CN101399147B

CN101399147B - Ion implantation method

Info

Publication number: CN101399147B
Application number: CN200710162318XA
Authority: CN
Inventors: 林伟政; 沈政辉
Original assignee: HANCHEN TECHNOLOGY Co Ltd
Current assignee: HANCHEN TECHNOLOGY Co Ltd
Priority date: 2007-09-27
Filing date: 2007-09-27
Publication date: 2011-11-02
Anticipated expiration: 2027-09-27
Also published as: CN101399147A

Abstract

An iron implantation method is used for implanting iron into target material; by adopting the iron implantation method, the target material is rotated and matched with constant-velocity scanning to implant a plurality of irons into the target material; or the variable-velocity scanning can be adopted to match the target material which is not rotated to implant a plurality of irons into the target material. The iron implantation result with special dosage distribution can be achieved without providing iron beam with even consistency distribution; the time of production process can be reduced and yield rate of the production process can be improved.

Description

Ion implantation method

Technical field

The present invention relates to a kind of ion implantation method, particularly a kind of ion implantation method of making special dosage ion distribution.

Background technology

In recent years, as large-scale integrated circuit (Large-scale integration, LSI) and the processing procedure of semiconductor device such as memory quite complicated, semiconductor substrate becomes dimensionally greatly and is very expensive, so controlled doping (doping) is an important issue to meet large-scale semiconductor device volume and density more accurately.What also therefore, the practical application of ion implantation method became is even more important.

Generally speaking, the molecular ionization that ion implantation method mixes desire, and quicken these ionizable doping, in the mode of scanning the ion of one given dose is implanted in the specific region of a substrate.Wherein, ion implantation method can more accurate controlled doping, so that the better uniformity to be provided.In addition, in the processing procedure of making semiconductor equipment, (critical dimension, distribution CD) directly influences manufacturing yield of products to grid (gate) critical size.Yet, according to grid CD on substrate distribution and other wall (sidewall) the other processing procedure that forms clearance wall (spacer) to come the variation of oxide-semiconductor control transistors parameter be unusual difficulty.When the size of substrate greater than 300mm semiconductor device more and more hour, the variation of oxide-semiconductor control transistors parameter will be a great problem.That is to say, the etch process of the hard mask of grid (hard mask) and gate pattern can be according to the position of substrate the fixing size of tool not.Therefore, it is inconsistent that the size of grid becomes, to produce the transistor parameter that changes according to different grid lengths.

So, ion implant procedure in multiple manufacture of semiconductor, often need be via allowing dose distribution characteristic uneven and that change arbitrarily in the base plan arbitrarily, to proofread and correct critical voltage (thresold voltage) problem of uneven distribution that in preposition processing procedure, is caused.

Known a kind of method of sweep speed when changing ion beam and implanting provides an ion concentration equally distributed ion beam, by changing sweep speed and rotary target material to finish the ion that the non-uniform dose of implanting predetermined pattern distributes.But this kind way, for providing ion concentration equally distributed ion beam, go the uniformity (uniformity) of adjustment ion beam in order to follow-up implantation operation, in addition in the reasonable time of needing cost, except the waste of collating time, being difficult for of adjustment technology also is another difficult problem.

Summary of the invention

In view of the above problems, one of the object of the invention provides a kind of ion implantation method, utilize to make special N type or P type dopant dose distribute with the compensation wafer in the previous operations processing procedure as little shadow, etching caused the element physical dimension inhomogeneous and cause element critical voltage in the wafer (threshold voltage) skewness.

One of the object of the invention provides a kind of ion implantation method, does not need to add with the change rate scanning simultaneously to rotate the effect that target can reach special dosage ion distribution.

One of the object of the invention provides a kind of ion implantation method, because do not need to provide even ion beam, can effectively reduce the collating time of ion beam CONCENTRATION DISTRIBUTION, moreover, also can reduce the processing procedure required time, and then improves production capacity.

One of the object of the invention provides a kind of method of adjusting ion-beam scanning speed, utilizes the relation of ion beam distribution concentration and target desired ion CONCENTRATION DISTRIBUTION to calculate ion-beam scanning speed, and it is respond well that ion is implanted.

