Simulator and simulation method

Abstract

[Problem] To provide a simulator and a simulation method capable of extracting simulation results of each of a plurality of ion implants. [Solution] A simulator according to the present disclosure comprises: a calculation unit that performs a simulation of a plurality of ion implants on a subject to be processed; and a storage unit that stores a calculation result of a concentration distribution of impurities implanted by ion implantation and a distribution of point defects generated in the processing target, each time simulation of each of the plurality of ion implants is executed, the storage unit being configured to store the calculation result of the concentration distribution of the impurities implanted by ion implantation and the distribution of point defects generated in the processing target. The calculation unit calculates a first difference in the impurity concentration distribution of the plurality of ion implants and a second difference in the point defect distribution of the plurality of ion implants.

Description

Technical Field

[0001] This invention relates to simulators and simulation methods. Background Technology

[0002] Ion implantation simulators that simulate the behavior of semiconductor substrates and ions during ion implantation are known.

[0003] Such an ion implantation simulator can simulate the physical phenomena of performing multiple ion implantations on the same semiconductor substrate under different conditions. In this case, the impurity concentration and point defect distribution after performing multiple ion implantations are calculated. Existing technical documents Patent documents

[0004] Patent Document 1: Japanese Patent Application Publication No. 2012-134271 Patent Document 2: Japanese Patent Application Publication No. 2000-294514 Patent Document 3: Japanese Patent Application Publication No. 2000-039870 Summary of the Invention The problem the invention aims to solve

[0005] However, if multiple ion implantations are performed consecutively, the crystal disorder caused by previous ion implantation simulations suppresses the channeling effect, thus altering the impurity distribution in subsequent ion implantation simulations. Therefore, even when the results of multiple ion implantations simulated independently are summed, the total differs from the result obtained from consecutive ion implantations. Based on the simulation results of consecutive ion implantations, it is difficult to determine through which ion implantation the impurity was introduced. Furthermore, if the specific ion implantation conditions change during multiple ion implantations, it is necessary to simulate all ion implantations again.

[0006] Therefore, this disclosure provides a simulator and simulation method capable of extracting the simulation results of multiple ion implantations separately. Solution to the problem

[0007] The simulator of one aspect of this disclosure includes: a computation unit configured to perform a simulation of multiple ion implantations on a processing object; and a storage unit configured to store, during the execution of each of the multiple ion implantations, computational results of the concentration distribution of impurities implanted by the ion implantation and the distribution of point defects generated within the processing object, wherein the computation unit calculates a first difference in the concentration distribution of the impurities and a second difference in the distribution of point defects in the multiple ion implantations.

[0008] The computation unit calculates the difference between the concentration distribution of the 1st to (n-1)th ion implantation and the concentration distribution of the nth ion implantation in n (n is an integer greater than 2) ion implantations as the first difference, and calculates the difference between the point defect distribution of the 1st to (n-1)th ion implantations and the point defect distribution of the nth ion implantation as the second difference.

[0009] The storage unit stores the first difference as the concentration distribution of the impurities caused by the nth ion implantation, and stores the second difference as the point defect distribution of the processed object caused by the nth ion implantation.

[0010] The computational 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.

[0011] The storage unit stores the first difference calculated for each of the 1st to nth ion implantations as the concentration distribution of the impurities caused by each of 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 the processed object caused by each of the 1st to nth ion implantations.

[0012] When the conditions of the kth (1 ≤ k ≤ n) ion implantation in the 1st to nth ion implantations are changed, the calculation unit performs the calculation of the kth ion implantation after the condition change on the calculation results of the concentration distribution and the point defect distribution of the 1st to (k-1)th ion implantations stored in the storage unit.

[0013] After the k-th ion implantation operation with changed execution conditions, the calculation unit performs the (k+1)-n-th ion implantation operation on the calculation results of the concentration distribution and the point defect distribution of the 1st to k-th ion implantations.

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

[0015] After multiplying the concentration distribution and point defect distribution of the kth ion implantation by m times and adding them to the calculation results of the concentration distribution and point defect distribution of the 1st to (k-1)th ion implantations, the calculation unit performs the calculation of the (k+1)th 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 implantation energy, dose, and implantation angle of each ion implantation are different from each other in the multiple ion implantations.

[0017] The same type of ions were implanted in all of the multiple ion implantations.

[0018] The simulation operations in the computation unit use any one of the following: the Monte Carlo method, the double Pearson function model, and the analytical method using a distribution function.

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

[0020] The object being processed is any one of single-crystal semiconductors, polycrystalline semiconductors, and amorphous semiconductors.

