HK1058417B - Man-machine interface, method and apparatus for analyzing image-mosaics - Google Patents

Description

Human-machine interface, method and device for analyzing image mosaic

Technical Field

The present invention relates generally to analysis of semiconductor integrated circuits, and more particularly to a human-machine interface that manipulates a plurality of images representing a surface of a decomposed semiconductor Integrated Circuit (IC) to extract design and layout information therefrom.

Background

In the semiconductor industry, it is often necessary to actually analyze semiconductor Integrated Circuits (ICs) for the purposes of product reliability verification, design verification, and identification of device configuration patterns. The IC is analyzed to extract design and/or layout information therefrom. This process is called reverse engineering. Reverse engineering is also part of the test and development process in large-scale manufacturing of ICs. In general, significant time and labor is required to reverse engineer the IC.

An IC is a single crystal silicon die on which a large number of transistors and other electronic components have been fabricated and interconnected to form useful circuits. During manufacturing, each die is part of a larger silicon wafer substrate that is easy to handle and process multiple ICs simultaneously.

The IC manufacturing process includes: doping a silicon substrate to change its conductive properties and using different techniques to build up a sequence of layers on the silicon substrate. Ion implantation is used to create the doped layer. The diffusion layer is created by depositing impurities on top of the substrate and heating the wafer. With each deposited layer, a different material is deposited and the deposited material is selectively removed by selective etching according to a predetermined pattern. The components fabricated on the silicon wafer span multiple layers. The oxide layer is used for insulation. The deposited metal layer serves to interconnect the respective terminals of the thus formed element.

The identification of these elements and the interconnections provided by the metal layers provide the basic information from which the design and/or layout of the IC can be extracted and verified.

In a reverse engineering sample IC, the die is broken up. The IC sample die is subjected to a sequential layer removal sequence using a rigorous series of treatments such as acidic etchants, each individual layer being specifically selected for removal at that time. Other decomposition processes include dry etching, polishing, and the like. With such a process, the metal layer of the interconnect, the polysilicon layer, the oxide layer, and the like are removed step by step. The surface of the partially decomposed IC is examined in each decomposition step.

The inspection technique includes the use of: optical microscopes, scanning electron microscopes, and other surface inspection devices. Generally, a scanning electron microscope is accurate but is itself expensive to manufacture and operate. The optical microscope can use bright field, contrast interference and dark field patterns in the illumination. In bright field or contrast interference modes, the actual limits of the elements on the die are distorted by edge effects. These edge effects can be explained by an experienced analyst, but require a large amount of computation to be analyzed by a computer.

"method of inspecting microcircuit patterns" has been described in U.S. patent No. 4,623,255 to Suszko on 11/18 1986. The method involves capturing the IC die between the decomposition steps. Film transparency is printed out and used by engineering analysts to extract design and layout information from the captured ICs. While the teachings of Suszko have advantages, design and layout extraction are hampered by the handling and cross-correlation of bulk transparency.

Another "automated system for extracting design and layout information from integrated circuits" is described in U.S. Pat. No. 5,086,477 issued to Yu et al, 2.4.1992. A digital camera and a controlled stage are used to capture images of the overlay pattern after each decomposition step. The captured digital images are stored in computer memory and recombined into an image mosaic according to an overlap at the boundaries of the respective overlay images. Yu et al describe pattern matching performed on the image mosaic of the decomposition step and point out the difficulties involved in extracting layout information from the overlay image. The automated system of Yu et al appears to be suitable for extracting design information from complex ICs that have difficulty reverse engineering. To accomplish this, a "cell" library is built. The cell library includes images of the particular arrangement of elements known to perform particular functions. The cell library is used for automatic pattern matching to facilitate reverse engineering of, for example, Application Specific Integrated Circuits (ASICs). Yu et al, however, do not describe how to manipulate multiple image mosaics representing different steps in a decomposed IC in order to extract design and layout information from them simultaneously. It is desirable to analyze image mosaics simultaneously as individual elements fabricated on a silicon wafer may span multiple film layers.

There is therefore a need for a human machine interface that enables manipulation of multiple images of an IC to facilitate simultaneous extraction of design and layout information therefrom.

Object of the Invention

It is an object of the present invention to provide a human machine interface that enables manipulation of multiple images of an IC to facilitate simultaneous extraction of design and layout information therefrom.