In order to achieve the above object, an ion implantation method of one embodiment of the invention is used for ion is implanted a target, and ion implantation method comprises: an ion beam is provided, wherein contains a plurality of ions in the ion beam; Rotate target; And the ion in the ion beam implanted target according to first-class rate scanning.

One ion implantation method of further embodiment of this invention is used for ion is implanted a target, and ion implantation method comprises: an ion beam is provided, wherein contains a plurality of ions in the ion beam; And the ion in the ion beam implanted target according to one scan speed, wherein sweep speed is a change value.

A kind of method of adjusting ion-beam scanning speed of further embodiment of this invention, be used for a plurality of ions of an ion beam are implanted a target, wherein ion beam can be the ion beam of concentration non-uniform Distribution, adjusts the method for ion-beam scanning speed: the CONCENTRATION DISTRIBUTION that obtains ion beam; Obtain the CONCENTRATION DISTRIBUTION of the required implanting ions of target; And the one scan rate curve that calculates ion beam, wherein the sweep speed curved needle gets via computing the CONCENTRATION DISTRIBUTION of ion beam and the CONCENTRATION DISTRIBUTION of the required implanting ions of target.

Below illustrate in detail by the specific embodiment conjunction with figs., when the effect that is easier to understand purpose of the present invention, technology contents, characteristics and is reached.

Description of drawings

Figure 1 shows that ion concentration distribution figure according to ion implantation method first embodiment of the present invention.

Figure 2 shows that schematic side view according to target, rotation axis and the vertical axis of ion implantation method first embodiment of the present invention.

Fig. 3 A and Fig. 3 B are depicted as the schematic diagram according to target, rotation axis and the vertical axis of ion implantation method second embodiment of the present invention.

Figure 4 shows that round shape for hat is scheduled to the required implanting ions dose distribution of target.

Figure 5 shows that sweep speed curve distribution figure according to ion implantation method the 3rd embodiment of the present invention.

Figure 6 shows that rate curve schematic diagram according to the variable Rate scanning of ion implantation method the 4th embodiment of the present invention.

Figure 7 shows that rate curve schematic diagram according to the variable Rate scanning of ion implantation method the 5th embodiment of the present invention.

Fig. 8 A, Fig. 8 B, Fig. 8 C and Fig. 8 D are depicted as the target angle of inclination schematic diagram according to ion implantation method one embodiment of the present invention.

Fig. 8 E is depicted as known ion and implants the pattern shift schematic diagram.

Figure 9 shows that the flow chart of steps of method one embodiment that adjusts ion-beam scanning speed according to the present invention.

Figure 10 shows that the flow chart of steps of ion implantation method the 6th embodiment according to the present invention.

Figure 11 A is depicted as the known ion bundle according to the formed dose distribution map of linear constant-speed scanning.

Figure 11 B is depicted as the formed dose distribution map of known non-constant-speed scanning.

Figure 11 C is depicted as the dose distribution map that ion implantation method produced of first embodiment of the invention.

Figure 11 D is depicted as the dose distribution map that ion implantation method produced of the present invention three embodiment.

Figure 11 E is depicted as the dose distribution map that ion implantation method produced of fifth embodiment of the invention.

The main element symbol description:

10 targets

20 rotation axiss

30 vertical axises

B01, B02, B0 3, the B04 concentration curve

V01, the V02 rate curve

A, the B direction

The C single scanning

The D angle

The Savg Mean Speed

S10 obtains the ion beam CONCENTRATION DISTRIBUTION

S20 obtains the CONCENTRATION DISTRIBUTION of the required implanting ions of target

S30 calculates the one scan rate curve of ion beam

S40 judges above-mentioned sweep speed curve

The S50 set-up procedure

S60 provides an ion beam

S70 implants the ion of ion beam according to above-mentioned sweep speed curve

Target

Embodiment

The present invention implants special dose distribution on target, and this special dose distribution can be a different shape, can certainly be flat condition, and its figure of uniform dose distribution promptly is a flat condition.The method that the present invention uses determines the sweep speed curve according to ion beam distribution, and rotates target to reach required effect under suitable situation.In addition, can need adjust the angle of inclination of target and vertical axis with the dose distribution in the complete control element according to processing procedure.It is described in detail as follows, and an explanation is only done in described preferred embodiment, and is non-in order to limit the present invention.

