US20070288116A1

US20070288116A1 - Method, system and medium for controlling semiconductor wafer processes using critical dimension measurements

Info

Publication number: US20070288116A1
Application number: US11/736,350
Authority: US
Inventors: Amir Al-Bayati; Babak Adibi; Majeed Foad; Sasson Somekh
Original assignee: Individual
Current assignee: Applied Materials Inc
Priority date: 2002-03-19
Filing date: 2007-04-17
Publication date: 2007-12-13
Also published as: KR20040093168A; US20030180972A1; US7225047B2; AU2003218285A1; KR101018618B1; WO2003081513A1

Abstract

Methods, systems, and mediums of controlling a semiconductor manufacturing process are described. The method comprises the steps of measuring at least one critical dimension of at least one device being fabricated on at least one of the plurality of wafers, determining at least one process parameter value on the at least one measured dimension, and controlling at least one semiconductor manufacturing tool to process the at least one of the plurality of wafers based on the at least one parameter value. A variation in the at least one critical dimension causes undesirable variations in performance of the at least one device, and at least one process condition is directed to controlling the processing performed on the plurality of wafers. The at least one manufacturing tool includes at least one of an implanter tool and an annealing tool.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of co-pending U.S. patent application Ser. No. 10/100,184 (APPM/006331), filed Mar. 19, 2002, which is herein incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to methods, systems and mediums for controlling processes for manufacturing micro-electronic devices based on, in part, one or more measurements made on one or more critical dimensions such as gate lengths of devices. In particular, the measured critical dimensions can be used in determining parameter values in, for example, feed-forward and/or feed-back controlling mechanisms to reduce variations on the critical dimensions.

BACKGROUND OF THE INVENTION

FIG. 1 illustrates a conventional semiconductor process module 101 that performs one or more processes for fabricating micro-electronic devices on a batch of wafers. Such a conventional process module includes a set of processing tools (e.g., an implanter tool 1 105, an implanter tool 2 107 and an annealing tool 109) and a controller for each tool 111, 112, 113. The conventional controllers 111, 112, 113 are configured to operate/control their respective processing tools using baseline parameter values (e.g., process conditions). The baseline parameter values define, for example, implant (e.g., a doping level) and anneal (e.g., a peak temperature) conditions for the implanter tools and annealing tool, respectively. However, in the conventional process module 101, the baseline parameter values are not adjusted for processing one wafer to another wafer. In other words, the conventional controllers 111, 112, 113, once they begin to use a certain set of baseline parameter values, apply the same baseline parameter values to all wafers in a batch. The baseline parameter values cannot be adjusted even when undesirable variations are detected. These variations can be caused by a previous processing step or by any of the tool 105, 107, 109.
These undesirable variations are unacceptable due to ever increasing demands on fabricated micro-electronic devices associated with ultra large scale integration that require increased transistor and circuit speed, density and improved reliability. In particular, these demands require formation of device features with high precision and uniformity, which in turn necessitates careful process monitoring and detailed inspection of the devices while they are still being processed in the form of semiconductor wafers. Indeed, the conventional process module 101 is incapable of processing devices with such high precision and uniformity because it cannot reduce the undesirable variations. This results in a device yield rate that is less than optimal.

SUMMARY OF THE INVENTION

Embodiments of the present invention advantageously overcome the above described shortcomings of conventional processing modules. In particular, embodiments of the present invention provide systems, methods and mediums for controlling processes for fabricating micro-electronic devices using critical dimension measurements. For instance, at least some embodiments of the present invention include a method of processing a number of wafers for manufacturing semiconductor devices. The method comprises the steps of measuring at least one dimension (e.g., gate length) of at least one of the devices being fabricated on at least one of the wafers and determining control parameter values (also referred to as process conditions) based on the at least one measured dimension. (It should be noted a control parameter value and a parameter value are used interchangeably in describing embodiments of the present invention.) The method may also include the step of controlling at least one semiconductor manufacturing tool to process the at least one of the wafers based on the parameter values (e.g., in a feed-forward/feed-back manner). The at least one processing tool can include at least one implanter tool.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description of the present application showing various distinctive features may be best understood when the detailed description is read in reference to the appended drawings in which:
FIG. 1 is a drawing illustrating a conventional controller and processing tools;
FIG. 2 is a graph illustrating relationships between variations of gate lengths of devices and percent in deviation of performance of produced devices;
FIGS. 3A and 3B are block diagrams showing first example embodiments of the present invention;
FIG. 4 is a schematic drawing illustrating an under etch condition and corrections thereof as contemplated by at least some embodiments of the present invention;
FIG. 5 is a block diagram/flowchart illustrating relationships between a module controller and a module/tool monitor as contemplated by at least some embodiments of the present invention;
FIG. 6 is a flowchart illustrating example steps performed by the first example embodiment of the present invention;
FIG. 7 is a block diagram illustrating a second example embodiment of the present invention;
FIG. 8 is a flowchart illustrating example steps performed by the second example embodiment of the present invention;
FIG. 9 is a block diagram illustrating a third example embodiment of the present invention;
FIGS. 10 a and 10 b are flowcharts illustrating example steps performed by the third example embodiment of the present invention;
FIG. 11 is a table illustrating improvements introduced by the corrections of the present invention;
FIG. 12 is a graph illustrating changes introduced by a compensated SDE dosage;
FIG. 13 is a block diagram representation of an example embodiment of a module controller; and
FIG. 14 illustrates one example of a memory medium which may be used for storing computer programs of the module controller of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENT INVENTION

