JPH0281448A - Method of mounting semiconductor integrated circuit - Google Patents

Abstract

PURPOSE:To apply bonding material with a predetermined film thickness and ensure the connection between an IC chip and wiring electrodes close to a step part by a method wherein a stamping jig is used for applying the bonding material to the wiring electrodes on a board and, after the tips of the jig are dipped into a bonding material layer having a certain thickness, the material is vertically stamped onto the wiring electrodes. CONSTITUTION:A square resin sink 11 is filled with paste resin 2 and a sqeegee 12 is moved to form a flat surface. A stamping jig 13 is composed of a metal plate 14 in which holes having a diameter of 0.2 mm are drilled and metal rods 15 inserted into the holes so as to form a lattice having the same pitch as wiring electrodes and to protrude less than 1mm. The tips of the metal rods 15 are dipped into the resin 2 and then lifted with the resin 2 adhering to them. The wiring electrodes 1 of a glass substrate 21 are visually aligned by using an X-Y-theta table so as to place the wiring electrodes 1 directly under the metal rods 15 and the resin 2 is transcripted onto the wiring electrodes 1. Separately, the protruding electrodes 4 of an IC chip 3 are coated with the paste resin. After the IC chip 3 is fixed by a vacuum chuck and aligned visually with the wiring electrodes 1, the resin adhering to both the electrodes is bonded to each other and cured.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to, for example, a liquid crystal display device driven by a semiconductor integrated circuit (hereinafter referred to as tC). The present invention relates to an IC mounting method in which protruding electrodes of an IC chip are aligned face-down with wiring electrodes on a substrate, and both electrodes are bonded and electrically connected using a paste-like connecting material applied to both electrodes.

[Conventional technology]

In recent years, image display using liquid crystal displays, which are small and consume low power, have been studied in many fields. Along with this, there is an increasing trend toward thinner and more compact designs, and the connection between liquid crystal displays and electronic components such as drive ICs is becoming increasingly finer and has more terminals. A method has been adopted in which electronic components such as drive ICs are directly connected onto a transparent glass substrate of a liquid crystal display. This method is a direct connection method and is called Chip On Glass (abbreviated as C0G).
), its construction means are highly space-efficient;
Because it is thinner and more compact, it is seen as promising for the future. However, in this connection, the number of image display electrodes of the liquid crystal display is large, for example, one screen is about 240 x about 480, and therefore the wiring electrodes are also 0.3M pinch x 0.4
Fine pinch patterning of Tsuru pinch and, for example, IC1
Each device has a multi-terminal pattern of approximately 120 terminals, and various methods of applying connection materials for direct connection are also being studied. Conventional methods for applying a connecting material include methods such as screen printing and a dispenser.

First, the screen printing method is shown in Figure 2 (ta) (bl).
Explain using. That is, the wiring electrodes 1 are patterned on the transparent glass substrate 21 of the liquid crystal display so as to correspond to the protruding electrodes of the drive IC.

A pattern with the same spacing as the wiring electrodes is formed on the printing screen 22. This screen 22 is placed above the substrate 21, aligned in advance with the wiring electrode pattern! Then, place the conductive paste resin 2 on the screen (Figure a) and move the squeegee 23 in the direction of the arrow while applying a load so that the bottom surface of the screen 22 adheres to the wiring electrode 1. Extrude and wire electrode 1
On the other hand, as shown in FIG. 3, a screen 22 is placed also on the protruding electrode 4 of the drive IC 3,
The resin 2 is applied by moving the squeegee 13 in the direction of the arrow. This drive IC 3 is turned over as shown in FIG. 4, and is bonded to the wiring electrode 1 of the glass substrate 21 in alignment with the protruding electrode 2, and the resin 2 is hardened to connect it. FIG. 5 shows the application method using a dispenser, and as shown in the figure, the dispenser 24 has a syringe-like structure.
The inside of the container is filled with paste resin 2, and a very small amount of the paste resin 2, which is the material inside, is extruded to a predetermined place using air pressure from the outside (not shown).

