Advanced process control method and apparatus

Abstract

The invention discloses an advanced process control method, which is used for realizing compensation of a first front-layer station for a first rear-layer station, and comprises the following steps of: 1, setting a mirror image station of the first rear-layer station, and simulating the first rear-layer station by adopting the mirror image station; and step 2, taking the mirror site as a second front-layer site for feed-forward advanced process control, taking the first front-layer site as a compensation site for feed-forward advanced process control, performing feed-forward advanced process control to realize setting of compensation parameters of the compensation site, and performing operation of the first front-layer site according to the set compensation parameters. And step 3, operation of the first rear-layer station is carried out. The invention further discloses an advanced process control device. According to the invention, the first front-layer station can compensate the first rear-layer station in a feed-forward manner, so that the product performance fluctuation of the first rear-layer station can be reduced.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor integrated circuit manufacturing, and in particular to an advanced process control (APC) method. The present invention also relates to an advanced process control device. Background Art

[0002] The huge volume of the furnace tube will cause the temperature and airflow at different positions to be inconsistent, forming an inherent trend inside the furnace tube that cannot be adjusted.

[0003] However, key film layers such as gate oxide and SONOS Nitride in CMOS devices are usually grown in furnace tube machines. This inherent trend will inevitably lead to differences in film thickness / quality between wafer boat slots in the furnace tube, ultimately causing great fluctuations in product performance.

[0004] In theory, by selecting wafers with appropriate doses implanted in the previous ion implantation step for each wafer boat slot, the inherent trends of film thickness and film quality in the furnace tube can be compensated.

[0005] Table 1

[0006] Crystal boat slot <![CDATA[Injection dose (cm -2 )]]> 1 2.8E12 2 2.85E12 3 2.95E12 4 3E12 …… 3.05E12 25 3.05E12 26 3.05E12 …… 3.05E12 47 3.1E12 48 3.15E12 49 3.2E12 50 3.25E12

[0007] As shown in Table 1, there are 50 wafer boat slots in a wafer boat, among which the injection doses corresponding to the 1st to 4th wafer boat slots are different, the 5th to 46th wafer boat slots use the same injection dose, and the injection doses corresponding to the 47th to 50th wafer boat slots are different. If the injection dose can be set according to Table 1, the problem corresponding to the difference in film thickness / film quality between the wafer boat slots of the furnace tube can be solved.

[0008] like Figure 1 The figure shows a theoretical process flow chart of ion implantation-furnace tube corresponding to the front layer compensating the back layer; including:

[0009] Step S101, performing a front layer site, where the front layer site is ion implantation.

[0010] Step S102, proceed to the rear layer site, where the rear layer site is the furnace tube.

[0011] As mentioned above, the furnace tube has an inherent tendency that cannot be adjusted. The fluctuations in film thickness or film quality caused by this inherent tendency cannot be adjusted by the furnace tube itself. These fluctuations are mainly reflected in the different temperature or airflow conditions at different positions of the crystal boat of the furnace tube, which makes the film thickness or film quality of the film formed at different positions of the crystal boat different.

[0012] To this end, in theory, if the wafer position in the wafer boat slot in the furnace tube is known, the ion implantation dose can be adjusted to compensate for the influence of the temperature or airflow conditions corresponding to the wafer boat slot on the film thickness or film quality of the thin film, and finally the film thickness or film quality of the wafers formed in each wafer boat slot is uniform.

[0013] However, by Figure 1 As shown in the figure, since step S101 is performed before step S102, when step S101 is performed, the position of the wafer in the wafer boat in step S102 cannot be known. Figure 1 The process shown is not achievable. The existing feedforward advanced process control method can only solve the problem of the back station compensating the front station, but cannot achieve Figure 1 The front station shown compensates the rear station.

[0014] The industry usually uses the feedforward advanced process control method to solve the problem of back-end compensation of front-end. The industry's common feedforward advanced process control includes front-end sites and compensation sites, namely back-end sites. Since there are differences in certain features between wafers at the front-end sites, it will cause great fluctuations in product performance. The front-end sites are usually measurement sites, and the common features are measurement values. Therefore, before the compensation site is operated, it is necessary to use the characteristics of the front layer of the wafer as input, calculate the value of the compensation parameter according to the specified algorithm, and then operate according to the compensation value, which can effectively reduce product performance fluctuations.

