US3730342A

US3730342A - Microscopically inspecting and sorting articles

Info

Publication number: US3730342A
Application number: US00117929A
Authority: US
Inventors: J Egan; M Kimmel; R Strohl; W Wanesky
Original assignee: Western Electric Co Inc
Current assignee: AT&T Corp
Priority date: 1971-02-24
Filing date: 1971-02-24
Publication date: 1973-05-01
Anticipated expiration: 1990-05-01

Abstract

Microscopically inspecting and sorting articles such as beamlead integrated circuits is carried out by positioning an array of articles on a transparent substrate in the field of a dualobjective microscope. The top and bottom sides of the articles are individually inspected with the upper and lower objective lenses of the microscope to determine whether these sides have various defects. A vacuum pickup needle is moved from a cut out portion of a disposal tube to and over each article having a defect to pick it up and hold it. The needle is then withdrawn to move it back into the cut out portion and to move the article into the opening of the tube. The article is then released from the needle and deposited in the opening of the tube; whereupon, a vacuum which has been applied to the tube draws the article into a filter jar. Also, the bottom sides of the articles are inspected for the defect of foreign particles and a determination is made as to whether the particles are associated with the articles or the substrate. If associated with the articles, they are deposited in the opening of the tube. Thus, only articles having nondefective sides are left remaining on the substrate.

Description

llite States Egan et al.

[ MICROSCOPICALLY INSPECTING AND SORTING ARTICLES [75] Inventors: James John Egan, Allentown; Millard Edward Kimmel, Emmaus; Ronald Irwin Strohl, Walnutport; William Robert Wanesky, Wescoesville, all of Pa.

[73] Assignee: Western Electric Company, Incorporated, New York, NY.

22 Filed: Feb. 24, 1971 21 App1.No.: 117,929

I IBM Technical Disclosure Bulletin, Vol. 9, No. 7,

December 1966 [451 May 1, 1973 Primary ExaminerRichard A. Schacher Assistant Examiner-Gene A. Church Attorney-W. M. Kain, R. P. Miller and R. Y. Peters [5 7] ABSTRACT Microscopically inspecting and sorting articles such as beam-lead integrated circuits is carried out by positioning an array of articles on a transparent substrate in the field of a dual-objective microscope. The top and bottom sides of the articles are individually inspected with the upper and lower objective lenses of the microscope to determine whether these sides have various defects. A vacuum pickup needle is moved from a cut out portion of a disposal tube to and over each article having a defect to pick it up and hold it. The needle is then withdrawn to move it back into the cut out portion and to move the article into the opening of the tube. The article is then released from the needle and deposited in the opening of the tube; whereupon, a vacuum which has been applied to the tube draws the article into a filter jar. Also, the bottom sides of the articles are inspected for the defect of foreign particles and a determination is made as to whether the particles are associated with the articles or the substrate. If associated with the articles, they are deposited in the opening of the tube. Thus, only articles having nondefective sides are left remaining on the substrate.

14 Claims, 6 Drawing Figures PATENTEUHAY H915 3,730,342

sum 1 0F 3 I I /v l/EN TOPS J. J. EGAN M E. K/MMEL RI. STROHL W. R, WA NESKV By A 55w? TTORNEV PATENTEB MAY 1 1973 SHEET 30F '3 W JOE MICROSCOPICALLY INSPECTING AND SORTING ARTICLES BACKGROUND OF THE INVENTION 1. Field ofthe Invention This invention relates to methods of and apparatus for inspecting articles for a characteristic and sorting them accordingly. More particularly, this invention relates to methods of and apparatus for microscopically inspecting for visual defects both the active and inactive sides of an array of beam-lead integrated circuits on a substrate without having to turn or otherwise touch them and selectively removing defective circuits from the substrate.

2. Description of the Prior Art This invention is particularly suitedfor use in the manufacture of small, fragile articles such as semiconductive devices or the like. An example of such a semiconductive device which is extremely small and fragile is the so-called beam-lead integrated circuit such as disclosed in M. P. Lepselter US. Pat. Nos. 3,287,612; 3,335,338 and 3,426,252. While the'invention is adapted to be used in conjunction with inspecting any small articles, it will be particularly described with respect to beam-lead integrated circuits. A beam-lead integrated circuit includes a semiconductive body with interconnected circuit elements associated on or within such body. Leads are formed on the body as an integral part of the device and extend from the body like cantilever beams to form both electrical and mechanical connections to a header or a circuit pattern formed on a substrate.