[0021] Another aspect of the simulator disclosed herein includes: a computation unit configured to simulate ion implantation of a processing object; and a storage unit configured to store computational results of the concentration distribution of impurities implanted by the ion implantation and the distribution of point defects generated within the processing object, wherein the computation unit calculates the concentration distribution of the ion-implanted impurities and the distribution of point defects, and when the ion implantation dose is changed by a factor of m, the computation unit multiplies the computational results of the concentration distribution and the distribution of point defects stored in the storage unit by a factor of m.

[0022] One aspect of this disclosure is a simulation method using a simulator, the simulator comprising: a computation unit configured to perform a simulation of multiple ion implantations on a processing object; and a storage unit configured to store, during the execution of each of the multiple ion implantations, computational results of a concentration distribution of impurities implanted by the ion implantation and a distribution of point defects generated within the processing object, and the simulation method comprising calculating a first difference of the concentration distribution of the impurities in the multiple ion implantations and a second difference of the distribution of point defects in the multiple ion implantations.

[0023] The above method further includes: calculating the difference between the concentration distribution of the 1st to (n-1st)th ion implantation and the concentration distribution of the nth ion implantation in n (n is an integer greater than 2) ion implantations as the first difference, and calculating the difference between the point defect distribution of the 1st to (n-1st)th ion implantations and the point defect distribution of the nth ion implantation as the second difference; and The first difference is stored in the storage unit as the concentration distribution of the impurities caused by the nth ion implantation, and the second difference is stored in the storage unit as the point defect distribution of the processed object caused by the nth ion implantation.

[0024] If the conditions of the kth (1 ≤ k ≤ n) ion implantation in the 1st to nth ion implantations are changed, the above method further includes: performing the calculation of the kth ion implantation after the condition change on the calculation results of the concentration distribution and the point defect distribution of the 1st to (k-1)th ion implantations stored in the storage unit.

[0025] The above method further includes: after the k-th ion implantation operation with changed execution conditions, performing the (k+1)-n-th ion implantation operation on the calculation results of the concentration distribution and the point defect distribution of the 1st to k-th ion implantations.

[0026] The above method further includes: when the dose of the kth (1 ≤ k ≤ n) ion implantation in the 1st to nth ion implantations is changed 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 a factor of m, and adding the result of the calculation of the concentration distribution and the point defect distribution of the 1st to (k-1)th ion implantations stored in the storage unit. Attached Figure Description

[0027] Figure 1 This is a block diagram illustrating an example of the construction of a simulator according to the first embodiment. Figure 2 This is a flowchart illustrating an operational example of the simulator according to the first embodiment. Figure 3 This is a diagram showing an example of the overall concentration distribution or point defect distribution of impurities generated in the first to nth ion implantations. Figure 4 This is a diagram showing an example of the concentration distribution or point defect distribution of impurities generated in each implantation from the 1st to the nth ion implantation. Figure 5 This is a flowchart illustrating an operational example of the simulator according to the second implementation scheme. Figure 6 This is a flowchart illustrating an operational example of a simulator according to a third implementation scheme. Figure 7 It is a diagram illustrating an example of the overall concentration distribution or point defect distribution of impurities generated in the first to nth ion implantations according to the third embodiment. Figure 8 It is a diagram showing an example of the respective concentration distribution or point defect distribution of impurities in the first to nth ion implantations according to the third embodiment. Detailed Implementation

[0028] In the following description, specific embodiments applying this technology will be detailed with reference to the accompanying drawings. The drawings are schematic or conceptual, and for example, the scale of the parts in the drawings may not be the same as the actual scale. In the specification and drawings, elements similar to those described in the prior drawings are indicated by the same reference numerals, and their detailed descriptions will be omitted where appropriate.

[0029] (First Implementation Plan) Figure 1 This is a block diagram illustrating a construction example of a simulator according to a first embodiment. The simulator 1 according to this embodiment includes an input unit 2, an arithmetic unit 3, an output unit 4, and a storage unit 5. The simulator 1 can be, for example, a computer simulating ion implantation into a substrate. Any of the input unit 2, output unit 4, and storage unit 5 can be located externally to the simulator 1.

[0030] Input unit 2 receives external input of ion implantation conditions for simulation. Ion implantation is, for example, a semiconductor manufacturing process that ionizes and implants impurities such as boron, arsenic, and phosphorus into a substrate. Ion implantation conditions include, for example, process conditions such as the target material, ion implantation energy (acceleration energy), impurity dose, and ion implantation angle. When performing multiple ion implantations, input unit 2 inputs the conditions for each of the multiple ion implantations. The conditions for multiple ion implantations can be different from each other or the same. Input unit 2 can be an interface circuit communicatively connected to an external device.