[0015] The following is a further explanation of the common dry etching-ion implantation feedforward advanced process control in the industry:

[0016] The process control capability of the dry etching site has reached its limit, and the difference between wafers cannot be further reduced. Therefore, it is necessary to use the dry etching measurement site as the front-layer site, the key dimension value as the front-layer feature, the ion implantation site as the compensation site, the ion implantation dose as the compensation parameter, and the wafer front-layer key dimension as the input to calculate the dose compensation value, and then select a unique compensation dose according to the dose compensation value range, and operate at this dose. Figure 2 As shown, it is a flow chart of an existing feedforward advanced process control method for compensating the front layer of the rear layer in dry etching-ion implantation; it includes:

[0017] Step S201, performing a front-layer site, the front-layer site is a dry etching measurement, and the dry etching measurement can obtain a measurement value. As described above, after the dry etching site process is completed, the corresponding measurement value is a critical dimension value.

[0018] Step S202, perform the post-layer site, which is ion implantation. Before the ion implantation operation, the corresponding compensation dose needs to be calculated according to the critical dimension value obtained above, and then the ion implantation is performed with the obtained compensation dose.

[0019] Considering that the ion implantation beam needs to be readjusted when switching between different doses, which wastes machine time, the industry adopts a piecewise function, that is, using the same dose within a specific range to minimize the number of ion implantation beam adjustments. For example, as shown in Table 2 below, if the calculated compensation value is 3.43E13, which is between [3.35E13, 3.45E13], 3.4E13 is used for the operation.

[0020] Table 2

[0021] <![CDATA[Lower limit of compensation value (not less than) (cm -2 )]]> <![CDATA[Upper limit of compensation value (less than) (cm -2 )]]> <![CDATA[Compensation dose (cm -2 )]]> 3.15E13 3.25E13 3.2E13 3.25E13 3.35E13 3.3E13 3.35E13 3.45E13 3.4E13 3.45E13 3.55E13 3.5E13 3.55E13 3.65E13 3.6E13

[0022] Figure 2 The process model of the feedforward advanced process control method shown is a general process model of the feedforward advanced process control method, and only the front-layer site, the back-layer site and the actual process site need to be applied.

[0023] If the general model is applied, the front layer site should be the ion implantation site, the front layer feature should be the ion implantation dose, and the dose of each wafer should be a variable; the compensation site should be the furnace tube site, and the parameter to be compensated should be the furnace tube wafer boat slot. The dose of the front layer ion implantation of the wafer should be used as input to calculate the wafer boat slot where the wafer should be placed, and it should be a unique value. Figure 3 As shown, it is applied Figure 2 The process is applied to the ion implantation furnace flow chart, including:

[0024] Step S201, performing a front layer site, the front layer site is ion implantation, and the measurement value corresponding to the ion implantation is the dose.

[0025] Step S202, proceed to the rear site, where the rear site is the furnace tube. The compensation value corresponding to the furnace tube is the wafer boat slot.

[0026] But in reality, Figure 3 The process shown is also impossible to implement, and is explained as follows:

[0027] In reality, the implant dose of each wafer at the front-layer site is a fixed value, and there is no difference between wafers, so it is not applicable to the universal model. Figure 3 In the embodiment, after step S201 is completed, the dose of each wafer is the same, so in the subsequent step S202, it is actually impossible to adjust the compensation value according to the difference in dose.

[0028] If the injection dose is randomly selected in the front layer, the filling rate of the furnace tube stations in the back layer will be reduced. For example, if all the injection doses are 3.05E12cm -2If the operation is combined with Table 1, it can be seen that only the 5-46 wafer slots can be used. There is no product wafer filling in other positions, so they can only be replaced by baffles. What is more serious is that the airflow should be shared by the product wafers with patterns, and the use of baffles without patterns will cause excessive airflow, which will change the microenvironment and make the 5-46 wafer slots unable to compensate for 3.05E12cm -2 The corresponding dose has a loading effect.

[0029] In addition, the compensation site uses the dose of the wafer front layer ion implantation as input, and the calculated wafer boat slot position where the wafer should be placed may be multiple, which is not applicable to the general model. For example, if the front layer dose is 3.05E12, the calculated wafer boat slot position is 5-46, with 42 possibilities, and it is impossible to lock the wafer boat slot position where the wafer should be placed.

