JPH01208836A - Bonding method and device - Google Patents

Abstract

PURPOSE:To equalize the adhesion of adhesives onto a bonded surface by applying adhesives onto a plane within a range larger than the mileage of an article to be bonded, relatively pushing the article to be bonded against adhesives and attaching adhesives onto the bonded surface of a article to be bonded. CONSTITUTION:Adhesives 7 fed to a recessed section formed by a plate 5, a roller 3 and a shield plate 6 are applied onto a glass plate 10 by the revolution of the roller 3 and the movement of the glass plate 10, and adhesives 7 are levelled off to a specified thickness by a scraping-out plate 9. An article to be bonded 28 sucked to a collet 25 for a suction head 24 is brought into contact with adhesives 7 on the glass plate 10, and the adhesives 7 are attached to the article to be bonded 28 on the glass plate 10. Since the adhesives 7 in specified thickness adhere onto the glass plate 10 wider than the adhesive bonded surface of the article to be bonded 28 at that time, the adhesives 7 uniformly adhere on the article to be bonded 28 in predetermined thickness. The article to be bonded 28, on which the adhesives 7 adhere, is carried by the suction head 24 as it is, and cemented with the fixed section of a member positioned at a bonding station.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to adhesion technology, and particularly to a technology that is effective for use in adhering a semiconductor element to a lead frame in the manufacture of semiconductor devices.

[Conventional technology]

As a conventional technique, Japanese Patent Application Laid-open No. 102671/1983 describes a method of attaching pellets to lead frames in the manufacture of semiconductor devices.

The outline is that the lead 7. −
In the method of attaching the pellets (d), small spherical silver paste is dropped onto the surface at multiple locations, and the pellets are placed on top of the pellets for pellet attachment (hereinafter referred to as adhesion).

[Problem to be solved by the invention]

The present inventor used the above-mentioned technique to adhere a pellet as an object to be adhered to a lead frame as a member in the manufacture of a semiconductor device, and found that the following problems occurred.

In other words, even if silver paste is dropped at multiple locations on the pellet adhesive surface, when the pellet is placed, the spherical silver paste will spread from the inside toward the circumference.
The problem is that the silver paste does not spread over the entire adhesive surface of the pellet because it spreads around the corners of the pellet.

The inventor of the present invention has clarified that there is a problem in that the pellet cannot be reliably bonded to a predetermined position of the lead frame, resulting in poor pellet adhesion.

However, even if the pellets are successfully adhered, there is a problem that the pellets may come off due to impact (e.g., heat or vibration) on the fences during the subsequent manufacturing process. revealed by.

An object of the present invention is to provide a technique that allows silver paste to be applied uniformly to the entire pellet adhesion surface.

Another object of the present invention is to provide a technique that can reliably adhere pellets to a predetermined portion of a lead frame.

Another object of the present invention is to provide a technique that can reliably adhere pellets to a predetermined portion of a lead frame, thereby improving the reliability of pellet adhesion.

The above and other objects and novel features of the present invention include:
It will become clear from the description herein and the accompanying drawings.

[Means to solve the problem]

A brief overview of typical inventions disclosed in this application is as follows.

Apply silver paste to the desired thickness on a flat plate in an area larger than the adhesive surface of the pellet, press the pellet relative to the silver paste, and apply silver paste to the adhesive surface of the pellet. After attaching the pellet, the pellet is glued to a predetermined portion of the lead frame.

[For production]

According to the above-mentioned method, the silver paste is coated on a flat plate with a desired thickness and larger than the adhesive surface of the pellets, and the pellets are pressed against the silver paste. Silver paste of a desired thickness is applied to the entire adhesive surface of the pellet.

Therefore, if the pellet is placed on a predetermined part of the lead frame and bonded 1, the entire adhesive surface of the pellet can be bonded to the predetermined part of the lead frame via the silver paste, and the spherical paste is divided into multiple parts. This allows the pellets to be bonded more reliably than those that are bonded by hand.