[0031] The computation unit 3 performs an ion implantation simulation on the object to be processed. For example, the object to be processed can be a semiconductor substrate such as a silicon substrate or a GaAs substrate. Furthermore, the object to be processed can be any of a single-crystal semiconductor, a polycrystalline semiconductor, or an amorphous semiconductor. In this embodiment, a semiconductor substrate is used as an example of the object to be processed. The simulation illustrates the behavior of impurities and the semiconductor substrate when impurities are implanted into the object to be processed based on ion implantation conditions. The computation unit 3 performs the ion implantation simulation by executing a simulation program according to the ion implantation conditions. The simulation can use a so-called Monte Carlo method or a double Pearson function model. The simulation can be a model using an analytical formula for a distribution function. The computation unit 3 can be, for example, a computer, a central processing unit (CPU), etc.

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

[0033] Output unit 4 outputs the results of analog calculations from arithmetic unit 3 or storage unit 5 to the outside. Output unit 4 can be an interface circuit that can be communicatively connected to an external device, or it can be an interface circuit integrated with input unit 2.

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

[0035] Figure 2 This is a flowchart illustrating an operational example of the simulator according to the first embodiment. Storage unit 5 pre-stores the programs required for simulating ion implantation. Note that in this specification, "execution" of ion implantation refers to the execution of the simulation operation.

[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 performing simulations of multiple ion implantations, the input unit 2 inputs the respective conditions for each ion implantation.

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

[0038] Here, it is assumed that the calculation unit 3 continuously performs n (n is an integer greater than or equal to 2) ion implantation simulations on the same substrate. The calculation unit 3 performs the simulation of the first ion implantation according to the conditions of the first ion implantation (S20). The simulation result of the first ion implantation is, for example, the calculation result of the concentration distribution of impurities and the distribution of point defects in the substrate obtained when the first ion implantation is performed on the substrate. The calculation result of the first ion implantation is stored in the storage unit 5 (S30).

[0039] Next, the calculation unit 3 performs a simulation of the second ion implantation based on the conditions of the second ion implantation (S40). At this time, the calculation unit 3 performs the second ion implantation based on the calculation results of the first ion implantation. That is, the calculation unit 3 performs a simulation of the second ion implantation for a substrate having the 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 (concentration distribution and point defect distribution) of the first and second ion implantations 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 caused by the second ion implantation by subtracting the concentration distribution caused by the first ion implantation from the concentration distribution caused by the first and second ion implantations. In addition, the calculation unit 3 sets the difference between the point defect distribution generated by the first ion implantation and the point defect distribution generated by the first ion implantation as the point defect distribution generated by the second ion implantation. This calculation result (concentration distribution and point defect distribution) of the second ion implantation is also stored in the storage unit 5 (S70).

[0041] Note that the result of the second ion implantation is the result of the second ion implantation operation performed on the result of the first ion implantation, and it is based on the premise of the disorder of crystallization within the substrate caused by the first ion implantation. Therefore, the result of the second ion implantation obtained in this embodiment is different from the result obtained when only the second ion implantation is performed.

[0042] Next, the calculation unit 3 performs a simulation of the third ion implantation based on the conditions for the third ion implantation (S80). At this time, the calculation unit 3 performs the third ion implantation based 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 through the first and second ion implantations. Therefore, the calculation result of the third ion implantation is the result obtained by performing the first to third ion implantations consecutively on the same substrate. This calculation result (concentration distribution and point defect distribution) of the first to third ion implantations is 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 in the third ion implantation by subtracting the concentration distributions caused by the first and second ion implantations from the concentration distributions caused by the first to third ion implantations. In addition, the calculation unit 3 sets the difference between the point defect distributions caused by the first to third ion implantations and the point defect distributions caused by the first and second ion implantations as the point defect distribution caused by the third ion implantation. This calculation result (concentration distribution and point defect distribution) of the third ion implantation is also stored in the storage unit 5 (S110).

[0044] Note that the result of the third ion implantation is a result of the third ion implantation operation performed on the results of the first and second ion implantations, and it assumes the disruption of crystallization within the substrate caused by the first and second ion implantations. Therefore, the result of the third ion implantation obtained in this embodiment differs from the result obtained when only the third ion implantation is performed.

[0045] Similarly, the calculation unit 3 performs a simulation of the kth (4 ≤ k ≤ n) ion implantation based on the conditions of the kth ion implantation (S120). At this time, the calculation result of the kth ion implantation is the result obtained when performing ion implantation from the 1st to the kth consecutive times on the same substrate. This calculation result (concentration distribution and point defect distribution) of the 1st to the kth ion implantations is 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-1)th ion implantations (S140). In this way, the calculation unit 3 can obtain the concentration distribution of the kth implantation by subtracting the concentration distribution caused by the 1st to (k-1)th ion implantations from the concentration distribution caused by the 1st to kth ion implantations. In addition, the calculation unit 3 sets the difference between the point defect distribution caused by the 1st to kth ion implantations and the point defect distribution caused by the 1st to (k-1)th ion implantations as the point defect distribution caused by the kth ion implantation. Such calculation results of the kth ion implantation (concentration distribution and point defect distribution) are also stored in the storage unit 5 (S150).

[0047] Note that the result of the k-th ion implantation is the result of the k-th implantation operation performed on the results of the 1st to (k-1)th ion implantations, and it assumes the disruption of crystallization within the substrate caused by the 1st to (k-1)th ion implantations. Therefore, the result of the k-th ion implantation obtained in this embodiment is different from the result obtained when only the k-th ion implantation is performed.

[0048] If k is less than n ("No" in S160), the operation unit 3 increments k by 1 and repeats steps S120 to S150 (S170). If k becomes n ("Yes" in S160), the simulation ends. Using this arrangement, the overall calculation results for the 1st to nth ion implantations and the calculation results for each of the 1st to nth ion implantations are obtained.

[0049] In this manner, the calculation unit 3 calculates the difference (first difference) in the concentration distribution of each of the 1st to nth ion implantations. Additionally, the calculation unit 3 calculates the difference (second difference) in the point defect distribution of each of the 1st to nth ion implantations. The storage unit 5 stores the difference in concentration distribution calculated for each of the 1st to nth ion implantations, as the concentration distribution of impurities in each of the 1st to nth ion implantations. Furthermore, the storage unit 5 stores the difference calculated for each of the 1st to nth ion implantations, as the point defect distribution caused by the 1st to nth ion implantations. Using this arrangement, the simulator 1 can obtain not only the overall calculation results (concentration distribution and point defect distribution) of the 1st to nth ion implantations, but also the individual calculation results of each of the 1st to nth ion implantations. The calculation results are output to the outside from the output unit 4 as needed.

[0050] Note that in continuous ion implantation, the ion implantation conditions (e.g., any one of implantation energy, dose, and implantation angle) can be different from one another. The ion implantation conditions for the 1st to the nth ion implantations can be different from one another.

[0051] Furthermore, the computation unit 3 can not only perform ion implantation simulations, but also simulations of subsequent thermal diffusion processes. In this case, the computation results (concentration distribution and point defect distribution) are the concentration distribution and point defect distribution of impurities after thermal diffusion.

[0052] Figure 3 This is a graph illustrating an example of the overall concentration distribution or point defect distribution of impurities resulting from the 1st to nth ion implantations. The vertical axis represents the concentration of the impurity (e.g., boron). The horizontal axis represents the depth from the substrate surface. All the calculation results for the 1st to nth ion implantations are illustrated in a single graph. After the simulation, the data on the overall concentration distribution or point defect distribution of the 1st to nth ion implantations are stored in storage unit 5. The ion species used in the 1st to nth ion implantations can be the same (e.g., boron).

[0053] Figure 4 This is a graph showing examples of the concentration distribution of impurities or point defect distribution for each of the 1st to nth ion implantations (e.g., n = 4). The vertical axis in the graph represents the concentration of impurities (e.g., boron). The horizontal axis represents the depth from the substrate surface.

[0054] Line L1 represents the concentration distribution of impurities or point defects resulting from the first ion implantation.

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

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

[0057] Line L4 represents the difference between the concentration distributions resulting from the 1st to 4th ion implantations and the concentration distributions resulting from the 1st to 3rd ion implantations, or the difference between the point defect distributions resulting from the 1st to 4th ion implantations and the point defect distributions resulting from the 1st to 3rd ion implantations. In other words, line L4 represents the concentration distribution or point defect distribution resulting from the 4th ion implantation.

[0058] After the simulation, the concentration distribution or point defect distribution data of the ion implantations from the first to the fourth time are stored in the storage unit 5.

[0059] Adding the concentration distributions or point defect distributions of lines L1 to L4 together, we get the following: Figure 3 The diagram shows a concentration distribution or a point defect distribution.

[0060] In this way, when multiple ion implantation simulations are performed consecutively, the concentration distribution of impurities and the distribution of point defects for each ion implantation are calculated and stored according to the simulator of this embodiment. The concentration distribution of impurities and the distribution of point defects for each ion implantation take into account the concentration distribution and distribution of point defects such as crystallinity disorder caused by the previous ion implantation.

[0061] (Second Implementation Plan) (Changes in ion implantation conditions) Figure 5 This is a flowchart illustrating an operational example of the simulator according to the second embodiment. In the second embodiment, the computation unit 3 performs the simulation under varying conditions of a specific ion implantation.

[0062] Figure 5 An example of simulator operation is shown under the conditional change of the k-th (1 ≤ k ≤ n) ion implantation. Note that it is assumed that the reference has been executed. Figure 2 The simulation results for the first to nth ion implantations have been stored in storage unit 5. Furthermore, the ion implantation conditions remain unchanged except for the kth ion implantation.