[0030] Therefore, it is necessary to design a new advanced process control method to solve the problem of using the front layer ion implantation dose to compensate for the differences between the slots in the rear layer furnace tube wafer boat. Summary of the invention

[0031] The technical problem to be solved by the present invention is to provide an advanced process control method, which can use a feedforward method to achieve the first front layer site to compensate the first rear layer site, thereby reducing the product performance fluctuation of the first rear layer site. To this end, the present invention also provides an advanced process control device.

[0032] In order to solve the above technical problems, the advanced process control method provided by the present invention is used to realize the first front layer site compensating the first rear layer site, comprising the following steps:

[0033] Step 1: Set a mirror site of the first back-end site, and use the mirror site to simulate the first back-end site.

[0034] Step 2: Use the mirror site as the second front-layer site of feedforward advanced process control, use the first front-layer site as the compensation site of the feedforward advanced process control, perform the feedforward advanced process control to set the compensation parameters of the compensation site and perform the operation of the first front-layer site according to the set compensation parameters.

[0035] Step 3: Perform operations on the first back-end site.

[0036] A further improvement is that in step 2, the feedforward advanced process control includes:

[0037] Step 21: simulate the mirror site to extract a first characteristic value.

[0038] Step 22: Calculate the compensation parameter using the first eigenvalue as an input value.

[0039] Step 23: Perform operation of the first front-layer site according to the set compensation parameters.

[0040] A further improvement is that, in step three, the operation of the first back-layer site is performed according to the setting of the first characteristic value.

[0041] A further improvement is that the first front layer site includes: an ion implantation site;

[0042] The first rear layer site includes a furnace tube site.

[0043] A further improvement is that the simulation of step 21 includes: according to the wafer loading rules of the furnace tube station, simulating the wafer boat slot position of each wafer in the batch in the furnace tube during actual operation and constructing the batch accordingly and recording the batch and the wafer boat slot position of each wafer in the batch, and the first characteristic value is the wafer boat slot position of each wafer.

[0044] A further improvement is that the compensation parameter includes an ion implantation dose, and in step 22, the ion implantation dose of the wafer is set according to the corresponding wafer boat slot of the wafer.

[0045] A further improvement is that the wafer boat includes multiple wafer boat area segments, each of the wafer boat area segments includes more than one wafer boat slot position, and one wafer boat area segment corresponds to a compensation dose; in step 22, the wafer boat area segment in which the wafer is located is determined according to the wafer boat slot position of the wafer, and then the corresponding compensation dose is selected according to the wafer boat area segment as the ion implantation dose of the wafer.

[0046] A further improvement is that, in step three, each wafer is loaded into a corresponding wafer boat slot according to the recorded batch and the wafer boat slot of each wafer in the batch and the operation is performed.

[0047] In order to solve the above technical problems, the advanced process control device provided by the present invention is used to realize the first front layer site to compensate the first rear layer site, including:

[0048] The mirror site setting module is used to set a mirror site of the first back-end site, and use the mirror site to simulate the first back-end site.

[0049] The feedforward advanced process control module is used to implement: using the mirror site as the second front-layer site of the feedforward advanced process control, using the first front-layer site as the compensation site of the feedforward advanced process control, performing the feedforward advanced process control to implement setting of compensation parameters of the compensation site and performing operations of the first front-layer site according to the set compensation parameters.

[0050] The second process control module is used to implement the operation of the first back-layer site.

[0051] A further improvement is that, in the feedforward advanced process control module, the step of the feedforward advanced process control includes:

[0052] Step 21: simulate the mirror site to extract a first characteristic value.

[0053] Step 22: Calculate the compensation parameter using the first eigenvalue as an input value.

[0054] Step 23: Perform operation of the first front-layer site according to the set compensation parameters.

[0055] A further improvement is that, in the second process control module, the operation of the first back-layer site is performed according to the setting of the first characteristic value.

[0056] A further improvement is that the first front layer site includes: an ion implantation site.

[0057] The first rear layer site includes a furnace tube site.

[0058] A further improvement is that the simulation of step 21 includes: according to the wafer loading rules of the furnace tube station, simulating the wafer boat slot position of each wafer in the batch in the furnace tube during actual operation and constructing the batch accordingly and recording the batch and the wafer boat slot position of each wafer in the batch, and the first characteristic value is the wafer boat slot position of each wafer.

[0059] A further improvement is that the compensation parameter includes an ion implantation dose, and in step 22, the ion implantation dose of the wafer is set according to the corresponding wafer boat slot of the wafer.

