CN101093212B - Method and device for detecting mechanical defect of the ingot component made of semiconductor material - Google Patents
Method and device for detecting mechanical defect of the ingot component made of semiconductor material Download PDFInfo
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/04—Analysing solids
- G01N29/11—Analysing solids by measuring attenuation of acoustic waves
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- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/04—Analysing solids
- G01N29/07—Analysing solids by measuring propagation velocity or propagation time of acoustic waves
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/22—Details, e.g. general constructional or apparatus details
- G01N29/225—Supports, positioning or alignment in moving situation
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/22—Details, e.g. general constructional or apparatus details
- G01N29/26—Arrangements for orientation or scanning by relative movement of the head and the sensor
- G01N29/265—Arrangements for orientation or scanning by relative movement of the head and the sensor by moving the sensor relative to a stationary material
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/04—Wave modes and trajectories
- G01N2291/044—Internal reflections (echoes), e.g. on walls or defects
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
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- G01N2291/2626—Wires, bars, rods
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Abstract
The subject matter of the invention is a method for detection of mechanical defects (4) in an ingot piece (1) which is composed of semiconductor material and has at least one planar surface (6) and a thickness, measured at right angles to this surface, of 1 cm to 100 cm, with the planar surface (6) of the ingot piece (1) being scanned during the method by at least one ultrasound head (2) which iscoupled via a liquid coupling medium (3) to the planar surface (6) of the ingot piece (1) and, at each measurement point (x,y) produces at least one ultrasound pulse (8) which is directed at the planar surface (6) of the ingot piece (1), and the ultrasound-pulse echo originating from the ingot piece (1) is recorded as a function of time, such that an echo (9) from the planar surface (6) , an echo(11) from a surface (7), opposite the planar surface, of the ingot piece (6) and, possibly, further echoes (10) are detected, with the positions (xP, yp, zP) of mechanical defects (4) in the ingot piece (1) being determined from the further echoes (10). The subject matter of the invention also includes an apparatus for carrying out the method according to the invention, and to the integration of the method in the process chain for production of semiconductor wafers.
Description
Technical field
The present invention relates to detect the method and apparatus of the mechanical defect in the ingot spare (ingot pieces) that constitutes by semiconductor material.
Background technology
In microelectronics, use the wafer that constitutes by semiconductor material as the substrate of producing microelectronic element.Suitable material for example has II/VI compound semiconductor, III/V compound semiconductor, perhaps the semiconductor of germanium or useful especially element silicon for example.
Semiconductor wafer at first prepares by the single crystal semiconductor ingot blank being cut into several centimetres of ingot spares until tens centimeter length.Then, these ingot spares are cut into the LED reverse mounting type of about 1 millimeters thick.Perhaps prepare the single crystal semiconductor ingot blank by so-called floating region (FZ) method or by cutting krousky crucible crystal pulling method not using under the crucible.Particularly under the situation of cutting krousky crucible crystal pulling method, bubble may be absorbed in the semiconductor ingot blank of growth.These bubbles appear in the cavity of gas filling with the bubble form in the semiconductor ingot blank, and its diameter can be that about 10 μ m are until about 10mm.In some cases, when the semiconductor ingot blank was cut into wafer, these bubbles were cut, so can see these bubbles on the surface of semiconductor wafer.These defective semiconductor wafers are sorted before payment and are not used in the preparation microelectronic element.
But some other bubble is not cut in cutting process, so although can't see defective from the outside, bubble remains in the affected semiconductor wafer as little cavity.If this type of semiconductor wafer is used to make microelectronic element, according to they positions in semiconductor wafer, described cavity may cause the fault of single component so, thereby reduces the productive rate that assembly is made.
For fear of this situation, adopted test method according to the prior art of the semiconductor wafer of forming by silicon, before paying wafer and using it for the preparation electronic component, check whether each semiconductor wafer after processing fully exists the cavity by this method.This method is based on the end with the illuminated with infrared radiation semiconductor wafer, and measures and transmission imaging on the semiconductor wafer other end, i.e. the intensity that sees through of measuring radiation.Infrared radiation penetrated semiconductor material, and on empty interface light refraction took place, thereby caused transmittance to reduce.This method can only be used for the semiconductor material that infrared radiation can pass through.
This method is used to the very little surface of roughness, with the transmittance reduction of avoiding the surface to go up serious light scattering and cause thus.This means and can not after preparing them, directly detect semiconductor wafer, and can only be after making other procedure of processing of surface smoothing by the cutting ingot part, and only limit to finish in preparation process, and to detecting after its polishing.Therefore, must carry out a large amount of unnecessary procedure of processings in letter sorting and before eliminating semiconductor wafer with cavity.But, for fear of with handle the relevant cost of defective semiconductor wafer, sorting in early days needs.