It is another object of the present invention to provide a human machine interface adapted to facilitate feature recognition and analysis across a plurality of images representing one or more surfaces of a semiconductor Integrated Circuit (IC).

It is another object of the present invention to provide a human machine interface that supports multiple windows, each of which displays a portion of an image mosaic and one of multiple, locked step cursors.

It is another object of the present invention to provide means for assisting an analyst in determining the structure of an IC using a photographic image of the IC.

It is another object of the present invention to provide means for assisting an analyst in defining a region of interest in one or more images to generate a plurality of mosaic windows for the region of interest.

It is yet another object of the present invention to provide a means for assisting an analyst in correlating the characteristics of individual mosaic windows using a primary cursor and a lock-step cursor in one of the mosaic windows that automatically tracks the relative position of the primary cursor in each of the other mosaic windows.

It is another object of the present invention to provide a method for analyzing an IC using a master cursor and multiple lock-step cursors to assist an analyst in analyzing the characteristics of the different image-mosaics of the associated IC.

It is a further object of the present invention to provide a method of generating slices of a low magnification image of an IC sample that define a plurality of image mosaics for use by an analyst analysis 1C.

Disclosure of Invention

According to an aspect of the invention, there is provided a human-machine interface for detecting image-mosaics to be scaled and aligned with a sample coordinate space defined for the image-mosaics during acquisition of an image, the human-machine interface comprising:

defining a display area displaying a coordinate space;

a system pointer having a position in the display coordinate space;

a plurality of mosaic windows having corresponding window boundaries in a display coordinate space, each mosaic window displaying at least a portion of an image mosaic, an

A plurality of lock step cursors sharing position coordinates relative to a sample coordinate space;

when the system pointer crosses the window boundary and enters one of the mosaic windows, the system pointer is displayed as the main cursor for controlling cursor event, and the locking step cursor is displayed in the other mosaic windows at the relative position of the main cursor relative to the sample coordinate space if the relative position is in the corresponding display coordinate space of the corresponding mosaic window of the other mosaic windows.

The present invention also provides a method of analyzing image-mosaics, the image-mosaics being scaled and aligned with a sample coordinate space defined for the image-mosaics during acquisition of the image, the method comprising the steps of:

displaying regions of interest of respective image mosaics of the plurality of image mosaics within respective mosaic windows displayed on a display coordinate space of a human-machine interface used to analyze the image mosaics; and

features of the IC spanning at least two of the mosaic windows are tracked using a master cursor in one of the mosaic windows and a lock-step cursor in the other mosaic window, the master cursor controlling a cursor event and the lock-step cursor being displayed within the other mosaic window at a relative position of the master cursor with respect to the sample coordinate space if the relative position is within the corresponding display coordinate space of the corresponding other mosaic window.

The present invention also provides an apparatus for analyzing image-mosaics, the image-mosaics being scaled and aligned with a sample coordinate space defined for the image-mosaics during acquisition of the image, the apparatus comprising:

a workstation having a display area defining a display coordinate space;

a pointing device controlling a system pointer that is movable within the display coordinate space;

a memory storing a plurality of mosaic windows having respective window boundaries, each mosaic window displaying at least a portion of an image mosaic, when displayed in a display coordinate space, and

means for displaying a lock step cursor within each mosaic window, the lock step cursor sharing position coordinates relative to the sample coordinate space;

when the system pointer moves across a window boundary into one of the mosaic windows by operation of the pointing device, the system pointer is displayed as a primary cursor for controlling cursor events, and the lock step cursor is displayed in the other mosaic windows at a relative position of the primary cursor with respect to the sample coordinate space if the relative position is in the corresponding display coordinate space of the corresponding mosaic window of the other mosaic windows.

According to the invention, the human-machine interface comprises: a display area, a system pointer, a plurality of mosaic windows and a corresponding plurality of lock step cursors. The image mosaic is aligned to the sample coordinate space. The display area defines a display coordinate space and the system pointer has a position relative to the display coordinate space. Each of the plurality of mosaic windows has a window boundary in the display coordinate space and displays one image mosaic of the plurality of mosaic windows. Each lock step cursor has a position in the display coordinate space and shares position coordinates in the sample coordinate space with all other lock step cursors. When the system pointer is positioned within at least one window boundary, the system pointer is represented with a primary cursor that controls cursor events. The lock step cursor is displayed in sample coordinate space in the other windows at the location of the main cursor. An image mosaic is, for example, a representation of a decomposed semiconductor Integrated Circuit (IC) sample.