At first, an ion implantation method of one embodiment of the invention is used for ion is implanted a target, and this ion implantation method comprises: an ion beam is provided, wherein contains a plurality of ions in the ion beam.Next, rotate target.At last, the ion in the ion beam is implanted target according to first-class rate scanning.In following first embodiment and second embodiment, promptly be speed such as utilization scanning target and cooperate and rotate target that it is described in detail as follows to reach required pattern.Please refer to Fig. 1, Figure 1 shows that according to the present invention ion implantation method first embodiment ion concentration distribution figure.Generally speaking, the ion beam CONCENTRATION DISTRIBUTION that the one chip ion is implanted is shown in the concentration curve B01 of Fig. 1, this is a uniform ion bundle, we can change the ion beam CONCENTRATION DISTRIBUTION easily, and provide required ion beam CONCENTRATION DISTRIBUTION (shown in concentration curve B02) according to actual demand, and in the process of implanting, sweep speed is a constant speed, and rotate target to reach required dose distribution, and this rotation can be continuity or combination at any angle, for example 0 degree and 180 degree or 0 degree, 90 degree, 180 degree or 270 degree.Moreover if continuity is rotated target, its slewing rate such as can be at speed or variable Rate, decides according to actual conditions; And noncontinuity is when rotating, and the dosage that each angle is implanted can be identical or different, decides according to required dose distribution map.

The above-mentioned explanation that continues in another embodiment, please be arranged in pairs or groups with reference to figure 1 and Fig. 2, and Fig. 2 is the schematic diagram of target, rotation axis and vertical axis.In this embodiment, the position of target, rotation axis and vertical axis concerns that as shown in Figure 2 the rotation axis of target 10 (twist) 20 is perpendicular to target 10, and when not tilting target 10, rotation axis 20 is also perpendicular to vertical axis 30.When ion beam scans target 10 with direction A, when if the ion beam CONCENTRATION DISTRIBUTION that provides is asymmetric, concentration curve B03 as Fig. 1, then, as long as target 10 is done to differ 180 degree with former angle to rotate, as double-head arrow direction B, the concentration curve B04 of its ion beam CONCENTRATION DISTRIBUTION such as Fig. 1 can produce symmetrical dose distribution.

Then, in second embodiment, the method for target is rotated in speed such as use still scanning collocation, and itself and the first embodiment difference are, in the scanning system of two dimension, control the dosage that ion is implanted by the scanning pattern density that changes target.Please refer to Fig. 3 A and Fig. 3 B, Fig. 3 A and Fig. 3 B are depicted as the schematic diagram in the two-dimensional scan path of different embodiment, the arrow direction indication is represented the scanning direction, as shown in the figure, scanning pattern density Gao Ze more represents the ion dose of implanting just high more, but is understandable that, its scanning pattern is not limited to graphic middle institute and illustrates, any scanning pattern that is changed according to the required implanting ions CONCENTRATION DISTRIBUTION of target, all letter is drawn together in category of the present invention.

In the foregoing description, change ion beam distribution or change scanning pattern density according to the required implant dosage distribution of target, and the bobbing target material is to reach optimum efficiency in scanning process, and its rotation can be continuous or discontinuous, and scan mode can be one dimension or two dimension.In addition, can allow machinery control easier etc. the speed scanning motion to reduce the load of control appliance.

In addition, also can use the mode of change rate scanning to carry out ion and implant operation, below promptly illustrate one by one with different implementation methods.

In the 3rd embodiment, calculate ion beam CONCENTRATION DISTRIBUTION and sweep speed curve according to the required implant dosage distribution of target.Being distributed as a circle shape for hat with required dosage is example, as shown in Figure 4, in the process of scanning and since when entering target when leaving target required dosage less, then its sweep speed is very fast; Target center desired ion dosage more for a long time, then its sweep speed is slower, so can produce the special dose distribution in the scanning direction, its sweep speed distribution map is shown in the rate curve V01 of Fig. 5.In an embodiment, ion beam distribution is vertical with the variable Rate scanning direction, so also can present required result in the dose distribution of vertical scanning direction.