To alleviate the shortcomings of the conventional technology, in at least some embodiments of the present invention, the undesirable variations mentioned above can be compensated for by first measuring a critical dimension of a device being processed. A critical dimension (CD) is a dimension of a particular location of a device (e.g., a gate length). Variations in the CD may cause undesirable performance variations on the device. If such variations in a CD are detected, a subsequent processing tool(s) may be adjusted such that the undesirable variation is alleviated. This is done by generating one or more parameter values based upon the amount of the variation. The parameter values are then used by the processing tool(s) to make the appropriate adjustment.
Examples of performance variations are depicted in FIG. 2, which shows a graph 201 illustrating deviations in device performances caused by variations in CDs of devices. More specifically, FIG. 2 illustrates deviations in a number of parameters that measure performances of produced micro-electronic devices (e.g., microprocessors) having a target for the CD as 130 nm. The parameters include: d Tau, d I_off, d I_DSATand d V_T(“d” represents change/deviation). The value of d Tau is deviation in gate delay time, which is defined as C*V_dd/I_DSAT(C: capacitance; V_dd: drain voltage; and I_DSATsaturation current), the value of d I_offis deviation in leakage current; the value of d I_DSATis deviation in saturation drive current; and the value of d V_Tis deviation in threshold voltage. As illustrated in FIG. 2, variations in the CD have a significant impact on device performances. A 10 nm variation (from 130 nm to 140 nm) in the CD is shown as resulting in about a 16% variation in Tau and more than a 30% variation in leakage current (I_off). Both Tau and I_offare critical as they affect device speed and battery life, respectively.
As noted above, the conventional processing modules and their process tools are incapable of correcting undesirable variations because, in part, they are not configured to measure CDs and/or use the CD measurements generating/adjusting parameter values.
At least some embodiments of the present invention are shown in FIGS. 3A-B, 7 and 9. More specifically, in FIG. 3A-B, an example module controller 305 that receives CD measurements of one or more devices on a wafer and generates parameter values based thereon is illustrated. In FIG. 7, another example module controller 705 is illustrated wherein the module controller 705 receives CD and junction depth measurements and generates parameter values based thereon. FIG. 9 illustrates yet another example module controller 905, wherein the module controller 905 includes metrology tools for checking dosages. These embodiments are provided only as examples, and various individual components, devices and/or tools of one embodiment can be omitted, added to, and/or combined with other embodiments. Detailed descriptions of these embodiments and other aspects of the present invention are provided below.
Referring to FIG. 3A, this figure illustrates an example embodiment process module 301 of the present invention in which critical dimension (CD) measurements are made and the measured CD values are used in controlling one or more processing tools by generating/adjusting parameter values. The example embodiment of FIG. 3A also includes a metrology tool 303, a module controller 305, a tool monitor 313 and a process tool 308. FIG. 3B illustrates a somewhat more specific example embodiment depicting similar concepts. More specifically, the example embodiment depicted in FIG. 3B further includes processing tools 307, 309, 311.
Now referring both to FIG. 3A and FIG. 3B, the metrology tool 303 is configured to measure CDs of one or more devices being fabricated on wafers. In at least some embodiments of the present invention, a CD is, for example, gate lengths of devices. In at least some embodiment of the present invention, CDs of devices on all dies of a wafer are measured. The average of the measured CDs is calculated and then communicated to the module controller 305. In at least some other embodiments, CD measurements are made on a sub-set of dies and their average is calculated and communicated to the module controller 305. In particular, the sub-set of dies can be a line of dies on a wafer (e.g., a horizontal line, a vertical line or a line of any orientation), a portion of dies on a wafer (e.g., an upper half or an upper left quadrant), any random combination of dies or any one die. Furthermore, it should be understood that gate length is a CD often mentioned herein only by way of example, and that embodiments of the present invention contemplate that a CD can also be any facet or dimension on a device that may cause performance variations in produced devices when it varies from a target by a certain amount.
The set of process tools in FIG. 3B, for example, can include one or any combination of processing tools such as an implanter tool 1 307, an implanter tool 2 309 and an annealing tool 311. It should also be noted that the tool 308 of FIG. 3A can be any one of an implanter tool or an annealing tool. In other words, the number of processing tools and their types are not limited to only having, for example, two implanter tools and one annealing tool as shown in FIG. 3B. It should also be noted that the various combinations of implanter and annealing tools do not necessarily represent all the tools that may be required to process a wafer. Other tools that can be included are, for example, photolithography tools, etchers, cleaners, etc. The implanter and annealing tools are illustrated as example tools that can be controlled by the module controller 305. The process tools, regardless which one of the above-described embodiments is used, are configured to provide various implant process(es), anneal process(es) and/or other process(es) by the module controller 305 and tool monitor 313. In addition, at least some embodiments of the present invention contemplate that the tool monitor 313 would be unnecessary, and that, e.g., at least some of the functions provided by the tool monitor 313 can be controlled by the module controller 305 and/or a processing tool, itself.
Embodiments of the present invention can be configured to include any type of implanter tools and annealing tools that can be controlled by using, in part, parameters and specific values thereof. For example, embodiments of the present invention can include any implant and annealing tools such as single wafer and batch tools that include: low energy, high current, medium current, high energy implanters, batch furnace, single RTP annealers, beamline and/or plasma based doping tools.
In the example embodiment shown in FIG. 3B, the implanter tool 1 307 is configured to perform source drain contracts and SDE implants. The implanter tool 2 309 is configured to perform halo/V_T/Well implants. The implanter tools 1 and 2 can be Quantum™ and Swift™, respectively, both of which are manufactured by Applied Materials, Inc. of Santa Clara, Calif. An example the annealing tool 311 is Radiance™, manufactured by Applied Materials, Inc. of Santa Clara, Calif. These process tools are provided herein only as examples. Other types of implanter and annealing tools that can thus also be used in embodiments of the present invention. It should be noted that, in addition to the module controller 305, each processing tool may be coupled to a tool controller 502 (shown in FIG. 5) configured to control its respective process control and set-up based on information (e.g., process conditions) received from the module controller 305.
As noted above regarding FIG. 3B, the process tools (e.g., the implanter tools 1 and 2 and the annealing tool) and their tool controllers are coupled to the module controller 305. In this example embodiment, the module controller 305 is configured to operate/control the implanter tools 1 and 2 and the annealing tool 311 using parameter values. In particular, based on CD measurements, the module controller 305 determines appropriate values for parameter values. Examples of parameters (for which values can be obtained) include a halo angle, a dose and energy level, a Source-Drain-Extension (SDE) dose level, an energy and tilt level, a pocket implant dose level, a channel and channel V_Tadjust implant dose level, an energy and tilt level, a Rapid Thermal Processing (RTP) peak temperature level, and/or anneal time length.
In order to provide the context in which the parameter values may be determined, an example of CD measurements is illustrated. In this example, the critical dimension is measured by the metrology tool 303. The measured CD can be different from a target CD (thus, possibly indicating the existence of an undesirable variation). For instance, as graphically shown in FIG. 4, a device may have been erroneously processed such that a measured CD (in this example, gate length) 403 is wider than a target 401, which may have been caused by a photoresist layer 405 that has been underetched in a previous processing step. The wider gate length 403 in turn can introduce undesirable variation into other aspects of devices such as effective channel length (e.g., it may cause a wider effective channel length 412). For example, had the gate length met the target gate length 401, the effective channel length would have met a target effective channel length 411. However, due to the wider gate length 403, the measured effective channel length is wider than the target effective channel length. When only baseline parameter values are used as in the conventional process module in FIG. 1, this undesirable variation cannot be compensated for. However, embodiments of the present invention can compensate for this undesirable variation by determining parameter values (based on the gate length) and using them to modify the operation of one or more processing tools to form final effective channel length to be substantially identical/similar to the target effective channel length.

