CN101458456B - Overlay precision control method and apparatus - Google Patents

Abstract

A control method and device for overlay accuracy, the control method for overlay accuracy includes: obtaining the lithography process conditions of the front layer lithography process; calculating the error introduced by the process according to the lithography process conditions of the front layer lithography process , and calculate the process compensation value of the current layer exposure machine according to the lithography process conditions of the previous layer lithography process and the error introduced by the calculated process; according to the calculated process compensation value of the current layer exposure machine, control the current layer The exposure machine performs the photolithography process. The method and device for controlling the overlay accuracy can reduce the position alignment error between the layers of the wafer and the photolithography pattern of the layer, so as to precisely control the overlay accuracy.

Description

The control method of alignment precision and device

Technical field

The present invention relates to photoetching process, particularly relate to a kind of control method and device of alignment precision.

Background technology

Photoetching is by series of steps such as aligning, exposures mask graph to be transferred to technological process on the wafer, in the manufacture process of semi-conductor chip, usually to just can finish whole manufacturing process by the multilayer photoetching process, and how to control position alignment when layer photoetching figure and anterior layer litho pattern (figure on the wafer), with the requirement of satisfying alignment precision (overlay) is crucial step in the multilayer photoetching process, and alignment precision is meant the position alignment error of layer with the litho pattern of layer of wafer.

At present, manufacturing company is to use advanced technologies control (APC, Advanced ProcessControl) system to carry out photoetching process mostly, to satisfy the requirement of alignment precision.The APC system is used for system that the technology board of each technological process is finely tuned and controlled, and it can adjust the running parameter of board in time, corrects the drift of board condition of work, makes the more approaching required specification of process results, obtains higher yield.In photo-etching technological process, the APC system adjusts the running parameter of exposure bench according to the error of exposure bench, the control exposure bench carries out photoetching process to wafer, simultaneously also can be according to the alignment precision that measures after the photoetching, readjusting the running parameter of exposure bench, is that the Chinese patent application patent of ZL200510111412.3 can find the relevant information of measuring the method for photoetching alignment precision at application number.

In the past, the multilayer photoetching process of whole manufacturing process all was to be finished by same manufacturing company, and the multilayer photoetching process, is accurately controlled alignment precision and also just become more and more easier along with the development of APC technology by the control of same set of APC system.Yet, continuous progress and development along with manufacturing technology, the multilayer photoetching process of whole manufacturing process can (be striden company by many companies respectively now, Cross Company) or a plurality of plant areas of a company (stride plant area, Cross Fab) finishes, the control of the alignment precision difficulty that becomes again like this, because different plant areas may use different exposure benchs, different companies may use different APC systems again, and board sum of errors systematic error can directly influence the position alignment error of layer with the litho pattern of layer of wafer.For instance, the A of company finishes front-end process (FEOL, frontend ofline) former layer photoetching technologies, the B of company finishes backend process (BEOL, back end ofline,) back which floor photoetching process because the APC system of the APC system of the A of company and exposure bench and the B of company and exposure bench is different, the position alignment of the litho pattern of the litho pattern of last one deck of front-end process and the ground floor of backend process just has bigger skew.

The method of alignment precision that existing a kind of control is striden company or striden the multilayer photoetching process of plant area is: the type according to exposure bench is set up the alignment precision control flow in the APC system, as shown in Figure 6, the A of company (plant area) uses exposure bench A1 and exposure bench A2, the B of company (plant area) uses exposure bench B1 and exposure bench B2,4 kinds of alignment precision control flows in the APC system of the B of company (plant area), have been stored, if that the anterior layer photoetching process is used is exposure bench A1, when layer photoetching technology will be used exposure bench B1, the APC system just selects control flow Loop1 to work as layer photoetching technology; If that the anterior layer photoetching process is used is exposure bench A1, when layer photoetching technology will be used exposure bench B2, the APC system just selects control flow Loop2 to work as layer photoetching technology; If that the anterior layer photoetching process is used is exposure bench A2, when layer photoetching technology will be used exposure bench B1, the APC system just selects control flow Loop3 to work as layer photoetching technology; If that the anterior layer photoetching process is used is exposure bench A2, when layer photoetching technology will be used exposure bench B2, the APC system just selects control flow Loop4 to work as layer photoetching technology.If the exposure bench that uses is many more, the quantity of alignment precision control flow is just many more, it is the quantity that the quantity that equals the exposure bench of the A of company (plant area) multiply by the exposure bench of the B of company (plant area), the quantity increase of alignment precision control flow has not only increased the storage volume of APC system, has also increased the complexity of APC system control.

Summary of the invention

The problem that the present invention solves is, a kind of control method and device of alignment precision is provided, with the layer that reduces wafer with layer the position alignment error of litho pattern, thereby accurately control alignment precision.

