CN1326588A

CN1326588A - Containers for cleaning wafers

Info

Publication number: CN1326588A
Application number: CN99812346A
Authority: CN
Inventors: 岩本义夫; 黑川博幸
Original assignee: SunEdison Inc
Current assignee: SunEdison Inc
Priority date: 1998-10-19
Filing date: 1999-10-15
Publication date: 2001-12-12
Also published as: WO2000024041B1; KR20010075619A; EP1138061A2; JP2000124183A; WO2000024041A1; TW558760B

Abstract

A carrier for holding and retaining a plurality of semiconductor wafers allows the surfaces of the wafers to be maximally exposed to ultrasonic waves during a wafer cleaning process in which the carrier and wafers are immersed in a liquid medium and ultrasonic waves are generated in the liquid medium. The carrier includes spaced apart side walls and a plurality of horizontal bars interconnected to the side walls and positioned together to support the wafer substantially upright, face-to-face, substantially parallel to each other, each bar extending between and interconnected to the side walls, the bars being spaced apart from each other and positioned to expose the wafer to the liquid medium and ultrasonic waves between the bars. The sidewall is dimensioned such that its maximum height is less than about one-half the diameter of the wafer. The carrier is adapted to hold the wafer such that ultrasonic waves are affected only by the minimal impedance of the carrier structure and generally pass unimpeded through the liquid medium to all portions of the wafer surface, thereby facilitating effective cleaning. A stabilizing rod extends horizontally between the central regions of the sidewalls for limiting movement of the wafers relative to the carrier to stabilize the wafers.

Description

The vessel that clean wafers is used

The present invention relates generally to the cleaning of semiconductor wafer, be specifically related to be used for to keep a plurality of wafers can be exposed to vessel under the ultrasonic wave simultaneously to greatest extent.

The semiconductor wafer of microelectronic industry at first is that the silicon wafer ingot is cut into thin wafer aborning.After the section, wafer is made milled processed, the thickness that makes them is homogeneous roughly.Again wafer is carried out etching and produce smooth surface to remove defective.Last operation is a polished wafer, makes and form highly reflective and flawless surface on the one side at least of each wafer.These wafers grind and the etching two procedures between must clean, for example to remove pollutant such as abrasive particle.If cleaning process is not very effective, the surface of wafer will be thin abrasive particle residual contaminants.The abrasive particle of this class remnants will pollute problem in the electric device manufacture process.

The cleaning of wafer normally is immersed in them and is exposed to ultrasonic wave in the liquid medium simultaneously and gets off to carry out.At first each wafer is placed box or vessel, this box or vessel are taken in down a plurality of wafers and they are held in the erect form of parallel partitioned arrangement.This vessel that is loaded with wafer is placed rinse bath, is immersed in the fluid that contains etchant solution, with or remove to disperse foul without surfactant.To be arranged in the ultrasonic wave that the supersonic generator of bottom of rinse bath sends and be incorporated into this liquid medium.Abrasive particle on the wafer surface or other pollutants are removed by being exposed under the ultrasonic wave.Then this vessel is inserted and use the deionized water rinsing wafer in the flushed channel, at last with the IPA vapor drying crystal wafer.

Above-mentioned vessel must limit the vibration of wafer in order to avoid cause damage.When vessel moves, in the time of for example in dropping it off rinse bath, these wafers might collide in vessel or conflict mutually, form breach or crackle.In order to prevent this class breakage, the vessel attempt of prior art can keep wafer once to be designed to very big structure under the mode of safety.In this class vessel some has many fossulas that are used for admitting and keeping the wafer perimeter zone.Every fossula is along the signal portion extension on wafer week edge, for example near the position bottom of wafer upwards up to its top 1/3.