[0060] A further improvement is that the wafer boat includes multiple wafer boat area segments, each of the wafer boat area segments includes more than one wafer boat slot position, and one wafer boat area segment corresponds to a compensation dose; in step 22, the wafer boat area segment in which the wafer is located is determined according to the wafer boat slot position of the wafer, and then the corresponding compensation dose is selected according to the wafer boat area segment as the ion implantation dose of the wafer.

[0061] A further improvement is that, in the second process control module, each wafer is loaded into a corresponding wafer boat slot and the operation is performed according to the recorded batch and the wafer boat slot of each wafer in the batch.

[0062] In the existing advanced process control methods, feedforward control is to compensate and control the process parameters of the rear-layer site according to the measurement parameters of the front-layer site, that is, to compensate for the parameter deviation of the front layer by adjusting the process parameters of the rear layer, that is, the rear layer compensates the front layer. It is impossible to realize the front-layer site to compensate the rear-layer site by the feedforward method. In the present invention, by setting a mirror site of the first rear-layer site, the mirror site can be placed before the first front-layer site, so that the mirror site can be used as a new front-layer site, that is, the second front-layer site, and the first front-layer site can be used as a new rear-layer site, that is, the second rear-layer site. The second rear-layer site can be used as a compensation site, so that feedforward control can be realized between the second front-layer site and the compensation site, and finally feedforward advanced process control can be realized. Since the front-layer site of the feedforward control is realized by the mirror site of the first rear-layer site, it is also called pseudo-feedforward advanced process control. Therefore, the present invention can realize the first front-layer site to compensate the first rear-layer site by the feedforward method, thereby reducing the product performance fluctuation of the first rear-layer site.

[0063] The present invention is particularly suitable for using the ion implantation dose of the front layer to compensate for the difference in film thickness or film quality between the slots of the furnace tube crystal boat of the rear layer, and finally reducing the product performance difference caused by the difference in the furnace tube film. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0065] Figure 1 It is a theoretical process flow chart of ion implantation - the front layer corresponding to the furnace tube compensates the back layer;

[0066] Figure 2 It is a flow chart of an existing feedforward advanced process control method for back layer compensation of front layer applied to dry etching-ion implantation;

[0067] Figure 3 It is applied Figure 2 Flow chart of the process when applied to ion implantation-furnace tube;

[0068] Figure 4 This is a flow chart of an advanced process control method according to an embodiment of the present invention when it is applied to an ion implantation furnace tube. DETAILED DESCRIPTION

[0069] like Figure 4 As shown, it is a flow chart of the advanced process control method of an embodiment of the present invention when it is applied to ion implantation-furnace tube; the advanced process control method of an embodiment of the present invention is used to realize the first front layer site to compensate the first rear layer site, including the following steps:

[0070] Step 1: Set a mirror site of the first back-end site, and use the mirror site to simulate the first back-end site.

[0071] Figure 4 In the example shown, the first front layer site includes: an ion implantation site;

[0072] The first rear layer station includes a furnace tube station. Step 1 corresponds to Figure 4 Step S401, mirror site (second front-layer site): furnace tube mirror.

[0073] Step 2: Use the mirror site as the second front-layer site of feedforward advanced process control, use the first front-layer site as the compensation site of the feedforward advanced process control, perform the feedforward advanced process control to set the compensation parameters of the compensation site and perform the operation of the first front-layer site according to the set compensation parameters.

[0074] In an embodiment of the present invention, the feedforward advanced process control includes:

[0075] Step 21: simulate the mirror site to extract a first characteristic value.

[0076] Figure 4 In the example shown, the simulation of step 21 includes: according to the wafer loading rules of the furnace tube station, simulating the wafer boat slot position of each wafer in the batch in the furnace tube during actual operation and constructing the batch accordingly and recording the batch and the wafer boat slot position of each wafer in the batch, and the first characteristic value is the wafer boat slot position of each wafer.

[0077] Usually, a batch (lot) of wafers is placed in the same wafer box, and the maximum number of wafers that can be placed in the wafer box is 25. The wafer boat of the furnace tube can hold multiple batches of wafers, and each batch corresponding to the wafer boat of the furnace tube forms a corresponding batch, and each wafer in the batch is each wafer in the corresponding batch. Through the simulation, the corresponding relationship between the wafer boat and the batch and between each wafer and the slot of the wafer boat can be obtained, thereby obtaining the first characteristic value.

[0078] Step 22: Calculate the compensation parameter using the first eigenvalue as an input value.

