Coarse Grid Design Methods and Structures
A layer of a mask material is deposited on a substrate. A beam of energy is scanned across the mask material in a rasterized linear pattern and in accordance with a scan pitch that is based on a pitch of conductive structure segments to be formed on the substrate. The beam of energy is defined to transform the mask material upon which the beam of energy is incident into a removable state. During scanning the beam of energy across the mask material, the beam of energy is turned on at locations where a conductive structure is to be formed on the substrate, and the beam of energy is turned off at locations where a conductive structure is not to be formed on the substrate.
This application is a continuation application under 35 U.S.C. 120 of prior U.S. application Ser. No. 15/150,152, filed May 9, 2016, and issued as U.S. Pat. No. 9,917,056, on Mar. 13, 2018, which is a continuation application under 35 U.S.C. 120 of prior U.S. application Ser. No. 14/187,088, filed Feb. 21, 2014, and issued as U.S. Pat. No. 9,336,344, on May 10, 2016, which is a continuation application under 35 U.S.C. 120 of prior U.S. application Ser. No. 13/473,439, filed May 16, 2012, and issued as U.S. Pat. No. 8,658,542, on Feb. 25, 2014, which:
1) claims priority under 35 U.S.C. 119(e) to U.S. Provisional Patent Application No. 61/487,247, filed May 17, 2011, and
2) is also a continuation-in-part application under 35 U.S.C. 120 of prior U.S. application Ser. No. 12/572,022, filed Oct. 1, 2009, issued as U.S. Pat. No. 8,253,173, on Aug. 28, 2012, which is a continuation application under 35 U.S.C. 120 of prior U.S. application Ser. No. 12/212,562, filed Sep. 17, 2008, issued as U.S. Pat. No. 7,842,975, on Nov. 30, 2010, which is a continuation application under 35 U.S.C. 120 of prior U.S. application Ser. No. 11/683,402, filed Mar. 7, 2007, issued as U.S. Pat. No. 7,446,352, on Nov. 4, 2008, which claims priority under 35 U.S.C. 119(e) to U.S. Provisional Patent Application No. 60/781,288, filed Mar. 9, 2006, and
3) is also a continuation-in-part application under 35 U.S.C. 120 of prior U.S. application Ser. No. 13/073,994, filed Mar. 28, 2011, issued as U.S. Pat. No. 8,356,268, on Jan. 15, 2013, which is a continuation application under 35 U.S.C. 120 of prior U.S. application Ser. No. 12/013,342, filed Jan. 11, 2008, issued as U.S. Pat. No. 7,917,879, on Mar. 29, 2011, which claims priority under 35 U.S.C. 119(e) to each of A) U.S. Provisional Patent Application No. 60/963,364, filed Aug. 2, 2007, and B) U.S. Provisional Patent Application No. 60/972,394, filed Sep. 14, 2007, and
4) is also a continuation-in-part application under 35 U.S.C. 120 of prior U.S. application Ser. No. 12/753,795, filed Apr. 2, 2010, issued as U.S. Pat. No. 8,258,581, on Sep. 4, 2012, which is a continuation application under 35 U.S.C. 120 of prior U.S. application Ser. No. 12/402,465, filed Mar. 11, 2009, issued as U.S. Pat. No. 7,956,421, on Jun. 7, 2011, which claims priority under 35 U.S.C. 119(e) to each of A) U.S. Provisional Patent Application No. 61/036,460, filed Mar. 13, 2008, and B) U.S. Provisional Patent Application No. 61/042,709, filed Apr. 4, 2008, and C) U.S. Provisional Patent Application No. 61/045,953, filed Apr. 17, 2008, and D) U.S. Provisional Patent Application No. 61/050,136, filed May 2, 2008.
Each of the above-identified patent applications and patents is incorporated herein by reference in its entirety.
BACKGROUNDUntil recently, integrated circuit (IC) scaling has been enabled to a large extent by improvements in photolithography equipment resolution and overlay. The resolution capability of the photolithography equipment was such that random logical functions could be drawn with two-dimensional (2D) bent shapes, with few restrictions on shape dimensions or relationships between shapes.
