Simulator and simulation method

Abstract

[Problem] To provide a simulator and a simulation method capable of extracting a simulation result for each of a plurality of ion implantations. [Solution] A simulator according to the present disclosure comprises: a calculation unit that executes simulation of a plurality of ion implantations for an processing object; and a storage unit that stores a concentration distribution of an impurity implanted by ion implantation and a calculation result of a point defect distribution generated in the processing object, every time a simulation of each of the plurality of ion implantations is executed. The calculation unit calculates a first difference of the impurity concentration distribution in the plurality of ion implantations and a second difference of the point defect distribution in the plurality of ion implantations.

Description

Simulator and simulation method

[0001] The present disclosure relates to a simulator and a simulation method.

[0002] 2. Description of the Related Art Ion implantation simulators are known that simulate the behavior of a semiconductor substrate and ions when ions are implanted into the semiconductor substrate.

[0003] The ion implantation simulator may simulate the physical phenomena occurring when multiple ion implantations are performed on the same semiconductor substrate under different conditions, and calculates the impurity concentration and point defect distribution after the multiple ion implantations.

[0004] JP 2012-134271 A JP 2000-294514 A JP 2000-039870 A

[0005] However, when multiple ion implantations are performed consecutively, channeling is suppressed by crystal disturbances caused by previous ion implantation simulations, which changes the impurity distribution in subsequent ion implantation simulations. Therefore, even if the results of multiple ion implantations performed independently are added together, the sum of the results is different from the results obtained by performing multiple ion implantations consecutively. From the simulation results obtained by performing multiple ion implantations consecutively, it is difficult to determine which ion implantation resulted in the introduction of the impurity. Furthermore, when changing the conditions for a specific ion implantation among the multiple ion implantations, it was necessary to re-run the simulations for all ion implantations.

[0006] Therefore, the present disclosure provides a simulator and a simulation method that can extract the simulation results of each of a plurality of ion implantations.

[0007] A simulator according to one aspect of the present disclosure includes a calculation unit that executes a simulation of multiple ion implantations into a processing object, and a memory unit that stores calculation results of the concentration distribution of impurities injected by the ion implantation and the distribution of point defects generated in the processing object each time the simulation of each of the multiple ion implantations is executed, and the calculation unit calculates a first difference in the concentration distribution of impurities in the multiple ion implantations and a second difference in the point defect distribution in the multiple ion implantations.

[0008] The calculation unit calculates, as a first difference, the difference between the concentration distribution of the 1st to (n-1th) ion implantations and the concentration distribution of the nth ion implantation out of n ion implantations (n ​​is an integer of 2 or more), and calculates, as a second difference, the difference between the point defect distribution of the 1st to (n-1th) ion implantations and the point defect distribution of the nth ion implantation.

[0009] The storage unit stores the first difference as the concentration distribution of impurities after the nth ion implantation, and stores the second difference as the point defect distribution of the processing target after the nth ion implantation.

[0010] The calculation unit calculates a first difference for each of the first to nth ion implantations, and calculates a second difference for each of the first to nth ion implantations.

[0011] The memory unit stores the first difference calculated for each of the 1st to nth ion implantations as the concentration distribution of each impurity resulting from the 1st to nth ion implantations, and stores the second difference calculated for each of the 1st to nth ion implantations as the point defect distribution of each processing target resulting from the 1st to nth ion implantations.

[0012] When changing the conditions for the kth ion implantation (1≦k≦n) among the 1st to nth ion implantations, the calculation unit performs calculations for the kth ion implantation after the conditions are changed on the calculation results of the concentration distribution and point defect distribution of the 1st to k-1th ion implantations stored in the memory unit.

[0013] After performing calculations for the kth ion implantation after changing the conditions, the calculation unit performs calculations for the k+1th to nth ion implantations based on the calculation results of the concentration distribution and point defect distribution of the 1st to kth ion implantations.

[0014] When the dose amount of the kth ion implantation (1≦k≦n) among the 1st to nth ion implantations is changed by a factor of m, the calculation unit adds the concentration distribution and point defect distribution of the kth ion implantation stored in the storage unit multiplied by m to the calculation results of the concentration distribution and point defect distribution of the 1st to k−1th ion implantations stored in the storage unit.

[0015] The calculation unit adds the concentration distribution and point defect distribution of the kth ion implantation multiplied by m to the calculation results of the concentration distribution and point defect distribution of the 1st to k-1th ion implantations, and then performs calculations for the k+1th to nth ion implantations on the calculation results of the concentration distribution and point defect distribution of the 1st to kth ion implantations.

[0016] The conditions of any one of the implantation energy, the dose amount, and the implantation angle of each ion implantation are different from one another in the multiple ion implantations.

[0017] The same ion species is implanted in the multiple ion implantations.

[0018] The calculation of the simulation by the calculation unit uses any one of the Monte Carlo method, the dual Pearson function model, and an analytical method using a distribution function.

[0019] The concentration distribution and point defect distribution are those after thermal diffusion of impurities.

[0020] The processing object is any one of a single crystal semiconductor, a polycrystalline semiconductor, and an amorphous semiconductor.