Before explaining how the parameter values are obtained and used, the step of creating parameter values as contemplated by at least some embodiments of the present invention is first described. In at least one example embodiment, the module controller 305 includes a technique for determining parameter values based on measured CD values. The parameter values can then be stored in an active channel control lookup table (LUT). The parameter values for the LUT are created, for example, by using a computer implemented simulation package (e.g., T CAD, manufactured by Integrated System Engineering, ISE, of Switzerland). In particular, the simulation package can be configured to generate (e.g., calculate) values of parameters for a particular CD measurement. In other words, in this example embodiment, the simulation package is configured to generate values of parameters (e.g., SDE, halo and RTP process conditions) for a particular gate length measurement in order to compensate for any CD variations (e.g., an over or under etching. In this way, an array of values of SDE, halo and RTP conditions are created for a series of gate lengths at a predetermined interval (e.g., every 0.1 nm, 1 nm or multiple nms of gate lengths). The array of parameter values along with their corresponding measured CD values is then collected into the LUT, which is then used to lookup a corresponding set of parameter values for any measured gate length. An example of the LUT is shown below in Table 1.

TABLE 1


Measured	SDE Implant	Halo Implant	Anneal (RTP)

Gate	Specie				Specie						Ramp
length CD	type		Dose		type		Dose	tilt	twist	Peak	up/cooldown
(nm)	(Boron)	E (keV)	(ion/cm{circumflex over ( )}2)	tilt/twist	(Arsenic)	E (keV)	(ion/cm{circumflex over ( )}2)	(degree)	(degree)	Temp (C.)	rate (C./sec)

70	B	0.4	1.00E+15	0.0	As	30	5.00E+13	22	0	1050	250/90
75	B	0.45	7.50E+14	0.0	As	30	5.00E+13	24	0	1050	250/90
80	B	0.45	1.00E+15	0.0	As	30	5.00E+13	26	0	1050	250/90
85	B	0.5	7.50E+14	0.0	As	30	5.00E+13	28	0	1050	250/90
90	B	0.5	1.00E+15	0.0	As	30	5.00E+13	30	0	1050	250/90
95	B	0.5	1.25E+15	0.0	As	30	5.00E+13	32	0	1050	250/90
100	B	0.55	1.00E+15	0.0	As	30	5.00E+13	34	0	1050	250/90
105	B	0.55	1.25E+15	0.0	As	30	5.00E+13	36	0	1050	250/90
110	B	0.6	1.00E+15	0.0	As	30	5.00E+13	38	0	1050	250/90