Traditional 2D designs have layout shape edges which can fall on a very fine grid, such as on a 1 nm (nanometer) grid, by way of example. A direct writing tool using a raster pattern needs to write along the finest grid on each design/pattern layer of an integrated circuit device (sometimes called a mask layer) in order to correctly place all edges of the layout shapes. Also, 2D layout patterns need to be written completely in two directions, resulting in a large amount of data for each layer to be written. It is within this context that the present invention arises.
SUMMARYIn one embodiment, a method is disclosed for fabricating an integrated circuit. The method includes depositing a layer of a mask material on a substrate. The method also includes scanning a beam of energy across the mask material in a rasterized linear pattern and in accordance with a scan pitch that is based on a pitch of conductive structure segments to be formed on the substrate. The beam of energy is defined to transform the mask material upon which the beam of energy is incident into a removable state. During scanning the beam of energy across the mask material, the beam of energy is turned on at locations where a conductive structure is to be formed on the substrate, and the beam of energy is turned off at locations where a conductive structure is not to be formed on the substrate.
In one embodiment, a method is disclosed for fabricating an integrated circuit. The method includes depositing a layer of a mask material on a substrate. The method also includes scanning a beam of energy across the mask material in a rasterized linear pattern and in accordance with a scan pitch that is equal to at least a width of the beam of energy as measured in a direction perpendicular to a scan direction of the beam of energy. The beam of energy is defined to transform the mask material upon which the beam of energy is incident into a removable state. During scanning the beam of energy across the mask material, the beam of energy is turned on at locations where a conductive structure is to be formed on the substrate, and the beam of energy is turned off at locations where a conductive structure is not to be formed on the substrate.
Other aspects and advantages of the invention will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the present invention.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without some or all of these specific details. In other instances, well known process operations have not been described in detail in order not to unnecessarily obscure the present invention.
As optical lithography has reached a cost-driven limit of the 193 nm ArF excimer laser light source and a lens numerical aperture of 0.93 (or 1.35 for water immersion systems), other approaches are required for fabrication of smaller IC feature sizes. One approach is spacer double patterning (SDP), in which the layout pattern is split into two parts, each of which can be processed with optical lithography equipment. With spacer double/triple/quadruple/etc. patterning, pitch division can extend line patterns to smaller and smaller feature sizes until some other limit is reached. The SDP approach uses the following sequence to reduce the pattern pitch by a factor of two:
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- 1. standard optical lithography to pattern a “core”
- 2. etch the core and remove the resist
- 3. deposit a different material which can be etched selectively relative to the core
- 4. etch the deposited film, leaving sidewall material and the core
- 5. etch the core, leaving only the sidewall material
- 6. cut the sidewall material to create separate parts
- 7. etch the underlying material using the sidewall material as the mask
- 8. remove the sidewall material, leaving the underlying material with the desired pattern.
A method of chip design and fabrication is described herein which uses a coarse grid layout. The coarse grid methods described herein may be implemented with or without the multiple patterning approach discussed above. In the coarse grid method, lines, cuts, and holes are positioned on the coarse grid. The coarse grid has a granularity set by the requirements of a particular IC layer. Structures to be fabricated on a semiconductor wafer are specified by lines, cuts, holes, or any combination thereof, on a coarse grid. In one example embodiment, the layout pattern of the structures to be fabricated can include one-dimensional (1D) lines and cuts and holes, as needed. In another example embodiment, the layout pattern of the structures to be fabricated can include 1D line segments and holes, as needed. In another example embodiment, the layout pattern of the structures to be fabricated can be 1D and 2D coarse-grid line segments and holes, as needed. The coarse grid applied to cuts and holes is also extendable. With electron beams, a feature size limit is on the order of less than 10 nm.