For addressing the above problem, the invention provides a kind of control method of alignment precision, comprising:

Obtain the photoetching process condition of anterior layer photoetching process;

Calculate the error that technological process is introduced according to the photoetching process condition of anterior layer photoetching process, and according to the photoetching process condition of anterior layer photoetching process with calculate Error Calculation that the technological process of gained the introduces technological compensa tion value when layer exposure bench;

According to the technological compensa tion value when layer exposure bench that calculates, control is worked as a layer exposure bench and is carried out photoetching process.

Optionally, described photoetching process condition according to the anterior layer photoetching process, the sum of errors that calculates the technological process introducing comprises when the technological compensa tion value of layer exposure bench: the format conversion of the photoetching process condition of anterior layer photoetching process being carried out data; According to the photoetching process condition of the anterior layer photoetching process after the format conversion, calculate the technological compensa tion value of the sum of errors of technological process introducing when layer exposure bench.

Optionally, the photoetching process condition of described anterior layer photoetching process comprises: the technological compensa tion value of the error amount of anterior layer exposure bench, anterior layer exposure bench, and described technological compensa tion value when layer exposure bench is calculated according to following formula:

PC(M0，l0)＝PC(m0，l-1)+[MS(m0，l-1)-MS(M0，l0)]+PIE(m0，M0)

Wherein, PC (M0, l0) expression is as the technological compensa tion value of layer exposure bench, PC (m0, l-1) the technological compensa tion value of expression anterior layer exposure bench, MS (m0, the l-1) error amount of expression anterior layer exposure bench, MS (M0, l0) expression is when the error amount of layer exposure bench, PIE (it calculates according to following formula for m0, the M0) error of expression technological process introducing:

$\mathrm{PIE}{(m0,M0)}_{\mathrm{new}}=\frac{\mathrm{PIE}{(m0,M0)}_{\mathrm{old}}*[R1(m0,M0)+k]+\mathrm{LPIE}(L0,l0)*C1}{R1(m0,M0)+k+C1}$

Wherein, and PIE (m0, M0) _NewThe error that the technological process of wafer required correspondence when carrying out exposure process that expression calculates is introduced, and PIE (m0, M0) _OldRepresent the error that existing technological process is introduced, k represents exposure technology weight factor first, and C1 represents weighting factor, R1 (m0, the M0) reliability coefficient of expression PIE,, it calculates according to following formula:

$R1{(m0,M0)}_{\mathrm{new}}=\frac{R1{(m0,M0)}_{\mathrm{old}}+C1}{1+C1},$

LPIE (it calculates according to following formula for L0, l0) every batch of pairing technological process error of wafer of expression itself:

LPIE(L0，l0)＝PC(M0，l0)-PC(m0，l-1)+MS(M0，l0)-MS(m0，l-1)-OV(L0，l0)

Wherein, (L0 l0) is the position alignment error of measuring the wafer gained after exposing to OV.

Optionally, the photoetching process condition of described anterior layer photoetching process comprises: the technological compensa tion value of anterior layer exposure bench, and described technological compensa tion value when layer exposure bench is calculated according to following formula:

PC(M0，l0)＝PC(m0，l-1)+MS(M0，l0)+PIE(m0，M0)

Wherein, and PC (M0, l0) expression is as the technological compensa tion value of layer exposure bench, PC (m0, l-1) the technological compensa tion value of expression anterior layer exposure bench, and MS (M0, l0) expression is when the error amount of layer exposure bench, PIE (it calculates according to following formula for m0, the M0) error of expression technological process introducing:

$\mathrm{PIE}{(m0,M0)}_{\mathrm{new}}=\frac{\mathrm{PIE}{(m0,M0)}_{\mathrm{old}}*[R1(m0,M0)+k]+\mathrm{LPIE}(L0,l0)*C1}{R1(m0,M0)+k+C1}$

Wherein, and PIE (m0, M0) _NewThe error that the technological process of wafer required correspondence when carrying out exposure process that expression calculates is introduced, and PIE (m0, M0) _OldRepresent the error that existing technological process is introduced, k represents exposure technology weight factor first, and C1 represents weighting factor, R1 (it calculates according to following formula for m0, the M0) reliability coefficient of expression PIE:

$R1{(m0,M0)}_{\mathrm{new}}=\frac{R1{(m0,M0)}_{\mathrm{old}}+C1}{1+C1},$

LPIE (it calculates according to following formula for L0, l0) every batch of pairing technological process error of wafer of expression itself:

LPIE(L0，l0)＝PC(M0，l0)-PC(m0，l-1)+MS(M0，l0)-MS(m0，l-1)-OV(L0，l0)

Wherein, (L0 l0) is the position alignment error of measuring the wafer gained after exposing to OV.

Optionally, the control method of described alignment precision also comprises: measure alignment precision; According to the alignment precision that measures, recomputate sum of errors that technological process introduces technological compensa tion value, and according to recomputating the technological compensa tion value that obtains when layer exposure bench when layer exposure bench, control is carried out photoetching process when a layer exposure bench.