In the above table, “E (keV),” “Dose,” “tilt/twist,” “peak temperature” and “up/cooldown rate” are example parameters and the entries of the table are example parameter values.
In at least some embodiments of the present invention, the LUT created using the simulation package is refined based on empirical data collected by performing experiments. In such an example embodiment, a set of test wafers is fabricated to form devices having different average gate lengths. The test wafers are then put through the processes by the implanter tools 1 and 2 and annealing tool (e.g., the tools illustrated in FIG. 3B) using the parameter values of the LUT by the module controller for that particular measured CD. When the test wafers are processed, the results are collected and compared against predicted results by the simulation package. If the test wafers are processed to produce devices with the predicted results, then no adjustment on the parameter values is made to the LUT. If not, then the LUT entry is replaced or adjusted in accordance with the data collected during the experiments. These steps of comprising/replacing the entries of the LUT can be repeated until all the entries of the LUT are checked/adjusted.
In at least some embodiments of the present invention, a number of LUTs can be created, each of which may relate to device types and/or technology nodes. Device types can be microprocessors, memory chips, programmable ROMs, etc. A technology node can be a 100 nm node, a 130 nm node, a 180 nm node, etc. In at least some embodiments of the present invention, a LUT can also be created using only experimental data without using a computer simulation package.
In at least some embodiments of the present invention, instead of a LUT, one or more equations are derived to determine the parameter values for measured CDs. In yet other embodiments of the present invention, a graphical representation may be used in determining the parameter values for measured CDs. It should be noted that the present invention can use a LUT, one or more equations, one or more graphical representations, or other mechanisms for determining parameter values.
Now turning to describe the module controller 305 and tool monitor 313 in more detail, FIG. 5 is a block diagram illustrating some example operations of the module controller 305 and tool monitor 313. More specifically, the module controller 305 can be configured to include an active channel control LUT. Embodiments of the present invention contemplate that the module controller 305 can also (or alternatively) use an external LUT to receive or determine parameter values (step 501). In any of these example embodiments, and in accordance with the example of Table 1 (for purposes of discussion), the module controller 305 then uses the parameter values of “SDE implant” from the LUT to control the implanter tool 1 (step 503) and uses the parameter values of “halo implant” from the LUT to control the implanter tool 2 (step 505). The module controller 305 uses the parameter values of RTP from the LUT to control the annealing tool (step 507). As indicated previously, steps such as those can be used to compensate an undesirable variance within devices on a wafer caused by some previous process step (e.g., lithography, photoresist and/or etching process steps) performed by a previous manufacturing tool. Consequently, these mechanisms of controlling the process tools based on parameter values from the LUT are referred to as feed-forward control mechanisms.
While the process tools are being operated and/or controlled by the module controller 305, at least some embodiments of the present invention contemplate that the tool monitor 313 is configured to monitor activities of each process tool (step 509). The module controller 305 can also be configured to adjust parameter values and setups of the process tools based on the results of the monitoring step 509 by the tool monitor (step 511). Examples of setups of the process tools can be one or any combination of a beam-current, a vacuum pressure, tool pressure, tool temperature, etc.
In the above-described example embodiments, the feed-forward control mechanism of the module controller 305 uses three parameter values (i.e., SDE, halo and RTP conditions) to operate/control three process tools. As noted above, the SDE parameter is used to control the implanter tool 1, the halo parameter is used to control implanter 2, and the RTP parameter is used in controlling the annealing tool. In at least some embodiments of the present invention, not all parameter values may be required. In particular, in at least one example embodiment, only the SDE parameter may be determined by using the LUT and only implanter tool 1 is controlled by the feed-forward control mechanism. In such an embodiment, other tools (i.e., the implanter tool 2 and the annealing tool), if they are present at all, would not be controlled using feed-forward parameter values, but would be controlled by, for example, the conventional control mechanism as described above in connection with FIG. 1 (i.e., using only baseline parameter values). In another example embodiment, only the halo parameter may be determined for the implanter 2, or only the RTP parameter may be determined for the annealing tool. In addition, embodiments of the present invention contemplate that any combination of two process tools can also be controlled by their respective parameter values. Accordingly, the present invention is not limited by having to use any specific number of parameter values. In FIG. 3B, lines 312 from the module controller 305 to the process tools are dotted rather than solid in order to represent that one, two or three of the process tools can be controlled by the feed-forward control mechanism. This dotted-line representation is also applicable to subsequent example embodiments depicted in FIGS. 7 and 9. It should also be understood that the specific parameters and associated values corresponding to the particular types of tools mentioned (i.e., implanter tools and annealing tools) are also by way of example, and that any number of other types of appropriate parameters and corresponding values are also contemplated by at least some embodiments of the present invention.