For example, since there are both diffusion and gate contacts (711-715, 721-725) to be formed, the X pitch (CPX) of the contact scan is one-half of the gate pitch (P) as shown in
As shown in
The example scan pattern shown in
As shown in
For horizontal scanning in the X direction (perpendicular to the gate lines 1101-1108), the diffusion/active regions 1121, 1123, 1125, 1127 can be divided into strips which each have a width as measured in the Y direction that is a fraction of the Metal-1 pitch (M1P). For example, in some embodiments, the strips into which the diffusion/active regions 1121, 1123, 1125, 1127 are divided have a width as measured in the Y direction that is either one-fourth (¼) or one-eighth (⅛) of the Metal-1 pitch (M1P). For vertical scanning in the Y direction (parallel to the gate lines 1101-1108) the horizontal edge placement of the diffusion/active regions 1121, 1123, 1125, 1127 depends on the timing accuracy of the beam switching (i.e., beam turning on or off depending on the type of photoresist used) and is not necessarily tied to a fraction of the Metal-1 pitch, such as discussed above with regard to the example scan pattern of
The example scan pattern shown in
In one embodiment, a scan beam cross-section 1231 size as measured in the X direction is substantially equal to one-half (½) of the gate pitch (P) of the gate lines 801-808 plus some small extension (e.g., 1 nm to 5 nm, by way of example) to account for overlay as the beam is scanned vertically in the Y direction. As shown in
It should be appreciated that the scan pitch (DSP2), i.e., raster size, which is substantially equal to one-half (½) of the gate pitch (P) is very coarse as compared to a 1 nm or finer scan pitch that is required to draw/form conventional diffusion/active regions. It should also be appreciated that for vertical scanning in the Y direction (parallel to the length direction of the gate lines 1101-1108), the edge placement of the diffusion/active regions 1121, 1123, 1125, 1127 depends on the timing accuracy of the beam switching (i.e., beam turning on or off depending on the type of photoresist used) and is not necessarily tied to a fraction of the Metal-1 pitch, such as discussed above with regard to the example scan pattern of
The example scan pattern shown in
As shown in
It should be appreciated that the scan pitch (SP2), i.e., raster size, of one-half (½) of the Metal-1 pitch (M1P) (e.g., SP2=35 nm for 22 nm CMOS node) is still relatively coarse as compared to a 1 nm or finer scan pitch that is required to draw/form conventional gate lines. It should also be appreciated that while the scan pitch (SP2) is not as large, i.e., coarse, as the scan pitch shown in the examples of
The example scan pattern shown in
As shown in
In one embodiment, the line-width of the conductive line segment 1511 as measured in the Y direction is determined by the beam cross-section size as measured in the Y direction. In this embodiment, the line-width of the conductive line segment 1511 as measured in the Y direction is substantially equal to one-half (½) of the Metal-1 pitch (M1P), since the line-width of the conductive line segment 1511 is defined by the width of the beam as measured in the Y direction, as opposed to the temporal accuracy of the beam switching. However, in this embodiment, it should be understood that the beam switching has a sufficient temporal resolution to allow for writing/creating the portions of the gate lines 1501-1508 of different widths W1, W2, the end gaps 1651, 1652, and the perpendicularly oriented (in the X direction) conductive line segment 1511.
It should be appreciated that the scan pitch (SP2), i.e., raster size, of one-half (½) of the Metal-1 pitch (M1P) (e.g., SP2=35 nm for 22 nm CMOS node) is still relatively coarse as compared to a 1 nm or finer scan pitch that is required to draw/form conventional gate lines. It should also be appreciated that while the scan pitch (SP2) is not as large, i.e., coarse, as the scan pitch shown in the examples of
The Dynamic Array Architecture developed by Tela Innovations, Inc., is described in part in U.S. Pat. No. 7,446,352, entitled “Dynamic Array Architecture,” and in part in U.S. Pat. No. 7,917,879, entitled “Semiconductor Device with Dynamic Array Section,” each of which is incorporated herein by reference in its entirety. Use of the Dynamic Array Architecture implemented with “lines” and “cuts,” as discussed herein, can force all features onto a “coarse grid.” For example, all gate electrode cuts can be on a gate pitch, so a beam writer (laser or electron) would only need to make one pass along the direction of a gate line to write the cuts. Since the gate pitch is about 80 nm for the 22 nm CMOS node, an improvement in write time by a factor of 80 or more can be realized as compared to a 1 nm grid. Further improvements in write time can be achieved with parallel or multiple beams. Also, worse-case layers like the diffusion/active layer could be designed with granular widths and locations such that it could be written with a relatively coarse grid. For example, using a grid of one-eighth (⅛) of the Metal-1 pitch would allow writing the pattern about 10 times faster than with a 1 nm fine grid. Also, “hole” patterns such as contact and via-N can be placed on a coarse grid layout within the Dynamic Array Architecture.