[0021] A simulator according to another aspect of the present disclosure includes a calculation unit that executes a simulation of ion implantation into a processing object, and a memory unit that stores calculation results of a concentration distribution of impurities implanted by ion implantation and a distribution of point defects generated in the processing object, wherein the calculation unit calculates the concentration distribution of impurities in the ion implantation and the point defect distribution in the ion implantation, and when the dose amount of the ion implantation is changed by a factor m, the calculation unit multiplies the calculation results of the concentration distribution and point defect distribution in the ion implantation stored in the memory unit by m.

[0022] A simulation method according to one aspect of the present disclosure is a method using a simulator including a calculation unit that executes a simulation of multiple ion implantations into a processing object, and a memory unit that stores calculation results of the concentration distribution of impurities implanted by the ion implantation and the distribution of point defects generated in the processing object each time the simulation of the multiple ion implantations is executed, and includes calculating a first difference in the concentration distribution of impurities among the multiple ion implantations and a second difference in the point defect distribution among the multiple ion implantations.

[0023] The above method further comprises calculating a difference between the concentration distribution of the 1st to (n-1th) ion implantations and the concentration distribution of the nth ion implantation as a first difference, and a difference between the point defect distribution of the 1st to (n-1th) ion implantations and the point defect distribution of the nth ion implantation as a second difference, storing the first difference in a memory unit as the concentration distribution of impurities resulting from the nth ion implantation, and storing the second difference in a memory unit as the point defect distribution of the processing target resulting from the nth ion implantation.

[0024] The above method further comprises, when changing the conditions for the kth ion implantation (1≦k≦n) among the 1st to nth ion implantations, performing a calculation for the kth ion implantation after the conditions are changed on the calculation results of the concentration distribution and point defect distribution of the 1st to k−1th ion implantations stored in the memory unit.

[0025] The above method further comprises, after performing a calculation for the kth ion implantation after changing the conditions, performing a calculation for the k+1th to nth ion implantations on the calculation results of the concentration distribution and point defect distribution of the 1st to kth ion implantations.

[0026] The method further comprises, when changing the dose amount of the kth ion implantation (1≦k≦n) among the 1st to nth ion implantations by a factor of m, multiplying the concentration distribution and point defect distribution of the kth ion implantation stored in the storage unit by m and adding them to the calculation results of the concentration distribution and point defect distribution of the 1st to k−1th ion implantations stored in the storage unit.

[0027] 1 is a block diagram showing an example of the configuration of a simulator according to a first embodiment; a flow diagram showing an example of the operation of the simulator according to the first embodiment; a graph showing an example of the overall impurity concentration distribution or point defect distribution after 1 to n ion implantations; a graph showing an example of the impurity concentration distribution or point defect distribution after 1 to n ion implantations; a flow diagram showing an example of the operation of a simulator according to a second embodiment; a flow diagram showing an example of the operation of a simulator according to a third embodiment; a graph showing an example of the overall impurity concentration distribution or point defect distribution after 1 to n ion implantations after the third embodiment; a graph showing an example of the impurity concentration distribution or point defect distribution after 1 to n ion implantations after the third embodiment;

[0028] Hereinafter, specific embodiments to which the present technology is applied will be described in detail with reference to the drawings. The drawings are schematic or conceptual, and the proportions of each part are not necessarily the same as those in reality. In the specification and drawings, elements similar to those described above with reference to the previous drawings are designated by the same reference numerals, and detailed descriptions thereof will be omitted as appropriate.

[0029] 1 is a block diagram showing an example of the configuration of a simulator according to a first embodiment. The simulator 1 according to this embodiment includes an input unit 2, a calculation unit 3, an output unit 4, and a storage unit 5. The simulator 1 may be, for example, a computer that executes a simulation of ion implantation into a substrate. Any of the input unit 2, the output unit 4, and the storage unit 5 may be provided outside the simulator 1.

[0030] The input unit 2 inputs the ion implantation conditions used in the simulation from an external device. Ion implantation is one of the semiconductor manufacturing processes in which impurities such as boron, arsenic, and phosphorus are ionized and implanted into a substrate. The ion implantation conditions include, for example, process conditions such as the processing target, ion implantation energy (acceleration energy), impurity dose, and ion implantation angle. When multiple ion implantations are performed, the input unit 2 inputs the conditions for each of the multiple ion implantations. The conditions for the multiple ion implantations may be different or the same. The input unit 2 may be an interface circuit connected to an external device so as to be able to communicate with the external device.

[0031] The calculation unit 3 performs an ion implantation simulation on the processing object. The processing object may be, for example, a semiconductor substrate such as a silicon substrate or a GaAs substrate. The processing object may also be any of a single crystal semiconductor, a polycrystalline semiconductor, and an amorphous semiconductor. In this embodiment, a semiconductor substrate is used as an example of the processing object. The simulation shows the behavior of impurities and the semiconductor substrate when ions of impurities are implanted into the processing object based on ion implantation conditions. The calculation unit 3 performs the ion implantation simulation by executing a simulation program in accordance with the ion implantation conditions. The simulation calculation may use either the so-called Monte Carlo method or a dual Pearson function model. The simulation calculation may also use an analytical model using a distribution function. The calculation unit 3 may be, for example, a computer, a CPU (Central Processing Unit), or the like.

[0032] The storage unit 5 stores the simulation program executed by the calculation unit 3, the ion implantation conditions, the simulation calculation results, etc. The storage unit 5 stores the simulation calculation results each time a simulation of each of multiple ion implantations is executed. The simulation calculation results are the calculation results of the concentration distribution of impurities implanted into the substrate by ion implantation and the distribution of point defects generated in the substrate.

