JPS5932135A - Bonding device for semiconductor wafer - Google Patents

Abstract

PURPOSE:To bond a wafer to a bonding plate in a uniform thickness of a wax film by pressing the plate which is deformed on a raised surface with high pressure air with a wafer which is placed through the wax on the plate, and expanding the pressed area from the center to the periphery. CONSTITUTION:A heating plate 3 is heated at the temperature higher by approx. 30 deg.C than the softening point of wax, the wax is thickly coated on the position to be bonded of a wafer 7 along the circumference of a bonding plate 5, a wafer is placed, and the plate 3 is intermittently rotated. High pressure air is fed to a slot 15 through a hole 17 of a pressing unit 14 from an air source 19 to deform the plate 16 in a raised surface, and a pressing mechanism 13 is moved downwardly. The wax 20 is gradually flowed to the peripheral edge of the wafer by continuing the static load to the wafer 7. At this time, in order to maintain the load per unit area constant, the load is gradually increased corresponding to the increase in the contacting area of the plate 16, and pneumatic pressure is gradually decreased. When the thickness of the wax film is at the prescribed value, the supply of the high pressure gas is stopped, the mechanism 13 is raised, and next wafer is set.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a semiconductor wafer bonding apparatus used during polygoning processing of semiconductor wafers.

[Technical background of the invention and its problems]

During the final polishing process of semiconductor wafers (hereinafter referred to simply as wafers), one side of the wafer is polished to a mirror finish. During processing, wafers are bonded in batches onto adhesive plates, which are metal or ceramic disks.

Adjust the rate to 30 to 40 degrees below the softening point of the wax used.
0 Heat to high. ■Apply this wax to the wafer and the intended bonding position of the bonding plate that has been heated to a predetermined temperature, so that it is slightly wider than the size of the wafer and has a uniform thickness over the entire surface. ■Place the wafer on the wax-coated adhesive plate at the above-mentioned intended bonding position, and use a bar-shaped jig with a contact surface formed at the tip to make uniform contact with the wafer and the entire surface to attach the wafer to the bonding plate. Adjust so that the wax film thickness between the sea urchin pigeon adhesive plate and the sea urchin pigeon adhesive plate is uniform. ■Finally, place the adhesive plate on a cooling plate to solidify the wax and complete the adhesive work.

By the way, with the recent increase in the degree of integration of electronic components, it has become essential to employ methods such as reduced exposure for pattern transfer, and wafers are required to have high shape accuracy. In particular, parallelism is a problem, and high accuracy is required, with the parallelism within a determined range of 1 to 2 μm. However, with conventional bonding methods, the bonding conditions are unstable due to manual work, making it extremely difficult to achieve reproducible bonding, resulting in uneven wax film thickness and a decrease in wafer parallelism. Ta. Furthermore, if the wafer is strongly pressed against the bonding plate using a pressing jig in order to make the wax film thickness uniform, there is an inconvenience that scratches may appear on the back surface of the wafer.

[Purpose of the invention]

The present invention has been made in consideration of the above circumstances, and it is an object of the present invention to provide a semiconductor wafer bonding device that can bond a wafer to a bonding plate with a uniform wax film thickness.

[Summary of the invention]

A pressing plate deformed into a υ convex curved surface is pressed by high-pressure air against the wafer placed on the adhesive plate via wax, and the wafer is suppressed by the pressing plate from the center to the periphery. It is designed to apply a static pressure load so that it expands in the form of ripples.

[Embodiments of the invention]

In FIGS. 1 and 2, a base (1) has a built-in intermittent drive mechanism (2) whose main component is, for example, an electric motor. On this base (1), a disc-shaped hot plate (3) is attached to an intermittent drive mechanism (2) so as to be rotatable in the direction of arrow (4) in FIG. Further, an adhesive plate (5) is placed on the hot plate (3) coaxially with the hot plate (3). Along the circumference (6) on the yarn surface of this play white 5), a plurality of wafers (7) are placed equidistantly through wax.