As the protruding electrodes of the IC chip 3, /s and j pump electrodes are generally used. Figure 6! All shown is gold 7sl
A multilayer wiring consisting of a lower layer M wiring 33 and an upper layer M wiring 34 is formed on a silicon substrate 31 having an oxide film 32 on the surface with a glabella insulating film 35 interposed therebetween, and an opening in a puffed substrate film 36 covering the upper layer M wiring 34 is formed. A7-N in the section
The Au bumps 41 are in contact with each other through a base metal layer 42 made of l. A recess is formed in the center of the surface of the Au bump 41. Figure 6 (bl) shows a gold bump 4 plated with copper 43 and a 5lsNa film 37 on an 81 substrate 31.
A polyimide film 39 is placed on the pad 38 that contacts at the opening.
A base metal layer 44 having a kl-Cr-Cu structure is provided through the resist WA40, and the Au bumps 41 are in contact with this base metal layer 44 at the openings of the resist WA40. Shown in FIG. 6 tc+ is a solder bump 510! on the SI board 31. A lower layer Cr45. Upper layer C
A base metal layer of U46 is provided, and solder bumps 47 are formed on this base metal layer. The bumps shown in No. 6) and fol are hemispherical.

[Problem to be solved by the invention]

In the case of screen printing, if the surface to be coated is flat, it can be formed without any problem, but when mounting the drive IC on the step between the glass substrate 21 and the glass substrate 25 of a liquid crystal display as shown in FIG. In order to minimize the space of the IC mounting section,
It is desirable to place the wiring electrode l as close to the upper substrate 25 as possible. As a result, the screen 22 collides with the upper substrate 25 in places with a narrow area and large steps. Therefore, there was a problem in that the paste resin was hardly coated on the wiring electrodes near the edges of the transparent glass substrate. Also, as shown in Figure 3, apply the resin paste 2.
The IC chip 3 coated by screen printing must be moved and reversed after coating.

When this operation is performed, there is a problem that the paste resin 2 placed on the protrusion amount 8i4 flows or is deformed and the film thickness changes. This is particularly noticeable when the protruding electrode is flat. However, in the case of a gold bump with a recess in the center as shown in Figure 6(a), the resin is confined in the recess under pressure, and when the pressure is removed due to the stress, the wiring electrode It has peeled off.)

Next, in the case of a dispenser, the nozzle diameter at the tip is generally 0.2×1 or more in diameter, making it difficult to control the thickness for dot-type electrodes with a fine pitch pattern, and the number of applications increases. It has the disadvantage that it takes a long time to work. For a coating area with a diameter of 0.2 ts or more, the wiring electrodes 1 are placed at intervals of several electrodes using a multiple dispenser, and the coating is repeated several times. A resin discharge coating method is used, but in addition, a fine pinch pattern is applied.

It has the disadvantage that it is difficult to adapt to multi-terminal patterns.

One of the objects of the present invention is to make it possible to easily apply a paste-like connecting material to wiring electrodes close to a step on a substrate with a step, and the other is to make it possible to easily apply a paste-like connecting material to a wiring electrode close to a step on a substrate with a step, and to The paste-like connecting material applied to the electrodes has strong adhesion to the electrodes, causing the IC chip to flip over.

An object of the present invention is to provide an IC mounting method that prevents changes in film thickness due to flowing down or deformation of a connecting material during movement, and ensures reliable connection between an IC chip and a wiring electrode.

(Means for solving 11! 11) In order to solve the above-mentioned problem i, the present invention aligns a plurality of protruding electrodes of an IC chip with a plurality of wiring electrodes with a substrate face down, and forms a paste-like structure. When bonding the picture electrodes with a connecting material and electrically connecting both electrodes, a stamping jig with protrusions at positions mirror-symmetrical to the positions of the wiring electrodes on the board is used to apply the connecting material to the wiring electrodes. The tip of each jig shall be dipped into a connecting material layer of a certain thickness, then pulled up and stamped onto the wiring electrode from the vertical direction.In addition, multiple A protruding electrode having radial grooves is used, and the tip of the protruding electrode is dipped into a layer of connecting material of a certain thickness and then pulled up to apply the adhering connecting material onto the wiring bridge.

[Effect]

If the connecting material is applied to the wiring electrodes by dipping the tip into the connecting material to a certain depth and stamping from a vertical direction with a stamping jig to which the connecting material is attached, the stepped portions will be close together. Also, it does not become a hindrance and can be uniformly applied to a plurality of wiring electrodes at the same time. In addition, by providing a plurality of grooves radially extending to the outer periphery on the end surface of the protruding electric bridge of the IC chip,
The concave grooves maintain the adhesive at a constant thickness, reducing the amount of adhesive that flows down and allowing application without the use of a screen.