[0033] The output unit 4 outputs the results of simulation calculations and the like from the calculation unit 3 or the storage unit 5 to the outside. The output unit 4 may be an interface circuit communicably connected to an external device, or may be an interface circuit integrated with the input unit 2.

[0034] Next, the operation of the simulator 1 according to this embodiment will be described.

[0035] 2 is a flow diagram showing an example of the operation of the simulator according to the first embodiment. The storage unit 5 stores in advance a program required for ion implantation simulation. In this specification, "execution" of ion implantation means execution of simulation calculations.

[0036] First, the input unit 2 inputs the ion implantation conditions from an external device (S10). The ion implantation conditions are stored in the storage unit 5. When a simulation of multiple ion implantations is performed, the input unit 2 inputs the conditions for each of the multiple ion implantations.

[0037] Next, the calculation unit 3 applies the ion implantation conditions to the simulation program to execute the simulation. When executing a simulation of multiple ion implantations, conditions are set for each ion implantation. Therefore, the calculation unit 3 executes simulation calculations for each ion implantation and stores the calculation results in the storage unit 5.

[0038] Here, the calculation unit 3 is assumed to continuously execute n simulations of ion implantation into the same substrate (n is an integer of 2 or greater). The calculation unit 3 executes a simulation of the first ion implantation in accordance with the conditions for the first ion implantation (S20). The calculation results of the simulation of the first ion implantation are, for example, calculation results of the impurity concentration distribution and point defect distribution in the substrate obtained when the first ion implantation is executed on the substrate. The calculation results of the first ion implantation are stored in the storage unit 5 (S30).

[0039] Next, the calculation unit 3 performs a simulation of the second ion implantation in accordance with the conditions for the second ion implantation (S40). At this time, the calculation unit 3 performs the second ion implantation on the calculation results of the first ion implantation. That is, the calculation unit 3 performs a simulation of the second ion implantation on a substrate having a concentration distribution and point defect distribution obtained by the first ion implantation. Therefore, the calculation results of the second ion implantation are the calculation results obtained when the first and second ion implantations are performed consecutively on the same substrate. These calculation results of the first and second ion implantations (concentration distribution and point defect distribution) are also stored in the storage unit 5 (S50).

[0040] Furthermore, the calculation unit 3 calculates the difference between the calculation results of the first and second ion implantations and the calculation result of the first ion implantation (S60). In this way, the calculation unit 3 can obtain the concentration distribution of the second ion implantation by subtracting the concentration distribution of the first ion implantation from the concentration distributions of the first and second ion implantations. The calculation unit 3 also determines the point defect distribution of the second ion implantation to be the difference obtained by subtracting the point defect distribution of the first ion implantation from the point defect distributions of the first and second ion implantations. The calculation results of the second ion implantation (concentration distribution and point defect distribution) are also stored in the storage unit 5 (S70).

[0041] The calculation result of the second ion implantation is the calculation result of the second ion implantation performed on the calculation result of the first ion implantation, and is based on the assumption that the first ion implantation has caused crystal disorder in the substrate, etc. Therefore, the calculation result of the second ion implantation obtained in this embodiment is different from the calculation result when only the second ion implantation is performed independently.

[0042] Next, the calculation unit 3 performs a simulation of the third ion implantation in accordance with the conditions for the third ion implantation (S80). At this time, the calculation unit 3 performs the third ion implantation on the calculation results of the first and second ion implantations. That is, the calculation unit 3 performs a simulation of the third ion implantation on a substrate having the concentration distribution and point defect distribution obtained by the first and second ion implantations. Therefore, the calculation result of the third ion implantation is the calculation result obtained when the first to third ion implantations are performed consecutively on the same substrate. These calculation results (concentration distribution and point defect distribution) of the first to third ion implantations are also stored in the storage unit 5 (S90).

[0043] Furthermore, the calculation unit 3 calculates the difference between the calculation results of the first to third ion implantations and the calculation results of the first and second ion implantations (S100). In this way, the calculation unit 3 can obtain the concentration distribution of the third ion implantation by subtracting the concentration distribution of the first and second ion implantations from the concentration distribution of the first to third ion implantations. The calculation unit 3 also determines the point defect distribution of the third ion implantation to be the difference obtained by subtracting the point defect distributions of the first and second ion implantations from the point defect distributions of the first to third ion implantations. The calculation results of this third ion implantation (concentration distribution and point defect distribution) are also stored in the storage unit 5 (S110).

[0044] The calculation result of the third ion implantation is the calculation result of the third ion implantation performed on the calculation results of the first and second ion implantations, and is based on the assumption that the first and second ion implantations have caused crystal disorder in the substrate, etc. Therefore, the calculation result of the third ion implantation obtained in this embodiment differs from the calculation result when only the third ion implantation is performed independently.

[0045] Similarly, the calculation unit 3 performs a simulation of the kth (4≦k≦n) ion implantation in accordance with the conditions for the kth ion implantation (S120). At this time, the calculation result for the kth ion implantation is the calculation result obtained when the 1st to kth ion implantations are successively performed on the same substrate. The calculation results (concentration distribution and point defect distribution) for the 1st to kth ion implantations are also stored in the storage unit 5 (S130).