〔Example〕

FIG. 1 is a schematic front view showing a paste adhering portion of a pellet adhering device according to an embodiment of the present invention.

FIG. 2 is a schematic front view showing a state in which silver paste is applied onto a glass plate in a paste application section of a pellet adhering device according to an embodiment of the present invention.

FIG. 3 is a schematic side view showing a bonding section of a pellet bonding device that is an embodiment of the present invention.

Figure WJ4 is a schematic front view showing a semiconductor device manufactured using an adhesive technique that is an embodiment of the present invention.

FIG. 5 is a schematic plan view showing the appearance of a pellet bonding device that is an embodiment of the present invention.

In FIG. 1, 1 indicates a paste-applied portion.

2Fi, a paste tank is used to store silver paste as a p1 adhesive and supply the silver paste onto a glass plate, which will be described later. 3 is a roller), which is a cylindrical object that has the role of storing the excellent paste and the role of applying the silver paste to the glass plate, which will be described later. This roller 3 is rotatable in the circumferential direction by a motor provided within the head 4, and is provided in a manner protruding from the head 4. Reference numeral 5 denotes a plate, which has a width similar to the width of the roller 3 in the cylindrical height direction, and has a shape in which the surface of the plate 5 in the thickness direction is approximately perpendicular to the circumferential surface of the roller 3. The silver paste can be stored in a concave portion formed as the circumferential surface of the roller 3, which is inclined and adjacent to the roller 3. The proximity between this plate 5 and the roller 3 (
The gap is close to (larger than) the thickness of the silver paste desired for attaching to the pellets described later.

6 is a shield plate, which is a substantially rectangular plate and is attached to each end face of the roller 3 in the cylinder height direction (the roller 3 rotates, but the shield plate 6 rotates). This is to support the plate 5 and to prevent the silver paste 7 from leaking from the sides.

A shaft 8 is attached to a motor (not shown) in the head 4 and rotatably supports the roller 3. Reference numeral 9 denotes a scraping plate, which is a plate-shaped member having a downwardly tapered tip, and is attached to the head 4 so as to stand upright with respect to a glass plate, which will be described later. This scraping plate 9Fi has the role of leveling the thickness of the silver paste applied on the glass plate to be described later as desired. Reference numeral 10 is a glass plate, which is a rectangular flat plate, and is used to apply silver paste of a thickness to be applied to the pellets, which will be described later, to an area larger than the adhesive surface of the pellets, and it moves up and down. and is supported for horizontal movement. 11 is a guide body that supports the glass plate 10 so as to be horizontally movable in the direction in which the circumferential surface of the roller 3 is extended; both sides of the glass plate 10 parallel to the moving direction are - Each book is supported by a guide body 11. Reference numeral 12 is a ball screw, and is arranged parallel to the moving direction of the glass plate 10 and below the glass plate 10.

Reference numeral 13 denotes a support member for supporting the ball screw 12 on a pace plate which will be described later.
is supported by two supporting members 13. Reference numeral 14 denotes a moving member, which is attached to the glass plate 10 and rotates the ball screw 12 by forward or reverse rotation of the ball screw 12.
It is possible to move back and forth in the longitudinal direction. The tab and the glass plate 10 are rotated by the forward and reverse rotation of the ball screw 12.
It is made reciprocating along the guide body 11.

