6.5 Methods for Restoring Electrical Circuit …
577
creating a library, it is necessary to include as many versions of the same elements
as possible in this library.
The database shall contain both topology elements acquired with the help of
various microscopy means and the images of elements obtained by using nontraditional preparation methods. For modern microcircuits containing five or more
metallization layers, acquisition of high-quality topology layers with classic layerto-layer etching is extremely difficult, since the quality of the bitmap image of
bottom layers is significantly affected by all irregularities and defects occurring
during etching of top layers. Therefore, today there is a tendency to etch IC chips
with large numbers of switching layers on the back (reverse) side of the crystal. This
in turn includes the necessity of including topology elements obtained using various
microscopy means when photographing the back part of the IC chip. Figure 6.51
contains optical images of the IC topology obtained by etching the front and back
sides of the chip [15].
A relevant problem for the created CAD (reverse engineering) bases is ensuring
effective viewing of information in image galleries. Sequential viewing of all
elements can take up a lot of time. Therefore, all information required for identification must be structured in a certain manner. Examples of such elements included
in the suggested databases are given in Figs. 6.52 and 6.53 [16].
A number of requirements can be formulated with regard to the structure of
libraries and the type of displayed data. Created databases (element libraries) must
have the following properties:
– Clear images of topology elements (high resolution, absence of flaws);
– Maximum number of implementation options of the same element;
– Possibility of changing a separate element (rotation, reflection, scaling);
– Division of all elements into logic groups for more effective viewing by the
operator;
– Quick search of a separate element or a group;
– Additional auxiliary information about topology elements;
– Separate viewing of main and auxiliary information.
Identification of each separate bitmap element of the topology is performed automatically by comparing it to a library element. Recognition is based on comparing
vector description of a library element with the selected bitmap element. This method
of comparison demonstrated maximum resistance to occurring noise and minimum
number of errors and helped significantly reduce hardware costs of data analysis
[17].
Vector description of an element is entered by the operator during database
creation. The information about vector elements of the topology (characteristic rectangles) includes information about their dimensions, position inside the element
contour, and average brightness of each rectangle.
In order to ensure successful operation of a program, it is also necessary to
follow a number of requirements when inputting characteristic boxes. For example,
characteristic boxes shall have the following features:
577
creating a library, it is necessary to include as many versions of the same elements
as possible in this library.
The database shall contain both topology elements acquired with the help of
various microscopy means and the images of elements obtained by using nontraditional preparation methods. For modern microcircuits containing five or more
metallization layers, acquisition of high-quality topology layers with classic layerto-layer etching is extremely difficult, since the quality of the bitmap image of
bottom layers is significantly affected by all irregularities and defects occurring
during etching of top layers. Therefore, today there is a tendency to etch IC chips
with large numbers of switching layers on the back (reverse) side of the crystal. This
in turn includes the necessity of including topology elements obtained using various
microscopy means when photographing the back part of the IC chip. Figure 6.51
contains optical images of the IC topology obtained by etching the front and back
sides of the chip [15].
A relevant problem for the created CAD (reverse engineering) bases is ensuring
effective viewing of information in image galleries. Sequential viewing of all
elements can take up a lot of time. Therefore, all information required for identification must be structured in a certain manner. Examples of such elements included
in the suggested databases are given in Figs. 6.52 and 6.53 [16].
A number of requirements can be formulated with regard to the structure of
libraries and the type of displayed data. Created databases (element libraries) must
have the following properties:
– Clear images of topology elements (high resolution, absence of flaws);
– Maximum number of implementation options of the same element;
– Possibility of changing a separate element (rotation, reflection, scaling);
– Division of all elements into logic groups for more effective viewing by the
operator;
– Quick search of a separate element or a group;
– Additional auxiliary information about topology elements;
– Separate viewing of main and auxiliary information.
Identification of each separate bitmap element of the topology is performed automatically by comparing it to a library element. Recognition is based on comparing
vector description of a library element with the selected bitmap element. This method
of comparison demonstrated maximum resistance to occurring noise and minimum
number of errors and helped significantly reduce hardware costs of data analysis
[17].
Vector description of an element is entered by the operator during database
creation. The information about vector elements of the topology (characteristic rectangles) includes information about their dimensions, position inside the element
contour, and average brightness of each rectangle.
In order to ensure successful operation of a program, it is also necessary to
follow a number of requirements when inputting characteristic boxes. For example,
characteristic boxes shall have the following features: