JPS6225262B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to connector devices for connecting leadless large scale integrated circuit (LSI) devices to printed circuit boards or other terminal devices. The connector device includes a leadless ceramic carrier, a leaded socket, and a cover component. Contact is established between the pad on the leadless LSI carrier and the printed circuit board through the contact parts of the leaded socket.

Semiconductors and printed circuits have a major impact on the electronics industry. As the circuit density of the resulting electronic devices increases, the demand for higher density terminal and contact arrangements increases. With recent advances in LSI technology, one chip can contain up to 20,000 or more
It became possible to produce high-density electronic circuits with up to 50,000 transistors.

For many years, dual-in-line (DIP) packaging structures have been the packaging in the electronics industry. Designs with up to 64 leads have been used, but the most commonly used sizes are 40 pins or less. As the capabilities of LSI technology increase and the complexity of devices increases accordingly, 40
There has been an increasing demand for package cages with more pins. A DIP consists of a body containing an integrated circuit and two parallel rows of leads or "legs" extending from either side of the body.

Attachment of the DIP to a printed circuit board has traditionally been accomplished by soldering the legs directly to the circuit board or by inserting the legs into sockets soldered in place on the circuit board. Although soldering provides a very reliable gas-tight electrical connection, it also makes assembly and disassembly difficult in that heat must be applied during assembly and disassembly of the package. Heat for soldering is immediately transferred through the leads to the integrated circuit package, causing excessive heating of the integrated circuit.
This excessive heating can crack the glass seal and damage the integrated circuit. This heat can also warp and/or deform printed circuit boards. When a circuit board is first assembled at a manufacturing company, the application of heat can be controlled relatively easily. However, many expensive components and board assemblies are destroyed by excessive heat at the installation site.

Another package, the leadless carrier, has many advantages over traditional DIP. 1st
In addition, the absence of legs means lower costs and higher manufacturing yields. Second
Additionally, leadless carriers are much smaller than the same DIP, thus allowing higher density placement and shorter lead lengths.

As with DIP, it is highly undesirable to unsolder leadless carriers at the installation site. Because of the problems of replacing soldered connections, many types of removable connectors have been developed that do not require the application of heat to make the electrical connection. These connectors use connections called crimp contacts for electrical connection.

Generally, connectors that are soldered in place require leads or legs to be soldered for the connector, and approximately
A minimum contact center-to-center distance of 2.54 mm (0.10 inch) is required. Connection pads on the carrier can be made along either the edges, top or bottom. However, in each case a pluggable connection is obtained by pressing individual metal contacts against pads on the carrier. The need for individual metal contacts means that the connector must be large to accommodate and isolate each individual contact. The contact itself must be large enough to apply an adequate spring force to ensure a good electrical connection. Additionally, the requirements for accurate stamping and assembly are very expensive.

The other problem that exists with DIP is the large pin count
This is especially true for DIPs, which have large thermal resistance due to long lead lengths, large pin-to-pin capacitance, and large lead resistance.

The present invention relates to a connector device for a leadless LSI device. The connector device includes a leadless ceramic carrier, a leaded socket, and a cover component. Leadless ceramic carrier is used for LSI devices and this
It plays the role of protecting the package that connects the LSI device to the carrier. A leaded socket connects the pads of this leadless carrier to the circuit board through contact parts within the leaded socket. The cover component holds the leadless carrier in place and dissipates heat generated by the LSI within the carrier.

In the illustrated embodiment, the leadless ceramic carrier 11 has (1) a size that allows the carrier 11 to reduce circuit board area by approximately 40 percent compared to conventional DIPs; (2) a contact pad structure; (3) Chip capacity, recess 1 in 64-pin package, with twice as many contact pads 13 in the same area;
2 has a size of 10.16 x 10.16 mm (400 x 400
mil), is 0.635 mm (25 mil) deep and can therefore accommodate large LSI chips,
Otherwise, they can be manufactured using generally conventional materials and designs.