Reference numeral 15 denotes a motor, which is mounted on a base plate to be described later and is capable of rotating the ball screw 12 in forward and reverse directions. 16 is a base plate on which the guide body 11, motor 15, etc. can be placed. Reference numeral 17 denotes a shaft, which is attached vertically to the back surface of the base plate 16 (the surface opposite to the surface on which the guide body 11 is placed), and the two shafts 17 support the base plate 16. It is shaped like this. 18 is a bearing;
This is for guiding the vertical movement of the shaft 17. The shaft 17 (base plate 16) is guided by this bearing 18 and can move up and down. Reference numeral 19 denotes a bearing, which rotates or moves up and down along a cam to be described later. The base plate 16 moves up and down as the bearing 19 moves up and down. Reference numeral 20 denotes a support member, which is attached to the back surface of the base plate 16 and supports the bearing 19 so as to be able to rotate once through the shaft 21f. A cam 22 contacts the bearing 19, and the rotation of the cam 22 causes the bearing 19 (base plate 16) to move up and down. Reference numeral 23 denotes a shaft, which is attached to the cam 22 and is driven by a motor (not shown) to rotate the cam 22.
can be rotated. Reference numeral 24 denotes a suction head as a supporting member, which suctions pellets, which will be described later, and is movable vertically and in parallel, and is used to adhere the pellets to a predetermined position on the lead frame. 25 is a collet, which is a rectangular prism-shaped object for adsorbing pellets.
A trapezoidal recess 26 and a through hole (not shown) penetrating into the recess 26 from the opposite surface are formed. 27 is an air pipe, and is installed upright on the opposite surface of the collet 25, which is different from the surface on which the recess 26 is formed;
In addition to supporting the collet 25, it is also capable of applying a negative pressure to the collet 25. In other words, negative pressure is applied from a negative pressure mechanism (not shown) such as a compam, through the air pipe 27, through the through hole (not shown) of the collet 250, to the recess 26.
This negative pressure adsorbs pellets, which will be described later. Reference numeral 28 denotes a pellet as an object to be adhered, which is the core of the semiconductor device.

In FIG. 2, after silver paste 7 is applied to a desired thickness on a glass plate 10, a pellet 28 sucked by a suction head 24 is pressed onto the silver paste 7, and the surface of the pellet 28 to be bonded is 2 shows the state in which silver paste 7 is applied.

In Figure 3, the adhesive part is shown, and the silver paste 7
The pellet 28 to which it has been attached is shown being transported to an adhesion stage 4, which will be described later. Reference numeral 29 denotes a portion at which a lead frame, which will be described later, is positioned at a predetermined position, and the lead frame is heated and bonded using a predetermined bonding temperature tube. Reference numeral 30 denotes a guide rail, which has a U-shaped cross section in a direction perpendicular to the longitudinal direction, and the two guide rails 30 are arranged so that the U-shaped cross sections face each other. . Reference numeral 31 is a heat block that heats a lead frame, which will be described later, to a predetermined temperature, and is lowered during conveyance of the lead frame so as not to interfere with conveyance of the lead frame. 32 is a lead frame as a member.

By the way, when transporting lead frames.

It is intermittently conveyed by rectangular movement of conveyance claws (not shown).

In FIG. 4, reference numeral 33 is a tab-shaped, rectangular portion on which the pellet is placed (adhered), and constitutes a lead frame. Reference numeral 34 denotes a lead, which is used to establish electrical conduction between the inside of the pellet 28 and the outside thereof, and constitutes a lead frame. 35 is a wire, and pellet 2
This is for establishing electrical continuity between the lead 8 and the lead 34. 36 is
This is a virtual line indicating a package. 37 is a semiconductor device, and in this embodiment, leads 34 protrude from two sides of a package (36). An example of application to a DIL (dual-in-line) type semiconductor device is shown.

In FIG. 5, 38 indicates a bonding device. 39 is a loader, and lead frames (before pellet bonding, not shown) as members are stored in multiple stages in racks to be described later, and an elevator mechanism (not shown) is used to raise the lead frame transport level (transport height). 1 and can rise (or fall) sequentially. Reference numeral 40 is a frame-like object having a rectangular cross section in the direction perpendicular to the rack and lead frame storage surface, and grooves in which the lead frames are stored are formed in multiple stages on both sides of the storage surface. . This loader 3
9 (on the left side in the figure) is the guide rail 30 described above.
is arranged, and the loader 3 is removed by a take-out claw (not shown).
The lead frame taken out from the rack 40 of No. 9 passes through an adhesion stage *y29 and is conveyed to an unloader to be described later. 41 is the unloader, guide rail 3
The rack 4o, which is placed opposite the loader 39 with the pellets sandwiched therebetween, and which can be moved up and down by an elevator mechanism (not shown), is provided with the pellet adhesion completed.