It should be further appreciated that the coarse grid methods described herein are scalable through use of multiple patterning. For example, lines can be created using “Spacer Double Patterning” once or multiple times to achieve pitch division by 2 (PD2), 4 (PD4), 8 (PD8), etc., and achieve line pitches of 30 nm and below. In one example, at the 22 nm CMOS technology node, the Metal-1 pitch is about 70 nm, with a Metal-1 width of about 36 nm and a Metal-1 -to-Metal-1 spacing of about 34 nm. This Metal-1 pitch and sizing cannot be directly patterned with 193 immersion lithography, but can be patterned using PD2 spacer double patterning.
In one embodiment, a relaxed version the Dynamic Array Architecture can be implemented in which all lines and holes are written with a coarse beam which makes two passes per pitch. This will allow the beam to write lines or cuts in either the normal line channel or the normal space channel. This embodiment may cause a reduction in throughput, but may be useful for special layout cases.
As mentioned above, the invention described herein can use the Tela Innovations, Inc., Dynamic Array Architecture (i.e., gridded design style). However, it should be understood that the invention is not limited to the Dynamic Array Architecture design style. Also, while CMOS transistors may be formed in accordance with the examples described herein, it should be understood that other components can be formed in an analogous fashion. It should also be noted that the Dynamic Array Architecture can be implemented with a coarse grid in the X and Y directions to facilitate identification of the locations of objects like transistors, contacts, and gaps in lines, i.e., linear conductive structures. The linear conductive structures can be positioned on and/or according to the grids.
In one embodiment, the scan pitch is equal to and aligned with the pitch of conductive structure segments to be formed on the substrate. In one instance of this embodiment, the conductive structure segments to be formed on the substrate are gate level conductive structure segments. Also, some of the gate level conductive structure segments form one or more transistor gate electrodes.
In one embodiment, the scan pitch is one-half of a gate electrode pitch, and the scan pitch is aligned with the gate electrode pitch. In one instance of this embodiment, the conductive structure segments to be formed on the substrate are contact structures. The contact structures can include at least one gate contact and at least one diffusion contact.
In one embodiment, the scan pitch is equal to and aligned with an interconnect level conductive structure pitch. In one instance of this embodiment, the conductive structure segments to be formed on the substrate are interconnect level conductive structures. In another instance of this embodiment, the conductive structure segments to be formed on the substrate are via structures.
In one embodiment, the beam of energy is turned on as the beam of energy is scanned perpendicularly across locations corresponding to a pitch of conductive structure segments to be formed on the substrate. The method can also include an operation for controlling a time period during which the beam of energy is turned on at each location corresponding to the pitch of conductive structure segments to be formed on the substrate, so as to control a width of the conductive structure segments to be formed on the substrate. Also, the method can include an operation for turning the beam of energy on between one or more locations corresponding to the pitch of conductive structure segments to be formed on the substrate, so as to transform the mask material between the one or more locations to provide for formation of a conductive structure that extends between the one or more locations.
It should be understood that in one embodiment the invention described herein can be embodied as computer readable code on a computer readable medium. For example, the computer readable code can include computer executable program instructions for operating the energy beam scanner. The computer readable medium mentioned herein is any data storage device that can store data which can thereafter be read by a computer system. Examples of the computer readable medium include hard drives, network attached storage (NAS), read-only memory, random-access memory, CD-ROMs, CD-Rs, CD-RWs, magnetic tapes, and other optical and non-optical data storage devices. The computer readable medium can also be distributed over a network of coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.