Because described test method must be carried out every single semiconductor wafer, this method self also causes higher cost.
In addition, described method also is subjected to other restriction relevant with dopant content, because along with dopant content increases, and the charge carrier absorbing light of release, thus greatly reduce the light intensity that sees through.
Also known a kind of supersonic test method in the prior art can detect various mechanical defects in the different materials by this method.Because the sensitivity of this method reduces at bigger degree of depth place, so the imaging of defective up to now only limits to several millimeters thickness of workpiece.
Therefore, the purpose of this invention is to provide and a kind ofly can be applicable to the classes of semiconductors material and allow early stage letter sorting that those have the method for the semiconductor wafer in cavity.
Known a kind of from prior art such as DE2504988A1 by ultrasound wave bidimensional scanning samples, and to the scanning ultrasonic microscope that passes or reflected sound wave is handled.
International Patent Application WO 01/86281A1 discloses a kind of scanning ultrasonic microscope that produces the sample 3-D view.In this case, image is that non-destruction ground produces, so obtained the information about the sample interior structure.
But above-mentioned prior art is not designed to the high-speed data recording of sample for reference, and is used for the measurement of length up to the ingot spare of 100cm.In addition, limited according to the device fabrication amount of prior art.
Summary of the invention
Therefore, purpose of the present invention provides a kind of equipment that is used for sound scanning microscopic method, and this equipment has reduced the Measuring Time of each sample, and can carry out reliable detection simultaneously.
Realized described first purpose by the method that detects mechanical defect 4 in the ingot spare 1, described ingot spare is made of semiconductor material, and has at least one flat surfaces 6, to measure its thickness be 1cm-100cm to meet at right angles with this surface, during described method, pass through by means of the flat surfaces 6 of liquid coupling medium 3 with the described ingot spare 1 of at least one ultrasonic head 2 scanning of flat surfaces 6 couplings of ingot spare 1, at each measurement point x, y is created at least one ultrasonic pulse 8 of flat surfaces 6 orientations of ingot spare 1, and record comes from ingot spare 1, ultrasonic pulse echo as the function of time, so that detect echo 9 from flat surfaces 6, from with the echo 11 of the flat surfaces facing surfaces 7 of described ingot spare 6 and other possible echo 10, determine the position x of mechanical defect 4 ingot spares 1 from other echo 10
p, y
p, z
p
Description of drawings
Fig. 1 has schematically shown the measuring-signal that obtains when implementing method of the present invention.
Fig. 2 has schematically shown scanning ultrasonic microscope of the present invention.
Fig. 3 has schematically shown first embodiment with scanning ultrasonic microscope of two ultrasonic heads of the present invention.
Fig. 4 has schematically shown second embodiment of scanning ultrasonic microscope of the present invention, has two ultrasonic heads in each case on two relative flat surfaces of sample.
Fig. 5 has schematically shown the angle of wedge of ingot spare and has been used for determining the angle of wedge of reference planes and the parameter of position.
Embodiment
For purpose of the present invention is described, wording ingot spare be by semiconductor material constitute and at least in one direction size greater than the workpiece of typical semi-conductor wafer.Usually by to meet at right angles, promptly prepare ingot spare with its outside surface ground cutting semiconductor ingot blank that meets at right angles with its longitudinal axis.If semiconductor material is to be made of single-crystal semiconductor material, its normally straight right cylinder form then.If semiconductor material is a monocrystalline silicon, the diameter of then described ingot spare is generally between 100 to 450mm.The length of ingot spare is 1cm-100cm, and the length that is at most 50cm is preferred for inspection method according to the present invention.But particularly under the situation of polycrystalline or compound crystal semiconductor material, described ingot spare can also have the rectangular parallelepiped form of the elongation of rectangle or square end faces.