It can be stored in multiple stages. 42Fi), the recesses on which the pellets are placed are plate-shaped objects formed in multiple rows and columns in the X-Y direction, and multiple pellets to be bonded to the lead frame are placed. has been done. This tray 42 is placed on an XY table (not shown) and is movable in the XY direction. 43 is a positioning pocket, and if the pellet is tilted in the plane direction with respect to the part of the inserted frame to be bonded, as shown in the figure,
A trapezoidal recess (not shown) that gradually narrows toward the bottom to ensure that the slope in the thickness direction is even.
is formed. Reference numeral 44 denotes a suction arm, and an air pipe 27 with the collet 25 attached thereto is attached to its tip, and the air pipe 27 is connected from the positioning pocket 43 through the glass plate 10 to the adhesion stage 29 by a cam mechanism (not shown), etc. This allows for reciprocating movement as well as vertical movement.

By the way, although not shown, the pellets from the tray 42 (
(not shown) to the positioning pocket 43 is carried out by an arm similar to the suction arm described above.

Hereinafter, the operation of an embodiment of the present invention having the above-described structure will be explained.

First, the function of the paste-attached portion will be explained.

In FIG. 1, silver paste 7 is supplied to a concave portion formed by plate 5, roller 3, and shield plate 6. In FIG. The gap between the plate 5 and the roller 3 is 5
The thickness is approximately 0 μm (several μm is better). By the way, in this example, the pellet 28 is
A silver paste of m thickness shall be applied. In this state, the roller 3 rotates in the direction of the arrow in the figure. Then, the silver paste 7 adheres to the circumferential surface of the roller 30, as shown in FIG. This silver paste 7 is made from the gap between the plate 5 and the roller 3, and is coated on the circumferential surface of the roller 3 with a thickness slightly thicker than 50 μm (hereinafter referred to as 50 μm).
(approximately m) silver paste will adhere to the surface. Therefore, while the roller 3 is rotating, the portion of the circumferential surface of the roller 3 that has passed through the plate 5 always has a thickness of 50 μm.
The amount of silver paste 7 will be deposited.

On the other hand, in Figures 8g1 and 2, the gap between the tip of the scraping plate 9 and the glass plate 10 is 50 μm due to the rise of the pace plate 16 due to the rotation of the cam 220.
rise until . Thereafter, the glass plate 10 is moved from the left side to the right side in the figure by the rotation of the motor 15. (The figure shows a state in which the glass plate 10 has completely moved to the right side.) The moving speed at this time is the same as the rotation (circumferential speed) of the roller 3, and the silver paste attached to the roller 3 is 7 is applied onto the glass plate 10. As the glass plate 10 continues to move (move to the right), the scraping plate 9 removes the silver paste 7 on the glass plate 10 by 50 μm.
It will be leveled so that it has a thickness K of m. In this way, the silver paste 7 with a thickness of 50 Am is applied to the glass plate 1.
0. After that, the pellet 28 adsorbed on the collet 25 of the adsorption rod 24 is
The silver paste 7 on the glass plate 10 adheres to the pellet 28 in contact with the silver paste 7 on the glass plate 10 . On this occasion,
Glass plate 10 wider than the silver paste attachment surface of pellet 28
Since the silver paste 7 with a thickness of 50 μm is attached to the top, the silver paste 7 is evenly spread on the pellet 28 with a thickness of 50 μm.
It adheres to a thickness of m.