[0063] If only the conditions of the kth (1 ≤ k ≤ n) ion implantation change during the 1st to nth ion implantations, the calculation unit 3 performs the calculation of the kth ion implantation after the condition change on the calculation results of the 1st to (k-1)th ion implantations stored in the storage unit 5 (S200). With this arrangement, the kth ion implantation after the condition change is performed on the substrate that has already undergone the 1st to (k-1)th ion implantations. The calculation results (concentration distribution and point defect distribution) of the 1st to kth 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-1)th ion implantations (S220). The calculation unit 3 can obtain the concentration distribution caused by the kth ion implantation after the condition change by subtracting the concentration distribution caused by the 1st to (k-1)th ion implantations from the concentration distribution caused by the 1st to kth ion implantations. Furthermore, the calculation unit 3 sets the difference between the point defect distribution caused by the 1st to kth ion implantations and the point defect distribution caused by the 1st to (k-1)th ion implantations as the point defect distribution caused by the kth ion implantation. The calculation unit 3 can obtain the point defect distribution caused by the kth ion implantation after the condition change by subtracting the point defect distribution caused by the 1st to (k-1)th ion implantations from the point defect distribution caused by the 1st to kth ion implantations. The calculation result of the kth ion implantation is the calculation result of the kth ion implantation after the condition change. The calculation results (concentration distribution and point defect distribution) of the kth ion implantation after the condition is changed are also stored in the storage unit 5 (S230).

[0065] Similarly, the calculation unit 3 performs the simulation of the (k+1)th ion implantation based on the conditions of the (k+1)th ion implantation (S240). At this time, the calculation result of the (k+1)th ion implantation is the calculation result obtained when the 1st to (k+1)th ion implantations are performed consecutively on the same substrate. The 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+1)th 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 caused by the (k+1)th ion implantation by subtracting the concentration distribution caused by the 1st to (k+1)th ion implantations from the concentration distribution caused by the 1st to (k+1)th ion implantations. Furthermore, the calculation unit 3 sets the difference between the point defect distribution caused by the 1st to (k+1)th ion implantations and the point defect distribution caused by the 1st to (k+1)th ion implantations as the point defect distribution caused by the (k+1)th ion implantation. This calculation result (concentration distribution and point defect distribution) of the (k+1)th ion implantation is also stored in the storage unit 5 (S270).

[0067] At this point, the computation unit 3 does not simply add the result of the (k+1)th ion implantation to the results of the 1st to kth ion implantations. Instead, it performs the simulation of the (k+1)th ion implantation on the results of the 1st to kth ion implantations. This is because the change in the conditions of the kth ion implantation affects the simulation of the (k+1)th to nth ion implantations after the kth implantation.

[0068] If k+1 is less than n ("No" in S280), the operation 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. Using this arrangement, the overall calculation results of the 1st to nth ion implantations, and the individual calculation results of the 1st to nth ion implantations, are obtained when the ion implantation conditions of the kth ion implantation have changed.

[0069] In this way, according to this embodiment, if the conditions for the k-th ion implantation change, the calculation results of the 1st to (k-1)th ion implantations under the same conditions can be used as is. Therefore, the calculation unit 3 does not need to perform simulations of the 1st to (k-1)th ion implantations. With this arrangement, the load on the calculation unit 3 is reduced, and the computational cost can be lowered.

[0070] In the above implementation scheme, only the ion implantation conditions for the kth time were changed. However, the ion implantation conditions can be changed multiple times. In this case, the calculation results of the ion implantation before the first change of conditions can be used as is.

[0071] (Third Implementation Plan) (Change the ion implantation dose) Figure 6 This is a flowchart illustrating an operational example of a simulator according to a third embodiment. In the third embodiment, the computation unit 3 performs simulations under varying conditions of specific ion implantation.

[0072] Figure 6 An example of simulator operation is shown with the dose of the k-th (1 ≤ k ≤ n) ion implantation changed. Note that it is assumed that a reference has been performed. Figure 2 The simulation results, including the calculations for each of the first to nth ion implantations, are stored in storage unit 5. Furthermore, the ion implantation conditions remain unchanged except for the kth ion implantation.

[0073] When the dose of the k-th ion implantation is multiplied by m, the calculation unit 3 multiplies the concentration distribution and point defect distribution of the k-th ion implantation stored in the storage unit 5 by m, and adds this multiplication to the calculation results of the concentration distribution and point defect distribution of the 1st to (k-1)th ion implantations stored in the storage unit 5 (S300). For example, if the dose of the k-th ion implantation changes from a to b, the calculation unit 3 multiplies the concentration distribution and point defect distribution of the k-th ion implantation by b / a. Then, the calculation unit 3 adds the result of multiplying by b / a to the calculation results of the 1st to (k-1)th ion implantations. That is, regarding the change in ion implantation dose, the past ion implantation calculation results are used, and no simulation calculation is performed.