Referring to the above-described example embodiments of FIG. 3B, using Table 1 to control each of the 3 tools mentioned therein, the module controller 305 of these embodiments are configured (in at least some embodiments of the present invention) to conduct steps shown in FIG. 6. The steps include receiving a wafer (step 601), measuring a critical dimension of one or more devices as described above (step 603), determining parameter values (step 605), and performing implant and anneal processes based on the results obtained by conducting the step of determining parameter values (step 607).
In the step of receiving a wafer (step 601), the wafer may be received from a batch of wafers, which are being fabricated to form a number of micro-electronic devices thereon.
In the step of measuring a critical dimension (CD) (step 603), a CD of a device, which can relate to a part of one or more micro-electronic devices, is measured. In at least some embodiments of the present invention, the CD can be the gate length of a selected device. In at least some other embodiments of the present invention, the CD can be an average of the gate lengths measured from many devices or test structures on the received wafer. The test structure can be a number of polysilicon lines fabricated on the wafers. The dimension of the test structure may be similar to those of devices fabricated on the wafers.
The measured CD is then received by the module controller 305, which performs the step of determining appropriate parameter values (step 605). As noted above in connection with FIG. 3, this step can be performed using a LUT, one or more equations, and/or graphical representations.
The module controller 305 then performs the step of operating/controlling the process tools (e.g., implanted tools 1 and 2 and/or the annealing tool) to process the received wafer using the determined parameter values. In other word, implant and anneal processes are performed based on the parameter values (step 607) such that undesirable variances may be compensated for. The processed wafer is then transported to a next process module (if any) to undergo further fabrication processes.
The results of such processing are graphically illustrated in FIG. 4. After processing by the process tools using the parameter (e.g., increased halo tilt 409), what might have been a wide effective channel length 412 is compensated to be closer to the target effective channel length 411.
FIG. 7 illustrates another example embodiment process module 701 of the present invention. At least some aspects of the example embodiments of FIG. 7 are similar to the example embodiments illustrated in FIG. 3 with respect to its example processing tools (e.g., implanter tools 1 707 and 2 709 and an annealing tool 711) and using a module controller 705. However, the example embodiments of FIG. 7 include a post-process metrology tool 715 and additional control mechanisms within its module controller 713.
The post process metrology tool 717 is configured to receive a wafer that has been processed by, for example, the processing tools 707, 709, 711 and to make a Measurement After the Process (MAP), a post process measurement, on the processed wafer. In at least some embodiments of the present invention, the MAP is made on, for example, junction depth of a test structure being fabricated on the processed wafer. The MAPs can be made on one or more test structures on the processed wafer. In embodiments that the MAP is performed on more than one test structure, the average of the MAPs can be used in a feedback process which is described in detail below.
FIG. 8 illustrates the steps performed by the example embodiments of FIG. 7 of the present invention. At least some aspects of the first four steps (e.g., the steps of receiving a wafer (step 801), measuring a CD (step 803), determining parameter values (step 805), and performing implant and anneal processes (step 807)) are similar to the corresponding steps described above in connection with FIG. 6 ( steps 601, 603, 605 and 607). After these steps, in the embodiments of FIG. 7, the post-processing metrology tool 715 makes a MAP (step 809). The module controller 705 may cause one of two different sets of steps be performed after the MAP is made, depending upon: (i) whether the MAP value is within a target range (determined in step 811); (ii) whether the MAP is within a correctable range, but it is outside of the target range (determined in step 815). An example of the target range of, e.g., junction depth, is 300±6 angstroms, and an example of the correctable range is ±30% of the target range. The information relating to the target ranges and correctable ranges is stored in a junction depth calibration database in the module controller 705. It should be noted that, in at least some embodiments of the present invention, the module controller can decide to instruct the metrology tool 717 not to make the MAP when the wafer is processed properly (e.g., the parameter values stayed within an acceptable range.).
When the MAP is within the target range, the processed wafer is considered to be correctly processed within an acceptable level of variation. The processed wafer is then transported to a next process module for subsequence processes, if any (step 813).
When the MAP is outside of the target range, for processing subsequent wafers, settings of the implanter and anneal tools are checked (step 829) by the module/tool monitor 713. Examples of the settings of the tools may include one or any combination of ion energy, ion dose, ion beam current, anneal temperature and/or anneal ramp up rate. An example value may be 500 eV for the ion energy setting. The module controller 705 determines whether or not the settings are correctly set (step 831). If not, the module controller 705 either adjusts the settings (step 833) or notifies an operator to adjust the settings. After settings have been adjusted or the module controller determines that the settings were set correctly, a new wafer is received and processed (step 835).
