GB2249868A

GB2249868A - A testing and finishing system for integrated circuit package units

Info

Publication number: GB2249868A
Application number: GB9116411A
Authority: GB
Inventors: Ng Wee Huat
Original assignee: SGS THOMPSON MICROELECTRONICS; SGS Thomson Microelectronics Sdn Bhd
Current assignee: SGS THOMPSON MICROELECTRONICS; STMicroelectronics Sdn Bhd
Priority date: 1990-11-15
Filing date: 1991-07-30
Publication date: 1992-05-20
Anticipated expiration: 2011-07-30
Also published as: GB2249868B; GB9116411D0

Abstract

A testing and finishing system for a discrete or combinational use of apparatus in an automated method of testing, marking, sorting and packing integrated circuit package units is disclosed. The assembly facility comprises:- an automated loading machine (30) feeding package units; an environmental test station (60) preceded by an environmental chamber that conditions the units; a transportation means (80) elevating the position of each unit to be processed; an ambient temperature test station (90); a unit flipper device (100); a degreasing means; a marking means; a curing means; a lead scanning and straightening mechanism (170); and an automated binning, buttoning and packing machine. <IMAGE>

Description

IMPROVEMENTS IN OR RELATING TO A TESTING AND FINISHING SYSTEM FOR INTEGRATED CIRCUIT PACKAGE UNITS.

BACKGROUND OF THE INVENTION: A wide variety of package classes have been developed for integrated circuit application. The basic requirement has been for a multi-lead (8 to 48) sealed package unit.

After a package unit is fabricated, its parameters need to be compared to both the technical specifications and the customer requirements. Commercially available testing systems can be categorised as the manual or one-at-a-time systems, and those capable of quickly making automatic tests on a large number of package units. Manual testing system including switching and handling are both tedious and costly as well as being subject to more testing errors than the automated testing system.

Critical issues of testing and finishing include how to avoid package unit damage, how to avoid lead damage, how to avoid package mix-up, and how to cope with mechanical and operational consequences as a result of temperature variations.

Placing package units into elongated plastic tubes allows handler equipment to accommodate an entire class of package units in carrier such as a single tube whose outside dimensions remain unchanged for all package units in that class. Assembled package units would usually fall by gravity sequentially, and the handler equipment would deliver them to testers, sort them at output, and deliver assembled package units to tubes.

A prior art test and finishing system includes steps of a rawline input, hot test, marking, ambient temperature test, lead straightening, packing and quality assurance outgoing control. This system module involves a length of 23.93 metres. The rawline input involves a step of manual loading and unloading of plastic tubes.

SUMMARY OF INVENTION Device handling improvement has been achieved by modifying the existing handler configuration. The present invention has integrated all individual operations in one assembly linking all the equipment and stations together forming an auto-test and finishing system.

One object of this invention is to eliminate the manual handling operations, such as loading and unloading, between equipment and stations. The chances of confusion and mixing the classes is also avoided. Another object of this invention is to shorten the cycle time of cooling from the hot test station to the ambient temperature test station.

A direct result of this integration is to save space and enhance the Just In Time concept. A reduction of manpower from five operators per shift per module to one operator per shift per module is possible.

The invention is also capable of testing and marking single or multiple binning integrated circuit package units.

An embodiment of the auto test and finish system according to the invention involves a total length of 11.95 metres, resulting in a saving of space of 11.98 metres. Loading of elongated plastic tubes with package units is done once at the beginning of the system. The package units are automatically tested, sorted, and loaded into various plastic tubes at the end of the system. There is also a saving in processing time taken.

According to the present invention there is provided a testing and finishing system for integrated circuit package units comprising the stations of:a multi-track auto loading machine (30), representing the rawline input; a hot chamber (50), with heated track means; a hot tester (60) a conveyor (80) with cooling/buffering means; an ambient temperature tester (90); a unit flipper mechanism (100) a hydrogen torch degreasing mechanism (110); a rotary marking head mechanism (130); A vision inspection system (140), comprising a vision camera (141), and a vision monitor (142); a ultra-violet cure chamber (160); a lead scanning/ straightening mechanism (170); a multi-binning and buttoning machine (180), including the packing section; and a quality assurance computer based supervisory control system.

Other and further objects, features and advantages will be apparent from the following description of a presently preferred embodiment of the invention given for the purpose of disclosure and taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure (la) shows a schematic block diagram of the prior art test and finish system; Figure (lob) shows a schematic block diagram of the improved system.