[0074] Next, similar to the second embodiment, steps S210 to S290 are executed. That is, after the calculation unit 3 multiplies the concentration distribution and point defect distribution of the kth ion implantation by m and adds them to the calculation results of the concentration distribution and point defect distribution of the 1st to (k-1)th ion implantations, it performs the calculation of the 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.

[0075] Even with this arrangement, accurate calculation results for ion implantation from 1 to n times can be obtained. When the dose of past ion implantation is changed to a constant multiple, the simulation can be omitted by similarly multiplying the calculation results of past ion implantation by this constant multiple. With this arrangement, calculation results up to the ion implantation with the changed dose can be used, and the load on the calculation unit 3 can be further reduced.

[0076] Figure 7 This is a graph illustrating an example of the overall concentration distribution or point defect distribution of impurities resulting from the first to nth ion implantations according to the third embodiment. The vertical axis in the graph represents the concentration of the impurity (e.g., boron). The horizontal axis represents the depth from the substrate surface.

[0077] Figure 8 This is a graph illustrating examples of the concentration distribution of impurities or point defect distribution for the first to nth ion implantations (e.g., n = 4) according to the third embodiment. The vertical axis in the graph represents the concentration of impurities (e.g., boron). Note that the vertical axis represents the impurity concentration logarithmically. The horizontal axis represents the depth from the substrate surface.

[0078] Here, lines L1, L2, and L4 are... Figure 4 The same as in [the previous sentence]. Line L13 indicates that [the following text is missing]. Figure 4The concentration distribution or point defect distribution shown by the centerline L3 is multiplied by 10. That is, in the third embodiment, for example, the dose of the third ion implantation is set to 10 times the dose of the third ion implantation in the first embodiment.

[0079] Adding the concentration distributions or point defect distributions of lines L1, L2, L4, and L13 together yields, as shown below: Figure 7 The diagram shows a concentration distribution or point defect distribution.

[0080] The above embodiment is a simulation of multiple ion implantations on a substrate. However, this technology is also applicable to the case of a single ion implantation (n = 1) on a substrate. In this case, when the dose of the single ion implantation changes by a factor of m, the calculation unit 3 only needs to multiply the calculation results of the concentration distribution and point defect distribution of the single ion implantation stored in the storage unit 5 by m.

[0081] The simulations of this disclosure are applicable even if an arbitrary mask is disposed on the substrate surface. The sides of the mask can have a tapered shape. Furthermore, in the simulations of this disclosure, the mask can be degraded by ion implantation, and the shape of the mask can be changed.

[0082] In the simulations of this disclosure, the impurity ions injected can be monatomic ions (e.g., B atoms). 3+ ) or molecular ions (e.g., BF2) + ).