[0046] Furthermore, the calculation unit 3 calculates the difference between the calculation results of the 1st to kth ion implantations and the calculation results of the 1st to k-1st ion implantations (S140). In this way, the calculation unit 3 can obtain the concentration distribution resulting from the kth ion implantation by subtracting the concentration distribution resulting from the 1st to k-1st ion implantations from the concentration distribution resulting from the 1st to kth ion implantations. The calculation unit 3 also determines the point defect distribution resulting from the kth ion implantation to be the difference obtained by subtracting the point defect distribution resulting from the 1st to k-1st ion implantations from the point defect distribution resulting from the 1st to kth ion implantations. The calculation results of the kth ion implantation (concentration distribution and point defect distribution) are also stored in the storage unit 5 (S150).

[0047] The calculation result of the kth ion implantation is the calculation result of the kth ion implantation executed on the calculation results of the 1st to k-1th ion implantations, and is based on the assumption that the 1st to k-1th ion implantations cause crystal disorder in the substrate, etc. Therefore, the calculation result of the kth ion implantation obtained in this embodiment is different from the calculation result when only the kth ion implantation is executed independently.

[0048] If k is less than n (NO in S160), the calculation unit 3 increments k by 1 and repeats steps S120 to S150 (S170). If k becomes n (YES in S160), the simulation ends. As a result, the overall calculation results for the first to nth ion implantations and the calculation results for each of the first to nth ion implantations are obtained.

[0049] In this way, the calculation unit 3 calculates the difference (first difference) between the concentration distributions for the first to nth ion implantations. The calculation unit 3 also calculates the difference (second difference) between the point defect distributions for the first to nth ion implantations. The memory unit 5 stores the difference (calculated for each of the first to nth ion implantations) as the impurity concentration distributions for each of the first to nth ion implantations. The memory unit 5 also stores the difference (calculated for each of the first to nth ion implantations) as the point defect distributions for each of the first to nth ion implantations. This allows the simulator 1 to obtain not only the overall calculation results (concentration distribution and point defect distribution) for the first to nth ion implantations, but also the calculation results for each of the first to nth ion implantations. The calculation results are output to the outside from the output unit 4 as needed.

[0050] In the successive ion implantations, the ion implantation conditions (e.g., any one of the implantation energy, the dose, and the implantation angle) may be different from each other. The ion implantation conditions in the 1 to n ion implantations may be different from each other.

[0051] The calculation unit 3 may also perform a simulation of not only the ion implantation but also the subsequent thermal diffusion process. In this case, the calculation results (concentration distribution and point defect distribution) are the concentration distribution and point defect distribution after thermal diffusion of the impurities.

[0052] 3 is a graph showing an example of the overall concentration distribution or point defect distribution of an impurity resulting from 1 to n ion implantations. The vertical axis of this graph represents the concentration of the impurity (e.g., boron). The horizontal axis represents the depth from the surface of the substrate. The calculation results obtained by simulating all of the 1 to n ion implantations are shown as a single graph. Data on the overall concentration distribution or point defect distribution of the 1 to n ion implantations is stored in the storage unit 5 after the simulation. The ion species implanted in the 1 to n ion implantations may be the same (e.g., boron).

[0053] 4 is a graph showing an example of the impurity concentration distribution or point defect distribution for each of 1 to n (e.g., n=4) ion implantations. The vertical axis of this graph represents the impurity (e.g., boron) concentration, and the horizontal axis represents the depth from the surface of the substrate.

[0054] The line L1 indicates the impurity concentration distribution or point defect distribution due to the first ion implantation.

[0055] Line L2 indicates the difference obtained by subtracting the concentration distribution resulting from the first ion implantation from the concentration distribution resulting from the first and second ion implantations, or the difference obtained by subtracting the point defect distribution resulting from the first ion implantation from the point defect distribution resulting from the first and second ion implantations. In other words, line L2 indicates the concentration distribution or point defect distribution resulting from the second ion implantation.

[0056] Line L3 indicates the difference obtained by subtracting the concentration distributions resulting from the first and second ion implantations from the concentration distributions resulting from the first to third ion implantations, or the difference obtained by subtracting the point defect distributions resulting from the first and second ion implantations from the point defect distributions resulting from the first to third ion implantations. In other words, line L3 indicates the concentration distribution or point defect distribution resulting from the third ion implantation.

[0057] Line L4 indicates the difference obtained by subtracting the concentration distribution resulting from the first to third ion implantations from the concentration distribution resulting from the first to fourth ion implantations, or the difference obtained by subtracting the point defect distribution resulting from the first to third ion implantations from the point defect distribution resulting from the first to fourth ion implantations. In other words, line L4 indicates the concentration distribution or point defect distribution resulting from the fourth ion implantation.

[0058] Data on the individual concentration distributions or point defect distributions of the first to fourth ion implantations are stored in the storage unit 5 after the simulation.

[0059] Adding up the concentration distributions or point defect distributions of lines L1 to L4 results in one concentration distribution or point defect distribution as shown in FIG.

[0060] In this way, the simulator according to this embodiment calculates and stores the impurity concentration distribution and point defect distribution for each ion implantation when simulating multiple consecutive ion implantations. The impurity concentration distribution and point defect distribution for each ion implantation take into account the crystallinity disturbances and the like caused by the ion implantations performed earlier.