Above-mentioned explanation continues, in another embodiment, the ion beam distribution that this method provided can not be single, after for example earlier doing variable Rate scanning, change the ion beam CONCENTRATION DISTRIBUTION again with a uniform ion bundle, with etc. speed scanning, its result can be equal to the result that change ion beam concentration adds variable Rate scanning, therefore, ion beam CONCENTRATION DISTRIBUTION and rate scanning curve are not restricted to single combination, can be two groups or above combination.In addition, the sweep speed curve is also asymmetric, and as the rate curve V02 of Fig. 5, asymmetric sweep speed only needs in the process of implanting, and adds target rotation and former angle are differed 180 degree angles, also can reach the result identical with the symmetrical rate curve.

Then, please refer to Fig. 6, Figure 6 shows that the rate curve schematic diagram of the variable Rate scanning of the 4th embodiment.In the 4th embodiment, change the density distribution of each scanning pattern of target and the variable Rate that changes each single scanning C according to the ion beam CONCENTRATION DISTRIBUTION according to the required implant dosage distribution of target.Be distributed as example with predetermined ion dose shown in Figure 4, it is very fast several times when target begins to enter ion beam, slow down speed afterwards, speed is accelerated again gradually after having crossed the target center line, thus generated inhomogeneities and the effect addition that changes path density can reach approaching dose distribution as shown in Figure 4.

Next, please refer to shown in Figure 7ly, Figure 7 shows that the rate curve schematic diagram of the variable Rate scanning of fifth embodiment of the invention.In the 5th embodiment, each single scanning C is variable Rate motion, and the Mean Speed of each single scanning C also distributes according to required dosage and make change, as the Savg in graphic.With ion distribution dosage shown in Figure 4 is example, in the method, as shown in Figure 7, each single scanning C speed still maintains " speed is fast " behavior, and the Mean Speed of single scanning when high dose, then reduces Mean Speed along with dose distribution adjusts each time; Otherwise increase.In the 3rd embodiment, the 4th embodiment and the 5th embodiment, because of need not rotating target, implant time of being spent to improve prouctiveness so can reduce ion.

In another embodiment, comprise that more the vertical axis angle of adjusting target is with the dose distribution in the control element.In the foregoing description, if the angle that ion is implanted non-vanishing (direction that refers to the ion implantation is not parallel with rotating shaft direction), and when using the ion beam of an inhomogeneous CONCENTRATION DISTRIBUTION, the angle of itself and vertical axis (is the inclination angle, tiltangle) needs to cooperate different target rotational angles (twist angle) do the forward or the adjustment of negative sense.It is described in detail as follows, and please arrange in pairs or groups with reference to figure 8A, Fig. 8 B, Fig. 8 C and Fig. 8 D, and wherein Fig. 8 A is the rotation front elevational schematic of 10 4 angles of target; Fig. 8 B is a predetermined pattern schematic side view of implanting; Fig. 8 C and Fig. 8 D are respectively the end view that target 10 rotates 0 degree differing tilt angles when spending with 180.Suppose on the target 10 that desire implants pattern shown in Fig. 8 B, implant that to be the 0 vertical axis 30 angle D that we adjust target 10 when spending implant for+θ degree rotational angle at the beginning, shown in Fig. 8 C when carrying out ion.Wherein, in graphic in target 10 predetermined patterns " point " density represent the dosage that ion is implanted.Then, when the rotational angle variation, the inclination angle is also and then different, shown in Fig. 8 D, when rotational angle is 180 when spending, this moment angle D be adjusted into-the θ degree is identical with the implantation direction that keeps each desire is implanted pattern, so, just can not cause the situation of the implantation pattern shift shown in Fig. 8 E to take place.This method of adjustment be applicable to above-mentioned all need rotate the embodiment of target, because of the element on the target is a stereochemical structure, utilizes different rotational angles and adjust dose distribution in the controllable elements of angle of inclination to improve the yield of element.