When the silver paste 7 to adhere to the pellets 28 on the glass plate 10 is exhausted, the cam 22 rotates, the glass plate 10 is lowered, and the glass plate 10 is rotated by the rotation of the motor 15 in the opposite direction. Move to the center left. Thereafter, the glass plate 10 is raised again by the rotation of the cam 22, and by repeating the above-described operation, the IQfK silver paste is applied to the glass plate.

Next, the overall operation of the pellet bonding apparatus, which is an embodiment of the present invention, will be explained.

In FIG. 5, first, a lead frame (not shown) before being bonded with a pellet is taken out from the two hooks 40 of the loader 39 by a take-out claw (not shown), and the lead frame is removed from the guide rail 30.
transported upwards. Thereafter, the lead frame is intermittently transported to the bonding stage 4 29 by the rectangular movement of transport claws (not shown). During this transportation, when the transportation of the lead frame is stopped, the heat block 31 is raised so that the lead frame can be heated to the temperature at which the lead frame is bonded to the pellet.

On the other hand, in the paste adhering part 1, as shown in FIGS. 1 and 2, a layer of 50 μm (desired thickness) is coated on the glass plate 10 by the rotation of the roller 3 and the movement of the glass plate 10. A thickness of silver paste 7 is applied. At the same time, pellets to be bonded (not shown) are taken out from the tray 42 shown in FIG.
43 and positioned. Next, the pellet in the positioning pocket is taken out by the collet 25 of the suction head 24, and its adhesive surface is brought into contact with the silver paste 7 on the glass plate 10, and the pellet 28 is
The silver paste 7 with a thickness of μm can be uniformly adhered to the entire adhesive surface of the pellet 28. Then, the pellet 28 to which the silver paste 7 was evenly adhered is conveyed as it is by the suction head 24, as shown in FIG.
The adhesive stage is positioned on the adhesive stage plate 29 and adhered to a predetermined portion of the frame 32.

As described above, according to this embodiment, the silver paste 7 of a desired thickness is adhered to the entire surface of the adhesive surface of the pellet 28, thereby making it possible to adhere the pellets, thereby ensuring the adhesion of the pellets. Therefore, as shown in FIG. 4, the semiconductor device 37 assembled according to this embodiment is subjected to various shocks sK during various steps after pellet bonding and even during a long period thereafter. , it is possible to reduce pellet adhesion defects and pellet peeling.

By the way, in this embodiment, the silver paste is applied onto the glass plate using a roller and a scraping plate, and then another mechanism may be used.

Furthermore, in this embodiment, the silver paste was applied to one glass plate before the silver paste was applied to the pellets, but a plate other than the glass plate may be used.

Although not explained in detail in this example, if the glass plate coated with silver paste to a desired thickness is made considerably larger than the pellets, the silver paste equivalent to multiple pellets can be applied. The adhesive can be applied as desired and the pellets can be successively adhered to the lead frame one after another.

In this example, silver paste was applied to the desired thickness (thickness considered desirable for pellet adhesion) on the glass plate, but when adhering to the pellets, there was a case where the adhesion of the silver paste to the pellets was not good. (Silver paste leaves a little thickness,
If the silver paste remains on the glass plate), the silver paste may be applied thickly to the glass plate in advance, taking into account the amount of silver paste remaining on the glass plate. The same can be said of the adhesion of silver paste from a roller to a glass plate.

Incidentally, in this embodiment, the K silver paste was deposited with the pellet side lowered, but it may also be deposited with the silver paste side, ie, the glass plate side raised.

(1) By applying silver paste of desired thickness on a flat plate in an area larger than the adhesive surface of the pellet, and pressing the pellet relative to the silver paste, the entire adhesive surface of the pellet can be coated. The effect is that the silver paste can be applied uniformly to the surface.