According to one aspect of the invention, the human-machine interface further comprises a navigation window having a window boundary in the display coordinate space and displaying a low magnification image representation of the IC sample. The navigation window also allows selection of at least one area of interest displayable in the plurality of mosaic visuals.

The present invention also provides a method of analyzing image-mosaics that are scaled and aligned with a sample coordinate space defined for the image-mosaics during acquisition of the image. The method comprises the following steps: a step of analyzing the region of interest within each mosaic window displayed on the display coordinate space of the human-machine interface of the image mosaic. The method also includes tracking a 1C feature across at least two of the mosaic windows using a primary cursor in one of the mosaic windows that controls a cursor event and a lock-step cursor in the other mosaic window that is displayed within the other mosaic window at a relative position of the primary cursor with respect to the sample coordinate space if the relative position is within the corresponding display coordinate space of the other mosaic window.

An image mosaic is generated, for example, by decomposing semiconductor Integrated Circuit (IC) samples. A slicing tool is used for generating slices to define regions of interest of the coordinate-generating image-mosaic in the sample coordinate space. The slice is preferably generated by dragging the system pointer along a diagonal path to define a region of interest rectangle on a low resolution die photograph of the IC sample. After the slice is generated, the image mosaic displayed in the mosaic window of the region or region of interest is selected. The image mosaic displayed in the mosaic window of the region of interest may be selected from a list of all image mosaics associated with the slice or automatically by the device. When the primary cursor is removed from one of the image mosaics, the primary cursor becomes a system pointer on the display surface of the human-machine interface, and the lock-step cursor is erased from each of the other mosaic windows.

The present invention also provides means for analyzing image-mosaics that are scaled and aligned with the sample coordinate space defined for the image-mosaics during acquisition of the image. The apparatus includes a workstation having a display area defining a display coordinate space and a pointing device controlling a system pointer movable within the display coordinate space. A plurality of mosaic windows having corresponding window boundaries are stored when displayed in the display coordinate space, each mosaic window displaying at least a portion of one of the image mosaics. An algorithm displays a lock-step cursor within each mosaic window that shares positional coordinates relative to the sample coordinate space. When a system pointer moves across a window boundary into one of the plurality of mosaic windows by operation of the pointing device, the system pointer is displayed as a primary cursor for controlling a cursor event, and the lock-step cursor is displayed in the other mosaic windows at a relative position of the primary cursor with respect to the sample coordinate space if the relative position is in the corresponding display coordinate spaces of the corresponding mosaic windows of the other mosaic windows.

When a cursor event indicating a cursor movement is detected, if the coordinates of the system pointer in the display coordinate space are within one of the mosaic windows, the displayed apparatus converts the coordinates of the system pointer in the display coordinate space to coordinates in the sample coordinate space and performs an iterative process to transmit the coordinates in the sample coordinate space to each of the other mosaic windows.

Advantages of the system include increased production and reduced analyst fatigue due to facilitating feature matching across image-mosaics and avoiding transposition errors while tracking components from one image-mosaic to another.

Brief description of the drawings

Further features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, in which

FIG. 1 is a work flow diagram showing an exemplary overview by which image mosaics representing steps in decomposing a semiconductor Integrated Circuit (IC) may be obtained;

FIG. 2 is a process diagram showing exemplary sequential steps in the manufacture of an IC;

FIG. 3 is a process diagram illustrating an exemplary sequence of steps in reverse engineering decomposition of an IC;

FIG. 4 is a schematic diagram illustrating a human-machine interface for displaying a visual display having multiple windows and associated lock step cursors in accordance with a preferred embodiment of the present invention;

FIG. 5 is a schematic representation of a display area of a human-machine interface displaying a plurality of windows and a lock step cursor in accordance with a preferred embodiment of the present invention;

FIG. 6 is another schematic representation of the display area shown in FIG. 5 illustrating a plurality of windows and a lock step cursor in accordance with another embodiment of the present invention;

FIG. 7 is a schematic diagram showing slice generation in accordance with a preferred embodiment of the present invention;

FIG. 8 is a schematic diagram illustrating the generation of a mosaic window according to a preferred embodiment of the present invention;

FIG. 9 is a flowchart showing a process of generating slices, defining regions of interest, and generating mosaic visuals in accordance with a preferred embodiment of the present invention; and

fig. 10 is a flowchart showing a procedure for controlling a locking step cursor action according to a preferred embodiment of the present invention.