On the other hand, an L-shaped support (8) is attached to the side surface of the base (1). The extending portion (9) of the supporting column (8) parallel to the main surface of the adhesive plate (5) is positioned directly above the adhesive plate (5), and the extending portion (9) of this extending portion (9) is located directly above the adhesive plate (5). An elevating mechanism OQ whose main component is, for example, an air cylinder is attached to the tip. This lifting mechanism (IQ
In I, the elevating axis αυ, which is the piston rod of the air cylinder whose axis is perpendicular to the circumference (6), can be freely raised and lowered in the axial direction, which is the direction of the arrows (12a) and (12b) in Fig. 2. connected. Furthermore, a suppression mechanism α■ is attached to the tip of the lifting shaft aυ. This suppression mechanism (I [has] wafer (preferably larger than the outer diameter of the force).In addition, on the end face of this suppressor (14) opposite to the lifting axis αυ, a plurality of circles formed coaxially with the axis of the IJ Groove portion 0! Consisting of annular grooves and radial grooves that are equally spaced radially from the center of these annular grooves and intersect with the annular grooves!
19... is engraved.

Further, on the groove portions 0!9... side of the suppressing body (14), a circular thin plate-shaped pressure contact plate (l [9 is sealed and fixed at its peripheral edge to the suppressing body side by, for example, brazing, and the covering bath part αω is sealed from the outside air.The thickness of the above 11E contact plate H is: In order to be able to freely expand and contract outwards due to the pressure gas introduced into the groove (1),
m or less, and the outer diameter is preferably greater than or equal to the outer diameter of the wafer (7). Additionally, the pressing body (14) has one end with a groove (11...
・A guide hole (17) is drilled in which the other end is open to the lifting shaft (1υ side end face. The opening of the lifting shaft 0υ111 of this guide hole αD is It is connected to the high pressure air source (l→). These dedicated and high pressure air source α fields constitute a high pressure air supply mechanism.

Next, the operation of the semiconductor wafer bonding apparatus of this embodiment will be described.

First, the hot plate (3) is heated until the temperature of the hot plate (3) is 30 to 40 degrees higher than the softening point of the wax used. Therefore, the adhesive is applied to the wafer to be pre-bonded (narrower than the surface area of the wafer) and thicker than the film thickness when the wafer (force bonding is completed).
As shown in the figure, after placing a plurality of wafers (7)... on the adhesive plate (5) at predetermined positions via the applied wax, the intermittent drive 71LII crosspiece structure (2) is activated. , until the center of force comes to a specific wafer (the extension line of the axis of the pressing body (14)), until the hot plate (3) is aligned with all the arrows (
4) Rotate in the direction. Then, from the high pressure air source ([1,
After supplying high-pressure air to 9 and deforming the 3-plate body (16) into a convexly curved shape, the suppression mechanism (
1 [present] is gradually lowered in the direction of arrow (12a) in FIG. Then, as shown in FIG. 4(a), a part of the pressure bonding plate that has been deformed into a convex curved surface comes into contact with the center of the wafer (7), and the force is applied to the bonding plate (5). At the same time, the Wankusure flows to the surrounding area.
At the same time, its thickness decreases. As the load on the wafer (3I) continues to be applied to the wafer (force) by the lifting mechanism (LO), the area of contact with the wafer (force) of the pressing plate αω expands in a ripple pattern, and as a result, the wafer ( Due to the static pressure load applied to the force, the wax wire gradually flows toward the periphery of the wafer (force), as shown in Figures 4(b) and (C). In order to keep the load per unit area υ constant, press plate α
Corresponding to the increase in the area of contact with the wafer Q (force), the load applied by the lifting mechanism αQ is gradually increased, while the pressure of high-pressure air from the high-pressure air source α■ is gradually decreased. As shown in FIG. 4(i), the wax (20) is applied to the entire surface of the wafer (7) and the adhesive plate (5
), and when the film thickness reaches a predetermined value,
At the same time as stopping the supply of high pressure air from the high pressure air source α
) direction to finish the adhesion work of the force. Then, the intermittent drive MJ mechanism (2) rotates the hot plate (3) at a predetermined angle, and the next Ueno '5.Then, similar operations are repeated for other wafers (7).In this way, the semiconductor wafer pressing device of this embodiment can be used to press the adhesive plate (5). ), a static pressure load is applied to the wafer (7) in a ripple pattern from the center to the periphery of the wax garden, allowing air bubbles contained in the wax to be released to the outside and causing the film to deteriorate. The thickness is uniform, and the parallelism of the wafer (7) to the adhesive plate (5) is reproducibly 1.
~2 μm.