With respect to the wafer that has been processed and its MAP has been determined as outside of the target range and outside of the correctable range, the processed wafer is considered as not usable and discarded (step 817). It should be noted that steps 829 and 815 can be performed in parallel.
When the wafer that has been processed and its MAP has been determined as outside of the target range but within the correctable range, settings of implanting and anneal tools are checked (step 819) by the module/tool monitor 713. The module controller 705 determines whether or not the settings are correctly set (step 821). If not, the module controller 705 either adjusts the settings (step 823) or notifies an operator to adjust the settings. After the settings have been adjusted or the module controller determines that the settings were set correctly, the difference between a target MAP and the measured MAP may be used in determining corrections to the processing conditions for the processed wafer (step 825). Subsequently, the implant process(es) are performed again on the processed wafer (step 827) using the correction parameter values. (For example, a anneal process(es) can also be re-performed.). In other words, the processed wafer which was incorrectly processed is reprocessed by the process module 601 using the correction parameter values. The correction parameter values can be determined using a LUT that has been created using similar steps as those used in creating the LUT for parameter values as described above in connection with Table 1.
The reprocessed wafer can then be transported to a next process module, if any, for further processing. Alternatively, the post-process metrology tool can make another MAP and perform the above-described steps again starting from step 809.
FIG. 9 shows yet another example embodiment process module 901 of the present invention. The example embodiment of FIG. 9 is, in at least some aspects, similar to the second example embodiment illustrated in FIG. 7 with respect to, e.g., its example processing tools (e.g., the implanter tools 1 907 and 2 911 and the annealing tool 913) and creating and using a module controller 905. However, in this example embodiment, metrology tools 909, 913 configured to check the dosage of each implementing step are placed between the implanter tool 1 907 and the implanter tool 2 911 and between the implanter tool 2 911 and the annealing tool 915.
In operation (and referring also to FIG. 10 a), after a doping step by the implanter tool 1 907, the metrology tool 909 measures the dosage (step 1009), if the dosage is within a target range (step 1011), then the wafer is sent to the implanter tool 2 911 (step 1015). If the measured dosage is not within a target range (e.g., it is under dosed), then the wafer is sent back to the implanter tool 1 907 and reprocessed (step 1013). An example of an under dose is 70-80% of 1×10¹⁵Ions/cm².
In an alternative embodiment, a correctable range can be defined to determine if the dosage can be corrected. If the measured dosage is within correctable range, then the wafer can be sent back to the implanter tool 1 907; however, if the dosage is outside of the correctable range, then the wafer is discarded. Similar processes take place at the metrology tool 913.
It should be noted that similar modifications can be made to the example embodiment of FIGS. 3A, 3B and 7. For example, in a modified embodiment of FIG. 3B, a dosage checking metrology tool can be inserted between process tools. In at least some other embodiments of the present invention, only one metrology tool to measure the dosage can be placed between the process tools (e.g., between the implanter tool 2 and the annealing tool).
FIGS. 10 a-b illustrate other steps that can be performed by at least some embodiments of the present invention. Each of the steps (steps starting from step 1017) is similar to the steps described above in connection with the example embodiment of FIG. 7 of the present invention.
In the above-described example embodiments, various components and steps have been illustrated and described. Relating to those example embodiments, FIG. 11 illustrates an example end result of using the above described steps of measuring the CD, obtaining parameter values from the LUT and using the parameter values to compensate for any undesirable variations.
The first column of a table 1101 lists the parameters relating to gate length affected by variations in a critical dimension. The second column shows percent deviation of values of those parameters when the photoresist is under etched 10 nm. When uncompensated parameter values are used, Tau deviates 16% and I_offdeviates 28% and I_DSATdeviates 7.45%. When a parameter of the implant is compensated, e.g., 120% of a baseline SDE dosage is applied. The deviation of Tau is reduced to 0.13%. However, I_offis increased to 48% and I_DSATis reduced to 5.5% and V_Tis at 1.92%. This effect can be further improved by applying 120% of SDE dose and additional 10% of halo tilt from their respective baseline conditions. When the compensated parameter values are used, the deviation in Tau is reduced to 1.92%, I_offis reduced to 9%, I_DSATis reduced to 3.5% and V_Tis reduced to 1%. It should be understood that the parameter and parameter values, results, etc. are all by way of example, and that one, some or all can depend on a variety of factors (e.g., device design and geometry).
Graphical illustrations of improvements in at least some embodiments of the present invention are provided in FIG. 12, which shows the results obtained for deviation in Tau and leakage current when SDE and halo tilt are adjusted to compensate an under etch process (e.g., 10 nm under etch). In particular, a line with cross-hair marks shows deviation in Tau when no halo tilt is provided and a line with rectangles shows deviation in Tau when 10% halo tilt is provided. Also, a line with triangles shows deviation in leakage current when no halo tilt is provided and a line with circles shows deviation in leakage current when 10% halo tilt is provided. Cross points of these lines with 0% deviation line represent partially optimal compensations.