Correspondingly, the present invention also provides a kind of control device of alignment precision, comprising:

Acquiring unit is used to obtain the photoetching process condition of anterior layer photoetching process;

Computing unit is used for the error according to the photoetching process condition calculating technological process introducing of anterior layer photoetching process, and works as the technological compensa tion value of layer exposure bench according to the photoetching process condition of anterior layer photoetching process with the Error Calculation that the technological process of calculating gained is introduced;

Control module, be used for according to described computing unit calculate when the layer exposure bench the technological compensa tion value, control when the layer exposure bench carry out photoetching process.

Optionally, the control device of described alignment precision also comprises: converting unit, and the photoetching process condition that is used for anterior layer photoetching process that described acquiring unit is got access to is carried out the format conversion of data; The photoetching process condition of the anterior layer photoetching process of described computing unit after according to format conversion is calculated sum of errors that technological process the introduces technological compensa tion value when layer exposure bench.

Optionally, the control device of described alignment precision also comprises: measuring unit is used to measure alignment precision, and gives described computing unit with measurement feedback; Described computing unit recomputates the technological compensa tion value of the sum of errors of technological process introducing when layer exposure bench according to the alignment precision that measures; Described control module is according to recomputating the technological compensa tion value when layer exposure bench that obtains, and control is worked as layer exposure bench and carried out photoetching process.

Compared with prior art, technique scheme is to have considered the photoetching process condition (mainly being the technological compensa tion value of anterior layer exposure bench) of anterior layer when the technological compensa tion value of calculating when layer exposure bench, that is to say, when the technological compensa tion value of layer exposure bench is that the sum of errors that combines the anterior layer exposure bench obtains when the Error Calculation of layer exposure bench, therefore, utilize this technological compensa tion value adjustment of working as layer exposure bench that calculates and control to work as a layer exposure bench wafer is carried out photoetching process, can reduce the position alignment error when layer photoetching figure and anterior layer litho pattern of wafer, and then reach the purpose of accurate control alignment precision.

And, technique scheme does not need to select different control flows according to different exposure benchs, that is to say, no matter what the front and back layer used is the exposure bench of which kind of type, only need just can obtain compensation way when layer exposure bench by a kind of account form, therefore, implement just more convenient.

In addition, technique scheme also has feedback system, promptly finish a collection of wafer after layer photoetching technology, the position alignment Error Feedback when layer photoetching figure and anterior layer litho pattern that the described wafer of measurement obtains is returned, recomputate technological compensa tion value when layer exposure bench, can adjust and optimize running parameter so in real time, and the control exposure bench is more accurately worked as layer photoetching technology to the next group wafer when layer exposure bench.

Description of drawings

Fig. 1 is the basic flow sheet of control method of the alignment precision of embodiment of the present invention;

Fig. 2 is the process flow diagram of control method of the alignment precision of first embodiment of the invention;

Fig. 3 is the structural representation of control device of the alignment precision of first embodiment of the invention;

Fig. 4 is the process flow diagram of control method of the alignment precision of second embodiment of the invention;

Fig. 5 is the structural representation of control device of the alignment precision of second embodiment of the invention;

Fig. 6 is existing APC system controls alignment precision according to the type of exposure bench a synoptic diagram.

Embodiment

The embodiment of the invention is to have considered the photoetching process condition (mainly being the technological compensa tion value of anterior layer exposure bench) of anterior layer when the technological compensa tion value of calculating when layer exposure bench, utilize this technological compensa tion value adjustment that calculates to work as the running parameter of layer exposure bench when layer exposure bench, control can compensate the position alignment error when layer photoetching figure and anterior layer litho pattern when layer exposure bench carries out photoetching process to wafer.

The basic procedure of the control method of the alignment precision of embodiment of the present invention comprises the steps: as shown in Figure 1

Step S11 obtains the photoetching process condition of anterior layer photoetching process.

Step S12 calculates the error that technological process is introduced according to the photoetching process condition of anterior layer photoetching process, and according to the photoetching process condition of anterior layer photoetching process with calculate Error Calculation that the technological process of gained the introduces technological compensa tion value when layer exposure bench.

Step S13, according to the technological compensa tion value when layer exposure bench that calculates, control is worked as a layer exposure bench and is carried out photoetching process.

Below in conjunction with drawings and Examples embodiment of the present invention is described in detail.

First embodiment

Fig. 2 is the process flow diagram of control method of the alignment precision of present embodiment, in the present embodiment, the photoetching process of front and back layer is striden plant area and is finished, the photoetching process of layer is that different plant areas by same company finish promptly, different plant areas can use different exposure benchs, also can use identical exposure bench.

Please refer to Fig. 2, the Aa of plant area of the A of company uses exposure bench A1 that wafer has been carried out the anterior layer photoetching process, and then, the Ab of plant area of the A of company uses exposure bench A2 to work as layer photoetching technology to wafer.