Figure 9 shows that the flow chart of steps of method one embodiment that adjusts ion-beam scanning speed according to the present invention.This method of adjusting ion-beam scanning speed is used for a plurality of ions of an ion beam are implanted a target (target), and in an embodiment, target can be wafer (wafer); And ion beam can be the ion beam (non-uniform ion beam) of concentration non-uniform Distribution.Wherein adjust ion implant concentration location mode, as shown in the figure, at first, read ion beam CONCENTRATION DISTRIBUTION (ion beam profile) (S10); Then, read the CONCENTRATION DISTRIBUTION (S20) of the required implanting ions of target; Come, the one scan rate curve (scan velocityprofile) of calculating ion beam (S30) again.In an embodiment, the calculating of sweep speed curve gets via computing at the CONCENTRATION DISTRIBUTION of the ion beam of being read and the CONCENTRATION DISTRIBUTION of the required implanting ions quantity of target.At this moment, ion beam can carry out ion implantation action to target according to the sweep speed curve that calculates.

The above-mentioned explanation that continues, in an embodiment, calculate sweep speed after, whether the sweep speed curve that more comprises judgement and calculated available, it judges whether this sweep speed curve falls in the valid interval value (S40).If the sweep speed curve that is calculated exceeds the valid interval value, then more comprise a set-up procedure (S50), in order to adjust the CONCENTRATION DISTRIBUTION of ion beam.In an embodiment, set-up procedure fine setting ion beam CONCENTRATION DISTRIBUTION, thereafter, repeating step S10, S20 and S30 implant operation to carry out ion after recomputating ion-beam scanning speed.

Following this method of adjusting ion-beam scanning speed that is about to is applied to do on the ion implantation method explanation.

Figure 10 shows that the flow chart of steps of ion implantation method the 6th embodiment according to the present invention.As shown in the figure, at first, provide an ion beam (S60), wherein contain a plurality of ions in the ion beam, in an embodiment, ion beam can be the ion beam of a concentration non-uniform Distribution, meaning promptly, the concentration of ion beam can be only to adjust through rough, and the error amount of distance objective value is rough to get final product at positive and negative about 30 percent ion beam, right, understandable, according to different machine control, error amount also can be different, and it is not limited to 30 percent; Then, carry out one and adjust ion-beam scanning speed step, this step comprises: the CONCENTRATION DISTRIBUTION (S10) that obtains ion beam; Obtain the CONCENTRATION DISTRIBUTION (S20) of the required implanting ions of target; And, the one scan bundle rate curve (S30) of calculating ion beam; At last, the ion in the ion beam is implanted target (S70) according to the sweep speed curve.In an embodiment, the calculating of sweep speed curve gets via computing at the CONCENTRATION DISTRIBUTION of the ion beam of being read and the CONCENTRATION DISTRIBUTION of the required implanting ions quantity of target.

The above-mentioned explanation that continues before ion is implanted target, more comprises and judges whether the sweep speed curve that calculates falls in the valid interval value (S40).In an embodiment, if the sweep speed curve exceeds valid interval, then more comprise a set-up procedure, in order to adjust the CONCENTRATION DISTRIBUTION (S50) of ion beam.In an embodiment, set-up procedure fine setting ion beam CONCENTRATION DISTRIBUTION, thereafter, repeating step S10, S20 and S30 implant operation to carry out ion after recalculating ion-beam scanning speed.In this embodiment, when ion is implanted, need rotary target material to meet the effect that different predetermined closes distribute to reach the uneven demand of ion dose CONCENTRATION DISTRIBUTION and to reach.

In this embodiment, because the ion beam that provided at the beginning needs not be very uniform ion bundle of ion concentration distribution, so when ion implantation device generation ion beam, can effectively shorten ion beam Production Time.In general, during for the equally distributed ion beam of generation ion concentration, its error amount apart from uniformity desired value need remain in positive and negative 5 percent, so the time for the CONCENTRATION DISTRIBUTION adjustment goes up, with respect to the time that does not generally need equally distributed ion beam and spent the many of the length that will come, also difficult control on the operating technology.Only, the ion beam of error amount in positive and negative 30 percent apart from uniformity desired value only need be provided among this embodiment herein, all can utilize the method for adjustment ion-beam scanning speed of the present invention, the ion that target is had the non-uniform dose distribution of predetermined pattern is implanted.