Furthermore, even if the adhesive is bonded to the wiring electrode under pressure, the adhesive communicates with the outside through the groove and is not confined, so no stress is applied and there is no risk of peeling.

〔Example〕

FIG. 1 shows the mounting process of an IC chip according to an embodiment of the present invention, and the same parts as those in the previous figures are given the same reference numerals. First, the rectangular resin reservoir 11 is filled with paste resin 2, and the squeegee 12 is placed on two opposing sides of the rectangular container 11, moving from left to right in the figure to produce a flat surface (Figure a).Next, a stamping jig 13 is used. Stamp jig 1
3, a hole with a diameter of 0.2 mm is made in the metal plate 14 using a drill, and a metal rod 15 is inserted into the hole so as to protrude within 1 m.

This metal rod 15 is attached to the metal plate 14 as shown in FIG.
They are embedded in a grid of 0.3u x 0.3 squares with the same pinch as the wiring electrodes. The jig 13 is lowered in the direction of the arrow so that the tip of the metal rod 15 touches the resin 2 (Figure b), and when the jig 13 is pulled up, the resin 2 adheres to the tip of the metal rod 15 (Figure c). Next, place the glass substrate 21 under the jig 13, so that the wiring electrode l is directly under the tip of the metal rod 15.
Visually align using the X, Y, and θ tables.
(Fig. e), the jig 13 is lowered and the resin 2 is transferred to the wiring electrode 1 (Fig. f). In this case, the wiring electrode 1 adjacent to the upper substrate 25 can also be transferred without any problem.

Separately, a paste resin was applied to the protruding electrodes 4 of the IC chip 3 using a printing screen, etc., and this was fixed using a vacuum chuck, and this was visually aligned from the bottom surface of the glass substrate 21 using an X-Y/θ table. Afterwards, both resins are bonded together (Fig. g), and then the IC chip 3 is pressurized from above and cured in that state. In the experiment, jig 13
The metal plate 14 is made of brass.

A soft metal such as aluminum or the like was used, and the metal rod 15 was made of a hard metal such as stainless steel am, which is not easily deformed during press-fitting. In another embodiment shown in FIG. 7, the tip 16 of the metal rod 15 of the jig 13 is made of, for example, silicone rubber, porous silicone rubber, urethane rubber, etc. The resin is now easier to clean. Furthermore, the jig 13 shown in FIG. 8 is made by embedding and molding a gold YA thin wire 15 into a silicone rubber 17. The feature of this jig is that the pitch is on the enemy side and 0.
．． It is designed to be able to handle up to about 1,000 II pitches. The thickness of the transferred film can be freely controlled from several tens of Jja to about 200 Jja by adjusting the depth of the recess of the resin reservoir 11. Figure 9+a+~ (Ql indicates another embodiment, in this case the doctor blade 19 as shown in Figure a)
After pouring 1J112 onto the PTFE sheet 1B, move the gap-adjusted doctor blade 19 in the direction of the arrow (Figure b).
The process after e (Figure c) is shown in Figure 1 (bl~(Kl
It is similar to This case is particularly effective when the film thickness can be thin.

Paste resin film thickness? Conductive material pickpocket: ``/In the case of resin etc., the thickness should be as low as <100~200~, and in the case of photocuring resin, it should be as thin as <10~20~
A good condition is about n. In the case of epoxy resin containing conductive material, N1. Cr, carbon-1 solder balls, etc. are mixed, and the contact between the electrodes is made with a low conduction resistance of several ohms to several tens of ohms. Epoxy resin is used to connect the protruding electrodes of the IC chip and the wiring electrodes with several kilograms per driving IC chip.

Adhesive strength of . In the case of photocurable resin, electrical connection is achieved by direct contact between the glass substrate electrode and the protruding electrode of the drive IC, and adhesion between the two electrodes is achieved by the resin remaining between the electrodes. Specifically, since the surface of the electrode has tens to hundreds of microscopic irregularities, the adhesive strength is maintained by the resin remaining in the gaps.

In the above embodiment, the paste resin was also applied to the protruding electrodes of the IC chip, but even if the resin is applied only to the wiring electrode side and both electrodes are bonded together, the above level of conductivity and adhesive strength can be obtained. .