A major issue in the above-mentioned cleaning process is, the some parts that vessel can hinder wafer suitably is exposed under the ultrasonic wave, and how much the vessel of prior art is huge being used for the structure of wafer supporting in fossula if having.This structure stop or overslaugh ultrasonic wave be distributed in the whole liquid medium, thereby the All Ranges that has also just stoped ultrasonic wave to arrive wafer goes to clean it with enough intensity.Particularly because ultrasonic wave was stopped just that before the top that arrives rinse bath the top of wafer surface is usually cleaned insufficiently and kept some harmful particulate pollutions.Like this, the cleaning of wafer is inhomogenous.In addition, the structure of above-mentioned vessel even can obstruct the drying of wafer surface.The surrounding zone that accommodates the wafer in fossula not by dry fully, formed watermark and has caused the decline of wafer quality in the dry run of isopropyl alcohol.

Can be pointed out that, among some purposes of the present invention and characteristics: the vessel that is used for containing and keeping the polylith semiconductor wafer is provided; The vessel that all parts of wafer surface can fully be cleaned in the ultrasonic wave radiation treatment is provided; The vessel that can prevent damage wafers when moving or vibrate is provided; The evenly vessel on drying crystal wafer surface is provided, and wieldy vessel is provided.

Briefly, vessel of the present invention can contain and keep many wafers, have in hyperacoustic clean wafers process it and a plurality of semiconductor wafer being immersed in the liquid medium and in liquid medium, producing, can allow the surface of each wafer to be exposed to greatest extent under the ultrasonic wave radiation, be used for keeping the size of this vessel of wafer to be determined by the diameter of wafer, comprise the sidewall and the some horizon bars that separate mutually, these horizon bars are positioned to be used for each wafer supporting is become roughly setting, the face-to-face position that roughly is parallel to each other together.Each bar extends between sidewall and interconnects with sidewall, and these bars are located with separated relation, make wafer can be exposed in the liquid medium between the bar with ultrasonic wave under, the orientation of each sidewall makes vessel can be used for wafer is kept roughly and parallel sidewalls.The selected size of sidewall makes its maximum height approximately less than wafer diameter partly, so that allow maintain wafer vessel in being immersed in liquid medium the time first half of each wafer be exposed to liquid medium, thereby this vessel is fit to keep wafer in this wise: can make ultrasonic wave only be subjected to the minimum impedance influence of this vessel structure, general do not arrive all parts of wafer surface by liquid medium with not being obstructed, help effective cleaning thus.

On the other hand, vessel of the present invention can contain and keep a plurality of semiconductor wafers.Have in hyperacoustic clean wafers process this vessel and wafer being immersed in the liquid medium and in liquid medium, producing, can allow the surface of each wafer to be exposed to greatest extent under the ultrasonic wave radiation.The size that is fit to this vessel of maintenance wafer is determined by the diameter of wafer.Such vessel comprises two mutually separated upright side walls and three horizon bars of separating the location, and they are used for wafer supporting is become the relation of mutual almost parallel.At least on a bar, be provided with the tooth that a column split is opened.Limit the peripheral part that a roughly V-shaped fossula contains wafer between every pair of adjacent tooth, be used for making wafer in vessel, to remain in the position that separates mutually with respect to other wafers.

Other purposes of the present invention and characteristics will partly be come to understand afterwards, partly will give to point out.

Fig. 1 is the top plan view of clean wafers of the present invention with vessel;

Fig. 2 is the end view of this vessel;

Fig. 3 is the end-view of this vessel;

Fig. 4 is the profile that intercepts along in the 4-4 line plane among Fig. 1, and the wafer that imaginary vessel thus keeps is shown;

Fig. 5 is the profile that intercepts along in the plane of 5-5 line among Fig. 1; And

Fig. 6 is the profile that intercepts along in the plane of 6-6 line among Fig. 1.

In above all accompanying drawings, refer to corresponding parts with corresponding label.

Now referring to accompanying drawing,, wherein be used for containing and keep the vessel of polylith semiconductor wafer generally to show with 10 especially referring to Fig. 1 and 4.Vessel 10 has in hyperacoustic wafer cleaning process in that it and wafer are immersed in to produce in the liquid medium and in this liquid medium in the rinse bath, and wafer W is exposed under the ultrasonic wave to greatest extent.