It is noted that throughout the drawings, like features are identified by like reference numerals.

Detailed Description

Fig. 1 is a work flow diagram showing an overview of the prior art by which an image mosaic representing steps in decomposing a semiconductor Integrated Circuit (IC) can be obtained. An IC 10 is fabricated on a wafer 12. Wafer 12 comprises a naturally insulating single crystal silicon substrate. Doping a silicon substrate with other chemical elements can change the properties of the silicon, including making the silicon substrate a semiconductor or a conductor. Such substrate processing is implemented as part of the fabrication process 14 of the chip 16. In packaging the chips 16, the die 20 is cut from the wafer 12 at step 18 and packaged to form the chips 16 at step 22.

The manufacture of integrated circuits typically involves a verification process 24 whereby the wafer 12, the diced dies 20, or portions thereof are inspected using a microimage system 26 to extract design and layout information for design validation or competitive analysis.

A reverse engineering procedure 28 is implemented on the chip 16, for example for the purpose of product quality validation or competitive analysis. The first step in reverse engineering program 28 is to remove die 20 at a decapsulation step 30 of chip 16. The die 20 is inspected using a micro-imaging system 26 to extract design and layout information. The micro-imaging system 26 may include a high magnification optical microscope, a scanning electron microscope, a field emission electron microscope, and the like. As described below in connection with fig. 3, the design and layout extraction from die 20 or a portion thereof involves a process of decomposition procedure 32 by which layers formed during manufacturing process 14 are removed step by step.

A high magnification overlay image 34 of the sample die 20 is obtained between the various decomposition steps 32 under the control of a computer workstation 36. Computer workstation 36 controls micro-imaging system 26 using control signals 38. Computer workstation 36 receives overlay image data 40 from micro-imaging system 26 and stores overlay image data 40 to a memory, physical storage device 42, typically a hard disk.

Stored overlay images 34 are assembled into image-mosaics 44, with each image-mosaic 44 displayed on the surface of die 20 at decomposition step 32. During the acquisition of the overlay image 34 of the die 20, a sample coordinate space 46 is defined. Sample coordinate space 46 is used to align overlay image 34 and image mosaic 44.

Fig. 2 is a flow chart showing sequential steps of the prior art during the manufacture of an IC. The figure shows a cross-sectional progression through a silicon substrate, showing exemplary steps in fabricating a component such as a junction. In step 52 of the fabrication process, the silicon substrate is doped using diffusion and/or ion implantation techniques to alter its characteristics, in particular to define a P-well, as is well known in the art. At step 54, implantation techniques are used to form n-type sources and drains. A gate oxide layer is deposited between the source and drain and a field effect oxide layer is deposited in the other regions in step 56. A polysilicon gate layer is deposited in step 58 and deposition of two oxide layers is achieved in steps 60 and 62. A metal layer providing connections between the gate, source and drain on the silicon substrate is deposited at step 64. Step 66 illustrates the deposition of a passivation layer that is typically used to protect the IC from physical damage and/or contamination by dust particles prior to packaging in step 22 (fig. 1).

FIG. 3 is a flow diagram illustrating an exemplary prior art process for reverse engineering a decomposition step of a sample IC. Step 70 illustrates a cross-section through the silicon substrate of die 20 after deblocking at step 30 (fig. 1). Steps 72, 74, 76, 78, 80 and 82 illustrate the sequential removal of deposited material layers such as passivation layers, metallization layers, polysilicon layers, base contact layers, field effect oxide layers, and the like. This results in exposing the silicon substrate (step 82) including the well structure fabricated during steps 52 and 54 (fig. 2). The back surface of die 20 may also be decomposed in order to expose the well structure. Steps 84 and 86 show a sequential decomposition of the back surface of die 20 to expose the P and N wells. Both surfaces of die 20 are preferably micro-imaged in extracting design and layout information and both represent surfaces of interest.