Single crystal rod spare 1 (referring to Fig. 2) has two smooth end faces 6,7 and curved exterior surface 5 usually.In order to implement method of the present invention, at least one flat surfaces 6 needs.In the method according to the invention, scan this flat surfaces 6 by at least one ultrasonic head 2 (being also referred to as converter).Ultrasonic head 2 contacts with flat surfaces 6 by means of the liquid coupling medium 3 that is preferably water.Ultrasonic head 2 produces at least one ultrasonic pulse 8 (Fig. 1), and it is at each measurement point x, and y is oriented on the flat surfaces 6 of ingot spare by the piezoelectric transducer layer usually.Detect the echo 9,10,11 that returns from ingot spare successively by ultrasonic head 2.Except the echo 9,11 that the apparent surface's (for example at second opposed end face 7 under the situation of cylindrical ingot spare) by flat surfaces 6 and ingot spare produces, can also detect other echo 10 that comes from mechanical defect 4 in the ingot spare.Can be from the distance z between defective 4 on the t calculating time delay Z direction of echo 10 and the flat surfaces 6
pFig. 1 shown as time delay t function and the signal amplitude A that draws.Determine defective 4 at x from the present position of ultrasonic head 2, the position x on y plane (parallel with flat surfaces 6 basically)
p, y
pTherefore, can determine the locus of defective 4 clearly.In order to obtain information, 2 scannings of flat surfaces 6 usefulness ultrasonic heads about whole ingot spare 1.During scanning process, preferably going up mobile at least one ultrasonic head 2 with the outside surface 5 rectangular planes (being called the plane of scanning motion 17 hereinafter) of ingot spare referring to Fig. 5.This measuring principle is known as scanning ultrasound wave microscopy or scanning acoustics microscopy, and is known from above-mentioned prior art.
Can all be the zone in ingot spare by the mechanical defect of microscopy detection of scanning ultrasound wave and location, its sound transmission characteristic be different with unspoilt semiconductor material.For example, these defectives comprise crackle, and particularly above-mentioned cavity.Described method can be used for detecting diameter 〉=100 μ m and even 〉=cavity of 50 μ m.
Can be in order to detect greatly to the material thickness of 50cm, the preferred described ultrasound wave of out-focus perhaps only slightly focuses on.Therefore preferably ultrasonic pulse should be focused on anomaly smooth surperficial 6 and have on the surface 7 of longer distance, focus in ideal conditions with flat surfaces 6 facing surfaces 7 on, promptly on the breech face of ingot spare 1.In the case, can use slight focusing or out-of-focus ultrasonic head 2 in conjunction with improved A/D converter.If only check ingot spare 1 from an end, then should select the recording period of echo, make echo 11 (Fig. 1) still comprise the apparent surface 7 (Fig. 3) of ingot spare 1.
In order to improve checking sensitivity, can be from two ends, preferably with length check ingot spare greater than 20cm.If ingot spare length greater than 50cm, then needs to measure on the flat surfaces 6,7 endways, thereby obtain information about whole ingot spare.In order to measure ingot spare 1 from two ends, at first by at least one ultrasonic head 2 from 6 scannings of first flat surfaces, then by whirligig around with the rectangular axle 15 of the longitudinal axis of ingot spare with ingot spare 1 Rotate 180 °, scan second flat surfaces 7 (Fig. 3) then.The another kind of selection is to use two relative ultrasonic heads 2, perhaps uses a plurality of ultrasonic heads 2 of two positioned opposite to scan.In the case, do not rotate ingot spare (Fig. 4).
If described semiconductor material is a monocrystalline silicon, so hyperacoustic velocity of propagation approximately is 8500m/s.Determine the duration that the recording voice echo is required from the ingot spare length of examine.For instance, if measure the long ingot spare of 40cm from the ingot spare of end measurement 20cm length or from two ends, the duration that just needs the about 100 μ s of record, temporal resolution is 10ns at least, preferred 1ns at least, thereby obtain information, and determine the position z in ingot spare cavity on the z direction from echo delay time about the whole length of ingot spare
pThe suitable estimation window of preferred definition is got rid of those signals 9,11 (referring to Fig. 1), and described signal is produced by the surface of described ingot spare for estimating detected acoustic echo.By the estimation window of finite time, acoustic echo of estimating and the ingot spare volume that detected thus are divided into the n section on the z direction, in section, can integrate acoustic signals to improve signal to noise ratio (S/N ratio).Therefore, selected length of window multiply by the volume that n represents the whole insonify of ingot spare.
If uncertain flat surfaces 6 meets at right angles with the outside surface 5 of ingot spare, so preferably estimate surface signal 9,11 (Fig. 1) as shown in Figure 5, so that determine by the crystal axis and the angle of wedge that cuts the uncertain caused ingot spare in the process.Because this angle of wedge,,, and will will be subjected to the influence of mechanical defect afterwards from the semiconductor wafer that ingot spare produces as following further describing so can not use one of end face 6,7 simply as the reference planes 16 that are used for deterministic process.Therefore, be positioned at meet at right angles with outside surface 5 and with end face 6 recently, but no longer be defined as reference planes 16 with its that plane of intersecting.If the plane of scanning motion 17 of selecting ultrasonic head meets at right angles with the outside surface 5 of ingot spare 1, from from the face of difference time delay between the longest of flat surfaces 6 echoes of the ingot spare of ultrasonic head and the short delaing time, use to concern tan (α)=(z so
Max-z
Min)/d just can easily determine the locking angle of ingot spare 1 on diameter d.Determine ultimate range z between the plane of scanning motion 17 and the flat surfaces 6 by the long delay time
Max, determine the shortest distance z from short delaing time
Min
For the outside surface that guarantees the plane of scanning motion and ingot spare meets at right angles, before measuring beginning, arrange ingot spare.The depression of groove form that for example can be by suitable adjustment is carried out this arrangement, the outside surface of ingot spare is put into described depression, and accurately arrange described ingot spare.