[0079] Figure 4 In the example shown, the compensation parameter includes an ion implantation dose. In step 22, the ion implantation dose of the wafer is set according to the corresponding wafer boat slot of the wafer.

[0080] In some embodiments, the wafer boat includes multiple wafer boat area segments, each of the wafer boat area segments includes more than one wafer boat slot, and one wafer boat area segment corresponds to a compensation dose; in step 22, the wafer boat area segment in which the wafer is located is determined according to the wafer boat slot of the wafer, and then the corresponding compensation dose is selected according to the wafer boat area segment as the ion implantation dose of the wafer.

[0081] In some examples, the compensation dose can be set according to the following Table 3:

[0082] Table 3

[0083] Compensation value lower limit (not less than) Compensation value upper limit (less than) <![CDATA[Compensation dose (cm -2 )]]> 1 2 2.8E12 2 3 2.85E12 3 4 2.95E12 4 5 3E12 5 47 3.05E12 47 48 3.1E12 48 49 3.15E12 49 50 3.2E12 50 51 3.25E12

[0084] In Table 3, the lower limit of the compensation value indicates the lower limit of the wafer boat area segment, and the upper limit of the compensation value indicates the upper limit of the wafer boat area segment. The wafer boat slot and the lower limit of the compensation value and the upper limit of the compensation value are compared to obtain the corresponding wafer boat area segment. In Table 3, the wafer boat includes 51 wafer boat slots, which are divided into 9 wafer boat area segments. For example, 1 to 2 are the first wafer boat area segment, and the corresponding compensation dose is 2.8E12cm -2 2 to 3 are the second wafer boat area segment, and the corresponding compensation dose is 2.85E12cm -2 Similarly, 50 to 51 are the ninth wafer boat area segment, and the corresponding compensation dose is 3.25E12cm -2 .

[0085] Step 23: Perform operation of the first front-layer site according to the set compensation parameters.

[0086] For example, if the wafer to be processed corresponds to the wafer boat slot between 5 and 47, the compensation parameter is 3.05E12cm -2 ; then use 3.05E12cm -2 Ions are implanted into the wafer with a corresponding ion implantation dose.

[0087] After each of the wafers in the batch corresponding to the wafer boat completes the operation of the previous layer of stations, the subsequent step three is performed.

[0088] Figure 4 In the process, step two corresponds to step S402, first front layer site (compensation site): ion implantation.

[0089] Step 3: Perform operations on the first back-end site.

[0090] In the embodiment of the present invention, the operation of the first back-layer site is performed according to the setting of the first characteristic value.

[0091] Figure 4 In the example shown, each wafer is loaded into a corresponding wafer boat slot according to the recorded batch and the wafer boat slot of each wafer in the batch, and the operation is performed.

[0092] Figure 4 In the step, step three corresponds to step S403, the first rear layer site: furnace tube.

[0093] In the existing advanced process control methods, feedforward control is to compensate and control the process parameters of the rear-layer site according to the measurement parameters of the front-layer site, that is, to compensate for the parameter deviation of the front layer by adjusting the process parameters of the rear layer, that is, the rear layer compensates the front layer. It is impossible to realize the front-layer site to compensate the rear-layer site by the feedforward method. In the embodiment of the present invention, by setting a mirror site of the first rear-layer site, the mirror site can be placed before the first front-layer site, so that the mirror site can be used as a new front-layer site, that is, the second front-layer site, and the first front-layer site can be used as a new rear-layer site, that is, the second rear-layer site. The second rear-layer site can be used as a compensation site, so that feedforward control can be realized between the second front-layer site and the compensation site, and finally feedforward advanced process control can be realized. Since the front-layer site of the feedforward control is realized by using the mirror site of the first rear-layer site, it is also called pseudo-feedforward advanced process control. Therefore, the embodiment of the present invention can use the feedforward method to realize the first front-layer site to compensate the first rear-layer site, thereby reducing the product performance fluctuation of the first rear-layer site.

[0094] The embodiment of the present invention is particularly suitable for using the ion implantation dose of the front layer to compensate for the difference in film thickness or film quality between slots of the furnace tube wafer boat of the rear layer, and finally reducing the product performance difference caused by the difference in the furnace tube film.

[0095] The advanced process control device of the embodiment of the present invention is used to realize the first front layer site to compensate the first rear layer site, including:

[0096] The mirror site setting module is used to set a mirror site of the first back-end site, and use the mirror site to simulate the first back-end site.