FIG. 5 shows a pressing mechanism C'l) in another embodiment (the parts other than the suppression mechanism QO are completely the same as in the previous embodiment, so the explanation will be omitted). (1q0υ has a cylindrical pressing body 0.

The pressing body (2) has one end surface fixed coaxially with the elevating shaft (14), and the other end surface of the pressing body 0,
The suppression mechanism (similar to 131, a plurality of concentric annular grooves γ!''・1 and radial γ1 intersecting these annular grooves)
- Grooves consisting of a combination of T's (2: grooves are carved).

First, the suppressing body (24) is provided with a groove (c) and guide holes 0,0 that open at the end surface of the pressing body 4 on the row descending shaft (11) side. ) is connected to the pressure air source C1 (D) via a dedicated pipe 05).On the other hand, the suppressor (
No. 24 - “Part (c) of the side end face is VJl, and the circular thin plate-shaped pressure contact plate 07) with a thickness of about 5 mm, which covers this end face so as to be able to freely approach and separate, has its peripheral edge fixed by, for example, brazing. As a result, the groove (C) is sealed from the outside air.Furthermore, on the surface facing the wafer (pressing plate 07), there are a plurality of annular S similar to m t71+Ia, 11. and a WfA section QQ consisting of a combination of radial grooves intersecting these annular grooves. One end opens into the groove section Q and the other end is connected to the pressing body (two lifting shafts).
A part of the guide hole (C) that opens on the 1υ side is provided inside the pressing plate Q7) and the pressing body hot water. This guide hole c11 is connected to the conduit (via 301) (air source 01).

By using the suppression mechanism 0υ with such a configuration, the wafer (7)
When adhering to the contact bob plate (5), first j′
(Air source (3)) f: Activate and apply force to the press plate 07). Next, high pressure air is supplied to the conduit 05) and the guide hole 04 by the high pressure air source 05).
) to the groove Q, and deforms the pressure 4 & plate (27) outward into a convex curve 1f (1 shape) as shown in FIG. 6(a). Similar to deformation 1, the wafer C1 is vacuum-adsorbed (deformed into a convex curved surface).
11 (ltl) to descend in the direction of arrow (34).

At this time, the wafer (r:l:, wax 00) is smoothed and applied to the entire area of the wafer (force J, 52) and the entire area fn1 of the adhesion 17η of the wafer (7) which is vacuum suctioned. Then, as shown in FIG. 6(b), the central part of the wafer (7), which has been deformed into a convex curved shape, is exposed to the wax G! Contact plate (5) with Cs'Ii29 via O.

Then, when the suppression mechanism (21) is pressed against the plate (5) in the same manner as in the previous embodiment, as shown in FIG.
) as shown in Wafer (7) via Wax (2(I)
) to the adhesive plate (5) expands in a ripple pattern from the center to the periphery, and a static pressure load is applied to the adhesive surface of the wafer (7). When the adhesion of Unino (7) to the adhesive plate (0) is completed, Unino (7)
]'(Empty suction is released and the suppression mechanism (2I) is raised. In this embodiment, as in the previous embodiment, air bubbles in the wax are dissipated to the outside, (
5) It is possible to reproducibly maintain the parallelism of 1 to 2 μm or less, but it is especially important to
Not only when the wax is applied only to the center 111 of the wafer bonding area of the mounting plate,
The required parallelism can also be obtained when the coating is applied at the center of the wafer bonding area of the bonding plate or bonding plate.