Although the integrated circuits may pass electrical tests, various visual mechanical defects in the circuits,

such as scratches, cracks, holes, smeared circuit elements, foreign particles or the like, may eventually cause circuit failures. Hence, to assure circuit reliability, it is necessary in the manufacture of the integrated circuits to inspect both sides of the circuits with a microscope for these defects to separate the defective circuits from the good ones.

In the past methods and apparatus have been used for rapidly inspecting both sides of the circuits (See copending application, Ser. No. 30,379, filed Apr. 21, 1970 by W. R. Wanesky, assignor to the Western Electric Co., Inc.) However, even more rapid inspection is desirable. Reduced handling of the circuits is also desirable to not only aid in reducing inspection time, but also to reduce the likelihood of damage to the fragile circuits. More accurate inspection with a consequent increase in the discrimination between defective and nondefective circuits is another desirable aspect. This results in not discarding good circuits and in improved circuit reliability by preventing utilization ofdefective circuits.

SUMMARY OF THE INVENTION It is, therefore, an object of this invention to provide new and improved methods of and apparatus for inspecting articles for a characteristic and sorting them accordingly.

Another object of this invention is the provision of methods of and apparatus for individually inspecting for visual defects both the active and inactive sides of beam-lead integrated circuits on a substrate and selectively removing defective circuits from the substrate.

With these and other objects in view, the present invention contemplates a new and improved method of inspecting articles having a characteristic and sorting them accordingly. The method includes the steps of positioning the articles in the field of a microscope, and viewing the articles with the microscope to determine whether they have the characteristic. A pickup needle is moved over each article having the characteristic to pickup and hold it. The needle holding the article is then withdrawn to move the article and the needle into an opening of a tubular member. Next, the article is released from the pickup needle to deposit the article into the opening.

This invention also contemplates an apparatus for inspecting articles for a characteristic and sorting them accordingly. The apparatus includes a microscope for viewing the articles to determine whether they have the characteristic. A needle is provided for picking up and holding the articles. Further, facilities are provided for positioning the articles in the field of the microscope and for disposing of the articles having the characteristic. The apparatus also includes facilities for moving the pickup needle over each article having the characteristic to pickup and hold the article, and for withdrawing the needle holding the article to move the article and the needle into the disposal facilities. Other facilities are provided for releasing the article from the pickup needle to deposit the article in the disposal facilities.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects and the advantages of the present invention may be more clearly understood by reference to the following detailed description and the accompanying drawings, wherein:

FIG. 1 is a greatly enlarged perspective view of a beam-lead integrated circuit, which is to be inspected in accordance with the present invention;

FIG. 2 is a front elevational view of an apparatus for inspecting, with a dual-objective microscope, both the active and inactive sides of an array of beam-lead integrated circuits;

FIG. 3 is a fragmentary top view taken along lines- 33 ofFIG. 2;

FIG. 4 is a fragmentary front elevational view, partly in section of a portion of the apparatus of FIG. 2 showing the upper and lower objective lenses of the microscope of FIG. 2, the path of travel of a vacuum pickup needle, and air and vacuum systems for operating the needle and a cooperating disposal tube;

FIG. 5 is an enlarged view taken along line 55 of FIG. 4, showing a view of the inactive side of the integrated circuit of FIG. I, as seen through the upper objective lens of FIG. 4; and

FIG. 6 is an enlarged view taken along line 6-6 of FIG. 4, showing a view of the active side of the integrated circuit of FIG. 1, as seen through the lower objective lens of FIG. 4.

DETAILED DESCRIPTION cuit 11 includes a semiconductive body 12 having a bottom or active side 13 and. a top or inactive side 14, and a plurality of beam leads 16 extending from the active side 13 of the body 12.

Typically, the integrated circuit 11 is very minute, the semiconductive body having a square shape, about to 90 mils wide and about 2 mils thick, while the leads are about 9 mils long and 3 mils wide. Usually, the body 12 is composed of silicon and the leads 16 are formed of gold. Extremely minute interconnected circuit elements (not shown), usually in the form of plated gold patterns, are formed on the active side 13 of the circuit 1 1. By the methods and apparatus of the present invention, these patterns, the leads 16, the body 12 and the active and

inactive sides

13 and 14 are to be inspected for certain characteristics, such as visual defects, and accordingly sorted.

