The Compiler Core

The compiler module reads the device schematic file generated by the Builder as its input. The compiler interface is shown in the following figure.

Invoking the Compiler

Description of the Interface

Menu area

The process compiler menu functions have the following structures:

• Device
  • Load -- Load a new device
  • Compile -- Start compilation of the loaded device
  • Quit -- Quit the Compiler
• Output
  • Save -- Save the compiled processes
  • Save as -- Save the compiled processes in new names
  • Statistics -- Show the statistics of compiled processes

Device name label

The device name label shows the name of the currently loaded device. If no device has been loaded to the compiler yet, this label shows the name 'default'.

Canvas

The canvas area is actually a drawing area widget which displays the currently loaded device.

Material legend area

This legend area shows the names of different materials that have been used in the currently loaded device and their corresponding colors.

Process options

The process option area shows a set of option menus for selecting different process choices for output processes. They are described below.

• Reactive growth order: This item can have any one of the following values.
  1. Thick to thin (default) -- This setting causes all output processes to have reactive growths in thick to thin sequence. Since this is the mostly used sequence of reactive growths in semiconductor industries, it is the default setting in MISTIC.
  2. Unrestricted -- In this setting the reactive growth steps can occur in any sequence regardless of their thickness.
  3. Thin to thin -- This setting causes all output processes to have reactive growths in only thin to thick sequence.
• Preset diffusion order: This item can have either a 'Yes' (default) or a 'No' value. If the 'Yes' value is selected, the compiler sequences the diffusion steps prior to actual compilation based on paired diffusion relations. While the 'Yes' choice reduces the compilation time significantly for a complicated device, in some cases it may fail to generate any valid process for a device when such process does exist. In such cases the 'No' choice would generate all possible processes, even if the compilation time can be longer.
• Force implant-through: A 'Yes' choice in this item generates processes where diffusion impurities are introduced through thin layers (usually oxide layers) instead of implanting dopants through bare substrate surfaces. Since this is the preferred method of impurity implantation, the 'Yes' choice is the default. A 'No' choice, however, generates all kinds processes in terms of implant-through thin layers. But, if the device structure does not permit implant-through thin layers, this choice is ignored by the compiler and process compilation proceeds regardless the setting of this menu.

Run-time option area

The run-time option area is divided into two parts. The first part is a set of radio boxes showing different choices about the output process files and the second part is a set of text fields which displays different run-time options and allows changing them. Details of both to these options are discussed below.

• Output choices: The output choice area contains four radio boxes.
  1. Suprem deck generation -- This radio box allows turning on of off the choice of generating SUPREM files for the generated processes. The default is 'No'.
  2. Save processes after generation -- This radio box allows or stops creation of process files for each of the generated processes after compilation is complete. The default value is 'Yes', which causes the generated processes to be saved to files after compilation.
  3. Generate only best process -- Choosing 'Yes' generates only one process from each linear extension of device components based on the highest merit and choosing 'No' generates all processes dictated by different process choices from each linear extensions.
  4. Run-time display level -- This radio box controls the amount of print-outs to the print window during compilation. The print window pops up at the beginning of compilation and shows the sequence of operations that are carried out by the compiler in generating process flows.
• Max outputs and directory paths: This area contains several text fields for specification of several run-time parameters.
  1. Max process output -- This field allows changing the limit on maximum number of output processes. The default is 50.
  2. Input directory -- This field shows the path of the directory from where the input device file is to be read. If the user issues a 'load' command from the menu or the command panel, the pop-up file selection box shows a listing of all files in this input directory.
  3. Output directory -- This field shows the path of the directory where all the output proces files are to be stored after compilation.
  4. Database file -- This field shows the complete pathname of the atom database file that is to be loaded for compilation.

Run-time data option area

This check box area allows generation of run-time debug data during compilation of a device. Although, by default, no such data are generated, any number of the following items can be selected to have corresponding debug data in a directory named `_mistic_debug' created under the 'output directory'.

1. Polygon lists
2. Adjacency matrices
3. Transitive closure matrices
4. Processes after topological sort
5. Final process list before optimization

Failure check option area

This chick box area is provided to help the user find the reason of failure of a device. Selection of one or more of thses items causes the compiler to check for failure in these particular modes. If the compiler finds that the device does fail in one or more of these selected modes, it reports such findings at the end of compilation. The possible error checking modes are:

1. Deposited layer sequence
2. Reactive growth schedule
3. Eching of layers
4. Diffusion schedule

Since simultaneous error-checking during compilation takes additional times, these error-checking options are by default turned off.

Command panel

The command panel implements three menu functions using push buttons for quick reachability. These are Load, Compile and Quit.

Input and Output Files

1. Detailed run sheet
2. A concise description of process steps
3. SUPREM deck
4. In-process device cross sections
5. Process summary

• General summary
• Process warnings
  1. Stringer warning
  2. Stepped alignment warning
• Total over-etch damage to layers
• Figures of merit
• Process step statistics
• Material/impurity statistics
• Time distribution of process steps
• Cost distribution of process steps
• Time and cost versus step number
• List of masks

The Compilation Procedure

1. Invoke the Compiler: The Compiler can be invoked either from the Manager or it can be run as a stand-alone program by typing 'sn' at the command prompt. If the compiler does not get invoked in either of these ways, please check your path setting and MISTIC installation at your site.
2. Load the device: Load the device in the compiler using the appropriate menu function and popped up file selection box.
3. Set options: Set different options described in the previous section. Under normal circumstances the default setting generates optimal results.
4. Compile: Compile the loaded device using the 'Load' menu function. If a 'Yes' option has been chosen in the Suprem Deck Generation run-time option, the compiler prompts the user to mark the location of SUPREM deck generation by clicking the left mouse button on the canvas. If the device is too complicated, in the beginning the compiler shows a warning that the compilation procedure might take a long time. This helps the user have an early idea about the required compilation time. If the device is too complicated to be compiled in a reasonable amount of time, the compiler generates an error message and aborts compilation.
5. Recompile for failed runs: If the compiler fails to generate any process, there can be several reasons for the failure. If there is no terminal problem in the device, one or two changes in the process option settings result in successful compilation. Restrictions in the process choices should be taken off one after another in this recompilation process. 'Reactive growth order' and 'preset diffusion order' choices should be manipulated first in order to get successful compiler run. If the device contains a terminal problem, it can be detected by using the failure-checking option box items. After the problem in the device is found, the compiler should be run again to get process flow outputs.
6. Save processes: If the automatic save option is not chosen in the run-time option check box, the generated processes can be saved by using the menu function Output-->Save or Output-->SaveAs.

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   Summary

   The compiler module of the software is the most important one and is the vehicle of process generation. A little understanding of the compiler algorithms can help the user use this module intuitively and efficiently. Usually, a brief amount of practice in this module is sufficient for learning how to compile most devices.

   

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   MISTIC version 1.0 (July 1997)

   Copyright © 1997 by University of Michigan. All rights reserved.