If the angle of wedge is known, then just can determine easily at position x from following relation of plane
p, y
pDistance z between detected mechanical defect 4 and the reference planes 16
p:
z
1＝tan(α)·(d-x
p)
z
0＝z
max-z
1
z
p＝z
tot-z
1
In the case, z
1Distance between expression flat surfaces 6 and the reference planes 16, z
0Expression is positioned at puts x, the distance between the ultrasonic head of y and the flat surfaces 6, z on the plane of scanning motion 17
TotIt is the distance between detected defective 4 and the flat surfaces 6.All distances of mentioning are measured abreast with outside surface.
Opposite with the experience of front, only be suitable for checking layer based on the experience of front scanning ultrasound wave microscopy near the relative thin on surface, have been found that particularly that under the situation of single-crystal semiconductor material described method can also be used to checking that thickness is until 25cm or even until the material of 50cm.By high-quality and there is not the semiconductor monocrystal of defective to explain this point, it can cause undisturbed ballistic acoustic propagation on longer distance and preferred direction.Therefore, even in depths also can very well locate single mechanical defect very.In the case, characteristic such as diameter, crystal orientation or the doping to ingot spare do not have other restriction.
Can use the equipment of second purpose that can also realize basis of the present invention to implement the method according to this invention.
Below be the scanning ultrasonic microscope: it has the fastening that is used for ingot spare to be detected 1, and has the x of being positioned at, at least one flat surfaces 6 on the y plane; Have at least two ultrasonic heads 2, be used to produce and detect ultrasonic signal; They have first fixed equipment, are fixed with described at least two ultrasonic heads in the above, so that can not move on x, y direction; Have regulating device, by this regulating device can with x with respect to described fastening, mobile ultrasonic head 2 on the rectangular z direction in y plane; Have mobile device, by this mobile device can be on x, y direction mobile relative to each other fixed equipment and fastening; Have control module 12, be used to control described mobile device and regulating device; And evaluation unit, be used to handle by described ultrasonic head 2 detected ultrasonic signals.
Because can detect a plurality of different x on the ingot spare simultaneously, the y position, so the use of this kind equipment is preferred, each position is by the acoustical signal sound transmission from a ultrasonic head in all cases, and the echo of each that detects them of the ultrasonic head by separately.This makes it possible to achieve the remarkable reduction of Measuring Time.
Hereinafter will scanning ultrasonic microscope of the present invention be described with reference to figure 2.
This scanning ultrasonic microscope has the fastening of the ingot spare 1 that is used for examine, and has at least one and be located substantially on x, the flat surfaces 6 on the y plane.
Therefore, it is different with the prior art that produces and detect ultrasonic signal by at least two ultrasonic heads 2.Can also use more, for example four ultrasonic heads.The preferably so-called main converter of ultrasonic head, and other all ultrasonic heads is auxilliary converter.Preferably supply high-frequency AC voltage to ultrasonic head, convert it into the acoustical signal of ultrasonic pulse form by the piezoelectricity conversion layer by radio-frequency generator 14.Then, the piezoelectricity conversion layer by each ultrasonic head 2 detects the echo of ingot spare 1 in the partial reflection of different depths successively, and converts electric signal to.Preferably should be signal digitalized and be transported to evaluation unit by A/D converter, this unit record is as x, the signal of the instant function of position of checking on the y plane.Ultrasonic frequency is preferably in the scope of 5-25MHz.For the ultrasonic head that reaches 25MHz, also can use the second interface (re-interfaces) of a plurality of 100MHz.
On first stationary installation, fix described at least two ultrasonic heads 2, make them on x, y direction, not move.
The associating regulating device is provided for all ultrasonic heads 2.In the case, all can on the z direction, unite all ultrasonic heads of adjusting.But, the device of meticulous adjusting being provided preferably for each ultrasonic head, by this device can with x, move ultrasonic head 2 with respect to fixed equipment on the rectangular z direction in y plane and irrelevant with another ultrasonic head 2.Then, according to making ultrasonic head detect the mode of the maximum signal maximum signal of echo of back flat surfaces 7 (for example from), each ultrasonic head of independent regulation on the z direction.Each regulating device preferably has independent motors and drives.This equipment also comprises x, y scanning device, it can support two or more ultrasonic heads simultaneously at focal position and focus on, so that for it provides the control of open loop or closed type loop, and it is irrelevant with another (referring to Deutsche Bundespatent, application documents reference number 1020060054482 was not announced before this patent).