Figure (2) shows a perspective view of the invention.

Figure (3) shows a perspective view of a multi-track autoloading station.

Figure (4a) shows a package unit orientation known as a "live bug" with the leads extending downwards; Figure (4b) shows a package unit orientation known as a "dead bug" with the leads extending upwards.

Figure (5) shows a perspective view of a hot chamber illustrating the heated track means.

Figure (6) shows a perspective view of a hot test station of the invention.

Figure (7) illustrates package units undergoing a hot test at the hot test station as shown in Figure (6).

Figure (8) shows a side view of a conveyor station with cooling system.

Figure (9) shows a perspective view of an ambient temperature test station.

Figure (10) shows a unit flipper mechanism which turns around each unit from a dead-bug orientation to a live-bug orientation.

Figure (11) shows a perspective view of a hydrogen torch degreasing mechanism.

Figure (12) shows an end view of a track guide mechanism with interlock feature.

Figure (13) shows a perspective view of a rotary marking head mechanism.

Figure (14) shows a perspective view of a mark vision inspection system.

Figure (15) shows a pick up mechanism for a rejected package unit.

Figure (16) shows a ultra-violet cure station.

Figure (17) shows a lead scanner/straightener station.

Figure (18) shows a perspective view of a multi-binning and auto buttoning station.

DESCRIPTION OF PREFERRED EMBODIMENT Referring to Figure (3), a multiple track auto loading machine (30). can carry up to 200 tubes which are used as a buffer feed to the system. Each elongated tube in turn carries a number of units. For an example, for IDF 14/16L class of integrated circuit packages, the number is 25 units; for IDF 20L class of integrated circuit packages, the number is 20 units. The invention can be designed to handle different classes of the packages such as 8L or 48L plastic DIP. (width of packages to be 300 mils to 600 mils). One of the tubes is selected one at a time by a rotating drum mechanism (32) in one of its slots.As the drum mechanism (32) rotates, the tube retained in the slot at the top position is properly orientated by an actuating medium, such as a pneumatic medium, so that the integrated circuit packages inside the tube are placed in a dead-bug orientation. (Figure 4). The multi-track loading machine (30) is slidable transversely to the direction of the units to be processed. These tubes are counter-checked by a sensor mechanism before moving them one at a time via a shuttle means (34). The shuttle means (34) picks up one loaded tube from the drum mechanism (32), moves it transversely, and then upwardly to the top of a hot chamber (50) under computer instruction. When another sensor mechanism identifies an empty track (51) in the hot chamber (50), the shuttle means (34) aligns the loaded tube with the track (51), and tilts the tube in a sloping position. Each integrated circuit package carried in the tube is fed by gravity, one by one, into the empty tracks (51) of the hot chamber (50).

Referring to Figures (5) and (6), in the hot chamber (50), there are preferably 13 track means (51); each track means (51) is able to take up preferably 25 units of package units. It is important to note that one end of the hot chamber (50) is at an elevated position relative to the other end, so that each unit to be processed will move by gravity towards the direction of the multi-binning system (180). The underside of the track means (51) is heated by a heating means to a pre-determined temperature. Inside this hot chamber (50), each package unit is held for a certain time period, preferably one minute. After this period, the units are selected one at a time by a shuffling means (54).

At the hot testing station (60), these units are individually tested, usually electrically, in accordance with the test specifications required. As illustrated in Figure (7), a unit waiting to be processed (61) is stopped by a first stopper means (62). Another unit undergoing hot test (63) is restrained in position by a second stopper means (64). Test results of the heated units are communicated via test finger means (65) which will engage the leads extended from the unit under test. A heater means (66) is also included at the underside of the conveyor chain carrying the package units. The conveyor chains are covered by a hot test cover (55).

Those units that fail the test (57) are sorted and segregated. Those units that pass the test (56) are allowed to proceed on and are released down into an acceptance track slot means, where a magazine block of five units maximum is fed into a conveyor (58).

As indicated in Figure (8), this conveyor (82) carries a plurality of magazines (81), preferably 70 in number. Each magazine (81) preferably carries five units. These magazines are transported by an externally driven conveyor (82), preferably operating at an inclined position. The driving means is preferably a motor (85). This arrangement will allow the magazines (81) to be sufficiently cooled by the time the magazines reach the top of the conveyor (82).