In at least some embodiments of the present invention, for the lowest deviation in leakage current: 1) no halo tilt and approximately 60% increase in SDE dosage (point 1203); and 2) 10% halo tilt and approximately 110% increase in SDE dosage (point 1205).
For the lowest deviation in Tau: 1) no halo tilt and approximately 120% increase in SDE dosage (point 1205); and 2) 10% halo tilt and approximately 140% increase in SDE dosage (point 1207).
Based on the above observations, 10% halo tilt and approximately 120% increase in SDE dosage may yield the lowest deviations in Tau and leakage current. For example, the percent deviation is minimal when the SDE dosage is increased by about 120% and the halo tilt was increased by 10%. It should be noted that similar compensations can also be achieved by adjusting other conditions (for example, energy, tilt angle of source drain extension, energy and angle of halo implants, etc.).
An example embodiment of the computer on which any of the module controller embodiments of various other aspects of the present invention may operate is described below in connection with FIGS. 13-14.
FIG. 13 illustrates a block diagram of one example of the internal hardware of (e.g., a module controller 1313), which represents any of the above described module controllers 305, 705 or 905. A bus 1356 serves as the main information highway interconnecting various components therein. CPU 1358 is the central processing unit of the module controller 1313, performing calculations and logic operations required to execute the control/operation processes of the present invention as well as other programs. Read only memory (ROM) 1360 and random access memory (RAM) 1362 constitute the main memory of model controller 1313. Disk controller 1364 interfaces one or more disk drives to the system bus 1356. These disk drives are, for example, floppy disk drives 1370, or CD ROM or DVD (digital video disks) drives 1366, or internal or external hard drives 1368. These various disk drives and disk controllers are optional devices.
A display interface 1372 interfaces display 1348 and permits information from the bus 1356 to be displayed on display 1348. Display 1348 may be used in displaying various graphs. Communications with external devices, such as the other components of the system described above, occur utilizing, for example, communication port 1374. Optical fibers and/or electrical cables and/or conductors and/or optical communication (e.g., infrared, and the like) and/or wireless communication (e.g., radio frequency (RF), and the like) can be used as the transport medium between the external devices and communication port 1374. Peripheral interface 1354 interfaces the keyboard 1350 and mouse 1352, permitting input data to be transmitted to bus 1356. In addition to these components, the module controller 1313 also optionally includes an infrared transmitter and/or infrared receiver. Infrared transmitters are optionally utilized when the computer system is used in conjunction with one or more of the processing components/stations/modules that transmit/receive data via infrared signal transmission. Instead of utilizing an infrared transmitter or infrared receiver, the computer system may also optionally use a low power radio transmitter 1380 and/or a low power radio receiver 1382. The low power radio transmitter transmits the signal for reception by components of the production process, and receives signals from the components via the low power radio receiver. The low power radio transmitter and/or receiver are standard devices in industry.
Although the module controller in FIG. 13 is illustrated having a single processor, a single hard disk drive and a single local memory, the analyzer is optionally suitably equipped with any multitude or combination of processors or storage devices. For example, the computer may be replaced by, or combined with, any suitable processing system operative in accordance with the principles of embodiments of the present invention, including sophisticated calculators, and hand-held, laptop/notebook, mini, mainframe and super computers, as well as processing system network combinations of the same.
FIG. 14 is an illustration of an example computer readable memory medium 1484 utilizable for storing computer readable code or instructions. As one example, medium 1484 may be used with disk drives illustrated in FIG. 13. Typically, memory media such as floppy disks, or a CD ROM, or a digital video disk will contain, for example, a multi-byte locale for a single byte language and the program information for controlling the modeler to enable the computer to perform the functions described herein. Alternatively, ROM 1360 and/or RAM 1362 illustrated in FIG. 13 can also be used to store the program information that is used to instruct the central processing unit 1358 to perform the operations associated with various automated processes of the present invention. Other examples of suitable computer readable media for storing information include magnetic, electronic, or optical (including holographic) storage, some combination thereof, etc.
In general, it should be emphasized that the various components of embodiments of the present invention can be implemented in hardware, software or a combination thereof. In such embodiments, the various components and steps would be implemented in hardware and/or software to perform the functions of embodiments of the present invention. Any presently available or future developed computer software language and/or hardware components can be employed in such embodiments of the present invention. For example, at least some of the functionality mentioned above could be implemented using Visual Basic, C, C++, or any assembly language appropriate in view of the processor(s) being used. It could also be written in an interpretive environment such as Java and transported to multiple destinations to various users.
The many features and advantages of embodiments of the present invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. In addition, it should be understood that aspects of the various embodiments and alternative embodiments mentioned therein can overlap and be combined, forming additional embodiments that are also contemplated herein. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