Step S21, the Ab of plant area at first need to obtain from the Aa of plant area the photoetching process condition of anterior layer photoetching process before using exposure bench A2 to work as layer photoetching technology.That is to say that the Aa of plant area offers the photoetching process condition Ab of plant area that will descend one deck (current one deck) photoetching process after using exposure bench A1 to finish the last layer photoetching technology of wafer.Wherein, the photoetching process condition that provides of the Aa of plant area mainly comprises: the technological compensa tion value of the error amount of anterior layer exposure bench A1, anterior layer exposure bench A1.Usually, the error amount of exposure bench by in the technological process to exposure bench monitor, its parameter of measurements and calculations obtains.The technological compensa tion value of anterior layer exposure bench A1 can obtain from the APC system of the Aa of plant area, and the APC system is the control exposure bench carries out photoetching process to wafer a system.In addition, the photoetching process condition that the Aa of plant area provides also comprises: batch sign (Lot ID, common 1 Lot comprises 25 wafer at most), layer identify the type of (layer ID), anterior layer exposure bench A1, directly offer the APC system of the Ab of plant area.

Step S22, according to the error amount of anterior layer exposure bench A1, the technological compensa tion value of anterior layer exposure bench A1, calculate the technological compensa tion value of the sum of errors of technological process (being meant that layer photoetching technology is to the technological process when layer photoetching technology in the past) introducing as layer exposure bench A2.When the technological compensa tion value of layer exposure bench is calculated according to formula (1):

PC(M0，l0)＝PC(m0，l-1)+[MS(m0，l-1)-MS(M0，l0)]+PIE(m0，M0) (1)

Wherein, M0 represents that m0 represents the anterior layer exposure bench when layer exposure bench, l0 represents that l-1 represents anterior layer, PC (M0 when layer, l0) the technological compensa tion value of layer exposure bench is worked as in expression, PC (m0, l-1) the technological compensa tion value of expression anterior layer exposure bench, MS (m0, the l-1) error amount of expression anterior layer exposure bench, MS (M0, l0) expression is when the error amount of layer exposure bench, PIE (it calculates according to formula (2) for m0, the M0) error of expression technological process introducing:

$\mathrm{PIE}{(m0,M0)}_{\mathrm{new}}=\frac{\mathrm{PIE}{(m0,M0)}_{\mathrm{old}}*[R1(m0,M0)+k]+\mathrm{LPIE}(L0,l0)*C1}{R1(m0,M0)+k+C1}---\left(2\right)$

Wherein, and PIE (m0, M0) _NewThe error that the technological process of wafer required correspondence when carrying out exposure process that expression calculates is introduced, and PIE (m0, M0) _OldRepresent the error that existing technological process is introduced; K represents exposure technology weight factor first, and the PIE that only is used for initial exposing wafer technology calculates, and value is 0.75, and later value is 0; C1 represents weighting factor, is a constant, and value is 0.25 usually; R1 (promptly by the safety factor of error in whole computation process of the technology skill process introducing of calculating gained, it calculates according to formula (3) for m0, the M0) reliability coefficient of expression PIE:

$R1{(m0,M0)}_{\mathrm{new}}=\frac{R1{(m0,M0)}_{\mathrm{old}}+C1}{1+C1}---\left(3\right)$

R1 (m0, M0) _NewSpan be 0＜R1 (m0, M0) _New＜0.9999, the initial value of R1 is artificial the setting, is generally one greater than 0 a small amount of, for example 0.01 or 0.1, calculate gained R1 (m0, M0) _NewAs R1 (m0, M0) substitution in the formula (2); LPIE (it calculates according to formula (4) for L0, l0) every batch of pairing technological process error of wafer of expression itself:

LPIE(L0，l0)＝PC(M0，l0)-PC(m0，l-1)+MS(M0，l0)-MS(m0，l-1)-OV(L0，l0)

(4)

OV (L0, l0) the position alignment error of the wafer gained after the measurement exposure.

According to formula (3), (4) calculate R1 (m0, M0) and LPIE (L0, l0) after, again according to formula (2) calculating PIE (m0, M0) _New, the PIE of calculating gained (m0, M0) _NewAs PIE (m0, M0) substitution in the formula (1).

Step S23, according to the technological compensa tion value as layer exposure bench A2 that step S22 calculates, control exposure bench A2 carries out photoetching process.Specifically, according to the technological compensa tion value PC (M0 that calculates as layer exposure bench A2, l0), utilize the running parameter that the APC system adjusts and layer exposure bench A2 is worked as in optimization of the Ab of plant area, control the photoetching process that exposure bench A2 finishes current one deck of wafer then.

Step S24, finished the photoetching process of current one deck of a collection of wafer at exposure bench A2 after, measure the alignment precision of wafer, that is to say, measure the position alignment error when layer photoetching figure and anterior layer litho pattern of wafer.Then be back to step S22, recomputate the error PIE that technological process introduces (m0, M0) and when the technological compensa tion value PC of layer exposure bench (M0, l0).With measure gained current a collection of wafer (finishing the wafer of the photoetching process of current one deck) the position alignment error as OV (L0, l0) substitution formula (4) calculate LPIE (L0, l0), calculate R1 (m0 according to formula (3), M0), again according to formula (2) calculate PIE (m0, M0) _New, the PIE of calculating gained (m0, M0) _NewThe error PIE that introduces as technological process (m0, M0) substitution formula (1) calculate technological compensa tion value PC when layer exposure bench (M0, l0).