Next is the protrusion of the IC chip! Figure 10 +8) to ffl show the steps of an example in which fat was applied only to the base).

The step of placing the paste resin 2 on the PTFE sheet 18 and flattening it with the doctor blade 19 (Fig. a) is the same as that shown in Fig. 9. When using a doctor blade, as in the case of FIG. 9, viscosity control is important. The viscosity is
It also affects film thickness control.

Usually, in the case of conductive injection repaste resin, 2000 to 50
00cP (centiboise), 5 for photocuring resin
00 to 2000 cP is preferable Next, the drive 1c tip 3 with the protrusion 1t$lj4 formed in advance is fixed with a vacuum chuck (not shown) and lowered (Fig. b
), immersed in flat paste resin 2 (Figure c).

When the IC chip is pulled up, resin 2 with a thickness of, for example, 200μ, which is determined by the thickness and viscosity of the resin on the sheet 18, adheres to the tips of the protruding electrodes, and the remaining IC chip 3 is transferred to the glass substrate 21 of the liquid crystal display. Move the transparent wiring 1 to 10 made of ITO formed on top, and use 1 ml to align the position while operating the X-Y/θ table that supports the base Fi 21 when viewed from below. (Figure e). And I
Lower the C-chip 3 in the vertical direction and press the protruding mold 8i4 with the resin 2 attached to the tip against the wiring electrode 10 with a pressure of about 1 g (Figure r).

The resin is cured in this state. In the case of a paste containing a conductive material, heat it at about 170° C. for 30 minutes to heat cure it. In the case of a photocurable resin, it is cured by irradiating it with ultraviolet rays at an illumination intensity of approximately 200 mW/cd for several tens of seconds. Excludes pressing force after curing.

Examples of the arrangement of protrusions on the IC chip are shown in FIGS. 11 and 12, in which (4) is a plan view and 5(b) is a side view. Fig. 11 shows an example in which the protruding electrodes 4 are arranged in a grid pattern, the pitch of the protruding electrodes 4 is 0.3 m, and the height is 20 to 50 m. Fig. 12 shows an example in which protruding electrodes are arranged on both sides. The pitch of the electrodes 4 is approximately 0.1 fi, and the height is 5 to 20 μm.

Figures 13 to 15 are examples of the shape of gold bumps according to the present invention, in which fat is a plan view, and (b) is a view along the 8-A gland, B-B gland, and c-cNIA of tal. FIG. These are bumps to which the paste resin adheres easily (and no stress is generated within the resin. Figure 13 is a square bump,
Figure 14 shows a large square shape with 4 Au bumps! It has a recess 5 in the center thereof, and recesses 6 of the same depth are formed in a cross shape. In Fig. 15, the recess 5 is not formed and the cross-shaped recess a6 is formed.
is formed only. The grooves 6 can be easily formed using a photo process; however, the solder bumps 47 require laser processing or the like. Figures 16 to 18
The figure shows an example in which the IC chip having the Au bumps shown in Fig. 15 is mounted using a paste resin. In Fig. 16, a resin containing a conductive material is used as the paste resin 2, and the resin thickness is about 200 nm or less. It was glued like this. At this time, the conduction resistance between the transparent wiring electrode 10 and the M wire &1133 was several ohms to several tens of ohms. Since the resin 2 enters the concave groove 6 of the bump 41, an adhesive strength of several kilograms per IC chip is obtained, and there is no practical problem. Figure 17 shows that the reliability of temperature resistance, adhesive strength, etc. is further improved. IC chip 3
The gap between the glass substrate 21 and the glass substrate 21 is vacuum impregnated with an insulating resin 7. In FIG. 18, a photocurable resin was used as the paste resin 2. In this case, bump 41 and transparent wiring type $110
40 to 100 per l bump so that there is direct contact with
It was pressurized with a force of 1.5 g and was cured with ultraviolet rays under pressure. The adhesive strength is determined between the protruding resin 2, the recess 5, and the groove 6.
It is held by the resin left behind. A conduction resistance of 20Ω or less was obtained. In this case as well, the gap may be filled with insulating resin as shown in FIG.

On the other hand, when bumps without grooves are used as shown in Fig. 19 (al, (bl, tc+),
In , fbl, the paste resin is held in the recess 5, but
Many continuity failures occurred after connection. As already mentioned, this is thought to be because the resin inside the recess 48 is trapped in the space between the opposing wiring electrodes, and the stress from pressurization remains, making it easy to peel off due to stress strain.