Although only one pressing mechanism (2υ) is installed in the semiconductor bonding apparatus of the above two embodiments, as shown in FIG. 7 and FIG. θυ
A holder (c) is attached to the lower end of the wafer (7), and the wafers (7) are pressed against the holder (c) at equal positions.
Support arm portions (04)... are provided protrudingly, and these support arm portions (3
4) Pressing mechanism 0th floor via support shaft (7)...
...or a pressing mechanism 0υ... may be installed. By doing this, a plurality of sea urchins (7) on the adhesive plate (5) can be bonded at the same time, so the work efficiency is significantly improved and the 111) de-energizing η1b mechanism (2) becomes unnecessary. Furthermore, the pressure contact plate in the first embodiment ([9] may be made of a heat-resistant synthetic resin such as silicone rubber, etc.).

〔Effect of the invention〕

The semiconductor wafer bonding device of the present invention presses the adhesive against the bonding plate using a pressing plate deformed into a convex curved shape, and applies a static pressure load in a ripple pattern from the center to the periphery of the adhesive. There are no air bubbles in the wax.
Since the thickness of the wax sample can be made uniform without leaving any residual wax, the parallelism of the wafer to the adhesive plate can be maintained at 1 to 2 μm or less. , also manual gluing and one! I'4, the adhesion conditions can be controlled to a constant level, resulting in high reproducibility. Furthermore, unlike the manual bonding work that requires a lot of effort, the pressing does not apply strong pressure to only a specific part of the sea urchin 1, so there will be no flaws on the surface of the sea urchin 1. Therefore,
The two effects work together to improve semiconductor product quality and yield.

[Brief explanation of drawings]

1 and 2 are plan views and front views showing a semiconductor wafer bonding apparatus according to an embodiment of the invention, and FIG. 3 is an enlarged 1Yji plane of the main part of the suppression mechanism shown in FIGS. 1 and 2. Figure, 4th
The diagram is created by the suppression mechanism in the g3 diagram! FIG. 5 is an explanatory diagram showing the pressing machine of another embodiment of the present invention (an enlarged sectional view of the main part of the surface structure), and FIG. 6 is an explanatory diagram showing the pressing machine of FIG. figure,
tA7 and 8 are a plan view and a front view showing a semiconductor wafer bonding apparatus according to another embodiment of the present invention. (3) Two hot plates 1 (5): Adhesive plate. (Crab semiconductor wafer, (10): Lifting mechanism. a increase, aυ: suppression mechanism, (1 also (c): pressing body. 4 clauses, (c): tp4 part, 4, Qη; pressure contact plate body. Ql, (c): High pressure air source (20): Wax. 0 barrel: Mizobe, 01): Vacuum source. Agent: Patent attorney Kensuke Norichika (and 1 other person) Porridge 5
times

Claims (2)

[Claims] (1) A semiconductor wafer bonding device characterized by having the following configuration. (B) A flat adhesive plate for bonding the semiconductor phenol through wax (B) A hot plate on which the above adhesive plate is placed and heated to a temperature that melts the wax (C) A groove is carved on one end surface. High-pressure air is applied to the groove of the suppressor, and the suppressor has an oval thin plate-like pressing plate that freely covers the groove and whose peripheral edge is M-attached to the suppressor. (e) A high-pressure air supply mechanism that deforms the pressure welding body into a convex curved shape by supplying air to the pressure welding body.゛The pressing against the semiconductor wafer placed on the adhesive plate via the wax causes ripples in the suppressed area of the semiconductor wafer by the pressure contact plate from the center of the semiconductor wafer to one periphery. Lifting and lowering to expand the shape 1
lii structure (2) Pressing a A groove section connected to a vacuum source is formed on the semiconductor wafer pressing surface of the pressure contact plate of 441, and the semiconductor wafer bonded to the adhesive plate is vacuum-adsorbed via this 1 m section. A semiconductor wafer bonding apparatus according to claim 1.