[0097] Figure 4 In the example shown, the first front layer site includes: an ion implantation site;

[0098] The first rear layer site includes a furnace tube site. Figure 4 In the embodiment, the mirror site setting module corresponds to the implementation step S401, mirror site (second front layer site): furnace tube mirror.

[0099] The feedforward advanced process control module is used to implement: using the mirror site as the second front-layer site of the feedforward advanced process control, using the first front-layer site as the compensation site of the feedforward advanced process control, performing the feedforward advanced process control to implement setting of compensation parameters of the compensation site and performing operations of the first front-layer site according to the set compensation parameters.

[0100] In the embodiment of the present invention, in the feedforward advanced process control module, the step of the feedforward advanced process control includes:

[0101] Step 21: simulate the mirror site to extract a first characteristic value.

[0102] Figure 4 In the example shown, the simulation of step 21 includes: according to the wafer loading rules of the furnace tube station, simulating the wafer boat slot position of each wafer in the batch in the furnace tube during actual operation and constructing the batch accordingly and recording the batch and the wafer boat slot position of each wafer in the batch, and the first characteristic value is the wafer boat slot position of each wafer.

[0103] Usually, a batch (lot) of wafers is placed in the same wafer box, and the maximum number of wafers that can be placed in the wafer box is 25. The wafer boat of the furnace tube can hold multiple batches of wafers, and each batch corresponding to the wafer boat of the furnace tube forms a corresponding batch, and each wafer in the batch is each wafer in the corresponding batch. Through the simulation, the corresponding relationship between the wafer boat and the batch and between each wafer and the slot of the wafer boat can be obtained, thereby obtaining the first characteristic value.

[0104] Step 22: Calculate the compensation parameter using the first eigenvalue as an input value.

[0105] Figure 4 In the example shown, the compensation parameter includes an ion implantation dose. In step 22, the ion implantation dose of the wafer is set according to the corresponding wafer boat slot of the wafer.

[0106] In some embodiments, the wafer boat includes multiple wafer boat area segments, each of the wafer boat area segments includes more than one wafer boat slot, and one wafer boat area segment corresponds to a compensation dose; in step 22, the wafer boat area segment in which the wafer is located is determined according to the wafer boat slot of the wafer, and then the corresponding compensation dose is selected according to the wafer boat area segment as the ion implantation dose of the wafer.

[0107] In some examples, the compensation dose can be set according to Table 3.

[0108] In Table 3, the wafer boat includes 51 wafer boat slots, which are divided into 9 wafer boat sections. For example, 1 to 2 is the first wafer boat section, and the corresponding compensation dose is 2.8E12cm -2 2 to 3 are the second wafer boat area segment, and the corresponding compensation dose is 2.85E12cm -2 Similarly, 50 to 51 are the ninth wafer boat area segment, and the corresponding compensation dose is 3.25E12cm -2 .

[0109] Step 23: Perform operation of the first front-layer site according to the set compensation parameters.

[0110] For example, if the wafer to be processed corresponds to the wafer boat slot between 5 and 47, the compensation parameter is 3.05E12cm -2 ; then use 3.05E12cm -2 Ions are implanted into the wafer with a corresponding ion implantation dose.

[0111] After each of the wafers in the batch corresponding to the wafer boat completes the operation of the previous layer of stations, the subsequent step three is performed.

[0112] Figure 4 In the embodiment, the feedforward advanced process control module corresponds to the implementation of step S402, the first front layer site (compensation site): ion implantation.

[0113] The second process control module is used to implement the operation of the first back-layer site.

[0114] In the embodiment of the present invention, the operation of the first back-layer site is performed according to the setting of the first characteristic value.

[0115] Figure 4 In the example shown, each wafer is loaded into a corresponding wafer boat slot according to the recorded batch and the wafer boat slot of each wafer in the batch, and the operation is performed.

[0116] Figure 4 In the embodiment, the second process control module corresponds to the implementation of step S403, the first rear layer site: furnace tube.

[0117] The embodiment of the present invention realizes a pseudo-feedforward advanced process control method. By setting a furnace tube mirror site before the ion implantation process, it disguises itself as a feedforward advanced process control problem, and uses the front-layer ion implantation dose to compensate for the difference in film thickness / film quality between the slots of the rear-layer furnace tube crystal boat, thereby reducing product performance fluctuations.