[0061] Second Embodiment (Changing Ion Implantation Conditions) Fig. 5 is a flow chart showing an example of the operation of a simulator according to a second embodiment. In the second embodiment, the calculation unit 3 changes certain ion implantation conditions and executes a simulation.

[0062] 5 shows an example of the operation of the simulator when the conditions for the kth (1≦k≦n) ion implantation are changed. It is assumed that the simulation described with reference to FIG. 2 has already been executed, and the calculation results for the 1st to nth ion implantations are stored in the storage unit 5. It is also assumed that the conditions for ion implantations other than the kth ion implantation are not changed.

[0063] When changing the conditions for only the k-th ion implantation (1≦k≦n) among the 1st to n-th ion implantations, the calculation unit 3 executes a calculation for the k-th ion implantation after changing the conditions for the calculation results for the 1st to k−1th ion implantations stored in the storage unit 5 (S200). As a result, the k-th ion implantation after changing the conditions is executed on the substrate on which the 1st to k−1th ion implantations have been executed. The calculation results (concentration distribution and point defect distribution) for the 1st to k-th ion implantations are also stored in the storage unit 5 (S210).

[0064] Furthermore, the calculation unit 3 calculates the difference between the calculation results of the 1st to kth ion implantations and the calculation results of the 1st to k-1st ion implantations (S220). The calculation unit 3 obtains the concentration distribution of the kth ion implantation after the condition change by subtracting the concentration distribution of the 1st to k-1st ion implantations from the concentration distribution of the 1st to kth ion implantations. The calculation unit 3 also determines the difference obtained by subtracting the point defect distribution of the 1st to k-1st ion implantations from the point defect distribution of the 1st to kth ion implantations as the point defect distribution of the kth ion implantation. The calculation result of this kth ion implantation is the calculation result of the kth ion implantation after the condition change. The calculation result of this kth ion implantation after the condition change (concentration distribution and point defect distribution) of the kth ion implantation after the condition change is also stored in the storage unit 5 (S230).

[0065] Similarly, the calculation unit 3 performs a simulation of the (k+1)th ion implantation under the conditions of the (k+1)th ion implantation (S240). At this time, the calculation results of the (k+1)th ion implantation are the calculation results obtained when the 1st to (k+1)th ion implantations are performed consecutively on the same substrate. These calculation results (concentration distribution and point defect distribution) of the 1st to (k+1)th ion implantations are also stored in the storage unit 5 (S250).

[0066] Furthermore, the calculation unit 3 calculates the difference between the calculation results of the 1st to k+1th ion implantations and the calculation results of the 1st to kth ion implantations (S260). In this way, the calculation unit 3 can obtain the concentration distribution of the k+1th ion implantation by subtracting the concentration distribution of the 1st to kth ion implantations from the concentration distribution of the 1st to k+1th ion implantations. Furthermore, the calculation unit 3 determines the difference obtained by subtracting the point defect distribution of the 1st to kth ion implantations from the point defect distribution of the 1st to k+1th ion implantations as the point defect distribution of the k+1th ion implantation. The calculation results of this k+1th ion implantation (concentration distribution and point defect distribution) are also stored in the storage unit 5 (S270).

[0067] At this time, the calculation unit 3 does not simply add the calculation result of the (k+1)th ion implantation to the calculation results of the 1st to kth ion implantations, but executes a simulation of the (k+1)th ion implantation on the calculation results of the 1st to kth ion implantations, because a change in the conditions for the kth ion implantation also affects the simulations of the (k+1)th to nth ion implantations after the kth.

[0068] If k+1 is less than n (NO in S280), the calculation unit 3 increments k+1 by 1 and repeats steps S240 to S270 (S290). If k+1 becomes n (YES in S280), the simulation ends. This provides the overall calculation results for the first to nth ion implantations when the conditions for the kth ion implantation are changed, as well as the calculation results for each of the first to nth ion implantations.

[0069] As described above, according to this embodiment, when the conditions for the kth ion implantation are changed, the past calculation results for the 1st to k-1th ion implantations, for which the conditions are not changed, can be reused as they are. Therefore, the calculation unit 3 does not need to execute simulations for the 1st to k-1th ion implantations. This reduces the load on the calculation unit 3 and reduces calculation costs.

[0070] In the above embodiment, the conditions for a single kth ion implantation are changed. However, the conditions for multiple ion implantations may be changed. In this case, the calculation results for the ion implantations prior to the first ion implantation for which the conditions are changed can be used as they are.

[0071] 6 is a flowchart showing an example of the operation of a simulator according to a third embodiment. In the third embodiment, the calculation unit 3 executes a simulation by changing certain ion implantation conditions.

[0072] 6 shows an example of the operation of the simulator when changing the dose amount of the kth (1≦k≦n) ion implantation. It is assumed that the simulation described with reference to FIG. 2 has already been executed, and the calculation results of the first to nth ion implantations have been stored in the storage unit 5. It is also assumed that the conditions for ion implantations other than the kth ion implantation are not changed.