For the flat surfaces 6 that can scan ingot spare, scanning ultrasonic microscope according to the present invention has mobile device, can be by this device at x, move described stationary installation and bracing or strutting arrangement on the y direction relative to each other.In the case, by measurement point and by the flat surfaces 6 of line sweep ingot spare, so that cover the whole flat surfaces of ingot spare.
In addition, control module also is provided for described mobile device of control and regulating device, and is used for the evaluation unit by the detected ultrasonic signal processing of ultrasonic head.Control module and evaluation unit can be combined in the unit, for example have the computing machine 12 of monitor 13.Preferably handling simultaneously and write down by the detected echo of two or more ultrasonic heads, is x with detected signal record, the function of the instant position of checking on the y plane, and determine the position x of mechanical defect thus
p, y
p, z
pThe preferred data item that is used for pattern displaying that produces simultaneously.
The improved scanning ultrasonic microscope of preferred use checks that length surpasses the ingot spare of 20cm, and it has and similar another fixed equipment of first fixed equipment, fixing in the above at least two other ultrasonic heads 2.Arrange this second fixed equipment, make fixed thereon ultrasonic head 2 can check second flat surfaces 7 of ingot spare 1, as shown in Figure 4.
Characteristic according to semiconductor material, can use equipment of the present invention check diameter at the most 450mm, length at the most 40cm (if checking) from two ends or at the most 20cm (if checking) from an end or even length respectively 50cm or 25cm at the most, or the ingot spare of 100cm or 50cm respectively.
The method according to this invention and according to equipment of the present invention, the semiconductor wafer that can influence by mechanical defect such as cavity in the early stage letter sorting of manufacture process, needn't all semiconductor wafers of single inspection, and those semiconductor wafers that are subjected to defective effect are accepted further-unnecessary-procedure of processing.So just can cause very big time and cost advantage.
Therefore, the invention still further relates to the method for a plurality of semiconductor wafers of preparation, this method comprises step according to order described below:
A) preparation semiconductor ingot blank,
B) this semiconductor ingot blank is cut into the ingot spare that length is 1cm-100cm,
D) determine the position of mechanical defect in each ingot spare, the position of each defective is uniquely by the coordinate x on the plane parallel with the otch that will make in step f)
p, y
pAnd the coordinate z vertical with this plane
pDetermine,
F) described ingot spare is cut into the semiconductor wafer that a plurality of thickness are 0.2-2mm, and
H) sort the semiconductor wafer that those comprise the position that has had been found that mechanical defect.
Hereinafter will describe each step of this method of described a plurality of semiconductor wafers produced according to the present invention in detail.
At first, preparation semiconductor ingot blank in step a).Described semiconductor ingot blank is monocrystalline preferably.Semiconductor ingot spare preferably is made up of silicon, particularly monocrystalline silicon.In the case, the about 100-450mm of described semiconductor ingot spare general diameter.For example prepare the semiconductor ingot blank by float-zone method or by cutting krousky crucible crystal pulling method.Because when using when cutting krousky crucible crystal pulling method the single crystal semiconductor ingot blank above-mentioned cavity takes place, so preferably the method according to this invention is used for this based semiconductor ingot blank.But method of the present invention also is applicable to waters foundry goods, polycrystalline or compound crystal semiconductor ingot blank (being also referred to as stock), and they for example are used in the solar cell.
In step b), described semiconductor ingot spare is cut into long 1cm-100cm, the preferred ingot spare of long 50cm.General band saw or the inside diameter saw of using made otch.The semiconductor ingot blank generally is cut to ingot spare under the angle vertical with its longitudinal axis.Under the situation of semiconductor ingot spare, this means that described ingot spare is straight right cylinder form basically with circular cross section.But as the result of crystal pulling process, described ingot spare has certain scrambling.
Generally speaking, in the step c) of the laggard line option of step b), wherein the outside surface to basically cylindrical ingot spare grinds, and makes described ingot spare have accurate cylindrical shape.In addition, can on the outside surface of ingot spare, produce orientation characteristic, for example be orientated breach or orientation plane.This step can be carried out after step d), but preferably carries out before it.
In step d), determine the position of mechanical defect in each ingot spare.The aforesaid scanning ultrasonic microscope of preferred use is implemented this step.