Examples of these defects are: wholely or partially missing beam leads 16; transverse bends in the leads 15 greater than one-half of the width of the leads 16; vertical bends in the leads 16 greater than 60; holes in the leads 16 resulting from probing in the making of electrical tests; etch pits, cracks or scratches in the silicon body 12; and deep scratches in, gold missing from or smeared on, or foreign particles on the circuit elements of the active side 13.

Supporting Circuits In accordance with the present invention, an array of integrated circuits 11 is removably supported on a substrate 21 (FIGS. 2-4) with the active sides 13 down and the inactive sides 14 up. The substrate 21 is transparent and as a matter of convenience may be formed from a flat sheet of glass with its top surface covered with a layer of pressure sensitive, vacuum holding material, such as silicone resin of the general type sold by Dow Corning Corporation under the tradename Sylgard 182." (See copending application Ser. No. 729,859, filed Apr. 10, 1968 by W. R. Wanesky, assignor to the Western Electric Co., Inc.)

Positioning Substrate The substrate 21 with the array of integrated circuits 11 thereon is positioned on a platform 23 of a conventional microscope stage, designated generally by the numeral 26 (FIGS. 2-4). Conveniently, the stage 26 may be the coaxially controlled X-Y stage sold by the American Optical Corporation under the name Reichert and under the trade designation Adabo.

The stage 26 also includes a pair of overlapping, apertured plates 28 and 29 (FIGS. 3 and 4) and a slide 30 (FIGS. 2 and 3). The stage 26 is located between and is perpendicular to a common axis 32 (FIG. 4) ofa pair of axially aligned

objective lenses

34 and 35 of a conventional dual-objective microscope, designated generally by the numeral 38 (FIG. 2), which is mounted to a base 39. Advantageously, the microscope 38 is ofthe type sold by the American Optical Corporation under the trade designation Dual I80 Aligning Microscope."

In positioning the substrate 21, the circuits 11 are located over an aperture 27 (FIG. 4) in the platform 23. The platform 23 lies on the top of the plate 28 and is laterally held by a pair of conventional fingers 41 and 42 (FIG. 3) for slidable movement on the top of the plate 28. One finger 41 is fixed to the slide 30, while the other finger 42 is pivotably mounted to and spring biased toward the finger 41 to retain the platform 23 between the fingers 41 and 42, as shown in FIG. 3.

The bottom plate 29 of the stage 26 is fastened to a conventional vertical microscope stage which includes a bifurcated support 44 (FIGS. 2 and 4) fixed to a rack 46 (FIG. 2). The rack 46 is vertically movable by a pinion (not shown) fixed to a shaft 51 (FIG. 3) mounted in a housing 53 (FIG. 2) fixed to the base 39. To one end of the shaft 51 a knob 56 is fixed, while a lever 58 is adjustably mounted through a clutch 61 to the other end of the shaft 51, as shown in FIG. 3. The lever 58 provides a quick and convenient way to raise or lower the table 26 and hence focus the microscope 38 on the circuit 1 1 undergoing inspection.

Next, the top of inactive sides 14 of the integrated circuits 11 on the substrate 21 are viewed with the upper objective lens 34 of the microscope 38. This viewing is accomplished by an operator (not shown) looking through a pair of eyepieces 62 (one of which is shown in FIG. 2) of the microscope 38 and energizing with conventional circuitry (not (shown), a conventional light source 63 (FIG. 2) associated with the microscope 38. The source 63 provides bright field illumination of the circuits 11.

Positioning Circuit to be Inspected While the circuits 1 1 are viewed with microscope 38, the top plate 28 and the platform 23 with the substrate 21 thereon are moved in the direction designated X in FIG. 3. Also, the slide 30, the fingers 41 and 42 and the platform 23 with the substrate 21 thereon are moved in the direction designated Y in FIG. 3, which is perpendicular to the X direction. This movement results in locating fully within the field of the upper lens 34 the inactive side 14 of a single circuit 11 to be inspected. The movement in the X direction is carried with a knob 66 and in the Y direction with a concentric knob 67 (FIGS. 2 and 3), both of which are joined to conventional shafts, racks and pinions (partially shown in FIG. 2) of the stage 26 to effectuate the moving.

