SU1600856A1 - Method and apparatus for cleaning flat parts ,particularly, semiconductor plates - Google Patents

Abstract

The invention relates to the cleaning of flat parts, mainly semiconductor wafers, and allows for improving the quality and productivity of cleaning. According to the method, the action of the jets of the washing liquid and nitrogen is carried out at an angle to the surfaces being cleaned, α = ARCSINH / D, where D is the diameter of the plates

H is the distance between the plates in the cassettes; in the process of cleaning the parts are turned in the opposite direction, relative to the direction of rotation of the parts in the cassettes, around the offset axes by an angle β = ARCTGL / H

where H is the length of the cassettes from the end on the supply side of the jets to the ledge of the cassette

L - the width of the ledge cassette. The cassettes are located on a rotating table, and the shower collector with nozzles is installed in the center of the washing chamber, each cassette mounted on the table between two adjustable stops and spring loaded to one of the stops, each cassette installed to rotate in the direction opposite to the direction of rotation of the table. in the cleaning process. 2 sec. f-ly, 4 ill.

Description

The invention relates to cleaning, in particular to the washing and drying of semiconductor wafers.

The aim of the invention is to increase the productivity and quality of cleaning semiconductor wafers by uniformly washing the entire surface of the wafer with washing liquid and by creating a laminar flow of vapor (droplets) of liquid and gas during drying.

This method consists in that the semiconductor plates in the cassettes are placed in receiving nodes in a cylindrical wash tank with a lid around the perimeter of the round table, then through a nozzle tube located in the center of the lid, a washing liquid, such as deionized water, is applied to the rotating table. speed P | plate and then at a speed of p.

O5

oh oh

00 SP

O5

moreover, nitrogen is supplied for drying, the semiconductor plates, are placed at an angle to the plane of the table, equal to

About

stcsin -

 h is a step. (distance) between plates in a cassette, 10; D, the diameter of the plates to be processed, Nrichem, when washing the cassette from the plate, is placed in the receiving nodes, facing the opposite side of the 15 Yrasheni table, at an angle L

R

arctg d

where H is the length of the cassette from the end of a hundred;

j L is the shoulder width of the cassette.

 then, during drying, the angle p increases — to 0–45 (5a in the washing and drying device {l-conductor plates, containing a single wash basin, the walls of which have an outlet fitting, and on the open upper part of the tank) a tube with nozzles for emitting jets of washing liquid and drying gas is lowered in the tank, a turntable placed inside the tank near its bottom, a group of receiving nodes fixed evenly around the perimeter of the table and accommodating mjix cassettes for the treated formation N, additionally contained mounted on the turntable, wherein the fixed nodes for receiving cassettes with plates, first and second adjustable stops and a spring.

The ratios of the angles make it possible to ensure uniform washing of the entire surface of the plate, as well as to create a laminar flow of vapor (drops) of liquid and gas during drying,

Example 1. In a washing and drying unit for semiconductor wafers of type KPVPSE-125/400, technological operations were performed to wash and dry 12 batches of semiconductor wafers, and the plates were placed in unified fluoroplastic cassettes KOF-100 1ShSh8.212391 in each cassette with 25 pieces .

To obtain comparable results, in parallel the other 12 batches of plates were processed at

five

0

five

installation of washing and drying semiconductor wafers.

The technological regimes in both cases were chosen the same: washing mode — at a rotational speed of a round table, p.J rpm, time t 3 min, consumption of washing liquid, deionized water, Q) 200 l / h, drying mode — at speed P2 100 ± rpm, drying time 5. min. nitrogen flow Q2 5-7 m / h.

The quality control of the process of washing and drying was carried out by the presence of defects on the surface of the semiconductor wafer, by four plates from each processing batch in the cassette.

To monitor the defectiveness, a Surfscan type surface laser analyzer (Tencor, USA) was used. The control was carried out on a total number of defects of 0.2 µm on the plate and on the density of defects per 1 cm area, and histograms and defects distribution on the plates were compared.

The semiconductor plates in the cassettes were located at an angle to the plane of the table, equal to

y-

arcs in -

five

, five

where d 5

0

diameter of the processed plates,

Schag plates in the cassette, plates with a diameter of 100 mm and

cassettes with wafers around

45

50

B - i.e. for pitch h 5.08 mm angle ui, 3.

Initial angle / 3 turns

axis of the arctg-

 12 ° (for a KOF-100 cassette), then in the drying mode the angle was increased to 40-45.

At the same time, the accuracy of installation for various angle cassettes in the modes of opening and drying amounted to about + 10%, which was determined by the accuracy of the measuring tools used during installation and the need to ensure the dynamic balance of the round table with the cassette during the processing of semiconductor plates.