[0118] In an embodiment of the present invention, a furnace tube mirror station is set before the ion implantation station. At this station, the wafer boat slot position of each wafer in the batch in the furnace tube during actual operation can be simulated according to the wafer loading rules of the furnace tube station, and the batch is constructed and the wafer boat slot position of each wafer is recorded accordingly; the mirror station is used as the front-layer station of pseudo-feedforward advanced process control, and the wafer boat slot position of each wafer is used as the front-layer feature.

[0119] The ion implantation site is used as the compensation site of pseudo-feedforward advanced process control, and the compensation parameter is the ion implantation dose. The wafer boat slot position recorded by the wafer at the front site is used as input, and a unique compensation dose is selected according to the interval where the wafer boat slot position is located, and the operation is performed with this dose. For example, as shown in Table 3, the front wafer boat slot position is 46, which is between [5,47], so 3.05E12 is used for operation.

[0120] The furnace tube station does not need compensation. It only needs to load each wafer into the designated wafer boat slot according to the batch constructed by the previous station and the wafer boat slot of each wafer in the batch.

[0121] Essentially, feedforward advanced process control cannot be used to compensate for the difference between the slots of the back-layer furnace tube wafer boat using the front-layer ion implantation dose. The embodiment of the present invention does the opposite and forges a furnace tube mirror site before the ion implantation site, successfully converting the problem into a feedforward advanced process control problem with the furnace tube site mirror as the front-layer site and the ion implantation site as the back-layer site.

[0122] The embodiment of the present invention can be easily integrated into the common feedforward advanced process control framework in the industry, and can be implemented by slightly modifying the dry etching-ion implantation feedforward advanced process control.

[0123] The embodiments of the present invention are further described below with reference to specific examples:

[0124] Embodiment 1:

[0125] SONOS devices are extremely sensitive to the properties of the ONO thin film grown in the SONOS furnace. Slight differences between different wafer boat slots will also affect device performance. Such slight differences cannot be adjusted by the SONOS furnace process.

[0126] However, by adjusting the tunnel ion implantation dose of the device unit below the ONO film in the SONOS device, the difference between different wafer boat slots can be compensated.

[0127] This problem can be solved using pseudo-feedforward advanced process control:

[0128] A furnace tube mirror site is set up before the Cell Tunnel Implant site to construct the batch of furnace tube sites in advance and set the wafer boat slot position for each wafer in the batch; the mirror site is used as the front-layer site for pseudo-feedforward advanced process control, and the wafer boat slot position of each wafer is used as the front-layer feature.

[0129] At this site, according to the wafer loading rules of the furnace tube site, the wafer boat slot position of each wafer in the batch in the furnace tube during actual operation is simulated, and the batch is constructed accordingly and the wafer boat slot position of each wafer is recorded.

[0130] The Cell Tunnel Implant site is used as the compensation site for pseudo-feedforward advanced process control. The compensation parameter is the ion implantation dose. The wafer boat slot position recorded by the wafer at the front site is used as the input. A unique compensation dose is selected according to the interval where the wafer boat slot position is located, and the operation is performed with the dose. For example, according to Table 3 above, if the front wafer boat slot position is 46, which is between [5,47], 3.05E12 is used for the operation.

[0131] The SONOS furnace tube station does not require compensation. It only needs to load each wafer into the designated wafer boat slot according to the batch constructed by the previous station and the wafer boat slot of each wafer in the batch.

[0132] Embodiment 2:

[0133] Low-power CMOS devices are extremely sensitive to the thickness of the gate oxide film grown in the furnace tube. There is an inherent S-shaped curve of film thickness-wafer boat slot inside the furnace tube. Even if the temperature is simply pulled to forcibly flatten the film thickness S-shaped curve, the change in film quality caused by temperature will also lead to differences in device performance between wafer boat slots.

[0134] However, by adjusting the Well Vt Adjust Implant dose under the Gate Oxide film in the Low-Power CMOS device, the film thickness and film quality differences between different wafer boat slots can be compensated. This problem can also be solved by using pseudo-feedforward advanced process control.

[0135] The present invention has been described in detail above through specific embodiments, but these do not constitute limitations of the present invention. Without departing from the principle of the present invention, those skilled in the art may also make many variations and improvements, which should also be considered as the protection scope of the present invention.

Claims

1. An advanced process control method, characterized in that: The method for realizing a first front-layer site compensating a first rear-layer site comprises the following steps: Step 1: Setting a mirror site of the first back-end site, and using the mirror site to simulate the first back-end site; Step 2: using the mirror site as the second front site of feedforward advanced process control, using the first front site as the compensation site of the feedforward advanced process control, performing the feedforward advanced process control to set compensation parameters of the compensation site and performing the operation of the first front site according to the set compensation parameters; Step 3: Perform operations on the first back-end site.