[0073] When the dose of the kth ion implantation is increased by a factor of m, the calculation unit 3 multiplies the concentration distribution and point defect distribution of the kth ion implantation stored in the storage unit 5 by m and adds them to the calculation results of the concentration distribution and point defect distribution of the 1st to k-1th ion implantations stored in the storage unit 5 (S300). For example, when the dose of a past kth ion implantation is changed from a to b, the calculation unit 3 multiplies the concentration distribution and point defect distribution of the past kth ion implantation by b / a. The calculation unit 3 then adds the calculation result multiplied by b / a to the calculation results of the 1st to k-1th ion implantations. In other words, when changing the dose of an ion implantation, the calculation results of the past ion implantations are reused and no simulation calculation is performed.

[0074] Next, steps S210 to S290 are executed in the same manner as in the second embodiment. That is, the calculation unit 3 adds the concentration distribution and point defect distribution of the kth ion implantation multiplied by m to the calculation results of the concentration distribution and point defect distribution of the 1st to k-1th ion implantations, and then executes calculations for the k+1th to nth ion implantations on the calculation results of the concentration distribution and point defect distribution of the 1st to kth ion implantations.

[0075] Even in this way, accurate calculation results for ion implantations 1 to n can be obtained. When the dose of a previous ion implantation is changed by a constant multiple, the calculation results of that previous ion implantation can also be multiplied by a constant, thereby eliminating the need for simulation. This allows the use of past calculation results up to the ion implantation for which the dose is changed, further reducing the load on the calculation unit 3.

[0076] 7 is a graph showing an example of the overall impurity concentration distribution or point defect distribution after 1 to n ion implantations according to the third embodiment. The vertical axis of this graph represents the concentration of the impurity (e.g., boron), and the horizontal axis represents the depth from the surface of the substrate.

[0077] 8 is a graph showing an example of the impurity concentration distribution or point defect distribution for each of 1 to n (e.g., n=4) ion implantations according to the third embodiment. The vertical axis of this graph represents the impurity (e.g., boron) concentration. The vertical axis represents the impurity concentration in logarithm. The horizontal axis represents the depth from the surface of the substrate.

[0078] Here, lines L1, L2, and L4 are the same as those in Fig. 4. Line L13 shows the calculation result obtained by multiplying the concentration distribution or point defect distribution shown by line L3 in Fig. 4 by 10. That is, in the third embodiment, for example, the dose amount of the third ion implantation is set to 10 times the dose amount of the third ion implantation in the first embodiment.

[0079] Adding up the concentration distributions or point defect distributions of lines L1, L2, L4 and L13 results in one concentration distribution or point defect distribution as shown in FIG.

[0080] The above embodiment is a simulation of multiple ion implantations into a substrate. However, the present technology can also be applied to a case where a single ion implantation (n=1) is performed on a substrate. In this case, when the dose amount of one ion implantation is changed by a factor m, the calculation unit 3 simply multiplies the calculation results of the concentration distribution and point defect distribution of that single ion implantation stored in the storage unit 5 by a factor m.

[0081] The simulation of the present disclosure can be applied even when any mask is provided on the surface of the substrate. The side of the mask may be tapered. Furthermore, the simulation of the present disclosure may be applied even when the mask shrinks due to ion implantation and the shape of the mask changes.

[0082] The impurity ions implanted in the simulations of the present disclosure are monatomic ions (e.g., B ３＋ ) or molecular ions (e.g., BF ２ ＋ ) is acceptable.

[0083] The present technology can be configured as follows.

[0084] (1) A simulator comprising: a calculation unit that executes a simulation of multiple ion implantations into a processing object; and a memory unit that stores calculation results of a concentration distribution of impurities implanted by the ion implantations and a distribution of point defects generated in the processing object each time the simulation of the multiple ion implantations is executed, wherein the calculation unit calculates a first difference in the concentration distribution of the impurities among the multiple ion implantations and a second difference in the point defect distribution among the multiple ion implantations.

[0085] (2) The simulator according to (1), wherein the calculation unit calculates, as the first difference, a difference between the concentration distribution of 1st to (n-1th) ion implantations and the concentration distribution of the nth ion implantation among the n ion implantations (n ​​is an integer of 2 or more), and calculates, as the second difference, a difference between the point defect distribution of 1st to (n-1th) ion implantations and the point defect distribution of the nth ion implantation.

[0086] (3) The simulator according to (2), wherein the storage unit stores the first difference as a concentration distribution of the impurity due to an n-th ion implantation, and stores the second difference as a point defect distribution of the processing target due to an n-th ion implantation.

[0087] (4) The simulator according to (2) or (3), wherein the calculation unit calculates the first difference for each of the first to nth ion implantations and calculates the second difference for each of the first to nth ion implantations.

[0088] (5) The simulator according to (4), wherein the storage unit stores the first difference calculated for each of the first to nth ion implantations as a concentration distribution of the impurity resulting from each of the first to nth ion implantations, and stores the second difference calculated for each of the first to nth ion implantations as a point defect distribution of the processing target resulting from each of the first to nth ion implantations.

[0089] (6) The simulator according to any one of (2) to (5), wherein, when changing conditions for a k-th ion implantation (1≦k≦n) among the 1st to n-th ion implantations, the calculation unit executes a calculation for the k-th ion implantation after the change of conditions for the calculation results of the concentration distribution and the point defect distribution for the 1st to k−1th ion implantations stored in the storage unit.

[0090] (7) The simulator according to (6), wherein the calculation unit executes calculations for the kth ion implantation after changing conditions, and then executes calculations for k+1 to nth ion implantations based on calculation results of the concentration distribution and the point defect distribution for the 1st to kth ion implantations.