FIG. 4 is a schematic diagram showing a human machine interface according to the present invention for analyzing an Integrated Circuit (IC). In analyzing the IC to extract design and layout information, the engineering analyst 210 utilizes a workstation 220 having a visual display 222, a keyboard 224, and a pointing device 226, such as, but not limited to, a mouse. The visual display 222 has a display area 228 that defines a corresponding display coordinate space. The system pointer displayed in the display area 228 is controlled by the pointing device 226. The system pointer has different shapes, sizes and colors.

The visual display 222 is typically a Cathode Ray Tube (CRT), Liquid Crystal Display (LCD), image projected by an image projector, or the like. Alternatively, the human-machine interface may include a distributed visual display provided by a multi-headed visual display (not shown), a distributed window environment of multiple workstations 220 spanning the visual display 222, and so forth. Distributed windowing environments are available from Xconssortinm *, NeXTstep */Openstep *, and others.

Fig. 5 is a detailed schematic diagram showing a display area of the man-machine interface shown in fig. 4. The display area 228 displays a navigation window 230 having window boundaries and mosaic windows 232, 234, 236, and 238. The navigation window 230 provides an entire view of the sample being analyzed. The navigation window 230 displays a low magnification digital image of the sample. When the sample being analyzed is a single IC die or a substantial portion thereof, the low magnification image displayed in the navigation window 230 is referred to as a die photo. The slice 240 selects and defines the area of interest on the die photograph in the navigation window 230. An exemplary process of generating slices is described below with reference to fig. 7 and 9.

Mosaic windows 232, 234, 236 and 238 each display a portion of an image mosaic obtained after a particular decomposition step in the process of decomposing the IC. The slice 240 defines the area of interest displayed in each of the mosaic windows 232-238. An exemplary process of generating the mosaic window is described below with reference to fig. 8 and 9.

Lock step cursors 252, 254, 25 and 258 are displayed within each mosaic window as appropriate. A corresponding lock step cursor 250 may also be displayed in the navigation window 230. Preferably, the shape, size and color of the lock step cursor are the same except for the mosaic color displayed at 258. When the system pointer is placed within the mosaic window, the main cursor 258 indicates the current position of the system pointer 250 as controlled by the pointing device 226. The primary cursor may have the same appearance as the system pointer, or may have a different shape, size, and/or color. Because the lock step cursors 250, 252, 254 and 256 share position coordinates in the sample coordinate space with the master cursor, they move in unison under the control of the master cursor. The locking step action is shown in the figure as a trailing effect. An exemplary process for implementing the lock step action is described below with reference to FIG. 10.

In accordance with a preferred embodiment of the invention, the mosaic windows 232, 234, 236 and 238 are scaled and/or moved in unison subject to the scaled or moved slices 240. The navigation window 230 is thus displayed with a moving slide bar.

FIG. 6 is another schematic diagram of the display area 228 of the human-machine interface according to another embodiment of the invention. The slice 260 is displayed with associated mosaic windows 262, 264, 266, and 268. According to this embodiment, all the mosaic windows push or pull the camera or move the display image when any one of the mosaic windows pushes or pulls the camera or moves the display image. To accommodate this window shot, each of the mosaic windows 262, 264, 266, and 268 is provided with a moving slide bar 241.

The navigation window 230 is also displayed with another slice 270 defined. The slice 270 is associated with mosaic windows 272, 274, 276, and 278. In accordance with this embodiment of the invention, mosaic windows 272, 274, 276 and 278 are displayed having different sizes, each of which can be independently resized and panned for panning.

Fig. 7 is a schematic diagram showing the generation of slices according to a preferred embodiment of the present invention. The slice 240 is generated in the navigation window 230 by positioning the system pointer in the navigation window using the pointing device 226. After the system pointer is positioned in the navigation window 230 reconfigured and displayed as the primary cursor 258, a triggering event, such as a mouse click, represented by reference numeral 300, is implemented by the engineering analyst 210 (fig. 4). The trigger event activates the tool selection menu 302. The tool selection menu may be, for example, a flip-up menu. A menu item 304 appearing in the tool selection menu 302 allows the engineering analyst 210 to activate the slice generation tool 306. The slice generation tool 306 is used to select a region of interest on a die photo by clicking on the pointing device and dragging the active cursor 258 diagonally to produce a rectangular slice 240 to define one corner 308 of the region of interest. The tool selection menu may also be implemented as a drop down menu. The slice generation tool represents one type of slice generator. According to another embodiment of the invention, the slice generation tool may be activated by issuing a slice generation command. According to a further embodiment, a "hot key" may be used to activate slice generation. Other methods of activating slice generation may also be used, as will be appreciated by those skilled in the art.