The position alignment Error Feedback when layer photoetching figure and anterior layer litho pattern of the wafer that measures is returned, recomputate the error PIE (m0 that technological process is introduced, M0), like this, the APC system of the Ab of plant area can be according to recomputating the technological compensa tion value PC (M0 when layer exposure bench that obtains, l0) adjust again and optimize a running parameter, control exposure bench A2 in real time and more accurately the next batch wafer is worked as layer photoetching technology as layer exposure bench A2.

In other embodiments, also can not comprise step S24, just after exposure bench A2 has finished the photoetching process of a collection of wafer, the APC system still can utilize the technological compensa tion value PC (M0 when layer exposure bench that calculated originally, l0), control exposure bench A2 carries out photoetching process to the next batch wafer.

The technological compensa tion value of the exposure bench A2 that aforementioned calculation obtains can offer the plant area or the company that will carry out lower floor's photoetching process to wafer.

Corresponding to the control method of the alignment precision of present embodiment, the control device of the alignment precision of present embodiment comprises as shown in Figure 3: acquiring unit 31, computing unit 33, control module 34, measuring unit 35.The control device of described alignment precision can be connected with the APC system, perhaps is arranged in the APC system.

Acquiring unit 31 is used to obtain the photoetching process condition of anterior layer photoetching process.Wherein, the photoetching process condition of anterior layer photoetching process mainly comprises: the technological compensa tion value of the error amount of anterior layer exposure bench and anterior layer exposure bench.In addition, the photoetching process condition also comprises: the type of batch sign, layer sign, anterior layer exposure bench A1.

Computing unit 33, the photoetching process condition that is used for the anterior layer photoetching process that gets access to according to acquiring unit 31 is calculated the error that technological process is introduced, and the photoetching process condition of the anterior layer photoetching process that gets access to according to acquiring unit 31 and calculate Error Calculation that the technological process of gained the introduces technological compensa tion value when layer exposure bench.In the present embodiment, computing unit 33 is the error amount MS (m0 according to the anterior layer exposure bench, l-1) and the technological compensa tion value PC (m0 of anterior layer exposure bench, l-1), utilize formula (2) to calculate the error PIE (m0 that technological process is introduced earlier, M0), utilize again formula (1) calculate technological compensa tion value PC when layer exposure bench (M0, l0).

Control module 34, be used for according to computing unit 33 calculate when the layer exposure bench the technological compensa tion value, control when the layer exposure bench carry out photoetching process.The technological compensa tion value when layer exposure bench that control module 34 will calculate offers the APC system, and the APC system adjusts and optimizes the running parameter of working as layer exposure bench, controls the photoetching process that exposure bench is finished current one deck of wafer then.

Measuring unit 35, be used to measure the alignment precision of having finished when the wafer of layer photoetching technology, and give computing unit 33 with measurement feedback, computing unit 33 recomputates the technological compensa tion value of the sum of errors of technological process introducing when layer exposure bench, control module 34 is according to recomputating the technological compensa tion value when layer exposure bench that obtains, and control is worked as layer exposure bench and carried out photoetching process.

Second embodiment

Fig. 4 is the process flow diagram of control method of the alignment precision of present embodiment, in the present embodiment, the photoetching process company of striding of front and back layer finishes, and promptly the photoetching process of front and back layer is finished by different company, different company can use different exposure benchs, also can use identical exposure bench.

Please refer to Fig. 4, the A of company uses exposure bench A2 that wafer has been carried out the anterior layer photoetching process, and then, the B of company uses exposure bench B1 that wafer is worked as layer photoetching technology.

Step S41, the B of company at first need to obtain from the A of company the photoetching process condition of anterior layer photoetching process before using exposure bench B1 to work as layer photoetching technology.That is to say that the A of company offers the photoetching process condition B of company that will descend one deck (current one deck) photoetching process after using exposure bench A2 to finish the last layer photoetching technology of wafer.Wherein, the photoetching process condition that the A of company provides mainly comprises: the technological compensa tion value of anterior layer exposure bench A2, it can obtain from the APC system of the A of company.The photoetching process condition that the A of company provides also comprises: batch sign, layer identify, the type of anterior layer exposure bench A1, directly offer the APC system of the B of company.In addition, the photoetching process condition of the anterior layer photoetching process among first embodiment also comprises the error amount of anterior layer exposure bench, in the present embodiment, owing to be that the company of striding carries out photoetching process, the restriction that transmitted by information, the B of company may not be the error amount that is easy to obtain the anterior layer exposure bench A2 of the A of company, the error amount of anterior layer exposure bench is very little usually, therefore present embodiment has been ignored the error amount of anterior layer exposure bench, and the error amount that is about to the anterior layer exposure bench is made as 0.Certainly, the error amount of the anterior layer exposure bench of first embodiment also is negligible.