While the circuits 11 are still being viewed with the microscope 38, the stage 26 is also moved in the direction designated Z in FIG. 4, which is coincident with the axis 32 of the lenses 34 and 35'. This movement results in focusing the upper lens 34 on the inactive side 14 of the circuit 11 undergoing inspection. The movement also results in positioning the stage 26 at a predetermined point along the axis 32 of the

lenses

34 and 35, at which point the lower lens 35 is also focused on the active side 13 of the circuit 11. The movement in the Z direction is carried out with the knob 56 or the lever 58, the shaft 51, the pinion (not shown) associated with the shaft 51 and the rack 46.

Inspecting Inactive Side Next, the top or inactive side 14 of the integrated circuit 11 is inspected for the aforementioned defects with the microscope 38 using the upper objective lens 34 and bright field illumination from the source 63.

In the event the circuit 11 is defective, it is picked up with the free end ofa needle 71 (FIGS. 2-4) which is normally positioned within a cut out portion 73 (FIG. 4) of an opening 76 ofa disposal tube 78. The opening 76 is larger than the largest dimension of the circuit 11. A vacuum from a source 79 (FIG. 4) is normally connected to the disposal tube 78 through a valve, designated generally by the numeral 81, a filter jar 83 for holding defective circuits 1'1 and tubing 84.

Both the pickup needle 71 and the disposal tube 78 are mounted to a housing 86 (FIGS. 2-4) attached to a support 88 which is fixed to the base 39.

In order to pick up the circuit 11 having a defective inactive side 14, the operator first depresses a button 89 (FIG. 4) of a valve, generally designated by the numeral 90, and then depresses a button 91 of the valve 81. 1

Depression of the button 89 connects air. under pressure from a source 92 through the valve 90 and tubing 93 to an air cylinder 94 mounted in the housing 86. This connection of air operates the cylinder 94 to move a rod 97 leftwardly, as viewed in FIGS. 2 and 4, against the action of a compression spring 99 until the rod 97 strikes a stop 101. The leftward movement of the rod 97 also moves leftwardly a connecting plate 103 and a tube 105 slidably mounted in the housing 86 and fixed to the plate 103 with a conventional fastening device 104.

The movement of the tube 105 linearly moves leftwardly the needle 71 connected to the tube 105 to position its free end at a predetermined point lying on the axis 32 of the upper and lower

objective lenses

34 and 35. Advantageously, this point is such that there is a gap of about 5 mils between the free end of the needle 71 and the inactive side 14 of the circuit 1 1 undergoing inspection. This spacing insures that the free end of the needle 71 will not strike or crush and thereby damage the circuit 11. This is particularly important if there is a foreign particle on the substrate 21 rather than on the circuit 1 1, as discussed hereinafter, and the circuit 11 is therefore not really defective.

Depression of the button 91 of the valve 81 disconnects the vacuum of the source 79 from the disposal .tube 78. The depression of the button 91 also simultaneously connects the vacuum to the now moved needle 71 through flexible tubing 109 to produce a vacuum at the free end of the needle 71 to thereby draw up the circuit 11 through the gap from the substrate 21 to such free end. If the circuit 11 is not drawn up through the gap, the lever 58 is operated to move the circuit 11 in the Z direction to shorten the gap until the circuit 11 is drawn up.

Next, the operator releases the button 89 of the valve 91 to release the cylinder 94. The release of the cylinder 94 moves linearly the needle 71, under urging of the spring 99, into the cut out portion 73 of the disposal tube 78 and also moves the circuit 11 with the defective active side 14 into the opening 76 of the tube 78.

Then, the operator releases the button 91 of the valve 81 to disconnect the vacuum of the source 79 from the needle 71 and to connect such vacuum to the disposal tube 78. Since the vacuum is disconnected from the free end of the needle 71 and connected to the disposal tube 78, the circuit 11 is released from the needle 71 and simultaneously drawn into the disposal tube 78; whereupon, the defective circuit 11 is drawn by the vacuum into the filterjar 83.

Inspecting Active Side In the event the inactive side 14 of the circuit 11 is not defective, it remains on the transparent substrate 21 and its active side 13 is inspected through the substrate 21- for the aforementioned defects with a microscope 38. This inspection is carried out by deenergizing the light source 63 and by energizing with conventional circuitry (not shown) a conventional light source 1 13 (FIG. 2) associated with the microscope 38. The de-energizing of the source 63 and energizing of the source 113 renders ineffective the upper objective lens 34 and renders efiective the lower objective lens 35.