FIG. 8 is a schematic diagram illustrating the generation of a mosaic window according to an exemplary embodiment of the present invention. According to a preferred embodiment of the invention, the slice 240 has an associated mosaic window generator that initiates generation of the mosaic window.

Fig. 9 is a flow chart showing a process of generating slices by selecting a region of interest on a die camera and generating a mosaic window for the slices according to a preferred embodiment of the present invention. The slice generation process begins at step 310. According to a preferred embodiment of the invention, the human machine interface is an event driven interface that examines events generated in response to activities of the engineering analysts 210. As is well known in the art, interface events may be generated in a variety of ways depending on the design of the human-machine interface and the preferences of the engineering analyst 210. For example, as described above, the generation of the slice is initiated using a command pattern of a flip-up menu, a pull-down menu, a hotkey, or an operation. Any one or more of these options are enabled in the human machine interface according to the invention.

An event is detected in step 312. At step 314, the event is analyzed to determine that it is a request slice generation. As noted above, slice generation may be initiated using, for example, a menu selection, a command line, or a hot key. If the event is not a slice generation request, the event is processed (step 315) and event monitoring resumes at step 312. If the event is determined to be a start slice event in step 314, the slice generation process monitors for a return of slice coordinates defining an area of interest on the die photograph. For example, if the coordinates have not returned within a predetermined time interval (not shown), the position of the system pointer may be tested at step 318 to determine if the system pointer is on the die photograph. If so, the process returns to monitoring for selection of the region of interest. If not, a message may be displayed at step 320 instructing the engineering analyst 210 to select an area of interest on the die camera.

When the slice coordinates are received, the slice coordinates are stored in memory in step 322, and the slice generation parameters are checked in step 324 to determine whether automatic mosaic window generation is enabled. Automatic mosaic window generation is a feature provided in accordance with a preferred embodiment of the invention that automatically generates a mosaic window for each image mosaic associated with a slice. Alternatively, a mosaic window displayed for a slice may be selected from a list of all image mosaics associated with the slice. If the slice generation parameter indicates that automatic mosaic window generation is enabled (step 324), then the image mosaic table is retrieved in step 326 and a mosaic window defined by the slice coordinates is generated for each image mosaic and displayed on display space 228.

If the slice generation parameter indicates that automatic mosaic window generation is active (step 324), then the image-mosaic table is retrieved in step 326 and a mosaic window defined by the slice coordinates is generated for each image-mosaic and displayed (step 328) on display space 228 (FIG. 4).

If it is determined (step 324) that automatic von-Saybook window generation is not enabled, then an image-mosaic list associated with the slice is displayed on display area 228, allowing the engineering analyst 210 to select an image-mosaic for the mosaic window to be generated (step 330). At step 332, the slice generation process determines that at least one image-mosaic has been selected from the displayed table at step 330. If not, a message is displayed in step 334 asking for the selection of an image mosaic or the cancellation of the process (step 334). At step 336, a mosaic window is generated for each image mosaic selected, and the slice generation process ends at step 340.

Fig. 10 is a flowchart showing a procedure of controlling a locking step cursor action according to a preferred embodiment of the present invention. The process begins at step 400 and is part of a cursor event processing loop in which a cursor event is detected at step 402 and analyzed at step 404 to determine whether the cursor event represents movement of a cursor. If not, the cursor event is processed in step 406. A cursor event such as "click exit button" at step 408 ends the process.

If the cursor event received in step 404 is determined to represent movement of the cursor, then in step 410 the process determines if the system pointer has crossed a window boundary of one of the mosaic windows relative to the display coordinates. If it is determined in step 410 that the system pointer has crossed the window boundary, then in step 412 the process determines whether the system pointer crossed into or out of the window. If it is determined in step 412 that the system pointer crosses into the window, then the system pointer is drawn over the display area to display the primary cursor in step 414. The display coordinates of the system pointer are converted to sample coordinates in step 416. A table of all currently registered windows is obtained in step 418 and the process repeats through all windows in the table in step 420, sending a cursor event to each window that includes the sample coordinates of the system's main cursor. The process steps implemented by the windows when receiving the sample coordinates are shown with dashed borders. Each window converts the sample coordinates of the master cursor to the display coordinates of the window in step 422, and the lock step cursor is drawn at the window coordinates in the window (step 424). The process then restarts at step 402.