The carrier 11 can be manufactured using any high quality ceramic used in the manufacture of DIPs. Excellent mechanical strength properties can be obtained in part by reducing the overall length. 64
Carrier 11 for pin structure is nominally 41.9×
25.4 x 2.159 mm (1.65 x 1.0 x 0.085 inch) thick, i.e. a comparable 64 pin
It is about 50% of the size of DIP. The high mechanical strength results in high yields in the semiconductor manufacturing industry, and therefore fewer assemblies are damaged by handling and inspection. Another advantage is that there are no conductors to bend or damage during handling or inspection steps.

In a 64-pin structure, the carriers 11 are 32
The contact pads 13 have a center-to-center distance of 1.27 millimeters (50 mils), and the center-to-center distance of the individual contact pads 13 within each row is 2.54 millimeters (100 mils). Along the edge of the other side, the 32 contact pads become probe contacts 14. The contact bodies 14 at each end are arranged in a row,
Its center-to-center distance is 1.27 millimeters (50 mils).

The carrier 11 also has a pair of position designation holes 15,1
6. These holes have different shapes,
When the carrier 11 is inserted into the draw-in socket 20, it is always inserted correctly. At the end of the carrier 11 there are cutouts 17, 18, which, as can be seen in FIG. 1, are slightly different in shape.

The retractable socket 20 has a lower part 21 and an upper part 3.
0. The lower part 21 is generally rectangular in shape, made of an insulating material, and has two rows of staggered holes 22 along each longitudinal edge, with a center-to-center distance of 1.27 mm (50 mm). mill), with individual recesses 22 within each row thereof.
The distance between the centers of is 2.54 mm (100 mil)
It is. The lower part 21 has a pair of positioning holes 23 whose shape and position correspond to the positioning holes 15 and 16 provided in the carrier 11. The end of the lower part 21 has a rectangular cutout in the center, resulting in an uneven end 25. The bottom of the end 25 is slightly shaved, and the end 25 is attached to the lower part 21.
The thickness is smaller than that of other parts. The central part of such an end 25 is further cut into a rectangular shape, creating a notch 26. Lower part 21
A substantially rectangular shape 27 is cut out at the center of the bottom surface of the base. However, an uncut portion is left on the bottom surface around the position designation hole 23. Small protrusions 28 at the four corners and near the locating holes 23 serve to separate the connector 10 from the circuit board.

The upper part 30 is generally rectangular in shape, made of an insulating material, and has two rows of staggered cavities 31 along each longitudinal edge, the distance between their centers being 1.27 mm. (50 mil). These recesses 31 are slightly larger than the recesses 22. The end walls 32 meet and a recess 33 is created therebetween in which the ceramic carrier 11 is placed. Upper part 3
A pair of locating posts 34, 35 are provided on each side of the carrier 11 and correspond in shape and position to the locating holes 15, 16 of the carrier 11 and the locating holes 23 of the lower part 21. The end of the upper part 30 having the end wall 33 has a rectangular cutout in the center corresponding to the size of the notch in the lower part 21, and has an uneven end 36. The central part of such an end 36 corresponds to the cutout of the lower part 21 and is further cut out in a rectangular shape to create a cutout 37 . The upper part 30 further has a central hole 38 for accommodating the cover seal 19 on the carrier 11. This cover seal is for enclosing the LSI device within the recess 12. A longitudinal groove 39 below the cavity 31 is provided in the lower surface of the upper part 30 for accommodating a contact part 40, as seen in FIG.

Contact part 40 is spring tempered copper nickel alloy
725, the nominal thickness of this elastic metal sheet is 0.127 mm (5 mils)
and this elastic metal plate is carrier 11
At the contact part 41 of the contact part 40 that comes into contact with the contact 13 of the nickel inner liner,
They typically have a conductive coating, such as a 24K gold coating, which is 0.00076 millimeters (0.00003 inches) thick.