The source 113also provides bright field illumination to accentuate certain defects such as missing beam leads 16; undesirable bends or holes in the leads 16; etch pits, cracks or scratches in the body 12. In addition, dark field illumination is provided by fiber optics connected to a conventional light source 1 17 fixed to the base 39. The dark field illumination accentuates certain defects such as excess gold in and foreign particles on the circuit elements. In carrying out the inspection of the active sides 13 of the circuits 11, the operator with conventional circuitry (not shown) first uses bright field illumination from the source 113 and then dark field llumination from the source 1 17, or vice ver- After the active side 13 is inspected, if it is found defective, the circuit 11 is picked up with the needle 71 and linearly moved into the opening 76 of the disposal tube 78 in the same manner that the circuit 11 is moved if it has a defective inactive side 14. Hence, only nondefective circuits 11 are left on the substrate 21, and in this way the defective circuits 11 are sorted from the nondefective circuits 1 1.

Inspecting Foreign Particles In the event a foreign particle, such as gold particle produced during the fabrication of the circuits 11, is located on the active side 13 of the circuit 11, the electrical characteristics and reliability of the circuit 11 may be deleteriously affected. Consequently, it is necessary to not only inspect the circuits 1] for the presence of such particles, but also to determine whether the particle is associated with the active side 13 or the substrate 21 on which the side 13 rests. Of course, if the foreign particle is on the substrate 21 rather than on the active side 13 of the circuit 11, the circuit is not defective. Obviously, it is important to make this distinction so as not to discard nondefective ones of the circuits 11.

Accordingly, after the active and

inactive sides

13 and 14 have been inspected with bright field illumination, the operator inspects the circuit 11 for foreign particles by viewing the active side '13 with the microscope 38. In so inspecting the circuits 11, dark field illumination from the fiber optics 115 and the lower objective lens 35 are used.

In the event it appears that the circuit 11 has a foreign particle on its surface, the pickup needle 71 is moved (as previously explained) over the circuit 11 and it is picked up and held by the needle 71.

The operator then views a first portion of the substrate 21 where the circuit 11 had been to determine whether the foreign particle remains either on the substrate 21 or on the active side 13 of the circuit. If the particle remains in focus, this is indicative of the particle being not associated with the circuit 11. The stage 26 is then moved to present a clear portion of the substrate 21 to the field of the microscope 38. Then, the button 91 of the valve 81 is released to deposit the circuit 1 1 at that location.

On the other hand, if the foreign particle goes out of focus after it is picked up by the needle 71, this is indicative of the particle being associated with the circuit 11. Hence, the circuit 11 is defective and is moved to the disposal tube 78 where it is deposited in the aforementioned manner.

An alternative method of determining the location of the particle is to move the stage 26 and the substrate 21 after the circuit 11 has been picked up by the needle 71. Movement of the foreign particle is indicative ofits presence on the substrate 21.

Other Features The precise location of the free end of the pickup needle 71 is adjustable by conventional facilities including threaded members 119 and 120 (FIG. 2).

Also, in the event the substrate 21 is opaque, the inactive sides 14 of the circuits 11 are first inspected. Then, the needle 71 is used to remove a circuit 11, the active side of which is to be inspected, from the substrate 21. Then, the substrate 21 is moved sideways by a mechanism (not shown) and out of the field of view of the microscope 38. With opaque substrate 21 so moved, the needle 71 is moved on the Z axis to focus the active side 13 of the circuit 11 relative to the lower objective lens 35. This lens 35 is then used to inspect the active side 13, and the circuit 11, if defective, is disposed ofas previously described.

While the movement of the stage 26 and the support 44 has been described above as being effected by manual facilities, it is to be understood that such movement may be effected by automatic facilities.

It is to be further understood that the abovedescribed arrangements are simply illustrative of the application of the principles of this invention. Numerous other arrangements may be readily devised by those skilled in the art which will embody the principles of the invention and fall within its spirit and scope.

What is claimed is:

1. A method of inspecting articles for a characteristic and sorting them accordingly, comprising:

positioning the articles in the field ofa microscope;

viewing the articles with the microscope to determine whether they have the characteristic;

moving a pickup needle from an opening in a tubular member and over each article having the characteristic to pick up and hold the article;

withdrawing the needle holding the article to move the article and the needle into the opening of the tubular member; and

releasing the article from the pickup needle to deposit the article into the opening.