2. The advanced process control method according to claim 1, characterized in that: In step 2, the feedforward advanced process control includes: Step 21: simulating the mirror site to extract a first characteristic value; Step 22, calculating the compensation parameter using the first characteristic value as an input value; Step 23: Perform operation of the first front-layer site according to the set compensation parameters.

3. The advanced process control method according to claim 2, characterized in that: In step three, the operation of the first back-layer site is performed according to the setting of the first characteristic value.

4. The advanced process control method according to claim 3, characterized in that: The first front layer site includes: an ion implantation site; The first rear layer site includes a furnace tube site.

5. The advanced process control method according to claim 4, characterized in that: The simulation of step 21 includes: according to the wafer loading rules of the furnace tube station, simulating the wafer boat slot position of each wafer in the batch in the furnace tube during actual operation, and constructing the batch accordingly and recording the batch and the wafer boat slot position of each wafer in the batch, and the first characteristic value is the wafer boat slot position of each wafer.

6. The advanced process control method according to claim 5, characterized in that: The compensation parameter includes an ion implantation dose. In step 22, the ion implantation dose of the wafer is set according to the corresponding wafer boat slot of the wafer.

7. The advanced process control method according to claim 6, characterized in that: The wafer boat includes multiple wafer boat area segments, each of the wafer boat area segments includes more than one wafer boat slot, and one wafer boat area segment corresponds to a compensation dose; in step 22, the wafer boat area segment where the wafer is located is determined according to the wafer boat slot of the wafer, and then the corresponding compensation dose is selected according to the wafer boat area segment as the ion implantation dose of the wafer.

8. The advanced process control method according to claim 5, characterized in that: In step three, each wafer is loaded into a corresponding wafer boat slot according to the recorded batch and the wafer boat slot of each wafer in the batch, and the operation is performed.

9. An advanced process control device, characterized in that: The method is used to realize compensation of the first rear-layer site by the first front-layer site, including: A mirror site setting module, used to set a mirror site of the first back-end site, and use the mirror site to simulate the first back-end site; A feedforward advanced process control module, used to implement: using the mirror site as a second front-layer site of the feedforward advanced process control, using the first front-layer site as a compensation site of the feedforward advanced process control, performing the feedforward advanced process control to implement setting of compensation parameters of the compensation site and performing the operation of the first front-layer site according to the set compensation parameters; The second process control module is used to implement the operation of the first back-layer site.

10. The advanced process control device according to claim 9, characterized in that: In the feedforward advanced process control module, the feedforward advanced process control step includes: Step 21: simulating the mirror site to extract a first characteristic value; Step 22, calculating the compensation parameter using the first characteristic value as an input value; Step 23: Perform operation of the first front-layer site according to the set compensation parameters.

11. The advanced process control device according to claim 10, characterized in that: In the second process control module, the operation of the first back-layer site is performed according to the setting of the first characteristic value.

12. The advanced process control device according to claim 11, characterized in that: The first front layer site includes: an ion implantation site; The first rear layer site includes a furnace tube site.

13. The advanced process control device according to claim 12, characterized in that: The simulation of step 21 includes: according to the wafer loading rules of the furnace tube station, simulating the wafer boat slot position of each wafer in the batch in the furnace tube during actual operation, and constructing the batch accordingly and recording the batch and the wafer boat slot position of each wafer in the batch, and the first characteristic value is the wafer boat slot position of each wafer.

14. The advanced process control device according to claim 13, characterized in that: The compensation parameter includes an ion implantation dose. In step 22, the ion implantation dose of the wafer is set according to the corresponding wafer boat slot of the wafer.

15. The advanced process control device according to claim 14, characterized in that: The wafer boat includes multiple wafer boat area segments, each of the wafer boat area segments includes more than one wafer boat slot, and one wafer boat area segment corresponds to a compensation dose; in step 22, the wafer boat area segment where the wafer is located is determined according to the wafer boat slot of the wafer, and then the corresponding compensation dose is selected according to the wafer boat area segment as the ion implantation dose of the wafer.

16. The advanced process control device according to claim 13, characterized in that: In the second process control module, each wafer is loaded into a corresponding wafer boat slot according to the recorded batch and the wafer boat slot of each wafer in the batch, and the operation is performed.

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