If it is determined in step 412 that the system pointer has moved out of the window, then the representation of the system pointer is restored as its operating system representation in step 426. At step 428, the process obtains a list of registered windows and repeats sending cursor events to each registered window through the list (step 430). Upon receipt of a cursor event, the windows erase the lock step cursor from the window, and the process restarts from step 402.

If it is determined that the cursor event represents movement of the cursor (step 404) and the system pointer has not crossed a window boundary (step 410), the process determines whether the system pointer is in the window (step 434). If not, the process continues from step 402.

If a cursor movement event is received while the system pointer is in the window, the display coordinates of the primary cursor are converted to sample coordinates (step 436). The table of registered windows is retrieved at step 438 and the cursor event and the new position of the primary cursor relative to the sample coordinate space are sent to each registered window in an iterative process at step 440. The window's lock step cursor is erased for the position occupied when the new coordinates are received (step 442), and the sample coordinates of the main cursor are converted to the display coordinates of the window in step 444. If the display coordinate is in the window, the window redraws the locking step cursor at the new display coordinate.

In another embodiment, a global data structure with a scope that extends to all windows is used to initiate the cursor action in the lock step. A global data structure is stored at least at the location of the master cursor relative to a sample coordinate space defined by the investigated physical sample IC. The human interface processes system pointer events received from the pointing device 226. When each system pointer event is received, typically through a system interrupt, the human machine interface displays the system pointer at the current location and updates the location of the primary cursor. If the system pointer is within the window boundary of the window, it is drawn on the display surface 228 in the shape and configuration of the primary cursor, and the position of the primary cursor in the sample coordinate space is calculated and stored in the global data structure. As part of the interrupt processing, each of the other windows determines whether the position of the primary cursor relative to the sample coordinate space can be displayed within the window boundaries of the window. If so, the window performs a comparison between the sample coordinate space of the displayed lock step cursor and the location stored in the global data structure, and if necessary erases and redraws the lock step cursor in the window.

If multiple workstations, each having a system pointer, are used to simultaneously extract design and layout information from multiple image mosaics representing a sample IC, the selection criteria can be used to determine which system pointer is the primary cursor to solve the primary cursor content problem. The selection criteria may include: restricting a particular system pointer for a particular workstation; selecting a last system pointer that generated a cursor event; and so on.

Industrial applicability

The present invention provides a tool set useful in analyzing semiconductor Integrated Circuit (IC) images for the purpose of ensuring product reliability, design verification, and identifying device structure patterns. The tool includes a master cursor and a plurality of lockstep cursors that track a relative position of the master cursor when the master cursor is within a boundary of a mosaic window generated from the image.

The master cursor and lock step cursor help the analyst look like features of different images representing different layers of the IC. This facilitates the analyst in determining the structure and function of the IC. Locking step cursors reduces analyst fatigue and increases productivity by simplifying feature cross-correlation and reducing translation errors.

The above-described embodiments of the invention are intended to be exemplary only. The scope of the invention is therefore intended to be limited solely by the claims appended hereto.

Claims (19)

1. A human-machine interface for analyzing image-mosaics, the image-mosaics being scaled and aligned with a sample coordinate space defined for the image-mosaics during acquisition of an image, the human-machine interface comprising:

a) a display area defining a display coordinate space;

b) a system pointer having a position in the display coordinate space;

c) a plurality of mosaic windows of decomposed integrated circuit samples, the mosaic windows having corresponding window boundaries in the display coordinate space, each mosaic window displaying at least a portion of one of the image mosaics; and

d) a plurality of lock step cursors sharing position coordinates relative to the sample coordinate space;

wherein the system pointer is displayed as a primary cursor for controlling cursor events when a window boundary crosses into one of the plurality of mosaic windows, and the lock-step cursor is displayed in the other mosaic windows at a relative position of the primary cursor with respect to the sample coordinate space, provided that the relative position is in the corresponding display coordinate space of the corresponding one of the other mosaic windows.