Claims

1. A semiconductor wafer processing module comprising:

a first metrology tool configured to measure at least one critical dimension of at least one device being fabricated on at least one of the plurality of wafers, wherein a variation in the at least one critical dimension causes a variation in performance of the at least one device;

a second metrology tool configured to measure at least one post process dimension of the at least one of the plurality of wafers, wherein the at least one post process dimension is junction depth;

a module controller configured to determine at least one parameter value based on the at least one measured dimension or the at least one post process dimension; and

a plurality of semiconductor manufacturing tools, configured to be controlled by the module controller in processing the at least one of the plurality of wafers based on the at least one parameter value, wherein the manufacturing tools include at least two implanter tools, and

wherein each implanter tool is configured for implanting ions into a junction of the at least one device for at least reducing deviation in gate delay.

2. A method of processing a plurality of wafers for manufacturing semiconductor devices, the method comprising:

(a) measuring at least one critical dimension of at least one device being fabricated on at least one of the plurality of wafers, wherein a variation in the at least one critical dimension causes a variation in performance of the at least one device;

(b) determining at least one parameter value based on the at least one measured dimension;

(c) controlling at least one semiconductor processing tool to process the at least one of the plurality of wafers based on the at least one parameter value, wherein the at least one manufacturing tool includes at least one implanter tool for implanting ions into a junction of said at least one device for at least reducing deviation in gate delay; and

(d) measuring at least one process dimension of the at least one of the plurality of wafers, wherein the at least one post process dimension is junction depth.

3. A semiconductor wafer processing system comprising:

a module controller configured to determine at least one parameter value based on the at least one measured dimension;

a first semiconductor processing tool configured to be controlled by the module controller in processing the at least one of the plurality of wafers based on the at least one parameter value, wherein the first manufacturing tool includes at least one implanter tool for implanting ions into a junction of said at least one device for at least reducing deviation in gate delay; and

a second metrology tool configured to measure at least one post process dimension of the at least one of the plurality of wafers.

4. A semiconductor wafer processing system comprising:

an implanter tool configured to be controlled by the module controller in processing the at least one of the plurality of wafers based on the at least one parameter value, to thereby reduce deviation in gate delay.

5. A semiconductor wafer processing system comprising:

a second metrology tool configured to measure at least one post process dimension of the at least one of the plurality of wafers, wherein the at least one post process dimension is junction depth; and

an annealing tool configured to be controlled by the module controller in processing the at least one of the plurality of wafers based on the at least one parameter value, to thereby reduce deviation in gate delay.