Vessel 10 comprises a framework, and this framework has two parallel sidewalls that separate mutually 14 and several to extend between this two side and perpendicular to the horizon bar 16 of this sidewall orientation.The outer wall 18 that separates is mutually with it arranged outside sidewall 14.Each sidewall is related with an outer wall.There are two end pieces parallel with horizon bar 20 that separate mutually in the outside of horizon bar 16, and they are positioned at the place, opposite end of vessel both sides.In plane graph shown in Figure 1, outer wall 18 and end pieces 20 limit the periphery of this vessel structure.All parts of vessel 10 all have fillet usually.

Each sidewall 14 has maximum height and in trend its

end

22,24 o'clock highly decrescence in the middle, as shown in Figure 4.In best form of implementation, the top edge 26 of each sidewall has the shape that is similar to down shell of slow dimpling.Thisly be shaped as both solid and the little vessel structure of surface area provides effective supporting.Above-mentioned two sidewalls generally are of similar shape and size.

Its size range of maximum height H of each sidewall 14 of determining this vessel height is for will be by 1/4～1/2 of the diameter of the wafer W that vessel kept.In fact, the sidewall in this altitude range has shown to have good vessel stability and maintain little surface area at large.The less surface area of comparing with the prior art vessel has just guaranteed that the first half of each wafer is exposed in the liquid medium when the vessel that keeps wafer is immersed in the liquid medium.This vessel 10 can allow ultrasonic wave under the maximum impedance of vessel structure, general all parts that unhinderedly arrive wafer surface by liquid medium, thus promoted effective cleaning.

The length L of each sidewall 14 is defined as being slightly less than the diameter of the wafer W that vessel keeps.In best form of implementation, this sidewall length be wafer diameter at least 90% and be more preferably its 94%.If this sidewall length is significantly less than 90% wafer diameter, this vessel might be unstable, and if it greater than 100% wafer diameter, vessel just will heavily arrive unnecessary degree.

Vessel 10 has 4 pillars 30 that it is bearing on its lower surface, for it provides stability.Extended two pillars have identical length from the bottom of each sidewall 14, in order to vessel is supported along horizontal alignment.These 4 pillars are done to be provided with symmetrically with respect to the center of vessel.

Shown in Fig. 2 and 3, two outer walls 18 roughly are parallel to sidewall 14 along the first half of vessel to be aimed at, and is positioned at outside the sidewall 14 and separates, and is connected on the sidewall 14 by isolating rib 32.In each outer wall 18 3 holes 34 are arranged so that vessel lightweight as much as possible, each hole has and the vessel profile is concordant is convenient to the economic simple shape of making.In this best form of implementation, above-mentioned 3 holes make the area of each outer wall 18 reduce 35%～55%.

The shape that the periphery 36 in each hole 34 is got makes and does not have the horizontal surface that may collect liquid and hinder finish-drying along this periphery.On the contrary, this periphery 36 is got the profile that reduces gradually towards the direction that is separated from vessel, so that from then on liquid flow away at the edge, the cone angle of this convergent is 15～60 ° and is preferably 30～45 °.Other surfaces of vessel 10 comprise each outer wall 18 and top perimeter each sidewall 14, get similar inclination form and gather or hold and stay with liquid proof.

The end pieces 20 of extending between two side 14 has formed with hand and has lifted the handle of vessel or be used for gripping handle with supporting by the arm end operating device.End pieces 20 has the bottom of rounding so that grip, and is hollow and alleviated the weight of vessel simultaneously.As shown in Figure 2, each sidewall 14 comprises near the nose 38 that is positioned at each end pieces, can make the arm end operating device can be from sidewall or end pieces slippage when lifting vessel.

Horizon bar 16 comprises that 4 are used for keeping bar 40 and as described below comprising with supporting wafer weight to stablize the 5th bar of using bar 42.These 4 cramp bars 40 are held in wafer W roughly and erect, location Face to face is parallel to each other.Each horizon bar 16 all is to extend between two side 14 and interconnection with it, can get cylinder or square column type etc.These bars 16 are separated the location of turning up the soil mutually, so that wafer can both expose in cleaning process to ultrasonic wave that produce and that propagate between each bar at the bottom of the rinse bath.Keep the horizon bar of other specifications of more or less number wafer also should be included within the scope of the present invention.