As can be seen in FIG. 3, the contact piece 40 has a generally U-shaped leg 42 formed by bending a flat plate at a generally right angle. The ends of the legs 42 are truncated at an acute angle to provide a pointed tip.
At the upper end of the leg 42 there is a
A pair of locking tabs 43 are provided. A pair of tabs 44 are provided at the upper ends of the legs 42 and serve to make the legs 42 sturdy.

The central part 45 of the contact part 40 is connected at one end to the leg 42 at right angles. The other end of this central section 45 is C-shaped and is joined to a spring beam section 46 that is generally parallel to the central section 45. Spring beam portion 46 is joined at right angles to contact portion 41, and this joint portion 41 is generally J-shaped.

In a particular exemplary embodiment using the metal plate, the overall length of contact piece 40 is 10.795 millimeters (0.425 inches) and its overall width is
It is 0.762 mm (0.03 inch). The length of leg 42 is 7.62 mm (0.3 inch) and its U-shaped portion is 0.381 mm (0.015 inch).
inch). The length of the central portion 45 is 3.175 mm (0.125 inch) and the height of the C-shaped portion is 1.27 mm (0.05 inch).
It is. The length of the spring beam section is 2.032 mm (0.08 inch) and its J-shaped contact leg is 1.905 mm (0.075 inch). The gold-coated curve is 0.762 x 0.0889 mm (0.03 x 0.035 inch).

As can be seen in FIG. 3, the contact piece 40 is not completely removed from the plate during the forming process.
Instead, the contact part 40 is stamped out from a plate 47.
A portion is left joined to the connection of the central part 45 and the spring beam part 46, so that the contact part 40 is interconnected in the form of a strip. The plate 47 can be scored along the joining line 48 during the die-cutting process, so that the contact part 4
0 can be easily separated into individual parts when needed.

The cover part 50 has a generally rectangular shape, its length is approximately equal to the length of the carrier 11, and its width is such that it does not come into electrical contact with the probe contacts 14 arranged on the surface of the carrier 11. small. The probe contacts 14 are aligned along the longitudinal edge of the carrier and are made of a copper alloy with high thermal conductivity. Cover parts 5
0 is preferably an annealed spring;
It is also desirable to have a thermally conductive finish coating such as nickel plate. The upper surface of the cover part 50 is divided into three approximately equal parts 51, 52 and 53. The central portion 52 is substantially flat so that the LSI chips are in close contact with the surface of the carrier 11 contained therein. The central portion 52 has longitudinal ribs 54 along its edges near its outer edges, which provide strength and stiffness to the cover part 50.

Each of the outer end portions 51 and 53 of the cover part 50 is bent slightly upwardly and outwardly at the junction with the central portion 52. Each end portion 51, 53 has a plurality of transverse grooves 55.

Extending from the outer edge of each end portion 51, 53 is an end wall 56 having a length measured along the bottom of end 25 from the combined thickness of carrier 11 and lead socket 20. is equal to minus
The width of this end wall is then equal to the recessed ends 25 and 36. A central rectangular opening 57 is cut out at the junction of each end portion 51, 53 and end wall 56, corresponding in size and location to the end notches 25 and 36.
At the free end of each end wall 56 is an inwardly bent lip 58.

The connector device 10 of the present invention first includes a carrier 11.
The chip is assembled by mounting the chip in the recess 12 in a conventional manner. And from the tip to the recess 12
Bonding of the leads to contact points provided along the periphery of is performed, after which the cover seal 19 is installed. The leadless socket 20 connects the interconnected strips of the contact part 40 to the lower part 2.
It is assembled by first inserting it into the hole 22 of No. 1. After the contact pieces 40 are secured within the holes 22, the bonded strip of plate material 47 is cut along line 48 to create an individual contact piece 40 within each hole 22.
is left behind. Upper part 30 is then assembled onto lower part 21. Then, locating posts 34 and 35 and supplementary locating holes 23
determines the correct placement of the upper part 30 relative to the lower part 21. In this assembly process,
The central portion 45 and spring beam portion 46 of the contact piece 40 enter the longitudinal groove 39 of the top piece 30 and, as can be seen in FIG. 2, the J-shaped contact portion 4
1 protrudes from the empty space 31. If desired, the two parts of leaded socket 20 are joined together by ultrasonic or thermal bonding, or by a suitable bonding agent.