On the other hand, in Fig. 19 fc), the paste resin retention is poor and the adhesive strength is low, but the conductivity through contact is quite good.
The bumps shown in FIGS. 13-15 eliminate these drawbacks.

〔Effect of the invention〕

As explained above, according to the present invention, a stamping jig is used to apply a connecting material to wiring electrodes on a board, and after dipping the tip of the jig into a layer of connecting material of a certain thickness, the wiring electrode is applied from a vertical direction. By applying the top stamp, it was possible to apply the connecting material to the desired thickness, and there was no problem in mounting the IC chip on the wiring electrode close to the step. Further, according to the present invention, by forming a radiation wand groove on the end surface of the protruding electrode of the IC chip, resin retention is improved, and like the stamping jig, after being dipped into a connecting material layer of a certain thickness, wiring It is now possible to align and connect to the electrodes, making it impossible to use screen printing or dispensers. Furthermore, the problem of confinement of the connecting material in the space between the central recess on the end face of the protruding electrode and the wiring electrode is eliminated, and an IC mounting method that is easy to work with and has high reliability is obtained.

[Brief explanation of the drawing]

Figures 1 (al to g) are cross-sectional views and plan views sequentially showing the IC mounting process of an embodiment of the present invention, and Figures 2 (al, f)
bl is a cross-sectional view showing the process of applying resin to the wiring electrodes using the conventional screen printing method, and FIG. 3 is a cross-sectional view showing the process of applying resin to the protruding electrodes of the IC chip using the screen printing method.
FIG. 4 is a cross-sectional view showing the connection process after the steps shown in FIGS. 2 and 3, FIG. 5 is a cross-sectional view showing the process of applying resin to wiring electrodes using a conventional dispenser, and )
, tel is a cross-sectional view of three types of bumps conventionally used as protrusions 1tllii of RC, and FIGS. 7 and 8 are 1
FIG. 9 is a cross-sectional view showing different embodiments of the stamping jig shown in the figures, FIG. ! al~
(fl is a cross-sectional view sequentially showing the IC mounting process of another embodiment of the present invention, FIGS. 11 and 12 show two examples of the protruding electric bridge arrangement of the IC chip, and in both cases, fal is a plan view, ( b)
13, 14, and 15 respectively show the ATL type bumps used in the embodiments of the present invention, (4) is a plan view, and (b) is a solitary view.
16, 17, and 18 are cross-sectional views of connecting portions formed according to three embodiments of the present invention. , Figure 19 fat~
(cl is 311I shown for comparison with Figures 13-15.
ff is a plan view of a bump. 1: Wiring electrode, 2: Paste resin, 3: IC chip, 4
: protruding electrode, 41: Au bump, 5: recess, 6: groove, 11: resin reservoir, 12: squeegee, 13: stamp jig, 14: metal plate, 15: metal rod, 19: doctor blade, 21 Niglass substrate. 115 Figure ii 6 Figure 7 518 Figure 9 (b) Figure 11 (b); 112 Figure 10 Figure 14 (Q) (b) Figure 15 Figure 16 A3 \ ( Figure 17 Figure 19

Claims (1)

[Claims] 1) When aligning a plurality of protruding electrodes of a semiconductor integrated circuit chip with a plurality of wiring electrodes on a substrate face down and electrically connecting both electrodes with a paste-like connecting material,
A stamping jig with a protrusion mirror-symmetrical to the position of the wiring electrode on the board is used to apply the connecting material to the wiring electrode, and the tip of each jig is dipped into the connecting material layer of a certain thickness and then pulled up. ,
A semiconductor integrated circuit mounting method characterized by stamping on wiring electrodes from a vertical direction. 2) When aligning multiple protruding electrodes of a semiconductor integrated circuit chip with multiple wiring electrodes on a substrate face down and electrically connecting both electrodes with a paste-like connecting material,
A protruding electrode with a plurality of radial grooves extending to the outer periphery with a certain depth on the end surface is used, and the tip of this protruding electrode is dipped into a layer of connecting material of a certain thickness and then pulled up to remove the attached connecting material. A method for mounting a semiconductor integrated circuit, characterized by coating on wiring electrodes.