As shown in Figure 4, each cramp bar 40 together with separated relation determine one section with each wafer W on the corresponding arc 44 of an arcuate perimeter section.The contact point of the bar 40 of arc 44 farthest, the left side in wafer W and Fig. 4 and wafer extend between the contact point of the bar 40 of farthest, the right among the figure therewith.Arc 44 is also crossing with other bar 40.For the determined arc 44 of these bars corresponding to comprise the wafer W whole circumference at least about 2/7 arc section of 2/5 preferably.Above-mentioned each cramp bar 40 determined segmental arc, preferably in the transportation of wafer and ultrasonic cleaning for keeping it to stablize the segmental arc of required minimum length.Cramp bar 40 shown in the accompanying drawing is done the roughly arrangement of symmetry with respect to the center of vessel 10 with uniform interval.Other positioning forms of these bars comprise asymmetrical interval, also do not depart from the scope of the present invention.

The the 1st and the 2nd bar in the cramp bar 40 is to extend between the position on each, two side 14 near the

end

22,24, and the 3rd is to extend between the position that roughly inwardly separates from

end

22,24 on the two side 14 with the 4th bar.On at least one cramp bar 40, be provided with the tooth 50 that row separate mutually.In this best form of implementation, tooth 50 is positioned on the 1st and the 2nd bar, and the 3rd and the 4th bar is then anodontia.Should know to have other combining forms, for example has only a bar or all bars have tooth.This row tooth 50 is to distribute on the whole length of each cramp bar 40 that tooth is arranged basically.Should know only on the part of this bar, have tooth also not depart from the scope of the present invention.

Adjacent paired tooth 50 defines as unified with the 52 V-arrangement fossulas of indicating that are used to contain wafer perimeter portion among Fig. 5.Each fossula 52 be fit to accommodate wafer W periphery so that this wafer remain in the separated position with respect to other wafers in the vessel.Tooth 50 has the gradient or the gradient of general conical, and 35～50 ° constant included angle A is arranged.The tooth tip 54 best roundings of each tooth are so that insert wafer in the fossula 52 and avoid because of carelessness collision tooth tip damage wafers.

The 5th horizon bar comprises stable with bar 42, and its restriction wafer is used for stablizing any vibration of wafer and keeps wafer on the throne with respect to the motion of vessel.This stablizes with bar 42 and is extending perpendicular to sidewall 14 and between the close position at each sidewall center.Should know that this stable can being positioned at along any position of vessel 10 with bar does not depart from the scope of the present invention.The stable tooth 56 that has row to separate mutually with bar 42 is determined the peripheral part that generally is used for accommodating wafer among Fig. 6 with the 58 Y shape paddy of indicating between each two adjacent teeth.The size and shape of each paddy 58 is selected to wafer is loosely accommodated wherein.The edge 60 of stablizing the approximate vertical that has with the tooth on the bar 42 56 has formed the side of above-mentioned paddy, and the dual-side of each paddy is to separate abreast greater than the interval S that accommodates wafer thickness wherein.The interval S that each paddy dual-side is separated is more preferably greater than wafer thickness about 10%～about 20%.Each wafer hangs on the top at the end 62 of paddy 58, and removing non-vibration or mismatch is not contact with tooth 56.The lowest point 62 is concordant, but for normal effectiveness of the present invention and nonessential be concordant.The shape that each paddy 58 is got can make wherein wafer, and (on this position, wafer hangs in the paddy in normal place; Be held in basically and with the tooth on the bar 42 56 any contact do not arranged with stable) and inflection point (on this position, wafer is at these each side 60 places and stablize and touch with a toe joint on the bar 42, in case wafer further does to vibrate deflection) between make oscillating movement.Stable have the gradient or the gradient of general conical with the tooth on the bar 56, and 35～50 ° constant included angle B is arranged.The tooth tip 64 best roundings of each tooth are in order to avoid wafer is caused injury when going up the tooth tip because of negligence of operation collision.