Step S42 carries out the format conversion of data to the photoetching process condition of obtaining from the A of company, and the APC system that obtains the B of company can the recognition data form.Usually, same company can use identical APC system, therefore, the plant area that carries out the anterior layer photoetching process will batch sign, when the technological compensa tion value of the type of layer sign, anterior layer exposure bench, anterior layer exposure bench offers the plant area that works as layer photoetching technology, the APC system that works as the plant area of layer photoetching technology can discern these data, therefore do not need these data are carried out format conversion, for example first embodiment does not just need to carry out the format conversion of data.In the present embodiment, owing to be the photoetching process of layer before and after the company of striding carries out, different company uses different APC systems respectively, like this, the A of company that carries out the anterior layer photoetching process will batch sign, when the technological compensa tion value of the type of layer sign, anterior layer exposure bench, anterior layer exposure bench offers the B of company that works as layer photoetching technology, the APC system of the B of company possibly can't discern these data, therefore, need carry out format conversion to these data, the APC system that converts the B of company to can the recognition data form.Batch sign, the layer that obtains through format conversion identifies, the type of anterior layer exposure bench A2 can offer the APC system of the B of company.

Step S43 according to the technological compensa tion value of the anterior layer exposure bench A2 after the format conversion, calculates the technological compensa tion value of the sum of errors of technological process (being meant that layer photoetching technology is to the technological process when layer photoetching technology in the past) introducing as layer exposure bench B1.When the technological compensa tion value of layer exposure bench is calculated according to following formula (5):

PC(M0，l0)＝PC(m0，l-1)-MS(M0，l0)+PIE(m0，M0) (5)

Wherein, M0 represents that m0 represents the anterior layer exposure bench when layer exposure bench, l0 represents that l-1 represents anterior layer, PC (M0 when layer, l0) expression is when the technological compensa tion value of layer exposure bench, PC (m0, l-1) the technological compensa tion value of expression anterior layer exposure bench, MS (M0, l0) expression is when the error amount of layer exposure bench, (its account form is identical with first embodiment for m0, the M0) error of expression technological process introducing for PIE.

In addition, if the B of company can obtain the error amount of anterior layer exposure bench A2, also can according to the error amount MS of the anterior layer exposure bench A2 after the format conversion (m0, l-1), the technological compensa tion value PC of anterior layer exposure bench A2 (m0, l-1), calculate the error PIE (m0 that technological process is introduced, M0) and when the technological compensa tion value PC of layer exposure bench B1 (M0, l0), wherein, (M0 l0) calculates according to formula (1) as the technological compensa tion value PC of layer exposure bench.

Step S44, according to the technological compensa tion value as layer exposure bench B1 that step S43 calculates, control exposure bench B1 carries out photoetching process.Specifically, according to the technological compensa tion value PC (M0 that calculates as layer exposure bench B1, l0), utilize the running parameter that the APC system adjusts and layer exposure bench B1 is worked as in optimization of the B of company, control the photoetching process that exposure bench B1 finishes current one deck of wafer then.

Step S45, finished the photoetching process of current one deck of a collection of wafer at exposure bench B1 after, measure the alignment precision of wafer, that is to say, measure the position alignment error when layer photoetching figure and anterior layer litho pattern of wafer.Then be back to step S43, recomputate the error PIE that technological process introduces (m0, M0) and when the technological compensa tion value PC of layer exposure bench (M0, l0).

The position alignment Error Feedback when layer photoetching figure and anterior layer litho pattern of the wafer that measures is returned, recomputate the error PIE (m0 that technological process is introduced, M0), like this, the APC system of the B of company can be according to recomputating the technological compensa tion value PC (M0 when layer exposure bench that obtains, l0) adjust again and optimize a running parameter, control exposure bench B1 in real time and more accurately the next batch wafer is worked as layer photoetching technology as layer exposure bench B1.

In other embodiments, also can not comprise step S35, just after exposure bench B1 has finished the photoetching process of a collection of wafer, the APC system still can utilize the technological compensa tion value PC (M0 when layer exposure bench that calculated originally, l0), control exposure bench B1 carries out photoetching process to the next batch wafer.

The technological compensa tion value of the exposure bench B1 that aforementioned calculation obtains can offer the plant area or the company that will carry out lower floor's photoetching process to wafer.

Corresponding to the control method of the alignment precision of present embodiment, the control device of the alignment precision of present embodiment comprises as shown in Figure 5: acquiring unit 51, converting unit 52, computing unit 53, control module 54, measuring unit 55.The control device of described alignment precision can be connected with the APC system, perhaps is arranged in the APC system.

Acquiring unit 51 is used to obtain the photoetching process condition of anterior layer photoetching process.Wherein, the photoetching process condition of anterior layer photoetching process mainly comprises: the technological compensa tion value of anterior layer exposure bench.In addition, the photoetching process condition also comprises: the type of batch sign, layer sign, anterior layer exposure bench A1.

Converting unit 52, the photoetching process condition that is used for anterior layer photoetching process that acquiring unit 51 is got access to is carried out the format conversion of data, and controlled APC system when layer photoetching technology can the recognition data form.