The cooling effect is preferably achieved by air blowing through a cooling header arrangement (86) on one side of the conveyor (82). The magazines are moved upwards along the conveyor (82), until they reach a required position marked as (84), where they are released to the ambient temperature test station (90) via a sorting track means (83).

Now referring to Figure (9), the magazines are individually selected in the sorting track means (83) by a sorter (91) and held in a queue before they are tested again at ambient temperature at the position indicated as (92). A quality assurance test program is built into the ambient temperature tester station (90) which also samples and checks the units passed. Following this ambient temperature test, these package units are sorted by a unit sorter mechanism (93).

Those satisfactory units will proceed on to the unit flipper mechanism (100). Those failing the normal test or the quality assurance test are diverted to either a quality assurance reject track means (94) or a normal reject track (95).

It should be noted that a supervisory computer control system is installed to monitor and coordinate the movement of the equipment and stations. The applicant has developed a computer software program that supervise all sensor devices installed in the system, to synchronise the handling and movement of the package units, and to memorise the inspection status of each package unit.

All this while, the binning results are communicated to a marking station.

Referring to Figure (10), a unit flipper mechanism (100) is illustrated. The function of the unit flipper mechanism (100) is to turn the passed units in a dead-bug orientation to a live-bug orientation, so that marking operation can be executed on the top surface of each unit. The mechanism (100) comprises essentially a swinging arm element (102) which is substantially rectangular. The arm element (102) is made rotatable by means of a rotating means (106) such as a motor or a pneumatic means. Near each end of the swing arm element (102) is a cavity (104) which is positioned in alignment with the entry track means (101) and the exit track means (107). The entry and the exit track means are laterally displaced and are running parallel to each other.

A unit in a dead bug orientation (108) will enter the housing cavity (104) on the swing arm element (102). When the swing element (102) makes a 180 degrees swing, the unit turns into a live bug orientation (109) and leaves the cavity (104) via the exit track means (107). The unit flipper mechanism (100) includes, a sensor device that detects the presence of a package unit in the housing cavity and actuates the flipping motion, and an ejector arrangement to positively eject the package unit preferably by pneumatic means after it has been flipped into a live bug position.

The next stage of the operation is the degreasing of the units. This involves the use of a hydrogen torch means as shown in Figure (11). This improves the ease of marking the units and the permanency of the markings. The units in live bug orientation are transported along an indexing track means (112) incorporated with indexing pin means (111). The indexing track means (112) is actuated by a pulley means (117). There are preferably six nozzle heads (116) which are placed sequentially over the top surface of the package unit. These nozzles (116) are ignited with a source of hydrogen supplied via a stainless steel tube (115). An air cylinder means (114) moves the nozzle heads (116) away from the transportation track when no degreasing is being carried out, so as not to overheat the track.

The results of the hot and cold testing stations are synchronised and memorised together with the indexed movement of the package units under computer supervisory control.

At this juncture, the units are required to be firmly gripped and held in steady position for the next stage of operation, which is the marking stage. A classification number is required to be applied to the top surface of each unit. Referring to Figure (12), the unit in a live bug orientation is carried along on an indexing belt (122), sandwiched by two side track guides (121) preferably made from stainless steel. These two guides and the indexing belt form a shallow cavity in which the unit is carried firmly along. The track guides interlock each unit in its respective position, and the supervisory computer memorises this information with regards to its binning type of marking and visual inspection.

Now referring to Figure (13) and for illustration only, when a unit reaches the fourth position (134) as indicated on the interlock track means (120), it is stopped by a unit stopper means (135). Directly overhead to the unit is a marking means (133). This marking means is adjustable in an up and down movement. The marking means (133) comprises preferably a rotary head means, on the outer circumference of which five marking stamp means (132) are equally spaced. Each marking means (132) carries different classification information for different package unit.

When the marking stamp means (132) is at its uppermost position, an ink transfer roller means (131) applies a thin layer of ink to the said marking stamp means (132). Under computer instruction, an appropriate marking stamp means (134) is moved to its lowest position and will mark a classification number on the top surface of each unit.

After the marking operation, the unit moves along to the fifth position as indicated by (145) (Figure (14)). When the unit is stopped at the sixth position as indicated by (146) by a pneumatic unit stopper means (147), the unit is visually inspected by a mark vision inspection system (140).

Usually, a model 1100/3900 vision system is used to check the quality of the markings. Referring to Figure (14), a vision camera (141) examines the unit placed in focus. The results are displayed in a vision monitor system (142).