Any of the operations described herein that form part of the invention are useful machine operations. The invention also relates to a device or an apparatus for performing these operations. The apparatus may be specially constructed for the required purpose, such as a special purpose computer. When defined as a special purpose computer, the computer can also perform other processing, program execution or routines that are not part of the special purpose, while still being capable of operating for the special purpose. Alternatively, the operations may be processed by a general purpose computer selectively activated or configured by one or more computer programs stored in the computer memory, cache, or obtained over a network. When data is obtained over a network the data maybe processed by other computers on the network, e.g., a cloud of computing resources.
The embodiments of the present invention can also be defined as a machine that transforms data from one state to another state. The data may represent an article, that can be represented as an electronic signal and electronically manipulate data. The transformed data can, in some cases, be visually depicted on a display, representing the physical object that results from the transformation of data. The transformed data can be saved to storage generally, or in particular formats that enable the construction or depiction of a physical and tangible object. In some embodiments, the manipulation can be performed by a processor. In such an example, the processor thus transforms the data from one thing to another. Still further, the methods can be processed by one or more machines or processors that can be connected over a network. Each machine can transform data from one state or thing to another, and can also process data, save data to storage, transmit data over a network, display the result, or communicate the result to another machine.
It should be further understood that the methods disclosed herein can be used to manufacture part of a semiconductor device or chip. In the fabrication of semiconductor devices such as integrated circuits, memory cells, and the like, a series of manufacturing operations are performed to define features on a semiconductor wafer, i.e., substrate. The wafer includes integrated circuit devices in the form of multi-level structures defined on a silicon substrate. At a substrate level, transistor devices with diffusion regions are formed. In subsequent levels, interconnect metallization lines are patterned and electrically connected to the transistor devices to define a desired integrated circuit device. Also, patterned conductive layers are insulated from other conductive layers by dielectric materials.
While this invention has been described in terms of several embodiments, it will be appreciated that those skilled in the art upon reading the preceding specifications and studying the drawings will realize various alterations, additions, permutations and equivalents thereof. Therefore, it is intended that the present invention includes all such alterations, additions, permutations, and equivalents as fall within the true spirit and scope of the invention.
Claims
1. A semiconductor device, comprising:
- a first gate line formed to extend lengthwise in a first direction, the first gate line having a first width measured in a second direction perpendicular to the first direction;
- a second gate line formed to extend lengthwise in the first direction, the second gate line having a second width measured in the second direction perpendicular to the first direction, the second width different than the first width; and
- a third gate line formed to extend lengthwise in the first direction, the third gate line having a third width measured in the second direction perpendicular to the first direction, the third width substantially equal to the first width,
- wherein the second gate line is positioned between the first gate line and the third gate line, wherein the second gate line is separated from the first gate line by a first separation distance as measured in the second direction, and wherein the second gate line is separated from the third gate line by a second separation distance as measured in the second direction, wherein the second separation distance is substantially equal to the first separation distance.
2. The semiconductor device as recited in claim 1, wherein the first gate line has a first overall length as measured in the first direction, wherein the second gate line has a second overall length as measured in the first direction, wherein the second overall length is less than the first overall length.
3. The semiconductor device as recited in claim 2, wherein the second overall length is less than one-half of the first overall length.
4. The semiconductor device as recited in claim 2, wherein the third gate line has a third overall length as measured in the first direction, wherein the third overall length is less than the second overall length.
5. The semiconductor device as recited in claim 4, wherein a difference between the third overall length and the second overall length is at least as large as a metal-1 pitch.
6. The semiconductor device as recited in claim 2, further comprising:
- a fourth gate line formed to extend lengthwise in the first direction, the fourth gate line having a fourth width measured in the second direction perpendicular to the first direction, the fourth width substantially equal to the first width, wherein a lengthwise centerline of the fourth gate line is substantially aligned with a lengthwise centerline of the third gate line.
