WO2016061889A1

WO2016061889A1 - Wafer vacuum bonding machine and bonding method

Info

Publication number: WO2016061889A1
Application number: PCT/CN2014/094300
Authority: WO
Inventors: 尹明; 唐昊
Original assignee: 浙江中纳晶微电子科技有限公司
Priority date: 2014-10-23
Filing date: 2014-12-19
Publication date: 2016-04-28
Also published as: CN104362107A; CN104362107B

Abstract

A wafer vacuum bonding machine and a bonding method. The position of a first wafer is limited after a positioning block moves forward for the first time, then a second wafer is placed, vacuum pumping is performed, the second wafer is enabled to fall onto the first wafer in a vacuum state when the positioning block is retreated, and afterwards, the position of the second wafer and the position of the first wafer are simultaneously limited by moving the positioning block forward, the first wafer and the second wafer are pressed together, and the positioning block is retreated after the first wafer and the second wafer are pressed together. The wafer vacuum bonding machine is simple in structure, convenient to operate, low in cost, and capable of achieving perfect bonding for the wafers.

Description

Wafer vacuum bonding machine and bonding method

Technical field

The invention relates to the field of microelectronics, in particular to a wafer vacuum bonding machine and a bonding method.

Background technique

Wafer bonding refers to the close contact of two wafers so that they can be firmly bonded together. Current wafer bonding technology requires a special wafer bonding system. Due to the material requirements of the wafer itself, the wafer bonding requirements are very high, requiring two wafers to be perfectly bonded without bubbles. If wafer bonding is required without bubbles, then it must be vacuum The bonding is completed in the environment, but the wafer bonding process requires two wafers to be perfectly matched. The existing wafer bonding system generally uses a robot to realize the positional correspondence of the two wafers in a vacuum environment. Complex and costly.

Summary of the invention

The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a wafer vacuum bonding machine which is simple in positioning, low in cost, and capable of perfectly bonding two wafers.

In order to solve the above technical problem, the present invention provides a wafer vacuum bonding machine, which comprises a box body, a vacuum generator is arranged in the box body, and the box body is provided with an internal closed press, the pressure The machine comprises a clamp disposed on the box body and a cover disposed on the clamp and closed inside when the cover is closed, the cover is provided with a pressure plate, and the lower surface of the pressure plate is provided with a heating plate, the pressure plate and the heating plate An insulating layer is disposed between the tray, and a tray for placing a wafer is disposed in the fixture, and a heating device is disposed under the tray, and a plurality of positioning blocks moving in a diameter direction are disposed around the tray, Each of the positioning blocks is driven by a cylinder disposed on the outer wall of the clamp, and the head of each of the positioning blocks is further provided with a bracket.

After adopting the above structure, the two wafers are perfectly matched by two advance and retreat of the positioning block, and then the two wafers are bonded by pressing down the pressing plate, and the first wafer and the second wafer are in the Contact in a vacuum state, so there is no bubble between the two, and then the two wafer positions are correspondingly operated by operating the positioning block. The operation of the positioning block is completed by the cylinder, the structure is simple, the operation is convenient, the cost is low, and the wafer can be realized. The perfect bond.

The bracket is made by bending a wire connected to the head of the positioning block outward. With this structure, the mounting of the bracket is relatively simple, and the friction with the wafer is small, and the position does not change greatly when the wafer is dropped, so that the subsequent operation is relatively simple, and the structure is simple and convenient for subsequent cleaning. Or replace the work.

A plurality of equal height limit blocks perpendicular to the bottom of the clamp are also disposed in the clamp. With this structure, the limiting block can be abutted against the pressing plate on the cover, so that the pressing plate can reach the set position when pressing, thereby ensuring the distance between the two wafers when the two wafers are bonded. The bonding effect is better.

There are three positioning blocks, and the three positioning blocks are evenly arranged around the tray. The position of the wafer on the tray can be positioned by using three positioning blocks, and the structure is simple and the cost is low.

The box body is provided with at least one "C" shaped chuck driven by a pushing mechanism. When the lid is attached to the clamp, the chuck is pushed inwardly to clamp the edge of the clamp and the cover, so that the clamp and the cover Clamping. With this structure, when the cover is placed on the jig, the cover and the jig can be sealed, and the clamp is clamped to ensure the connection strength and the sealing degree inside the press, thereby keeping the inside of the press vacuum. .