Vessel 10 is the single-piece molded structure.Material be to the compound effects in the cleaning solution and to the influence of high temperature be substantially inertia and stabilized resins, thereby can not damage, be out of shape or softening being exposed to compound and high temperature following time.In this best form of implementation, this vessel is to form by fluoro resin such as PFA or PTFE or by other resin such as PEEK or PBT.

In the operation, place vessel 10 to clean many wafer W to remove trickle grit and abrasive particle residue.Every wafer will make its edge contact simultaneously and cramp bar 40 corresponding 4 contact points (Fig. 4) when inserting, to support this wafer.These 4 points be included in the 1st with the 2nd bar on do not have tooth on two points combining with V-arrangement fossula 52 among Fig. 5 of Waffer edge and the 3rd and the 4th bar and to two points of wafer at its edge upper support.The a bit of peripheral part of each wafer accommodate simultaneously in stable with two adjacent teeth on the bar 42 between one of in the Y shape paddy 58 (Fig. 6), wafer this hang on the lowest point 62 above.Can or grip end pieces 20 with hand and lift this vessel by the arm end operating means.Vessel is transported in the rinse bath, and any vibration of wafer is limited with the tooth 56 on the bar 42 by stable in the transportation.The vessel 10 that is loaded with wafer is dipped in the liquid medium of compound solution for example, normally produces ultrasonic wave in the rinse bath on bottom land.Because vessel 10 has low outstanding degree and minimum body structure, this ultrasonic wave will can not hinder for the top of vessel, thereby arrive all parts of wafer surface.This vessel and wafer are with deionized water rinsing and with the IPA vapor drying then.Owing to be that wafer is supported by slit with a contact supporting rather than some other vessel in prior art here, do not accumulate liquid and hinder dry part with regard to not having.Therefore, this vessel is can be drier and be suppressed at and form watermark or similar other vestiges on the wafer surface.

Like this, vessel 10 of the present invention can contain and keep many semiconductor wafers and can make all parts of wafer surface obtain to clean fully and dry uniformly.This vessel also can prevent damage wafers when it moves or vibrates.

From as can be known above-mentioned, aforementioned several purposes of the present invention reach, and have obtained other useful result simultaneously.

During parts in introducing of the present invention or its best form of implementation, the article that relates to " ", " this " and " described " are to be used for showing one or more of this kind parts.Again, wherein used speech " comprises ", " having " etc. is as the meaning that includes, and promptly means the parts that other are still arranged except that listed parts.

Owing to during not departing from the scope of the present invention, can make all changes to the above, thus should the above and full content shown in the drawings regard as the property illustrated but not limited significance.

Claims

1. A container capable of containing and maintaining many semiconductor wafers, which allows the surface of each wafer to be exposed to the maximum extent possible during wafer cleaning by immersing the container and the wafers in a liquid medium in which ultrasonic waves are generated. Ultrasonically, the receptacle is adapted to hold wafers whose dimensions are determined by the diameter of the wafer, and the receptacle includes: spaced apart side walls; and a plurality of horizontal bars positioned together to support the wafers generally upright, face-to-face with each other substantially parallel, with respective rods extending between and interconnecting the side walls, these rods being spaced apart from each other and positioned so as to expose the wafer to the aforementioned liquid medium and to ultrasonic waves between said rods,

The side walls are oriented such that the receptacle is suitable for holding wafers generally parallel to the side walls, which are dimensioned such that their maximum height is less than about half the diameter of the wafer so that the receptacle carrying said wafer is submerged. When in a liquid medium, the upper half of each wafer is exposed to the liquid medium, so that the container can be used to hold the wafer in such a way that the ultrasonic wave is only affected by the minimum impedance of the container structure, and generally reaches it through the liquid medium without hindrance. All parts of the wafer surface, thus facilitating efficient cleaning.

2. A container as claimed in claim 1, wherein each of said side walls generally has a maximum height at its center and decreases in height along the sides towards opposite ends of the side wall.