7. The semiconductor device as recited in claim 6, wherein a spacing between the third gate line and the fourth gate line as measured in the first direction is substantially equal to one-half of a metal-1 pitch.
8. The semiconductor device as recited in claim 6, wherein a first end of the second gate line is substantially aligned with a first end of the fourth gate line in the second direction.
9. The semiconductor device as recited in claim 6, further comprising:
- a fifth gate line formed to extend lengthwise in the second direction, the fifth gate line physically connected to the second gate line, the fifth gate line physically connected to the fourth gate line.
10. The semiconductor device as recited in claim 9, wherein the fifth gate line has a fifth width measured in the first direction perpendicular to the second direction, wherein the fifth width is substantially equal to a spacing between the third gate line and the fourth gate line as measured in the first direction.
11. The semiconductor device as recited in claim 10, wherein the fifth width is substantially equal to one-half of a metal-1 pitch.
12. The semiconductor device as recited in claim 10, wherein the fifth width is less than the fourth width.
13. The semiconductor device as recited in claim 9, wherein a first end of the fifth gate line is substantially aligned with a first side of the second gate line in the first direction.
14. The semiconductor device as recited in claim 13, wherein a first side of the fifth gate line is substantially aligned with a first end of the fourth gate line in the second direction.
15. The semiconductor device as recited in claim 9, further comprising:
- a sixth gate line formed to extend lengthwise in the first direction, the sixth gate line having a sixth width measured in the second direction perpendicular to the first direction, the sixth width substantially equal to the second width.
16. The semiconductor device as recited in claim 15, wherein a lengthwise centerline of the sixth gate line is substantially aligned with a lengthwise centerline of the second gate line.
17. The semiconductor device as recited in claim 16, wherein the sixth gate line is positioned between the first gate line and the fourth gate line.
18. The semiconductor device as recited in claim 17, wherein a spacing between the sixth gate line and the fifth gate line as measured in the first direction is substantially equal to one-half of a metal-1 pitch.
19. The semiconductor device as recited in claim 17, wherein the sixth gate line is separated from the first gate line by a third separation distance as measured in the second direction, wherein the sixth gate line is separated from the fourth gate line by a fourth separation distance as measured in the second direction, wherein the third separation distance is substantially equal to the first separation distance, wherein the fourth separation distance is substantially equal to the first separation distance.
20. The semiconductor device as recited in claim 19, further comprising:
- a seventh gate line formed to extend lengthwise in the first direction, the seventh gate line having a seventh width measured in the second direction perpendicular to the first direction, the seventh width less than the first width of the first gate line, the seventh gate line separated from the first gate line by a fifth separation distance as measured in the second direction, the fifth separation distance substantially equal to the first separation distance.
21. The semiconductor device as recited in claim 20, further comprising:
- an eighth gate line formed to extend lengthwise in the first direction, the eighth gate line having an eighth width measured in the second direction perpendicular to the first direction, the eighth width less than each of the third width of the third gate line and the fourth width of the fourth gate line, the eighth gate line separated from the third gate line by a sixth separation distance as measured in the second direction, the eighth gate line separated from the fourth gate line by the sixth separation distance as measured in the second direction, the sixth separation distance substantially equal to the first separation distance.
22. The semiconductor device as recited in claim 21, further comprising:
- a ninth gate line formed to extend lengthwise in the first direction, the ninth gate line having a ninth width measured in the second direction perpendicular to the first direction, the ninth width substantially equal to the eighth width of the eighth gate line, the ninth gate line separated from the eighth gate line by a seventh separation distance as measured in the second direction, the seventh separation distance substantially equal to the first separation distance.
Type: Application
Filed: Mar 13, 2018
Publication Date: Jul 19, 2018
Inventors: Michael C. Smayling (Fremont, CA), Scott T. Becker (Scotts Valley, CA)
Application Number: 15/919,884