The cover is connected to the box body through a support frame. The box body is provided with a support seat. One end of the support frame is hinged with the support base, and the other end of the support frame is hinged with the middle of the outer side of the cover to make the cover relatively Rotate on the support frame. With this structure, when the cover is rotated relative to the clamp, the cover can be rotated again, so that the cover can be rotated at a larger angle with respect to the clamp, or even turned upward, so that the air can be better contacted, and the heat dissipation effect is further improved. it is good.

The cover is hinged to the support frame, and the support frame is provided with a rotating hole and a pin hole. The cover is connected to the support frame through a rotating shaft through a rotating shaft and can rotate relative to the support frame, and the cover passes through a pin. The pin hole is connected to the support frame. With this structure, when the pin is inserted, the cover does not rotate relative to the support frame, and when the pin is removed, the cover rotates relative to the support frame, preventing the cover from rotating when the cover cover is pressed on the clamp. .

The rotating hole is a waist hole, the rotating shaft is movable left and right in the waist hole, the clamp is provided with a guiding groove, and the cover is provided with a guiding protrusion matched with the guiding groove, the cover cover When on the clamp, the guide projections are embedded in the guide grooves. With this structure, the guiding protrusion and the guiding groove can be used to ensure the centering of the cover when the cover is placed on the clamp, and the alignment precision is very high, so that the alignment of the wafer during bonding is very good, and the wafer is guaranteed. The quality of the bond.

The invention also provides a wafer bonding method, which comprises the following steps:

S1, placing the first wafer coated with the bonding glue on the tray;

S2, controlling a plurality of positioning blocks to advance in the direction of the tray by the cylinder, and positioning the first wafer;

S3, placing a second wafer on the positioning block bracket, then closing the cover to close the pressing machine, and vacuuming;

S4, when the vacuum reaches the set value, controlling the plurality of positioning blocks to retreat, and the second wafer is dropped from the positioning block bracket onto the first wafer;

S5, controlling a plurality of positioning blocks through the cylinder to advance toward the tray again, and positioning the two wafers;

S6, controlling the pressure plate downward through the press, pressing the first wafer and the second wafer to maintain t minutes;

S7, controlling a plurality of positioning blocks to retreat again, and then controlling the heating plate and the heating device to perform heating to cure the bonding glue;

S8. After the bonding is completed, the press is opened, and the bonded wafer is taken out.

In the step S4, the set value of the degree of vacuum is 5 to 15 Pa, the time t of the pressing in the step S6 is 2 to 10 minutes, and the heating temperature in the step S7 is 200 to 300 degrees. It is 5 to 15 minutes. With the above parameters, wafer bonding is more effective and more efficient.

After the above method is adopted, the present invention has the following advantages: the present invention defines the position of the first wafer after the first positioning block advances, and then places the second wafer, and then vacuums, and the positioning block is returned. When the second wafer is written in a vacuum state, it is dropped onto the first wafer, and then the position of the second wafer and the first wafer is simultaneously defined by the advancement of the positioning block, and then pressed. After the pressing, the positioning block is retracted, so that the position of the two wafers is perfectly matched when the pressing is performed, that is, the two wafers coincide on the plane, and there is no bubble between the two wafers. After pressing, it is heated and solidified. By adopting the above method, the steps are simple, and the PLC can be used for automatic control, and the bonding effect is good, the cost is low, and the efficiency is high.

DRAWINGS

1 is a schematic structural view of a wafer bonding machine;

2 is a schematic structural view of a press;

Figure 3 is an enlarged schematic view of a portion A of Figure 1.

4 is a schematic structural view of another embodiment of a wafer bonding machine;

5 is a schematic structural view showing an open state of a cover of another embodiment of a wafer bonding machine;

6 is a schematic view showing a connection structure of a cover and a jig in a wafer bonding machine.

As shown: 1, box, 2, press, 2.1, cover, 2.2, fixture, 3, tray, 4, positioning Block, 5, cylinder, 6, limit block, 7, pressure plate, 8, insulation layer, 9, heating plate, 10, press cylinder, 11, push mechanism, 12, chuck, 13, support frame, 13.1, Rotating hole, 13.2, pin hole, 14, support seat, 15, shaft, 16, guide groove, 17, guide protrusion.