Perhaps, can be with an end of illuminated with infrared radiation ingot spare, and the infrared radiation that sees through in the other end measurements of described ingot spare, to determine the position of mechanical defect (particularly empty).Preferably on the outside surface of cylindrical ingot spare, carry out this measurement, must pass long distance to avoid light.Because excessive roughness can be disturbed this measurement, thus preferred before measurement the appropriate combination by fine grinding, etching, polishing or these methods so that the relevant surfaces of ingot spare is level and smooth.The roughness of relevant surfaces should preferably be no more than Ra=0.2 μ m.In described method, use the internal image of the camera generation ingot spare of infrared ray responsive with suitable object lens.Gas inside inclusion or defective cause the refraction of incident light or are absorbed.Determine the degree of depth of defective by the object lens setting that causes producing focusedimage.
Because use the infrared transmission method to need the extra level and smooth of described surface, in step d), preferably use the scanning ultrasonic microscope.
In step f), according to the corresponding mode of prior art, may cut into the semiconductor wafer that thickness is 0.2-2mm with the ingot spare of other ingot spare.According to prior art, preferably cut by multifibres saw (MWS).Preferably described ingot spare is cut into semiconductor wafer with its outside surface with meeting at right angles.Then, clean usually and the separating semiconductor wafer, that is, handle the semiconductor wafer of the folded form of back separating plate at the multifibres saw, and place it in separately in the compartment of wafer case or magazine.
At step h) in, sort those then and be included in the semiconductor wafer of having found cavity position in the step d), and usually it is eliminated.This can manually or by robot carry out automatically.
In order to make the easier letter sorting of these semiconductor wafers, preferably at step d) and f) between additional step e) in, for example by milling, grind or bore pit, the z coordinate of each mechanical defect position of mark on ingot spare.Planning to cut under the situation of cylindrical ingot spare of semiconductor wafer preposition z in step d) with its outside surface with meeting at right angles
pApply mark to outside surface.At last, at step h) in, sort out all that semiconductor wafer that has mark at it on every side.For example, this can be based on to the visual identity of mark and manually carry out.According to the mark and the mechanical defect position z that are applied on the outside surface
pThe levels of precision of coupling, and according to the precision of the thickness and the cutting process of the semiconductor wafer that cuts in the step f), what all needed is exactly to sort the wafer that those have mark, otherwise the adjacent separately wafer of letter sorting.
As the alternatives of using mark, can be in step e) from the position z of mechanical defect
pAnd those semiconductor wafers (and quantity) that at least one mechanical defect is determined to have in the position of manufacturing otch from step f).At last, can be at step h) in manually or by robot sort these semiconductor wafers automatically.If the automatization level that semiconductor wafer is made is enough high, for instance, the material tracking system just can determine the number of wafers of being correlated with.The material tracking system for example can use the reference planes that are complementary with the semiconductor wafer at first finished the position, and the summation of otch spacing (corresponding to the summation of the semiconductor wafer thickness of cutting and the material unaccounted-for (MUF) that in cutting process, causes) determine the quantity of affected semiconductor wafer.In this alternatives, may need to sort adjacent semiconductor wafer equally, to determine that having removed all has the semiconductor wafer of mechanical defect.
For fear of sorting unnecessary a large amount of semiconductor wafers, can be at the additional step g that is used for mechanical defect according to prior art), check individually that based on the number of wafers of mark or calculating and the definition quantity of adjacent semiconductor wafers those have the mechanical defect of the semiconductor wafer of at least one mechanical defect.For example, this can be undertaken by scanning ultrasonic microscope, infrared transmission measurement or the measurement of X-radiation absorption.For instance, check mark or calculated semiconductor wafer and immediate separately neighbor thereof.At last, only at step h) in be actually those wafers of in step g), having found mechanical defect by the semiconductor wafer that sorted out.With in step g) all other semiconductor wafers of individual inspiration reinstall in wafer case or the magazine, go forward side by side one the step process.This makes the inspection one by one of the semiconductor wafer can be avoided consuming time and expensive on the one hand, avoids the letter sorting of unnecessary flawless semiconductor wafer on the other hand.
In order when ratio of defects is low, to prevent to pay semiconductor wafer effectively, when only on semiconductor wafer, checking, need 100% ground to check all semiconductor wafers in principle with cavity or other mechanical defect.Ingot spare by having determined the mechanical defect position in advance according to inspection of the present invention and the combination of only checking subsequently at the single semiconductor wafer of determining in advance a small amount of wafer to be carried out around the position, make the inspection of each semiconductor wafer can guarantee under the detection efforts of minimum that the semiconductor wafer of all payment all is flawless, and can make the productive rate maximization of semiconductor wafer.Just when in step d), having found mechanical defect, need in step g), to detect subsequently single semiconductor wafer.The detection efforts of single semiconductor wafer is dropped in the corresponding manner when the error rate of ingot spare descends.