2. The method of claim 1, wherein the top and bottom surfaces of the article are individually and sequentially viewed with a dual-objective microscope without moving the article, and the articles are picked up, held, and deposited into the opening of the tubular member if either surface has the characteristic.

3. The method of claim 1, wherein the needle is moved linearly over each article having the characteristic and is withdrawn linearly.

4. A method of inspecting articles for various characteristics and sorting them accordingly, comprising:

positioning the articles individually within the field of a microscope;

viewing'the articles individually with the microscope to determine whether they have the characteristic;

moving the articles along the axis of the microscope to focus the microscope individually on the articles;

moving a pickup needle from the opening of the tubular member to a position over each article that has the characteristic;

connecting a vacuum source to the needle over the article having the characteristic to pick up and hold the article;

withdrawing the pickup needle to move the needle and the article into the opening of the tubular member; and

disconnecting the vacuum source from the pickup needle to deposit the article into the opening, and simultaneously connecting the vacuum source to the tubular member, whereby the vacuum draws the article through the tubular member.

5. A method of microscopic inspecting articles for foreign particles on a surface and sorting the articles accord ngly, comprising:

positioning in the field of a microscope a transparent substrate having the articles thereon with the surface to be inspected facing down on the substrate; moving the substrate to locate the articles individually within the field of the microscope; viewing said surfaces of the articles individually through the substrate with the microscope; moving a pickup needle over each article having a foreign particle on said surface to pick up and hold the article; viewing a first portion of the substrate where the article had been to determine whether the foreign particle remains either on the substrate or on said surface of the article; moving the substrate to place a second portion of the substrate in the field if the foreign particle does remain on the substrate, which is indicative of the article being free of the particle, and releasing the article free of the particle from the pickup needle to deposit the article on the second portion of the substrate; withdrawing the needle holding the article to move the article into an opening of a tubular member if the foreign particle does not remain on the first portion of the substrate; and releasing the article from the withdrawn pickup needle to deposit the article in the opening. 6. The method of claim 5, wherein the article moves out of focus of the microscope upon such article being picked up by the needle and any foreign particle on the substrate remains in focus.

7. The method of claim 5, wherein the substrate is moved after the article is picked up by the needle and the substrate is viewed with the microscope during such movement to determine whether the foreign particle microscope, the axis of the lens being coincident with the Z direction;

viewing the inactive sides of the circuits with the upper objective lens, and simultaneously moving the table in the X and Y directions to locate a single integrated circuit fully within the field of the upper lens; moving the table along the Z direction to focus the upper lens on the inactive side of the single integrated circuit and to position the circuit at a predetermined point along the axis of the lenses at which point the lower lens is also focused on the active side of the circuit; inspecting the inactive side of the integrated circuit with the upper lens; connecting a vacuum to a disposal tube having an opening larger than the integrated circuit and a cut out portion at the opening which normally contains the free end of a pickup needle; moving linearly the free end of the needle from the cut out portion of the opening of the disposal tube to a predetermined distance from the predetermined point of the inactive side of the circuit is defective; disconnecting the vacuum from the disposal tube and simultaneously connecting the vacuum to the moved needle to pick up and hold the circuit having the defective inactive side; moving linearly the needle holding the defective integrated circuit to move the free end of the needle into the cut out portion of the disposal tube and to move the circuit into the opening of the tube; disconnecting the vacuum from the needle to deposit the defective integrated circuit into the opening, and simultaneously connecting the vacuum to the disposal tube to draw the deposited defective circuit through the tube to dispose of the defective circuit; inspecting the active side of the integrated circuit with the lower lens without turning the article over if its inactive side was not defective; moving linearly the free end of the needle from the cut out portion of the opening of the disposal tube to the predetermined distance from the predetermined point if the active side of said circuit is defective; disconnecting the vacuum from the disposal tube and simultaneously connecting the vacuum to the moved needle to pick up and hold the circuit having the defective active side; moving linearly the needle holding the defective integrated circuit to move the free end of the needle into the cut out portion of the disposal tube and to move the circuit into the opening of the tube; and

disconnecting the vacuum from the pickup needle to deposit the defective integrated circuit into the opening, and simultaneously connecting the vacuum to the disposal tube to draw the deposited defective circuit through the tube to dispose of the defective circuit, whereby circuits having defective inactive or active sides are removed from the substrate.