2. A human-machine interface according to claim 1, characterised in that each mosaic window displays a portion of an image mosaic subject to a magnification factor and in that the transformation of the locking step cursor coordinates is performed between the sample coordinate space and said display coordinate space.

3. A human-machine interface according to claim 2, characterised in that all mosaic windows are subject to the same magnification factor.

4. A human-machine interface according to claim 2, wherein images within all mosaic windows are displayed moving together.

5. A human-machine interface according to any preceding claim, further comprising a navigation window adapted to display a low magnification image of the sample integrated circuit die, the navigation window enabling selection of a slice of the sample integrated circuit die, the slice defining regions of interest of the corresponding image mosaic, each region of interest being displayed arbitrarily in one of the plurality of mosaic windows.

6. A human-machine interface according to claim 5, characterised in that the navigation window further comprises associated slice generation means for generating slices to define regions of interest of the image mosaic.

7. A human-computer interface as claimed in claim 6, wherein the slice generation tool generates a plurality of mosaic windows after the slice is generated.

8. A human-computer interface according to any one of claims 1-4, characterised in that the system pointer has a first different shape and size.

9. A human-computer interface as claimed in claim 8, wherein the main cursor has a second different shape and size.

10. A human-machine interface according to claim 9, characterised in that said lock step cursor has a third different shape and size.

11. A method of analyzing image mosaics, the image mosaics being scaled and aligned with a sample coordinate space defined for the image mosaics during acquisition of the image, the method comprising the steps of:

a) displaying a region of interest of a respective image mosaic of the plurality of image mosaics within a respective mosaic window of the decomposed integrated circuit, the respective mosaic window being displayed in a display coordinate space of a human-machine interface used to analyze the image mosaic;

b) a master cursor in one mosaic window and a lockstep cursor in the other mosaic window are used to track features of the integrated circuit across at least two mosaic windows, whereby the master cursor controls cursor events and the lockstep cursor is displayed within the other mosaic window at a relative position of the master cursor with respect to the sample coordinate space, provided that the relative position is within the corresponding display coordinate space of the corresponding other mosaic window.

12. The method of claim 11, further comprising the step of defining the region of interest by defining coordinates on the sample coordinate space using a slice generation tool.

13. The method of claim 12, further comprising the step of generating a slice by dragging a system pointer along a diagonal path to define a rectangular area of interest on a low resolution die photograph of the integrated circuit sample.

14. The method of claim 13, further comprising the step of selecting an image mosaic to be displayed in a mosaic window of the region of interest after the slice is generated.

15. The method of claim 14, further comprising the step of selecting an image mosaic to be displayed in a mosaic window of the region of interest from a list of all image mosaics associated with the slice.

16. A method according to any one of claims 11-15, characterized by: when the primary cursor is moved from one of the mosaics, the primary cursor becomes a system pointer on the display surface of the human-machine interface, and the lock-step cursor is erased from each of the other mosaic windows.

17. An apparatus for analyzing image-mosaics, the image-mosaics being scaled and aligned with a sample coordinate space defined for the image-mosaics during acquisition of an image, the apparatus comprising:

a) a workstation having a display area defining a display coordinate space;

b) a pointing device that controls a system pointer movable within the display coordinate space;

c) a memory for storing a plurality of mosaic windows of a decomposed integrated circuit, the mosaic windows having corresponding window boundaries when displayed in the display coordinate space, each mosaic window displaying at least a portion of an image mosaic; and

d) means for displaying a lock-step cursor within each mosaic window, the lock-step cursor sharing positional coordinates relative to the sample coordinate space;

thus, when the system pointer is moved across the window boundary to one of the plurality of mosaic windows by operating the pointing device, the system pointer is displayed as the main cursor for controlling the cursor event and the lock-step cursor is displayed in the other mosaic windows at the relative position of the main cursor with respect to the sample coordinate space, as long as the relative position is in the corresponding display coordinate space of the corresponding one of the other mosaic windows.

18. The apparatus of claim 17, wherein the means for displaying the lock step cursor is event driven.

19. The apparatus of claim 18, wherein upon detecting a cursor event indicating cursor movement, the display apparatus converts coordinates of the system pointer in the display coordinate space to coordinates in the sample coordinate space and performs an iterative process to send the coordinates in the sample coordinate space to each of the other mosaic windows if the coordinates of the system pointer in the display coordinate space are in one of the mosaic windows.