier removed	TRANSFER_READY	Clear LP
10	READY_TO_UNLOAD	Timeout/Cancel	TRANSFER_READY	Cancel request

6. Load Port Attributes¶

Attribute	Type	Description
PortID	U2	Load port number (1, 2, ...)
TransferState	U1	Current transfer state
AssociationState	U1	Current association state
AccessMode	U1	Current access mode (see Access Mode chapter)
CarrierID	A	Associated carrier ID (if any)
ReservationState	U1	Reserved by host/equipment

6.1 Transfer State Values¶

Value	State
0	OUT_OF_SERVICE
1	TRANSFER_BLOCKED
2	TRANSFER_READY
3	READY_TO_LOAD
4	READY_TO_UNLOAD

6.2 Association State Values¶

Value	State
0	NOT_ASSOCIATED
1	ASSOCIATED

7. Load Port Commands¶

7.1 Service Control¶

Command	Effect
EnableLoadPort	OUT_OF_SERVICE → IN_SERVICE
DisableLoadPort	Any → OUT_OF_SERVICE

7.2 Transfer Control¶

Command	Effect
BlockTransfer	TRANSFER_READY → TRANSFER_BLOCKED
UnblockTransfer	TRANSFER_BLOCKED → TRANSFER_READY
RequestLoad	TRANSFER_READY → READY_TO_LOAD
RequestUnload	TRANSFER_READY → READY_TO_UNLOAD
CancelRequest	READY_TO_LOAD/UNLOAD → TRANSFER_READY

Message	Direction	Description
S3F23	H→E	Port Action Request
S3F24	E→H	Port Action Acknowledge

8.1 S3F23 - Port Action Request¶

Structure:

S3F23 W
<L[3]
  <DATAID>
  <PORTACTION>         // Action code
  <L[n]                // Port list
    <PORTID>
    ...
  >
>

PORTACTION Values:

Value	Action
1	Reserve port
2	Cancel reservation
3	Carrier out request
4	Carrier in request
5	Cancel carrier out
6	Cancel carrier in

8.2 S3F24 - Port Action Acknowledge¶

Structure:

S3F24
<L[2]
  <PORTACTIONRESULT>
  <L[n]                // Per-port results
    <L[2]
      <PORTID>
      <PORTRESULT>
    >
    ...
  >
>

9. Load Sequence¶

sequenceDiagram participant Host participant Equipment participant AMHS Note over Equipment: LP1: TRANSFER_READY Host->>Equipment: S3F23 (RequestLoad, Port=1) Equipment-->>Host: S3F24 (Success) Note over Equipment: LP1: READY_TO_LOAD Equipment->>Host: S6F11 (LoadPortStateChange) Host-->>Equipment: S6F12 Equipment->>AMHS: Load Request Signal AMHS->>Equipment: Carrier delivered Note over Equipment: LP1: TRANSFER_READY Note over Equipment: LP1: ASSOCIATED Equipment->>Host: S6F11 (CarrierArrived) Host-->>Equipment: S6F12

10. Unload Sequence¶

sequenceDiagram participant Host participant Equipment participant AMHS Note over Equipment: LP1: TRANSFER_READY, ASSOCIATED Host->>Equipment: S3F23 (RequestUnload, Port=1) Equipment-->>Host: S3F24 (Success) Note over Equipment: LP1: READY_TO_UNLOAD Equipment->>AMHS: Unload Request Signal AMHS->>Equipment: Carrier removed Note over Equipment: LP1: TRANSFER_READY Note over Equipment: LP1: NOT_ASSOCIATED Equipment->>Host: S6F11 (CarrierRemoved) Host-->>Equipment: S6F12

CEID	Name	Description
`[9001]`	LoadPortStateChange	Transfer state changed
`[9002]`	LoadPortAssociated	Carrier associated
`[9003]`	LoadPortDisassociated	Carrier removed
`[9004]`	LoadPortReserved	Port reserved by host
`[9005]`	LoadPortReleased	Port reservation released

SVID	Name	Type	Description
`[9001]`	LoadPort1TransferState	U1	LP1 transfer state
`[9002]`	LoadPort1AssociationState	U1	LP1 association state
`[9003]`	LoadPort1CarrierID	A	LP1 carrier ID
`[9010]`	LoadPort2TransferState	U1	LP2 transfer state
...	...	...	...

13. Multi-Port Configuration¶

Parameter	Value
Number of Load Ports	`[2]`
Port Numbers	1, 2
Carrier Capacity per Port	1 FOUP

14. Error Handling¶

Error Condition	Response
Load timeout	READY_TO_LOAD → TRANSFER_READY
Unload timeout	READY_TO_UNLOAD → TRANSFER_READY
Invalid port	S3F24 with error code
Port out of service	S3F24 with error code