9. The method of claim 8, wherein the predetermined distance that the free end of the pickup needle is moved from the predetermined point is 5 mils.

10. An apparatus for inspecting articles for a characteristic and sorting them accordingly, comprising:

a microscope for viewing the articles to determine whether they have the characteristic;

means for positioning the articles in the field of the microscope;

a needle for picking up and holding the articles;

means containing the pickup needle for disposing of the articles;

means for moving the pickup needle from the disposing means and over each article having the characteristic to pick up and hold the article;

means for withdrawing the needle holding the article to move the article and the needle into the disposing means; and

means for releasing the article from the pickup needle to deposit the article into the disposing means.

117 The apparatus of claim 10, wherein the means for disposing of the articles includes a tubular member having an opening and a passageway, both larger than the largest dimension of the article, the opening having a cut out portion normally containing the free end of the pickup needle. 7

12. The apparatus of claim 10, wherein the microscope is a dual-objective microscope and both the top and bottom surfaces of the articles are individually and sequentially viewed with the dual-objective microscope, and the articles are picked up, held, and deposited into the disposing means if either surface has the characteristic.

13. An apparatus for inspecting articles for various characteristics and sorting them accordingly, comprismg:

a microscope for viewing the articles individually to determine whether they have the characteristics; means for positioning the articles individually in the field of the microscope;

a needle having a free end for picking up and holding the articles;

a tubular member having an opening normally containing the free end of the pickup needle for disposing of the articles;

a vacuum source;

means for connecting the vacuum source to either the tubular member or the needle;

means for moving the free end of the pickup needle over each article having the characteristics;

means for operating the connecting means to disconnect the vacuum source from the tubular member and to connect the source to the needle to pick up and hold the article having the characteristics with the free end of the needle;

means for withdrawing the needle holding the article to move the article and the free end of the needle into the opening of the tubular member; and

means for operating the connecting means to disconnect the vacuum from the needle to release the article therefrom to deposit the article into the opening of the tubular member and to connect the vacuum to the disposal means, whereby the vacuum draws the article through the tubular member.

Claims

1. A method of inspecting articles for a characteristic and sorting them accordingly, comprising: positioning the articles in the field of a microscope; viewing the articles with the microscope to determine whether they have the characteristic; moving a pickup needle from an opening in a tubular member and over each article having the characteristic to pick up and hold the article; withdrawing the needle holding the article to move the article and the needle into the opening of the tubular member; and releasing the article from the pickup needle to deposit the article into the opening.

4. A method of inspecting articles for various characteristics and sorting them accordingly, comprising: positioning the articles individually within the field of a microscope; viewing the articles individually with the microscope to determine whether they have the characteristic; moving the articles along the axis of the microscope to focus the microscope individually on the articles; moving a pickup needle from the opening of the tubular member to a position over each article that has the characteristic; connecting a vacuum source to the needle over the article having the characteristic to pick up and hold the article; withdrawing the pickup needle to move the needle and the article into the opening of the tubular member; and disconnecting the vacuum source from the pickup needle to deposit the article into the opening, and simultaneously connecting the vacuum source to the tubular member, whereby the vacuum draws the article through the tubular member.

5. A method of microscopic inspecting articles for foreign particles on a surface and sorting the articles accordingly, comprising: positioning in the field of a microscope a transparent substrate having the articles thereon with the surface to be inspected facing down on the substrate; moving the substrate to locate the articles individually within the field of the microscope; viewing said surfaces of the articles individually through the substrate with the microscope; moving a pickup needle over each article having a foreign particle on said surface to pick up and hold the article; viewing a first portion of the substrate where the article had been to determine whether the foreign particle remains either on the substrate or on said surface of the article; moving the substrate to place a second portion of the substrate in the field if the foreign particle does remain on the substrate, which is indicative of the article being free of the particle, and releasing the article free of the particle from the pickup needle to deposit the article on the second portion of the substrate; withdrawing the needle holding the article to move the article into an opening of a tubular member if the foreign particle does not remain on the first portion of the substrate; and releasing the article from the withdrawn pickup needle to deposit the article in the opening.

6. The method of claim 5, wherein the article moves out of focus of the microscope upon such article being picked up by the needle and any foreign particle on the substrate remains in focus.

7. The method of claim 5, wherein the substrate is moved after the article is picked up by the needle and the substrate is viewed with the microscope during such movement to determine whether the foreign particle remains on the substrate.