Computing unit 53, the photoetching process condition that is used for the anterior layer photoetching process that is converted to according to converting unit 52 is calculated the error that technological process is introduced, and the photoetching process condition of the anterior layer photoetching process that is converted to according to converting unit 52 and calculate Error Calculation that the technological process of gained the introduces technological compensa tion value when layer exposure bench.In the present embodiment, computing unit 33 be according to the anterior layer exposure bench that is converted to technological compensa tion value PC (m0, l-1), utilize formula (2) to calculate the error PIE (m0 that technological process is introduced earlier, M0), utilize again formula (5) calculate technological compensa tion value PC when layer exposure bench (M0, l0).

Control module 54, be used for according to computing unit 53 calculate when the layer exposure bench the technological compensa tion value, control when the layer exposure bench carry out photoetching process.The technological compensa tion value when layer exposure bench that control module 54 will calculate offers the APC system, and the APC system adjusts and optimizes the running parameter of working as layer exposure bench, controls the photoetching process that exposure bench is finished current one deck of wafer then.

Measuring unit 55, be used to measure the alignment precision of having finished when the wafer of layer photoetching technology, and give computing unit 53 with measurement feedback, computing unit 53 recomputates the technological compensa tion value of the sum of errors of technological process introducing when layer exposure bench, control module 54 is according to recomputating the technological compensa tion value when layer exposure bench that obtains, and control is worked as layer exposure bench and carried out photoetching process.

In sum, technique scheme is to have considered the photoetching process condition (mainly being the technological compensa tion value of anterior layer exposure bench) of anterior layer when the technological compensa tion value of calculating when layer exposure bench, that is to say, when the technological compensa tion value of layer exposure bench is that the sum of errors that combines the anterior layer exposure bench obtains when the Error Calculation of layer exposure bench, therefore, utilize this technological compensa tion value adjustment of working as layer exposure bench that calculates and control to work as a layer exposure bench wafer is carried out photoetching process, can reduce the position alignment error when layer photoetching figure and anterior layer litho pattern of wafer, and then reach the purpose of accurate control alignment precision.

And, technique scheme does not need to select different control flows according to different exposure benchs, that is to say, no matter what the front and back layer used is the exposure bench of which kind of type, only need just can obtain compensation way when layer exposure bench by a kind of account form, therefore, implement just more convenient.

In addition, technique scheme also has feedback system, promptly finish a collection of wafer after layer photoetching technology, the position alignment Error Feedback when layer photoetching figure and anterior layer litho pattern that the described wafer of measurement obtains is returned, recomputate technological compensa tion value when layer exposure bench, can adjust and optimize running parameter so in real time, and the control exposure bench is more accurately worked as layer photoetching technology to the next group wafer when layer exposure bench.

Though the present invention with preferred embodiment openly as above; but it is not to be used for limiting the present invention; any those skilled in the art without departing from the spirit and scope of the present invention; can make possible change and modification, so protection scope of the present invention should be as the criterion with the scope that claim of the present invention was defined.

Claims (8)

1. the control method of an alignment precision is characterized in that, comprising:

Obtain the photoetching process condition of anterior layer photoetching process;

Calculate the error that technological process is introduced according to the photoetching process condition of anterior layer photoetching process, and according to the photoetching process condition of anterior layer photoetching process with calculate Error Calculation that the technological process of gained the introduces technological compensa tion value when layer exposure bench;

According to the technological compensa tion value when layer exposure bench that calculates, control is worked as a layer exposure bench and is carried out photoetching process,

Wherein, the photoetching process condition of described anterior layer photoetching process comprises: the technological compensa tion value of the error amount of anterior layer exposure bench, anterior layer exposure bench, and described technological compensa tion value when layer exposure bench is calculated according to following formula:

PC(M0，l0)＝PC(m0，l-1)+[MS(m0，l-1)-MS(M0，l0)]+PIE(m0，M0)

Wherein, PC (M0, l0) expression is as the technological compensa tion value of layer exposure bench, PC (m0, l-1) the technological compensa tion value of expression anterior layer exposure bench, MS (m0, the l-1) error amount of expression anterior layer exposure bench, MS (M0, l0) expression is when the error amount of layer exposure bench, PIE (it calculates according to following formula for m0, the M0) error of expression technological process introducing:

$\mathrm{PIE}{(m0,M0)}_{\mathrm{new}}=\frac{\mathrm{PIE}{(m0,M0)}_{\mathrm{olc}}*[R1(m0,M0)+k]+\mathrm{LPIE}(L0,l0)*C1}{R1(m0,M0)+k+C1}$

Wherein, and PIE (m0, M0) _NewThe error that the technological process of wafer required correspondence when carrying out exposure process that expression calculates is introduced, and PIE (m0, M0) _OldRepresent the error that existing technological process is introduced, k represents exposure technology weight factor first, and C1 represents weighting factor, R1 (it calculates according to following formula for m0, the M0) reliability coefficient of expression PIE:

$R1{(m0,M0)}_{\mathrm{new}}=\frac{R1{(m0,M0)}_{\mathrm{olc}}+C1}{1+C1},$

LPIE (it calculates according to following formula for L0, l0) every batch of pairing technological process error of wafer of expression itself:

LPIE(L0，l0)＝PC(M0，l0)-PC(m0，l-1)+MS(M0，l0)-MS(m0，l-1)-OV(L0，l0)

Wherein, (L0 l0) is the position alignment error of measuring the wafer gained after exposing to OV.