(2) Apply silver paste to the desired thickness on a flat plate in an area larger than the adhesive surface of the pellets, and press the pellets relative to the silver paste to make the silver paste adhere to the pellets. After that, the pellet is glued to the lead frame. Since the entire adhesive surface of the pellet is glued through the silver paste, the pellet can be firmly attached to the predetermined part of the lead frame compared to when using a dispenser. The effect of adhesion can be obtained.

(3) Silver paste was applied to the desired thickness on a flat plate in an area larger than the adhesive surface of the pellets, and the pellets were pressed relative to the silver paste to adhere the silver paste to the pellets. After adhering the pellet to the lead frame, the entire adhesive surface of the pellet is adhered via silver paste, making it easier to securely attach the pellet to the lead frame than when using a dispenser. Partial pressure bonding is possible. Therefore, the effect of improving the reliability of pellet adhesion can be obtained.

Although the invention made by the present inventor has been specifically explained above based on examples, it goes without saying that the present invention is not limited to the above examples and can be modified in various ways without departing from the gist thereof. Nor.

In the above description, the invention made by the present inventor is mainly applied to pellet adhesion technology in the manufacture of semiconductor devices, which is the background of the invention, but the invention is not limited thereto.

〔Effect of the invention〕

A brief explanation of the effects obtained by typical inventions disclosed in this application is as follows.

In other words, after leveling and applying the Senshi paste on a flat plate,
By pressing the pellets onto the silver paste on a flat plate and adhering the silver paste to the pellets, it is possible to apply the silver paste evenly over the entire adhesive surface of the pellets, compared to the method using a dispenser.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a schematic front view showing a paste adhesion part of a pellet bonding device which is an embodiment of the present invention, and FIG. FIG. 3 is a schematic front view showing a state in which silver paste is applied onto a glass plate in the paste application part of FIG. FIG. 4 is a schematic front view showing a semiconductor device manufactured using the bonding technology which is an embodiment of the present invention, and FIG. 5 is a schematic front view showing the entire outline of a pellet bonding device which is an embodiment of the present invention. FIG. 1...Paste adhesion part, 2...Based tank, 3
...Roller, 4...Head, 5...Grate,
6... Shield plate, 7... Silver paste, 8, 17
．． 21.23... Shaft, 9... Scraping board, 1
0... Glass plate, 11... Guide body, 12... Ball screw, 13゛, 20... Supporting member, 14... Moving member, 15... Motor, 16... Base plate , 18
．． 19...Bearing, 22...Cam, 24...
suction spatula)", 25... collet, 26... recess,
27...Air pipe, 28...Pellet, 29...
・Adhesive stage 4, 30...Guide rail, 31・
... Heat block, 32 ... Lead frame, 33
...Tab, 34...Lead, 35...Wire, 3
6...Package, 37...Semiconductor device, 38...
・Adhesive device, 39...Loader, 40...Rack, 4
1... Unloader, 42... Tray, 43... Positioning pocket, 44... Suction arm. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1. A bonding method for bonding an object to be bonded to a part of a member via an adhesive, the bonding method being such that the object to be bonded is placed relatively on a substantially flat surface. A bonding method characterized in that the adhesive is inserted into an adhesive coated larger than the bonding area, and the adhesive is adhered to the bonding surface of the object to be bonded, and then the bonding method is bonded to the part of the member to be bonded. 2. The bonding method according to claim 1, wherein the member is a lead frame used for manufacturing semiconductor devices. 3. The bonding method according to claim 1, wherein the object to be bonded is a pellet, which is a semiconductor element. 4. The rail on which the parts are transported and the adhesive is applied.
Adhesion characterized by having a stage larger than the bonding area of the object to be bonded, a mechanism for applying adhesive to the stage in an area larger than the bonding area of the object to be bonded, and a support member for supporting the object to be bonded. Device. 5. The bonding device according to claim 4, wherein the member is a lead frame used for manufacturing semiconductor devices. 6. The bonding device according to claim 4, wherein the object to be bonded is a pellet, which is a semiconductor element.