The method which kind of needs is frequency, production cost, the inspection of semiconductor wafer and the cost of letter sorting and robotization and material tracking that preferably depends on mechanical defect for letter sorting.
Claims (17)
1. method that detects mechanical defect (4) in the ingot spare (1), this ingot spare is made of semiconductor material, and has a smooth first surface (6), with with first surface (6) opposing second surface (7), with with first surface (6) measurement that meets at right angles, thickness between first surface (6) and the second surface (7) is 1cm-100cm, in described method, pass through by means of the first surface (6) of liquid coupling medium (3) with at least one ultrasonic head (2) described ingot spare of scanning (1) of first surface (6) coupling of ingot spare (1), at each measurement point (x, y) produce the directed ultrasonic pulse (8) of at least one first surface (6) in ingot spare (1), and record comes from described ingot spare (1), ultrasonic pulse echo as the function of time, so that detect echo (9) from first surface (6), from the echo (11) of second surface (7) and possible other echo (10) that is derived from mechanical defect (4), determine the position (x of mechanical defect (4) the described ingot spare (1) from described other echo (10)
p, y
p, z
p).
2. the method in the claim 1, wherein with described first surface (6) the described thickness of measuring that meets at right angles be 1cm-50cm.
3. the method for one of claim 1-2, wherein said ingot spare (1) is made of single-crystal semiconductor material.
4. the method for one of claim 1-2 wherein meets at right angles with respect to the outside surface (5) with described ingot spare (1) and determines the position z of mechanical defect (4) on the z direction with the rectangular reference planes of the longitudinal axis (16) of described ingot spare (1)
p, described reference planes (16) are irrelevant with the locking angle of ingot spare (1), and the position of these reference planes is by the ultimate range z between the flat surfaces (6) and the plane of scanning motion (17)
MaxLimit, the same and outside surface (5) of the plane of scanning motion (17) and the described longitudinal axis meet at right angles, and at least one ultrasonic head (2) is positioned on this plane of scanning motion.
5. method for preparing a plurality of semiconductor wafers, it comprises the step of following statement order:
A) preparation semiconductor ingot blank,
B) described semiconductor ingot blank and its longitudinal axis are cut into the ingot spare that length is 1cm-100cm with meeting at right angles,
D) determine the position of mechanical defect in each ingot spare, the position of each defective is uniquely by the coordinate x on the plane parallel with the otch that will make in step f)
p, y
pAnd the coordinate z vertical with this plane
pDetermine that wherein the position of mechanical defect is determined by means of the method for claim 1 in each ingot spare,, and determine in the infrared intensity that the other end measurement of described ingot spare sees through perhaps by a end with illuminated with infrared radiation ingot spare,
F) described ingot spare and its longitudinal axis are cut into the semiconductor wafer that a plurality of thickness are 0.2-2mm with meeting at right angles, and
H) sort the semiconductor wafer that those comprise the position that has had been found that mechanical defect.
6. the method for claim 5, wherein said semiconductor ingot blank is made of single-crystal semiconductor material.
7. the method for claim 6 is wherein prepared in step a) by cutting krousky crucible crystal pulling method by the semiconductor ingot blank that single-crystal semiconductor material constitutes.
8. the method for one of claim 5-7, the length of the described ingot spare that wherein prepares in step b) is 1cm-50cm.
9. the method for one of claim 5-7, the described ingot spare that wherein prepares in step b) are straight right cylinder form basically, and after step b), grind the outside surface of described ingot spare in additional step c).
10. the method for one of claim 5-7 is wherein at step d) and f) between additional step e) in the z coordinate of each mechanical defect position on the mark ingot spare, and at step h) in letter sorting after step f), have those semiconductor wafers of described mark.
11. the method for one of claim 5-7, wherein at step d) and f) between additional step e) in determine to have at least one mechanical defect from the z coordinate of mechanical defective locations and the incision site from step f), made those semiconductor wafers, and at step h) in these semiconductor wafers of letter sorting.
12. the method for one of claim 5-7, wherein at step d) and f) between additional step e) in determine to have at least one mechanical defect from the z coordinate of mechanical defective locations and the incision site from step f), made those semiconductor wafers, wherein at step f) and h) between additional step g) in the mechanical defect of adjacent chip of these semiconductor wafers of individual inspiration and definition quantity, and at step h) in sort all and in step g), found those semiconductor wafers of mechanical defect.