The qualitative results of the implementation of the proposed method are summarized in the table.

Example 2. Equipment, process and drying

51

semiconductor wafers as well as the conditions remained similar to example 1.

The angle was set equal to 6+ + 10%, and the angle of rotation of the cassettes with plates was 6 + 10% during washing and 40-45 ± 10% during drying.

Modes of washing and drying remained similar to example I.

The results of example 2 are summarized in the table.

Example 3. It was carried out similarly to Examples I and 2 with the exception of the initial angle / 3 of the turning of the cassettes with the plates, which is set when washing is equal to L 20 ° and when drying 40-45.

 The results of example 3 are summarized in the table.

A comparison of the results of processing semiconductor wafers in different modes shows that the best in terms of the quality of wafer processing is the mode of example 1.

The deviation from the proposed limits of the angles and the washing and drying of semiconductor wafers in the direction of decreasing or increasing leads to an increase in the number of defects on the wafer, which can be clearly seen in the histograms of the distribution of defects over the area of the wafer with laws of increased defectiveness, i.e. zones in which the conditions for washing and drying the surface of the semiconductor are sharply deteriorated; nikov plates.

As a result of analyzing the quality indicators of the semiconductor wafer processing process (Example 1), empirically, based on the results of defectiveness testing, the time of washing and drying was selected while maintaining the remaining technological modes (process speed and gas and material consumption, which showed that washing can be reduced by 20-30 s, i.e. by 10-15%, and drying time - by 15-30 s or by 5-10%, i.e. by using this method and device for its suppression, it allows to increase productivity on operation shaking and drying by about 7-13%).

In addition, as can be seen from the table, the use of the indicated method and device for processing semiconductor 008566

These wafers lead to an increase in the percentage of 1011 x X chips.

The deviation from the claimed limits of the OS angles and when washing and drying the semiconductor wafers to a decrease leads to an increase in the processing time and an increase in the number of defects on the wafer, the same happens with increasing the specified angles. FIG. 1 shows a device for performing a method for cleaning flat parts, preferably semiconductor wafers, a section; on fkt. 2 - J5 is the same, top view; in fig. 3 - fastening of the receiving unit for cassettes with semiconductor platinum sh {in Fig. 4 - position of the cassette with semiconductor plates. 20 A device for carrying out the method of cleaning flat parts, mainly semiconductor plates, contains a washing chamber in the form of a cylindrical wash tank 25, in the wall of which there is an outlet nozzle 2, a cover 3, a tube 4 with nozzles 5, a turntable 6, fixed along axis 7, receiving units 8 for cassettes 9 with semiconductor 30 plates 10, axis II, first 12 and second 13 adjustable stops, spring 14.

FIG. 1-3 shows the angles: с - the angle of inclination of the plates; / 3- angle of the gate of the cassette with plates, the direction of rotation of the turntable 6 - arrow A, the direction of the turn of receiving nodes 8 with cassettes 9 - arrow B.

dd FIG. Figure 1 shows in dotted lines the direction of the washing liquid or shedding gas when washing and drying the semiconductor wafers 10. In addition, the defining

 angle Ы srcsin-, dimensions: h - step (distance) between the plates in the cassette; D is the diameter of the plates; and in fig. 3 - the initial angle of rotation of the cassettes with plates during washing

50 and when drying.

FIG. 4, arrow B shows the direction in which the jets of the washing liquid and the drying gas are supplied, and the values that determine

55 the initial angle of rotation of the cassette with plates, which is equal to

R

y-8

F

V where L is the width of the ledge of the cassette,

 H - the length of the cassette from the ledge to

her butt

as well as diagrams of the velocities of the liquid and gas trapped on the plate, t. e.

V is the radial velocity determined by the velocity ejected from the nozzle

component speed as a result of plate rotation on a round table {resultant velocity of liquid and gas on a plate

The device works as follows;

: In the receiving units 8 on the turntable 6, 4 cassettes are installed: J9 with semiconductor wafers 10. | 11 the receiving nodes 8 are made in such a way: to provide the plate installation angle. The cylindrical prom, the storage tank 1 is closed by the lid 3 and the rotation of the rotary table 6 begins at a speed n, while washing liquid, for example deionized water, is supplied through the tube 4 and the nozzle 5. Through the time it washes away contamination from the plate surface.

The initial angle of rotation of the cassettes from the plate ft c virtually eliminates the formation of unfavorable zones for washing the plate. At the same time, the angles of arrangement of the plates about and) force the plates, when rotating them on the Q turntable, to work as fan blades, thereby facilitating the effective removal of contaminants with a washing liquid.