8. A method of individually inspecting for visual defects both the inactive and active sides of beam-lead integrated circuits spaced on a transparent substrate with the active siDes down and inactive sides up and of selectively removing defective circuits from the substrate, comprising: positioning the substrate having the integrated circuits thereon on a table having a central aperture therein, the table being movable in three mutually perpendicular directions designated X, Y and Z, the table being located between, and perpendicular to the common axis of an upper and a lower axially aligned objective lens of a dual-objective microscope, the axis of the lens being coincident with the Z direction; viewing the inactive sides of the circuits with the upper objective lens, and simultaneously moving the table in the X and Y directions to locate a single integrated circuit fully within the field of the upper lens; moving the table along the Z direction to focus the upper lens on the inactive side of the single integrated circuit and to position the circuit at a predetermined point along the axis of the lenses at which point the lower lens is also focused on the active side of the circuit; inspecting the inactive side of the integrated circuit with the upper lens; connecting a vacuum to a disposal tube having an opening larger than the integrated circuit and a cut out portion at the opening which normally contains the free end of a pickup needle; moving linearly the free end of the needle from the cut out portion of the opening of the disposal tube to a predetermined distance from the predetermined point of the inactive side of the circuit is defective; disconnecting the vacuum from the disposal tube and simultaneously connecting the vacuum to the moved needle to pick up and hold the circuit having the defective inactive side; moving linearly the needle holding the defective integrated circuit to move the free end of the needle into the cut out portion of the disposal tube and to move the circuit into the opening of the tube; disconnecting the vacuum from the needle to deposit the defective integrated circuit into the opening, and simultaneously connecting the vacuum to the disposal tube to draw the deposited defective circuit through the tube to dispose of the defective circuit; inspecting the active side of the integrated circuit with the lower lens without turning the article over if its inactive side was not defective; moving linearly the free end of the needle from the cut out portion of the opening of the disposal tube to the predetermined distance from the predetermined point if the active side of said circuit is defective; disconnecting the vacuum from the disposal tube and simultaneously connecting the vacuum to the moved needle to pick up and hold the circuit having the defective active side; moving linearly the needle holding the defective integrated circuit to move the free end of the needle into the cut out portion of the disposal tube and to move the circuit into the opening of the tube; and disconnecting the vacuum from the pickup needle to deposit the defective integrated circuit into the opening, and simultaneously connecting the vacuum to the disposal tube to draw the deposited defective circuit through the tube to dispose of the defective circuit, whereby circuits having defective inactive or active sides are removed from the substrate.

10. An apparatus for inspecting articles for a characteristic and sorting them accordingly, comprising: a microscope for viewing the articles to determine whether they have the characteristic; means for positioning the articles in the field of the microscope; a needle for picking up and holding the articles; means containing the pickup needle for disposing of the articles; means for moving the pickup needle from the disposing means and over each article having the characteristic to pick up and hold the article; means for withdrawing the needle Holding the article to move the article and the needle into the disposing means; and means for releasing the article from the pickup needle to deposit the article into the disposing means.

11. The apparatus of claim 10, wherein the means for disposing of the articles includes a tubular member having an opening and a passageway, both larger than the largest dimension of the article, the opening having a cut out portion normally containing the free end of the pickup needle.

13. An apparatus for inspecting articles for various characteristics and sorting them accordingly, comprising: a microscope for viewing the articles individually to determine whether they have the characteristics; means for positioning the articles individually in the field of the microscope; a needle having a free end for picking up and holding the articles; a tubular member having an opening normally containing the free end of the pickup needle for disposing of the articles; a vacuum source; means for connecting the vacuum source to either the tubular member or the needle; means for moving the free end of the pickup needle over each article having the characteristics; means for operating the connecting means to disconnect the vacuum source from the tubular member and to connect the source to the needle to pick up and hold the article having the characteristics with the free end of the needle; means for withdrawing the needle holding the article to move the article and the free end of the needle into the opening of the tubular member; and means for operating the connecting means to disconnect the vacuum from the needle to release the article therefrom to deposit the article into the opening of the tubular member and to connect the vacuum to the disposal means, whereby the vacuum draws the article through the tubular member.

14. The apparatus of claim 13, wherein the articles are beam-lead integrated circuits and both the inactive and active sides are viewed with the microscope and the circuits are picked up by the needle if either side is defective and are released in the disposal tube.