[0083] Note that this technology can also have the following configurations. (1) A simulator comprising: The computation unit is configured to perform simulations of multiple ion implantations on the object being processed; and The storage unit is configured to store, during the execution of each of the multiple ion implantation simulations, the calculation results of the concentration distribution of impurities implanted through the ion implantation and the distribution of point defects generated within the processed object. The computation unit calculates a first difference in the concentration distribution of the impurities and a second difference in the distribution of point defects during the multiple ion implantations. (2) According to the simulator described in (1), the arithmetic unit calculates the difference between the concentration distribution of the 1st to (n-1)th ion implantation and the concentration distribution of the nth ion implantation in n (n is an integer greater than 2) ion implantations as the first difference, and calculates the difference between the point defect distribution of the 1st to (n-1)th ion implantations and the point defect distribution of the nth ion implantation as the second difference. (3) According to the simulator described in (2), the storage unit stores the first difference as the concentration distribution of the impurities caused by the nth ion implantation, and stores the second difference as the point defect distribution of the processed object caused by the nth ion implantation. (4) According to the simulator described in (2) or (3), the computational part calculates the first difference for the first to nth ion implantations and calculates the second difference for the first to nth ion implantations respectively. (5) According to the simulator described in (4), the storage unit stores the first difference calculated for each of the first to nth ion implantations as the concentration distribution of the impurities for each of the first to nth ion implantations, and stores the second difference calculated for each of the first to nth ion implantations as the point defect distribution of the processing object for each of the first to nth ion implantations. (6) According to any one of (2) to (5) of the simulator, wherein, when the conditions of the kth (1 ≤ k ≤ n) ion implantation in the 1st to nth ion implantations are changed, the calculation unit performs the calculation of the kth ion implantation after the condition change on the calculation results of the concentration distribution and the point defect distribution of the 1st to (k-1)th ion implantations stored in the storage unit. (7) According to the simulator described in (6), after the k-th ion implantation operation with changed execution conditions, the calculation unit performs the k+1-n-th ion implantation operation on the calculation results of the concentration distribution and the point defect distribution of the 1st to k-th ion implantations. (8) According to any one of (2) to (5) of the simulator, wherein, when the dose of the kth (1 ≤ k ≤ n) ion implantation in 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 a factor of m, and adds them to the calculation results of the concentration distribution and the point defect distribution of the 1st to (k-1)th ion implantations stored in the storage unit. (9) According to the simulator described in (8), after multiplying the concentration distribution and the point defect distribution of the kth ion implantation by m times and adding them to the calculation results of the concentration distribution and the point defect distribution of the 1st to (k-1)th ion implantations, the calculation unit performs the calculation of the k+1th to nth ion implantations on the calculation results of the concentration distribution and the point defect distribution of the 1st to kth ion implantations. (10) The simulator according to any one of (1) to (9) wherein any of the conditions of implantation energy, dose and implantation angle of each ion implantation are different from each other in the multiple ion implantations. (11) The simulator according to any one of (1) to (10) wherein the types of ions implanted in the multiple ion implantations are the same. (12) The simulator according to any one of (1) to (11) wherein the simulation operation in the arithmetic unit uses any one of the Monte Carlo method, the double Pearson function model and the analytical method using the distribution function. (13) The simulator according to any one of (1) to (12), wherein the concentration distribution and the point defect distribution are the concentration distribution and point defect distribution of the impurities after thermal diffusion. (14) The simulator according to any one of (1) to (13), wherein the processing object is any one of single crystal semiconductor, polycrystalline semiconductor and amorphous semiconductor. (15) A simulator comprising: The computation unit is configured to simulate ion implantation of the object being processed; and The storage unit is configured to store the calculation results of the concentration distribution of impurities implanted through the ion implantation and the distribution of point defects generated within the processed object, wherein... The computation unit calculates the concentration distribution of the impurities implanted by the ion implantation and the point defect distribution of the ion implantation, and When the ion implantation dose is changed by a factor of m, the calculation unit multiplies the calculation results of the concentration distribution and the point defect distribution of the ion implantation stored in the storage unit by a factor of m. (16) A simulation method using a simulator, the simulator comprising: The computation unit is configured to perform multiple ion implantation simulations on the object to be processed; and the storage unit is configured to store, during the execution of each of the multiple ion implantation simulations, the computational results of the concentration distribution of impurities implanted by the ion implantation and the distribution of point defects generated within the object to be processed. The simulation method includes calculating a first difference in the concentration distribution of the impurities from the multiple ion implantations and a second difference in the point defect distribution from the multiple ion implantations. (17) According to the method of (16), the method further includes: calculating the difference between the concentration distribution of the first to (n-1)th ion implantations and the concentration distribution of the nth ion implantation in n (n is an integer greater than 2) ion implantations as the first difference, and calculating the difference between the point defect distribution of the first to (n-1)th ion implantations and the point defect distribution of the nth ion implantation as the second difference; and The first difference is stored in the storage unit as the concentration distribution of the impurities caused by the nth ion implantation, and the second difference is stored in the storage unit as the point defect distribution of the processed object caused by the nth ion implantation. (18) According to the method of (17), it further includes: when the conditions of the kth (1 ≤ k ≤ n) ion implantation in the 1st to nth ion implantations are changed, performing the calculation results of the concentration distribution and the point defect distribution of the 1st to (k-1)th ion implantations stored in the storage unit after the condition change for the kth ion implantation. (19) According to the simulator described in (18), it further includes: after the operation of the kth ion implantation after the execution condition is changed, performing the operation of the (k+1)th to the nth ion implantation on the operation results of the concentration distribution and the point defect distribution of the 1st to the kth ion implantations. (20) The method according to (17) further includes: when the dose of the kth (1 ≤ k ≤ n) ion implantation in the 1st to nth ion implantations is changed 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 a factor of m, and adding the result of the calculation of the concentration distribution and the point defect distribution of the 1st to (k-1)th ion implantations stored in the storage unit. Note that this disclosure is not limited to the above embodiments, and various modifications can be made without departing from the spirit of this disclosure. Furthermore, the effects described in this specification are merely exemplary and not limiting, and may provide other effects. List of reference numerals

[0104] 1. Simulator 2 Input Section 3. Arithmetic Unit 4 Output Section 5. Storage Section

Claims

1. A simulator, comprising: The computation unit is configured to simulate multiple ion implantations onto the object being processed; as well as The storage unit is configured to store, during the execution of each of the multiple ion implantation simulations, the calculation results of the concentration distribution of impurities implanted through the ion implantation and the distribution of point defects generated within the processed object. The computation unit calculates a first difference in the concentration distribution of the impurities and a second difference in the distribution of point defects during the multiple ion implantations.