The final angle of rotation of the plate 15, which is chosen in the range of 40-45 °, contributes to the fact that when drying gas, the passage between the plates flows along a trajectory close to the tangent to the turntable. In addition, this arrangement of the cassette with plates provides resistance to the flow of gas, eliminates turbulence, for example, due to the gas flowing around the upper, deaf edge of the cassettes.

Thus, the final angle of rotation of the plates leads to the formation of a laminar flow of gas flowing around the plane of the plates, which

20

25

35

The supply of washing liquid stops- 30 allows for good and quick removal.

residues of moisture and contamination from their surface.

This eliminates the flow turbulence and the reflection of contaminants from the i side walls of the wash tank, i.e. the possibility of re-contamination of the plates is eliminated.

An exhaust ventilation system connected to outlet nozzle 2 removes excess gas, liquid vapors and contaminants from the wash tank.

The present invention allows, in comparison with the known, for 45 products 565RU5 (64 Kbps POP) to increase the yield of chips by 4-6%.

c, table 6 begins to rotate at a rate of ng, with n, and through the pipe 4 and nozzles 5, nitrogen is supplied to tank i for drying.

When removing the receiving units 8 with cassettes .9 and semiconductor plates 10 by the spring 14 are pressed against the first recess 12 fixed on the table 6.

When going to the drying mode, i.e. increasing the speed of rotation of the table 6 increases the centrifugal force acting on the receiving nodes 8, which, having overcome the force of the spring 4, turn in the direction opposite to the direction of rotation of the table 6 (arrow B in FIGS. .

After the completion of the washing process, the rotation of the table 6 is stopped, the receiving unit 8 by the spring 14 is returned to its original position - to the first stop 12.

The installation angle of the plates On ensures that the jet of washing liquid is at an angle to the plane of the plate (dotted line in figure 1), which leads to an effective and uniform

40

50

55

Claims (2)

1. A method of cleaning flat parts, mainly semiconductor wafers, consisting in the action of jets of washing liquid on parts rotating together with cassettes with subsequent exposure to nitrogen while simultaneously increasing the speed of rotation of the parts, while the cassettes are made with ledges, about tons and h y u and yeny with so that with the purpose of increasing removal of contaminants from the plate surface. The initial angle of rotation of the cassettes from the plate ft c virtually eliminates the formation of unfavorable zones for washing the plate. At the same time, the angles of arrangement of the plates about and) cause the plates, when rotated on the turntable, to work as fan blades, thereby facilitating the effective removal of contaminants with a washing liquid. The final angle of rotation of the plate, 5 which is chosen in the range of 40-45 °, contributes to the fact that when drying the gas, the passage between the plates flows along a trajectory close to the tangent to the turntable. In addition, the specified location of the cassette with plates provides resistance to the flow of gas, eliminates. vortexes, for example, due to the gas flowing around the upper, hollow edge of the cassettes. Thus, the final angle of rotation of the plates leads to the formation of a laminar flow of gas flowing around the plane of the plates, which 0 five 0 five Formula invented shadows 1. A method of cleaning flat parts, mainly semiconductor wafers, consisting in the action of jets of washing liquid on parts rotating together with cassettes with subsequent exposure to nitrogen while simultaneously increasing the speed of rotation of the parts, while the cassettes are made with ledges, about tons and h y u and yeny with so that with the purpose of increasing quality and productivity of cleaning, the action of jets of washing liquid and nitrogen is carried out at an angle oi to the surfaces being cleaned About , h srcsin - Where D is the diameter of the plates plate spacing in cassettes, in the process of cleaning, the parts are turned in the direction opposite to the direction of rotation of the cassettes around the axes of the cassettes displaced relative to their center by an angle L R arctg- where H is the length of the cassettes from the end from the side, the supply of jets to the ledge; L - strip width of the cassette. 2. A device for cleaning flat parts, preferably semiconductors. five 0 nikov plates containing ko.hechnuyu camera with krppku, dutiruyushchy collector with nozzles, installed in the center of the camera, swivel table, placed in the chamber under the shower collector, and the holders of details in. The cassettes are installed evenly around the perimeter of the table, characterized in that, in order to achieve quality and productivity of cleaning, it is equipped with at least two adjustable stops and a spring for each of the cassettes, while the stops are mounted opposite the table on the table. respective cassette planes, each spring being installed between the corresponding cassette and the stop, and the cassettes mounted on the table with the possibility of rotation in the direction opposite to Table rotation in the cleaning process. Output fit, Z Fy Fiv.g Fi.Z l Yu 73 ten Editor L. Gratilllo Compiled by G. Kudrov Tehred M. Hodannch Proofreader C, Cherni Order 3233 Circulation 509 VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab. 4/5  - - - ----. ------.-. - ..----  - - ----- - - - - - "- --- - - .. Production and Publishing Combine Patent, Uzhgorod, st. Gagarin, 101 fizl Subscription