The above-mentioned explanation that continues, below promptly relatively at the work one of known technology and ion implantation method of the present invention.

Please refer to Fig. 4, Figure 11 A (known technology), Figure 11 B (known technology), Figure 11 C, Figure 11 D and Figure 11 E, Fig. 4 is the required implanting ions dose distribution of the predetermined target of an embodiment; Figure 11 A, Figure 11 B, Figure 11 C, Figure 11 D and Figure 11 E dose distribution map for being presented according to the different ions method for implantation.Wherein, Figure 11 A is depicted as the known ion bundle according to the formed dose distribution map of linear constant-speed scanning; And Figure 11 B is depicted as known a kind of even ion beam produces different scanning speed according to the required implanting ions dose distribution of target the formed dose distribution map of method; At last, Figure 11 C, Figure 11 D and Figure 11 E dose distribution map of utilizing ion implantation method of the present invention to produce.By comparison diagram 11A (known technology), Figure 11 B (known technology), Figure 11 C, Figure 11 D and Figure 11 E as can be known, according to the result (Figure 11 C, Figure 11 D and Figure 11 E) that ion implantation method of the present invention produced, the distribution of all more pressing close to the required implanting ions dosage of predetermined target as shown in Figure 4.

According to above-mentioned, one of feature of the present invention provides a specific inhomogeneous dose distribution, can with by inhomogeneous work one complementary effect of the physical dimension that produces in the previous operations to reach the equally distributed purpose of characteristic electron in the target, and the distribution of ion implant dosage is not limited to any geometric distribution, for example can be polygon.In addition, be understandable that said method can be finished on any general-purpose computer system or other devices; In addition, also can be applicable to have the computer system of special hardware equipment.What is more, this kind ion implantation method also can be by real as a plurality of formulas and be stored in the Storage Media that any electronic installation can read, be written into, carry out formula by electronic installation and finish above-mentioned ion implantation method, wherein electronic installation can be a computer, and formula is not limited to any manifestation mode and any programming language.

Comprehensively above-mentioned, the invention provides a kind of ion implantation method, utilize to make special N type or P type mix dose distribution with the compensation wafer in the previous operations processing procedure as little shadow, etching caused the element physical dimension inhomogeneous and cause element critical voltage skewness in the wafer.And ion implantation method of the present invention does not need to add with the scanning of speed change degree simultaneously and rotates the effect that target can reach special dosage ion distribution.Again,, can effectively reduce the collating time of ion beam CONCENTRATION DISTRIBUTION, moreover, also can reduce the processing procedure required time, and then improve production capacity because do not need to provide even ion beam.In addition, utilize the relation of ion beam CONCENTRATION DISTRIBUTION and target desired ion CONCENTRATION DISTRIBUTION to calculate ion-beam scanning speed, it is respond well that ion is implanted.

Above-described embodiment only is explanation technological thought of the present invention and characteristics, its purpose makes the personage who has the knack of this skill can understand content of the present invention and is implementing according to this, when can not with qualification claim of the present invention, promptly the equalization of doing according to disclosed spirit generally changes or modifies, and must be encompassed in the claim of the present invention.

Claims

1. an ion implantation method is used for ion is implanted a target, and this ion implantation method comprises following step:

One ion beam is provided, wherein contains a plurality of ions in this ion beam; And

Those ions in this ion beam are carried out two-dimensional scan according to one scan speed to this target, and wherein this sweep speed is meant that the sweep speed of a single scanning and this sweep speed are a change value; Reach CONCENTRATION DISTRIBUTION, control the one scan rate curve of each this single scanning, and a Mean Speed of each single scanning is along with dose distribution adjusts according to the required implanting ions of this target.

2. ion implantation method as claimed in claim 1, it is characterized in that, more comprise this sweep speed curve that calculates this ion beam and rotate this target, wherein this sweep speed curved needle gets via computing the CONCENTRATION DISTRIBUTION of this ion beam and the CONCENTRATION DISTRIBUTION of the required implanting ions of this target.

3. ion implantation method as claimed in claim 1 is characterized in that, more comprises the angle of a vertical axis of adjusting this target.