2. The simulator of claim 1, wherein, The computation unit calculates the difference between the concentration distribution of the 1st to (n-1)th ion implantation and the concentration distribution of the nth ion implantation in n (n is an integer greater than 2) ion implantations as the first difference, and calculates the difference between the point defect distribution of the 1st to (n-1)th ion implantations and the point defect distribution of the nth ion implantation as the second difference.

3. The simulator of claim 2, wherein, The storage unit stores the first difference as the concentration distribution of the impurities caused by the nth ion implantation, and stores the second difference as the point defect distribution of the processed object caused by the nth ion implantation.

4. The simulator of claim 2, wherein, The computational 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 storage unit stores the first difference calculated for each of the 1st to nth ion implantations as the concentration distribution of the impurities for each of 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 the processed object for each of the 1st to nth ion implantations.

6. The simulator according to claim 2, wherein, When the conditions of the kth (1 ≤ k ≤ n) ion implantation in the 1st to nth ion implantations are changed, the calculation unit performs the calculation of the kth ion implantation after the condition change on the calculation results of the concentration distribution and the point defect distribution of the 1st to (k-1)th ion implantations stored in the storage unit.

7. The simulator according to claim 6, wherein, After the k-th ion implantation operation with changed execution conditions, the calculation unit performs the (k+1)-n-th ion implantation operation on the calculation results of the concentration distribution and the point defect distribution of the 1st to k-th ion implantations.

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

9. The simulator according to claim 8, wherein, After multiplying the concentration distribution and point defect distribution of the kth ion implantation by m times and adding them to the calculation results of the concentration distribution and point defect distribution of the 1st to (k-1)th ion implantations, the calculation unit performs the calculation of the (k+1)th 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, The implantation energy, dose, and implantation angle of each ion implantation are different from each other in the multiple ion implantations.

11. The simulator according to claim 1, wherein, The same type of ions were implanted in all of the multiple ion implantations.

12. The simulator according to claim 1, wherein, The simulation operations in the computation unit use any one of the following: the Monte Carlo method, the double Pearson function model, and the analytical method using a distribution function.

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

14. The simulator according to claim 1, wherein, The object being processed is any one of single-crystal semiconductors, polycrystalline semiconductors, and amorphous semiconductors.

15. A simulator comprising: The computing unit is designed to simulate ion implantation of the object being processed. as well as The storage unit is configured to store the calculation results of the concentration distribution of impurities implanted through the ion implantation and the distribution of point defects generated within the processed object, wherein... The computation unit calculates the concentration distribution of the impurities implanted by the ion implantation and the point defect distribution of the ion implantation, and When the ion implantation dose is changed by a factor of m, the calculation unit multiplies the calculation results of the concentration distribution and the point defect distribution of the ion implantation stored in the storage unit by a factor of m.

16. A simulation method using a simulator, the simulator comprising: The computation unit is configured to simulate multiple ion implantations onto the object being processed; And a storage unit configured to store, during the execution of each of the multiple ion implantation simulations, the calculation results of the concentration distribution of impurities implanted through the ion implantation and the distribution of point defects generated within the processed object. The simulation method includes calculating a first difference in the concentration distribution of the impurities from the multiple ion implantations and a second difference in the point defect distribution from the multiple ion implantations.

17. The method of claim 16, further comprising: The difference between the concentration distribution of the 1st to (n-1)th ion implantation and the concentration distribution of the nth ion implantation in n (n is an integer greater than 2) ion implantations is calculated as the first difference, and the difference between the point defect distribution of the 1st to (n-1)th ion implantations and the point defect distribution of the nth ion implantation is calculated as the second difference. as well as The first difference is stored in the storage unit as the concentration distribution of the impurities caused by the nth ion implantation, and the second difference is stored in the storage unit as the point defect distribution of the processed object caused by the nth ion implantation.

18. The method of claim 17, further comprising: If the conditions of the kth (1≤k≤n) ion implantation in the 1st to nth ion implantations are changed, the calculation results of the concentration distribution and the point defect distribution of the 1st to (k-1)th ion implantations stored in the storage unit are used to perform the calculation of the kth ion implantation with the changed conditions.

19. The method of claim 18, further comprising: After the k-th ion implantation operation with changed conditions, the (k+1)-n-th ion implantation operation is performed on the results of the concentration distribution and point defect distribution of the 1st to k-th ion implantations.

20. The method of claim 17, further comprising: When the dose of the kth (1≤k≤n) ion implantation in the 1st to nth ion implantations is changed by a factor of m, the concentration distribution and point defect distribution of the kth ion implantation stored in the storage unit are multiplied by a factor of m, and added to the calculation results of the concentration distribution and point defect distribution of the 1st to (k-1)th ion implantations stored in the storage unit.

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