[0091] (8) The simulator according to any one of (2) to (5), wherein, when the dose amount of a kth ion implantation (1≦k≦n) among the 1st to nth ion implantations is changed by a factor of m, the calculation unit multiplies the concentration distribution and the point defect distribution of the kth ion implantation stored in the storage unit by m and adds them to the calculation results of the concentration distribution and the point defect distribution of the 1st to k−1th ion implantations stored in the storage unit.

[0092] (9) The simulator according to (8), wherein the calculation unit adds the concentration distribution and the point defect distribution of the kth ion implantation multiplied by m to the calculation results of the concentration distribution and the point defect distribution of the 1st to k-1th ion implantations, and then performs calculations for k+1 to nth ion implantations on the calculation results of the concentration distribution and the point defect distribution of the 1st to k-1th ion implantations.

[0093] (10) The simulator according to any one of (1) to (9), wherein any one of the conditions of implantation energy, dose amount, and implantation angle for each of the ion implantations is different from one another in the plurality of ion implantations.

[0094] (11) The simulator according to any one of (1) to (10), wherein the same ion species is implanted in the multiple ion implantations.

[0095] (12) The simulator according to any one of (1) to (11), wherein the calculation unit performs simulation calculations using any one of a Monte Carlo method, a dual Pearson function model, and an analytical method using a distribution function.

[0096] (13) The simulator according to any one of (1) to (12), wherein the concentration distribution and the point defect distribution are concentration distribution and point defect distribution after thermal diffusion of the impurities.

[0097] (14) The simulator according to any one of (1) to (13), wherein the processing object is one of a single crystal semiconductor, a polycrystalline semiconductor, and an amorphous semiconductor.

[0098] (15) A simulator comprising: a calculation unit that executes a simulation of ion implantation into a processing object; and a memory unit that stores calculation results of a concentration distribution of impurities implanted by the ion implantation and a distribution of point defects generated in the processing object, wherein the calculation unit calculates the concentration distribution of the impurities in the ion implantation and the point defect distribution in the ion implantation, and when changing the dose amount of the ion implantation by a factor m, the calculation unit multiplies the calculation results of the concentration distribution and the point defect distribution in the ion implantation stored in the memory unit by m.

[0099] (16) A simulation method using a simulator including a calculation unit that executes a simulation of multiple ion implantations into a processing object, and a memory unit that stores calculation results of a concentration distribution of impurities implanted by the ion implantations and a distribution of point defects generated in the processing object each time a simulation of the multiple ion implantations is executed, the simulation method comprising calculating a first difference in the concentration distribution of the impurities among the multiple ion implantations, and a second difference in the point defect distribution among the multiple ion implantations.

[0100] (17) The method according to (16), further comprising: calculating, as the first difference, a difference between the concentration distribution of 1st to (n-1th) ion implantations and the concentration distribution of the nth ion implantation among n ion implantations (n ​​is an integer of 2 or more), and calculating, as the second difference, a difference between the point defect distribution of 1st to (n-1th) ion implantations and the point defect distribution of the nth ion implantation; storing, in the storage unit, the first difference as the concentration distribution of the impurity resulting from the nth ion implantation; and storing, in the storage unit, the second difference as the point defect distribution of the processing object resulting from the nth ion implantation.

[0101] (18) The method according to (17), further comprising, when changing conditions for a kth ion implantation (1≦k≦n) among the 1st to nth ion implantations, executing a calculation for the kth ion implantation after the conditions are changed on the calculation results of the concentration distribution and the point defect distribution for the 1st to k−1th ion implantations stored in the storage unit.

[0102] (19) The simulator according to (18), further comprising: after executing a calculation for the kth ion implantation after changing conditions, executing a calculation for k+1 to nth ion implantations on the calculation results of the concentration distribution and the point defect distribution for the 1st to kth ion implantations.

[0103] (20) The method according to (17), further comprising, when changing the dose amount of a kth ion implantation (1≦k≦n) among the 1st to nth ion implantations by a factor of m, multiplying the concentration distribution and the point defect distribution of the kth ion implantation stored in the storage unit by m and adding them to the calculation results of the concentration distribution and the point defect distribution of the 1st to k−1th ion implantations stored in the storage unit.

[0104] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the gist of the present disclosure. Furthermore, the effects described in this specification are merely examples and are not intended to be limiting, and other effects may also be obtained.

[0105] 1 Simulator 2 Input section 3 Calculation section 4 Output section 5 Storage section

Claims

1. A simulator comprising: a calculation unit that executes a simulation of multiple ion implantations into a processing object; and a memory unit that stores calculation results of a concentration distribution of impurities injected by the ion implantation and a distribution of point defects generated within the processing object each time a simulation of the multiple ion implantations is executed, wherein the calculation unit calculates a first difference in the concentration distribution of the impurities among the multiple ion implantations and a second difference in the point defect distribution among the multiple ion implantations.

2. The simulator according to claim 1, wherein the calculation unit calculates, as the first difference, a difference between the concentration distribution of 1st to n-1th ion implantations and the concentration distribution of the nth ion implantation out of n ion implantations (n ​​is an integer of 2 or more), and calculates, as the second difference, a difference between the point defect distribution of 1st to n-1th ion implantations and the point defect distribution of the nth ion implantation.