Computer instructions are accessible via a key board (144) linked to the supervisory computer control system (190). If the markings are not satisfactory with regards to the level of shape score, each unsatisfactory unit will be stopped by a pneumatic unit stopper (151) and picked up at the eighth indexed position as indicated as (153). As shown in Figure (15), these unsatisfactory units are re-orientated laterally by a pick up system (150). The pick up system (150) comprises preferably an elevated swing arm (157), rotatable preferably by a 180 degrees rotary pneumatic cylinder; and adapted near its end with a pneumatic picker means (152) extendable in a up and down movement.

These unsatisfactory units are fed, one at a time, into a metallic tube (158) where the unsatisfactory marks are erased, the units re-tested and remarked. Those satisfactory units proceed on and are fed to an ultra-violet chamber (160) via a conveyor belt (164) preferably made of stainless steel. - Referring to Figure (16), the ultra-violet chamber (160) comprises an open ended enclosure (161), through which the conveyor belt (164) passes. Above the belt and inside the enclosure (161) is located an ultra-violet source means (162), preferably a lamp. To control the temperature within the enclosure (161), a ventilation means is included, consisting of preferably a sliding exhaust pipe (165) and a fan (163). The marking ink on top of each unit becomes permanently cured by the time the unit leaves the ultraviolet chamber (160).The ultra-violet chamber (160) is also made retractable from the track when no package unit is being processed.

As illustrated in Figure (17), after the ultra-violet chamber (160), the units are then sequentially moved down a track to a lead scanning/straightening machine (170). They pass through a roller means (171) for positively forming the leads. A scanning sensor mechanism is used to detect any bent lead. Those units with excessive bent leads are sorted and segregated into reject tubes (173). Those units with slight bent leads are straightened via a pair of comb mechanism. The units with straight leads (182) proceed on and are released to the next station via the track means (174).

As illustrated in Figure (18), a binning camera (181) is used with the said vision inspection system (140) to identify the classification number marked on the units so that each unit (182) is sorted under computer coordination to each respective binning track and the associated tube adjacent to the track.

A multiple track tube unloader unit (186) is equipped with a shuttle means which loads and stacks empty tubes already buttoned at one end into the slots which are substantially empty or short of tubes. Whenever a tube is filled with package units, each tube is finally buttoned with a plastic stopper means automatically by a buttoner machine (185).

Through a rotator mechanism, the loaded tube drops into a packing box (184) placed underneath and simultaneously an empty tube is put in place.

There are preferably four buttoner machines (185) and correspondingly four packing trays, each isolated from one another.

Now referring once again to Figure (2), the auto test and finishing system is also monitored by an alarm and three light indicator system (191), supervised by computer control. When a green light is switched on, it would indicate that all stations are running smoothly. A blinking orange light with intermittent buzzer sound would indicate that one or more stations is not running smoothly due to jamming. This is an alert signal to an operator. A red light would indicate an urgent call for technical assistance due to long jamming.

The test and finishing system is mounted on a high structure.

Positioned underneath this structure are the accessories of the supervisory computer control system and other storage compartments (193), including the tester stations (192), and terminal monitors (194). By this arrangement also, the units to be processed are kept in view by a standing inspector person.

Claims

WHAT WE CLAIM IS:

1) A testing and finishing system for integrated circuit package units involving a discrete or combinational use of apparatus in an automated method of testing, marking, sorting and packing integrated circuit package units comprising in sequence: an automated loading machine feeding package units; an environmental test station preceded by an environmental chamber that conditions the units; a transportation means elevating the position of each unit to be processed from the environmental test station and equipped with a gas cooling mechanism; an ambient temperature test station; a a unit flipper device for reversing the orientation of a unit; a degreasing means for cleaning the top surface of a unit; a marking mechanism equipped with a rotary head stamping means; a a curing means for curing the markings on the units; a lead scanning and straightening mechanism; and an automated binning, buttoning and packing machine for packing the tested units in package boxes.

2) Apparatus for use in a testing and finishing system according to Claim 1 in which the automated loading machine includes a rotary drum mechanism adapted with multiple slot tracks and a shuttle pick up means movable in horizontal and vertical directions, the movement being synchronised under computer control.

3) Apparatus for use in a testing and finishing system according to Claim 1 in which the environmental test station includes testing at elevated temperature.

4) Apparatus for use in a testing and finishing system according to Claim 1 in which the environmental test station includes testing at below ambient temperature.

5) Apparatus for use in a testing and finishing system according to Claim 1 in which the environmental chamber includes a hot chamber.