3. A container as claimed in claim 2, wherein each said side wall has an upper periphery which defines the generally convex shape of the side wall.

4. The vessel of claim 3, wherein the height of each of said side walls is from about 1/4 to about 1/2 the diameter of the wafer.

5. The container of claim 4, wherein the two side walls are substantially aligned and have substantially the same size and shape.

6. The container of claim 1, wherein said plurality of horizontal bars are positioned together in spaced relation to define an arc corresponding to a segment of the arcuate perimeter on each wafer, the bars being adapted to fit along the arc of the wafer. Points on the perimeter are bonded to the wafer.

7. The container of claim 6, wherein at least one of said rods further comprises a row of spaced apart teeth, each adjacent pair of teeth being adapted to receive a peripheral portion of a wafer for holding the wafer relative to each other. Other wafers in this container are positioned separately.

8. The carrier of claim 7, wherein said adjacent pairs of teeth define a V-shaped slot shaped to receive a peripheral portion of a wafer.

9. The container of claim 7, wherein said rods are at least four, including two rods with teeth and two rods without teeth.

10. The container of claim 1, wherein said horizontal rods comprise support rods and at least one stabilizing rod extending horizontally between the central regions of the two side walls to limit the movement of the wafer relative to the Movement of the container stabilizes the wafer, the stabilizing rods being oriented perpendicular to the side walls.

11. The container of claim 10, wherein said stabilizing rod further comprises a row of spaced apart teeth, and a valley for receiving wafers is formed between every two adjacent teeth on said stabilizing rod, The size and shape of each valley is selected to loosely receive a wafer therein so that the wafer therein is in a nominal position supported by the support rods substantially without any contact with the teeth on the stabilizing rods and in said valley. Oscillatory movement is made between deflected positions where one side contacts a tooth on the stabilizing rod to prevent further vibrational deflection of the wafer.

12. A container capable of accommodating and maintaining many semiconductor wafers, which allows the surface of each wafer to be exposed to the maximum extent possible during wafer cleaning by immersing the container and the wafers in a liquid medium in which ultrasonic waves are generated. ultrasonically, a receptacle adapted to hold wafers whose dimensions are determined by the diameter of the wafer, the receptacle comprising: two spaced apart upstanding side walls; at least three horizontal bars positioned in spaced apart relationship to support the wafer in generally parallel relationship to each other , each horizontal bar extending between the side walls; and a row of spaced apart teeth on at least one of said bars, each adjacent pair of teeth defining therebetween a generally V-shaped slot for receiving a wafer The peripheral portion of the wafer keeps the wafer in a separate position relative to other wafers in the container.

13. The carrier of claim 12, wherein said horizontal rods include support rods and at least one stabilizing rod extending horizontally between the two side walls to limit movement of wafers relative to said carrier, to stabilize the wafer.

14. The container of claim 13, wherein said stabilizing rod includes a row of spaced apart teeth, a valley for receiving a wafer is formed between two adjacent teeth, each valley is sized and shaped to The wafer is received loosely therein.

15. The container of claim 14, wherein the teeth on the stabilizing rods have substantially vertical edges forming the sides of the valleys, the sides of each valley being in a parallel spaced apart relationship by more than the distance between the valleys. The thickness of the wafer placed between nanometers.

16. The carrier of claim 15, wherein the sides of the valleys are separated by a distance that is about 10% to about 20% greater than the thickness of the wafer.

17. The receptacle of claim 12, wherein said horizontal bars are positioned together in spaced relation to define an arc corresponding to a section of the arcuate perimeter on each wafer, the bars being adapted to fit along the arc of the wafer. Bond with the wafer at points around the shape.

18. The container of claim 17, wherein said rods are at least four, including two rods with teeth and two rods without teeth.

19. The container of claim 12, wherein each of said side walls generally has a maximum height at its central portion and tapers in height as it approaches opposite ends of the side wall along the sides.

20. The carrier of claim 12, wherein each of said side walls is dimensioned to have a maximum height less than about half the diameter of a wafer.