The socket 20 thus assembled is placed on a printed circuit board (not shown) with the legs 42 projecting through the holes in the circuit board, and these are then soldered in a conventional manner. Note that the leaded socket 20 is mechanically positioned by the staggered arrangement of the legs 42 within the hole 22 and by the shape of the hole in the circuit board so that it cannot be accidentally inserted into the circuit board. I want to be After the circuit board has been cleaned, the leadless ceramic carrier 11 is placed in the recess 33 with the recess 12 facing downward, as seen in FIGS. 1 and 2. Again, locating posts 34 and 35 and locating holes 15 and 16 prevent carrier 11 from being inserted into socket 20 in any other configuration than the correct one. Finally, the cover part 50 is placed on the carrier 11 and snapped into the socket 20, and the end wall 56 is attached to the top part 3.
0 and into the rectangular notch in the lower part 21, and the lip 58 goes inside and attaches to the notch along the bottom of the end 25. The upwardly curved end portions 51 and 53 of the cover part 50 provide tension between the inwardly curved lip 58 and the end 25. In this way, the carrier 11 is pressed firmly downwards within the recess 33 and the contact pad 13 is pressed firmly against the protruding J-shaped contact portion 41 of the contact part 40.
pressed against. J-shaped contact portion 4 of contact component 40
1 rubs against the contact pad 13 on the carrier 11, an electrical connection is established. This rubbing contact is maintained by the action of the spring beam part 46, which also, by its bending action upon contact with the contact pad 13, maintains the electrical isolation of the contact part 41 of the adjacent contact part 40. It will be done. Second
As can be seen in the lower left corner of the figure, the contact section 41 of the contact part 40 that is closest when viewed from the front bends to the right, and the farthest contact part bends to the left. As previously mentioned, the cavity 31 in the top part 30 is somewhat larger to allow this bending of the J-shaped contact 41. The electrical connection is made more reliable by coating the contact portion 41 with gold. For diagnostic, "debugging", maintenance or other purposes,
When it is necessary to remove the carrier 11 from the socket 20, insert the screwdriver vertically into the opening 57 of the cover part 50 and also remove the notches 26 and 3.
7 and apply slight outward pressure on the end wall 56 to release the inwardly curved lip 58 from the end 25. The cover part 58 can then be lifted upwards and the carrier 11 removed.

The connector device 10 of the present invention provides a large pin count package that can incorporate advances in LSI technology without physically increasing the size of the package. The connector device of the present invention is actually about 60 percent smaller than a comparable DIP.

The electrical characteristics of an electronic package are of course influenced by its size and shape. The package shape reflects the uniformity of trace length and width. Lead resistance and lead-to-lead capacitance are directly affected by
It can also vary with different path lengths. For example, the longest trace of a typical 64-lead DIP is more than six times as long as the corresponding trace of one type of leadless carrier. The ratio of the longest trace to the shortest trace for a 64-lead DIP is 7:1, whereas for the leadless carrier of the present invention, this ratio is 5:1. These unequal trace lengths and long electrical paths in the DIP are severe limitations for high performance applications. Shorter trace lengths generally result in lower resistance and lead-to-lead capacitance, which provides faster switching times and improved overall performance. The maximum lead resistance of the leads of the connector device of the present invention is 0.3 ohms, and the maximum lead-to-lead capacitance is less than 3 picofarads. These values should be compared to a comparable DIP resistance of 1.1 ohms and capacitance of 6.6 picofurads.

Traditionally, high pin count packages, particularly DIPs, have required considerable force when inserting or removing the package from a socket. This caused bending and damage to the leads, damage to the package, and damage to the socket. As a result, there is a limit to the number of package cages that can be inserted into sockets without causing damage. The device according to the invention has both "zero insertion force" and "zero removal force", so that multiple insertions and removals can be carried out safely.