6) Apparatus for use in a testing and finishing system according to either of Claims 1 or 5 in which the hot chamber incorporates heated tracks and is sloping downwardly towards the end of the processing line, the angle of slope being substantially thirty five degrees.

7) Apparatus for use in a testing and finishing system according to Claim 1 in which the transportation means includes a conveyor.

8) Apparatus for use in a testing and finishing system according to either of Claims 1 or 7 in which the conveyor (80) is sloping upwardly towards the end of the processing line, thereby elevating the positions of the units to be processed, and is equipped with air blowing cooling means, to cool down the units to be processed.

9) Apparatus for use in a testing and finishing system according to Claim 1 in which the unit flipper device includes a swinging arm, adapted with a housing cavity near its end and each cavity being in alignment with the transportation tracks, the device being equipped with a sensor device to sense the presence of a package unit in the said cavity and to actuate the flipping action, and an ejector mechanism to positively eject the package unit after it has flipped.

10) Apparatus for use in a testing and finishing system according to Claim 1 in which the degreasing station uses hydrogen gas for combustion.

11) Apparatus for use in a testing and finishing system according to Claim 10 in which the degreasing station uses several nozzles in sequence.

12) Apparatus for use in a testing and finishing system according to either Claim 10 or 11 in which the degreasing station is demountable from the transportation track when not in use.

13) Apparatus for use in a testing and finishing system according to Claim 1 in which the marking station includes a rotary head mechanism equipped with a plurality stamping means, each carrying a separate classification identification , and operable under a computer supervisory control program, and each package unit to be marked being positioned by an interlock means on the transportation track.

14) Apparatus for use in a testing and finishing system according to Claim 1 in which the curing means incorporates ultra-violet heating means.

15) Apparatus for use in a testing and finishing system according to either of Claims 1 or 14 in which the curing means is demountable from the transportation track when not in use.

16) Apparatus for use in a testing and finishing system according to either Claim 1 or Claim 2 in which the multibinning, buttoning and packing station includes an automated button supply to a plurality of buttoning machines, and an automated loading machine loading empty tubes having one end already buttoned onto a plurality of slot tracks acting as a buffer.

17) Apparatus for use in a testing and finishing system according to Claim 16 in which the number of buttoning machines or slot tracks is four.

18) Apparatus for use in a testing and finishing system according to Claim 16 in which the slot track incorporates a rotator mechanism that drops a buttoned full tube into a packing box and replenishes an empty tube from the buffer slot track.

19) Apparatus for use in a testing and finishing system according to any preceding claims in which the movement of package units is coordinated and synchronised by computer control which also operates a panel of lighting displays to facilitate the diagnosis of faulty operation.

20) Apparatus for use in a testing and finishing system according to any preceding claims in which the equipment and operating stations are elevated, being mounted on a support frame such that the package units to be processed are substantially in full view of a standing inspector person.

21) An automated method of testing, marking, sorting and packing integrated circuit package units sequentially comprises a discrete or combinational use of the following apparatus:an auto-loading machine; an environmental test station preceded by a environmental condition chamber; a conveyor equipped with cooling means; an ambient temperature test station; a unit flipper mechanism; a degreasing station using a plurality of nozzles; a marking station, including a rotary head stamping mechanism; an ultra-violet chamber; a lead scanning/straightening machine; a multi-binning, buttoning and packing machine.

22) An automated method of testing, sorting, and packing according to Claim 21 in which the environmental test station includes testing at elevated temperatures.

23) An automated method of testing, sorting and packing according to Claim 21 in which the environmental station includes testing at below ambient temperatures.

24) An automatic method of testing, sorting and packing integrated units sequentially according to Claim 21 comprises the steps of: feeding the units one at a time; testing under environmental conditions, including above or below ambient temperature; degreasing the units; marking the units; curing the units; scanning/straightening the leads of the units; and binning, buttoning and packing the units.

25) An automated method of testing, sorting and packing integrated circuit package units sequentially according to Claim 21 or 24 in which the entire sequence is done automatically with the exception of: loading carrier tubes with assembled package units into the auto-loading machine; loading empty carrier tubes having one end already buttoned; and unloading buttoned carrier tubes full with processed units, the remainder of the sequential steps being automated.

26) An automated method of testing, sorting and packing according to Claim 21 or 24 in which the sequence is automatically carried out under computer control the movement of equipment and package units supervising, synchronising and coordinating.