3. The simulator according to claim 2, wherein the memory unit stores the first difference as a concentration distribution of the impurity due to the nth ion implantation, and stores the second difference as a point defect distribution of the processing object due to the nth ion implantation.

4. The simulator according to claim 2, wherein the calculation unit calculates the first difference for each of the 1st to nth ion implantations, and calculates the second difference for each of the 1st to nth ion implantations.

5. The simulator according to claim 4, wherein the memory unit stores the first difference calculated for each of the 1st to nth ion implantations as a concentration distribution of the impurity resulting from each of the 1st to nth ion implantations, and stores the second difference calculated for each of the 1st to nth ion implantations as a point defect distribution of the processing target resulting from each of the 1st to nth ion implantations.

6. The simulator according to claim 2, wherein, when conditions for a kth ion implantation (1≦k≦n) among the 1st to nth ion implantations are changed, the calculation unit executes a calculation for the kth ion implantation after the conditions are changed on the calculation results of the concentration distribution and the point defect distribution of the 1st to k-1th ion implantations stored in the memory unit.

7. The simulator according to claim 6, wherein the calculation unit executes calculations for the kth ion implantation after changing conditions, and then executes calculations for k+1 to nth ion implantations based on the calculation results of the concentration distribution and point defect distribution of the 1st to kth ion implantations.

8. The simulator according to claim 2, wherein, when the dose amount of a kth ion implantation (1≦k≦n) of the 1st to nth ion implantations is changed to m times, the calculation unit adds the concentration distribution and point defect distribution of the kth ion implantation stored in the storage unit multiplied by m to the calculation results of the concentration distribution and point defect distribution of the 1st to k-1th ion implantations stored in the storage unit.

9. The simulator according to claim 8, wherein the calculation unit adds the concentration distribution and point defect distribution of the kth ion implantation multiplied by m to the calculation results of the concentration distribution and point defect distribution of the 1st to k-1th ion implantations, and then performs calculations for k+1 to nth ion implantations on the calculation results of the concentration distribution and point defect distribution of the 1st to kth ion implantations.

10. The simulator according to claim 1, wherein any one of the conditions of implantation energy, dose amount, and implantation angle for each of the multiple ion implantations is different from one another in the multiple ion implantations.

11. The simulator of claim 1, wherein the ion species implanted in said multiple ion implantations is the same.

12. The simulator according to claim 1, wherein the calculation unit performs simulation calculations using any one of a Monte Carlo method, a dual Pearson function model, and an analysis method using a distribution function.

13. The simulator according to claim 1, wherein the concentration distribution and the point defect distribution are concentration distribution and point defect distribution after thermal diffusion of the impurities.

14. The simulator according to claim 1, wherein the processing object is one of a single crystal semiconductor, a polycrystalline semiconductor, and an amorphous semiconductor.

15. A simulator comprising: a calculation unit that executes a simulation of ion implantation into a processing object; and a memory unit that stores calculation results of a concentration distribution of an impurity implanted by the ion implantation and a distribution of point defects generated in the processing object, wherein the calculation unit calculates the concentration distribution of the impurity of the ion implantation and the point defect distribution of the ion implantation, and when the dose amount of the ion implantation is changed by a factor m, the calculation unit multiplies the calculation results of the concentration distribution of the ion implantation and the point defect distribution stored in the memory unit by m.

16. A simulation method using a simulator having a calculation unit that executes a simulation of multiple ion implantations into a processing object, and a memory unit that stores calculation results of a concentration distribution of an impurity injected by the ion implantation and a distribution of point defects generated in the processing object each time a simulation of each of the multiple ion implantations is executed, the simulation method comprising calculating a first difference in the concentration distribution of the impurity in the multiple ion implantations, and a second difference in the point defect distribution in the multiple ion implantations.

17. The method according to claim 16, further comprising: calculating, as the first difference, a difference between the concentration distribution of 1st to n-1th ion implantations and the concentration distribution of the nth ion implantation, among n ion implantations (n ​​is an integer of 2 or more), and calculating, as the second difference, a difference between the point defect distribution of the 1st to n-1th ion implantations and the point defect distribution of the nth ion implantation; storing, in the memory unit, the first difference as the concentration distribution of the impurity due to the nth ion implantation; and storing, in the memory unit, the second difference as the point defect distribution of the processing object due to the nth ion implantation.

18. The method according to claim 17, further comprising, when changing conditions for a kth ion implantation (1≦k≦n) of the 1st to nth ion implantations, executing a calculation for the kth ion implantation after the conditions are changed on the calculation results of the concentration distribution and the point defect distribution of the 1st to k-1th ion implantations stored in the memory unit.

19. The method according to claim 18, further comprising, after performing a calculation for the kth ion implantation after changing conditions, performing a calculation for k+1 to nth ion implantations on the calculation results of the concentration distribution and point defect distribution of the 1st to kth ion implantations.

20. The method according to claim 17, further comprising, when changing the dose amount of a kth ion implantation (1≦k≦n) of the 1st to nth ion implantations by a factor of m, multiplying the concentration distribution and the point defect distribution of the kth ion implantation stored in the storage unit by m and adding them to the calculation results of the concentration distribution and the point defect distribution of the 1st to k-1th ion implantations stored in the storage unit.

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