Note that the leadless chip carrier according to the present invention makes contact with a bottom side contact piece and a set of probe contacts is provided on the opposite or top surface of the carrier. Although this structure allows direct electrical measurements to be made at any point of contact, the chip operates in situ and is a very useful diagnostic and maintenance tool.

In addition to ensuring that the leadless chip carrier 11 contacts the electrical contacts of the socket 20, the cover part 50 also serves to dissipate heat through the cover part material in intimate contact with the surface of the carrier 11. Heat dissipation is achieved through the central portion 52 of the cover part 50.
This can be strengthened by attaching a heat sink, for example. The thermal resistance value of the connector device of the present invention is 35℃
per watt, which is extremely small considering the small circuit board area occupied by this device.

[Brief explanation of the drawing]

FIG. 1 is an exploded three-dimensional view of the connector device of the present invention;
FIG. 2 is a side sectional view of the connector device of the invention, FIG. 3 is an enlarged three-dimensional view of the contact part of the invention, and FIG. 4 is an enlarged plan view of a portion of the leadless ceramic carrier of the invention. 11... Leadless ceramic carrier, 20
...Socket with lead, 50...Cover parts.

Claims (1)

[Claims] 1. A leadless ceramic carrier 11 with a small size and a large number of pins, a leaded socket 20 having a contact part 40, and a cover part 50, the leadless ceramic carrier 11 being elongated, and It has contact pads 13 closely spaced in two alternating rows on one surface along each of its longitudinal edges, the distance between the centers of said two rows being
1.27 mm (50 mils), and the center-to-center distance of the contact pads 13 in each row is 2.54 mm (100 mils);
terminates on the other surface of the ceramic carrier 11 as a row of probe contacts 14 along each of the longitudinal edges at a center-to-center spacing of 1.27 mm (50 mils), and the leaded sockets 20 are connected to each other. The upper part 30 and the lower part 21 have the same elongated outer circumference and are attached to the upper part 30 and the lower part 21.
1 houses a contact part 40 therein, said upper part 30 containing said leadless ceramic carrier 11
The upper part 30 has recesses 33 provided in its upper surface for receiving the leadless ceramic carrier 11.
3, and a longitudinal groove 39 is provided in the lower surface of the upper part 30 for accommodating the central part 45 of the contact part 40, the lower part 21 has a cavity 31 respectively aligned with the contact part 40. a corresponding cavity 31 in said upper part 30 for inserting a
The contact part 40 has a hole 22 aligned with the leg 42 and a contact part 45 joined to the spring beam with a central part 45 joined at one end to the leg and at the other end to the spring beam part 46. Part 4
1, and the contact portion 41 is connected to the carrier 11.
said cover part 50 is elongated, its length being essentially equal to the length of said carrier 11 and its width substantially greater than said carrier 11. narrow, thereby exposing the row of probe contacts 14 along each longitudinal edge of the carrier 11; It has a central portion 52 and end portions 51, 53 which are slightly upwardly curved and joined to an end wall 56 with an inwardly curved lip 58 at its free end.
8 are adapted to engage the ends of said lower part 21, thereby latching said cover part 50 to said leaded socket; connecting a leadless large scale integrated circuit device to a printed circuit board; Connector device for on-the-spot electrical measurements at any contact point while the circuit device is in operation. 2. In claim 1, the contact piece 40 comprises legs 42, a flat, generally C-shaped central portion 45, a flat spring beam portion 46, and a flat, generally J-shaped contact portion 41. the leg has at its free end a guiding tip for guiding the leg into the hole in the printed circuit board and at its other end a retaining device 43; joined to the legs, said spring beam portion being generally parallel to said central portion and joined to said central portion at one end, said J-shaped contact portion being joined at right angles to said spring beam portion, said contact portion of said contact part being joined to said central portion; A connector device in which a curved portion of the top part protrudes above the surface of the top part to provide an electrical connection by rubbing with the contact pad when the wireless ceramic carrier is pressed onto the top part.