2. the control method of alignment precision according to claim 1 is characterized in that, described photoetching process condition according to the anterior layer photoetching process, and the sum of errors that calculates the technological process introducing comprises when the technological compensa tion value of layer exposure bench:

The photoetching process condition of anterior layer photoetching process is carried out the format conversion of data,, calculate sum of errors that technological process introduces technological compensa tion value when layer exposure bench according to the photoetching process condition of the anterior layer photoetching process after the format conversion.

3. the control method of alignment precision according to claim 1 is characterized in that, and the error amount MS of described anterior layer exposure bench (m0, l-1)=0.

4. the control method of alignment precision according to claim 1 is characterized in that, also comprises: measure alignment precision; According to the alignment precision that measures, recomputate sum of errors that technological process introduces technological compensa tion value, and according to recomputating the technological compensa tion value that obtains when layer exposure bench when layer exposure bench, control is carried out photoetching process when a layer exposure bench.

5. the control device of an alignment precision is characterized in that, comprising:

Acquiring unit is used to obtain the photoetching process condition of anterior layer photoetching process;

Computing unit is used for the error according to the photoetching process condition calculating technological process introducing of anterior layer photoetching process, and works as the technological compensa tion value of layer exposure bench according to the photoetching process condition of anterior layer photoetching process with the Error Calculation that the technological process of calculating gained is introduced;

Control module, be used for according to described computing unit calculate when the layer exposure bench the technological compensa tion value, control when the layer exposure bench carry out photoetching process,

Wherein, the photoetching process condition of described anterior layer photoetching process comprises: the technological compensa tion value of the error amount of anterior layer exposure bench, anterior layer exposure bench, described computing unit are calculated the technological compensa tion value of working as layer exposure bench according to following formula:

PC(M0，l0)＝PC(m0，l-1)+[MS(m0，l-1)-MS(M0，l0)]+PIE(m0，M0)

Wherein, PC (M0, l0) expression is as the technological compensa tion value of layer exposure bench, PC (m0, l-1) the technological compensa tion value of expression anterior layer exposure bench, MS (m0, the l-1) error amount of expression anterior layer exposure bench, MS (M0, l0) expression is when the error amount of layer exposure bench, PIE (it calculates according to following formula for m0, the M0) error of expression technological process introducing:

$\mathrm{PIE}{(m0,M0)}_{\mathrm{new}}=\frac{\mathrm{PIE}{(m0,M0)}_{\mathrm{olc}}*[R1(m0,M0)+k]+\mathrm{LPIE}(L0,l0)*C1}{R1(m0,M0)+k+C1}$

Wherein, and PIE (m0, M0) _NewThe error that the technological process of wafer required correspondence when carrying out exposure process that expression calculates is introduced, and PIE (m0, M0) _OldRepresent the error that existing technological process is introduced, k represents exposure technology weight factor first, and C1 represents weighting factor, R1 (it calculates according to following formula for m0, the M0) reliability coefficient of expression PIE:

$R1{(m0,M0)}_{\mathrm{new}}=\frac{R1{(m0,M0)}_{\mathrm{olc}}+C1}{1+C1},$

LPIE (it calculates according to following formula for L0, l0) every batch of pairing technological process error of wafer of expression itself:

LPIE(L0，l0)＝PC(M0，l0)-PC(m0，l-1)+MS(M0，l0)-MS(m0，l-1)-OV(L0，l0)

Wherein, (L0 l0) is the position alignment error of measuring the wafer gained after exposing to OV.

6. the control device of alignment precision according to claim 5 is characterized in that, also comprises: converting unit, and the photoetching process condition that is used for anterior layer photoetching process that described acquiring unit is got access to is carried out the format conversion of data; The photoetching process condition of the anterior layer photoetching process of described computing unit after according to format conversion is calculated sum of errors that technological process the introduces technological compensa tion value when layer exposure bench.

7. the control device of alignment precision according to claim 5 is characterized in that, and the error amount MS of described anterior layer exposure bench (m0, l-1)=0.

8. the control device of alignment precision according to claim 5 is characterized in that, also comprises: measuring unit is used to measure alignment precision, and gives described computing unit with measurement feedback; Described computing unit recomputates the technological compensa tion value of the sum of errors of technological process introducing when layer exposure bench according to the alignment precision that measures; Described control module is according to recomputating the technological compensa tion value when layer exposure bench that obtains, and control is worked as layer exposure bench and carried out photoetching process.

Images