SECS/GEM实现

SECS/GEM是半导体以及光伏行业等采用的通讯基础，在此之上进行搭建EAP，MES等管理系统。
SECS/GEM使用起来会有许多注意内容，例如通讯过程中的稳定性问题，以及通讯安全问题等。 通讯双方认证，避免信息暴露以及后门问题等。
软件模块稳定安全，且经过用户终端工厂严格考验，其中不乏JECT，科瑞，OSRAM等，在稳定性、效率要求极高的SECS/GEM也带来设备的极好体验，让客户工程师使用满意，也将让客户高层更加认可设备。

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.