13. a scanning ultrasonic microscope, it has the fastening that is used for ingot spare to be detected (1), and has and be positioned at (x, y) flat surfaces of at least one on the plane (6); Have at least two ultrasonic heads (2), be used for producing and detecting ultrasonic signal; They have first fixed equipment, are fixed with described at least two ultrasonic heads in the above, so that can not move on x, y direction; Have at least one regulating device, by this regulating device, can with respect to the rectangular z direction in x, y plane of described fastening on mobile ultrasonic head (2); Have mobile device, can on x, y direction, move described fixed equipment and fastening relative to each other by this mobile device; Have control module (12), be used to control described mobile device and regulating device; And evaluation unit, be used for handling by the detected ultrasonic signal of described ultrasonic head (2).
14. the scanning ultrasonic microscope of claim 13, it comprises a regulating device that is used for each ultrasonic head (2), by this regulating device, each ultrasonic head (2) can with x, move with respect to described fixed equipment on the rectangular z direction in y plane, and irrelevant with another ultrasonic head (2).
15. the scanning ultrasonic microscope of one of claim 13-14, it comprises another and the similar fixed equipment of first fixed equipment, be fixed with at least two other ultrasonic heads (2) in the above, and it is arranged to described ingot spare (1) to be arranged between described two fixed equipments, thereby can be by means of the ultrasonic head (2) that is fixed on first fixed equipment, check ingot spare (1) by first flat surfaces (6), and by means of the ultrasonic head (2) that is fixed on second fixed equipment, check ingot spare (1) by second flat surfaces (7) parallel with first flat surfaces (6).
16. the scanning ultrasonic microscope of one of claim 13-14, wherein said ultrasonic head (2) are slight focus on or non-focusing ultrasonic heads.
17. the method for one of claim 1-2, wherein said ultrasonic pulse (8) out-focus or only slightly focusing.
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| DE102006028650 | 2006-06-22 | ||
| DE102006028650.2 | 2006-06-22 | ||
| DE102006032431.5 | 2006-07-13 | ||
| DE102006032431A DE102006032431B4 (en) | 2006-06-22 | 2006-07-13 | Method and device for detecting mechanical defects in a rod made of semiconductor material |
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| CN101093212A CN101093212A (en) | 2007-12-26 |
| CN101093212B true CN101093212B (en) | 2011-02-16 |
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| CN2007101120477A Active CN101093212B (en) | 2006-06-22 | 2007-06-22 | Method and device for detecting mechanical defect of the ingot component made of semiconductor material |
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| JP (1) | JP5331745B2 (en) |
| CN (1) | CN101093212B (en) |
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| US7952187B2 (en) * | 2008-03-31 | 2011-05-31 | General Electric Company | System and method of forming a wafer scale package |
| DE102008002832B4 (en) | 2008-04-24 | 2010-12-09 | Institut für Akustomikroskopie Dr. Krämer GmbH | Method and device for nondestructive detection of defects in the interior of semiconductor material |
| US8508239B2 (en) * | 2009-05-05 | 2013-08-13 | Lam Research Corporation | Non-destructive signal propagation system and method to determine substrate integrity |
| DE102009044254A1 (en) | 2009-10-15 | 2011-05-05 | Institut für Akustomikroskopie Dr. Krämer GmbH | Device for nondestructive inspection of the interior of components and transducers therefor |
| DE202009018526U1 (en) | 2009-10-15 | 2011-12-09 | Institut für Akustomikroskopie Dr. Krämer GmbH | Device for nondestructive inspection of the interior of components and transducers therefor |
| WO2012117088A1 (en) | 2011-03-03 | 2012-09-07 | Institut für Akustomikroskopie Dr. Krämer GmbH | Apparatus for non-destructively inspecting the interior of components |
| CN102928280A (en) * | 2012-11-15 | 2013-02-13 | 苏州华碧微科检测技术有限公司 | Treatment method of ultrasonic scanning device |
| CN104022182A (en) * | 2014-05-29 | 2014-09-03 | 浙江矽盛电子有限公司 | Production control and sorting method of silicon chips |
| JP5931263B1 (en) * | 2015-10-14 | 2016-06-08 | 株式会社日立パワーソリューションズ | Ultrasound imaging device |
| JP7012538B2 (en) * | 2018-01-11 | 2022-01-28 | 株式会社ディスコ | Wafer evaluation method |
| DE102019208670A1 (en) | 2019-06-14 | 2020-12-17 | Siltronic Ag | Process for the production of semiconductor wafers from silicon |
| FI3940124T3 (en) | 2020-07-14 | 2024-04-03 | Siltronic Ag | Monocrystalline silicon crystal article |
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| JP2010175560A (en) | 2010-08-12 |
| JP5331745B2 (en) | 2013-10-30 |
| TWI356165B (en) | 2012-01-11 |
| CN101093212A (en) | 2007-12-26 |
| DE102006032431B4 (en) | 2011-12-01 |
| TW200801508A (en) | 2008-01-01 |
| DE102006032431A1 (en) | 2007-12-27 |
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