What is GEM control state?
GEM plate control state is a basic requirement of the GEM E30. It defines the level of cooperation between the host and device, and designated operators how to interact at different levels of the host control.
In the semiconductor factory, the host or the operator may control the processing equipment. Both sides control equipment will also cause problems. Therefore, when one control device, the other operations can be performed is limited. For example, if the operator suspended the process, it should not be allowed to resume processing or host sends a command to start a new job. GEM state control is to prevent the occurrence of such problems have been created.
How to control the state of the job?
Basic control state provides three levels of control. Each level described with the host device side and which operations may be performed.
Remotely
Host can maximize control device.
local
The operator may control the apparatus as much as possible.
Host full access to information. The host can use other GEM characteristics (such as collecting events, status tracking and data collection) to collect data.
How to limit the influence of the host device operation:
Start prohibition process (e.g. START) or to cause physical movement of the remote command. During processing, also prohibits remote commands that affect treatment (stop, suspend, pause, resume).
Offline
The operator has full control of the apparatus.
Host does not have control of equipment operation, information-gathering capabilities are very limited.
In many equipment control applications there is a need for a GEM host to modify one or a small set of
process parameters associated with a recipe. The number of parameters modified, frequency of modification (e.g.,
wafer-to-wafer, batch-to-batch, etc.), range of modification, etc., is largely a function of the equipment control
application. Utilizing GEM, at least two methods are envisioned for modifying process parameters on a tool. With the
first method, ‘Equipment Constants’ can be used to relate process parameters of the updated recipe. Equipment
Constants can also be used in a mode where they relate suggested modifications to process parameters from the stored
recipe; that is, the constants contain only the ± differential from a nominal value. The former mode is preferred because
it better ensures data integrity between the controller and tool. With the second method the entire recipe could be
downloaded, but this results in an enormous amount of communication overhead. Note that, in all cases, the Equipment
Constants do not replace the process parameters inside a recipe, but are associated with (e.g., linked to) these
parameters to relate modifications. The remainder of this application note provides a description of how process
parameter modification can be implemented using existing GEM capabilities. The method may be used in a GEM
compliant system provided that the specific GEM capabilities described are supported.
The equipment constants should represent the actual values of the process parameters with which they are
associated. Depending on the equipment operation and control application, the equipment constant could represent
the actual value of a process parameter at a recipe step, or over the entire recipe. The equipment constants could also
be utilized to represent the differentials of process parameters from nominal values. However it is important to note
that, when using differential values to relate process parameter modifications, any loss of synchronization between
equipment and host could result in an incorrect assessment of the value of a process setpoint by the host. Note also
that, upon system startup, and whenever the appropriate process parameters are modified, the equipment constants
should also be modified as necessary to always reflect the (absolute or relative) values of the associated process
parameters.
NOTICE: This Related Information is not an official part of SEMI E19.3 and was derived from the work of the
Physical Interfaces & Carriers Global Technical Committee. This Related Information was approved for publication
by full letter ballot procedures on August 22, 2013.
NOTE 1: The material contained in this Related Information is not intended to modify or supersede the Standard SEMI E19.3 in
any way. These notes are provided as a source of information to aid in the application of the Standard, and are to be considered
reference material. Determination of the suitability of the material is solely the responsibility of the user.
R1-1.1 A Related Information to SEMI E19 provides the position of existing reticle SMIF pod (RSP150) sensors and
implementation advice. The users of this Standard are recommended to consult this Related Information for reticle
SMIF pod detection.
NOTICE: SEMI makes no warranties or representations as to the suitability of the Standards and Safety Guidelines
set forth herein for any particular application. The determination of the suitability of the Standard or Safety Guideline
is solely the responsibility of the user. Users are cautioned to refer to manufacturer’s instructions, product labels,
product data sheets, and other relevant literature, respecting any materials or equipment mentioned herein. Standards
and Safety Guidelines are subject to change without notice.
By publication of this Standard or Safety Guideline, SEMI takes no position respecting the validity of any patent rights
or copyrights asserted in connection with any items mentioned in this Standard or Safety Guideline. Users of this
Standard or Safety Guideline are expressly advised that determination of any such patent rights or copyrights, and the
risk of infringement of such rights are entirely their own responsibility.
5.3.1 The actual shape of these curves and time intervals is dependent on the design of the MFC under test, the
elastomer used, if any, and the characteristics of the leak detection system. These time intervals must be determined
using sound engineering judgment following qualification testing of the specific MFC model and test set-up. Once
determined, it is recommended that receiving inspection consist of measuring for leak rate value w1 at the end of
interval t2.
5.3.2 Following qualification testing, report typical values for t1 through t4 and w1 and w2. w1 is primarily the
mechanical portion of the leak, and w2 is mechanical plus permeation. In the case where w2 is significantly greater
than w1, w2 is primarily permeation. In the case of a gross mechanical leak, w1 could greatly exceed, and thereby
mask, w2.
NOTE 4: To prevent false leak rate readings that could arise from helium permeation, this test should be performed with elastomers
that were not previously exposed to helium. If exposed to helium, the MFC must be purged of helium by the passage of time and/or
baking.
5.3.3 In good leak testing practice, the background level should be verified before the application of helium to ensure
that the elastomers are in a helium degassed state and that the leak detecting system is in proper operation.
5.2.3 Control Valve Seat Leak Test — The purpose of this test is to determine the leakage through the control valve
under simulated operation in the closed control mode. The MFC should be electrically energized for normal operation
and placed in the closed position as specified for the operation of the MFC. The input pressure to the MFC should be
100 kPa ± 20%. The outlet should be connected directly to the helium leak detector, and pressure should be as low as
possible using good leak detector practice (see Figure 3).
5.1 General Requirements
5.1.1 Leak Detector — The leak detector shall be of the helium mass spectrometer type. It shall have sensitivity at
least equal to or smaller than the specified leak rating of the MFC to be tested. If the actual leak rate is to be reported,
the sensitivity shall be five times smaller than the leak to be measured. If the sensitivity is not five times smaller, the
actual leak rate may be reported if the sensitivity of the detector is also reported.
5.1.2 Helium must have access to all primary seals.
5.1.3 Connections between the MFC and the leak detector must be leak-tight.
5.1.4 The ambient temperature of the MFC should be 25°C ± 5°C unless otherwise specified. If another test
temperature is used, it must be recorded during the test.
5.2 Test Procedures — There are two basic setups which may be used to measure the leak rate from the external
environment to the internal gas passages of the MFC or from the internal passages to the external environment. Results
for either test method may be reported. The method used must be reported as well. A third test, the through-the-valve
setup, is intended to measure the quality of the valve seat shutoff.
5.2.1 Internally-Pressurized Leak Test — The purpose of this test set-up is to simulate operation of the MFC under
conditions where the internal pressure is above ambient. The recommended internal pressure is 300 kPa absolute
(30 psig) of helium (see Figure 1).