detailed description

The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

As shown in FIG. 1-3, the present invention provides a wafer vacuum bonding machine, which comprises a box body 1 in which a vacuum generator is disposed, and the box body 1 is provided with an internal closed pressure. The press 2 includes a clamp 2.2 disposed on the casing 1 and a cover 2.1 disposed on the clamp 2.2 and closing the interior when the cover is closed. The cover 2.1 is provided with a pressure plate 7 therein. A heating plate 9 is disposed on the lower surface thereof, and a heat insulating layer 8 is disposed between the pressing plate 7 and the heating plate 9. The tray 2 is provided with a tray 3 for placing a wafer, and the tray 3 is provided with heating under the tray 3. a plurality of positioning blocks 4 that are diametrically moved around the tray 3, each of the positioning blocks 4 being driven by a cylinder 5 disposed on an outer wall of the clamp 2.2, the head of each positioning block 4 There is also a bracket 4.1.

The press 2 has an inner closed chamber, the chamber is connected to a vacuum generator, the vacuum generator can evacuate the chamber, and the outer side of the upper cover of the press 2 is provided with a press cylinder 10, and the press cylinder 10 The output shaft is connected to the pressure plate of the press 2 to drive the platen to move down. The cover 2.1 is connected to the clamp 2.2 by two cylinders, and when the cover 2.1 is placed on the clamp 2.2, the closed space inside the press 2 is formed. In the embodiment, the tray 3 is circular, and a heating device is disposed under the tray 3 to heat the tray 3. After the pressing plate 7 presses down the wafer, the heating plate on the pressing plate 7 and the tray 3 simultaneously perform wafer processing on the wafer. heating. The positioning block 4 is driven by the cylinder 5 provided on the outer wall of the clamp 2.2, and can move toward the tray or away from the tray along the diameter direction of the tray 3. By setting the stroke of the cylinder 5, the positioning block 4 is advanced. Can be positioned against the edge of the wafer to position the wafer. The positioning of the circular wafer can be achieved by using three positioning blocks. The head of the positioning block is provided with a bracket, and the bracket 4.1 is disposed at the upper end of the positioning block. The positioning block below the bracket is opposite to the wafer, and the bracket is provided with a distance between the wafer and the wafer. In this embodiment, the bracket 4.1 is formed by bending a wire connected to the head of the positioning block 4 outward. In this embodiment, the wire is bent into an arc shape. Since the wafer has a bonding glue at the time of bonding, in order to maintain the bonding effect, the positioning block 4 needs to be periodically cleaned during use, in this embodiment. The wire is pressed on the positioning block 4 by the pressing plate, and the removal is convenient when cleaning. Of course, the positioning block may also be 4, 5 or more, but it is still within the protection scope of the present application.

A plurality of equal height limit blocks perpendicular to the bottom of the clamp are also disposed in the clamp. In the process of wafer bonding, the thickness of the bonding glue needs to be controlled, that is to say, after the two wafers are bonded, the distance between the two needs to be within the set range. With this structure, the pressing plate is pressed. At the same time, the pressure is stopped when the limit block is reached, so that the distance between the two wafers is determined. For different required wafer bonding, only the limit blocks of different heights need to be replaced. In the embodiment shown in FIG. 1, the limiting block 6 is disposed on the outer side of the tray and has a columnar shape. In the embodiment shown in FIG. 5, the limiting block is disposed on the outer circumference of the upper surface of the tray and has a sheet shape. Although the limiting blocks of the two embodiments have different shapes, they are all limit blocks. The purpose is to control the thickness of the bonding glue.

As shown in FIG. 4 and FIG. 5, the box body 1 is provided with at least one "C" shaped chuck 12 driven by the pushing mechanism 11. When the cover 2.1 is placed on the clamp 2.2, the chuck 12 is facing The inner push can clamp the edges of the clamp 2.2 and the cover 2.1 to clamp the clamp 2.2 and the cover 2.1. In the embodiment, the pushing mechanism is a cylinder, and may also be a linear motion mechanism driven by a motor, or other linear motion mechanism.

The cover 2.1 is connected to the box body 1 through a support frame 13. The box body 1 is provided with a support base 14, one end of the support frame 13 is hinged with the support base 14, and the other end of the support frame 13 and the cover 2.1 The outer middle hinge is hinged such that the cover 2.1 can be rotated relative to the support frame 13. The support frame 13 is provided with a rotating hole 13.1 and a pin hole 13.2. The cover 2.1 is connected to the support frame 13 through a rotating shaft 13.1 and is rotatable relative to the support frame 13. The cover 2.1 passes through a pin hole through a pin. 13.2 is connected to the support frame 13. When the pin is inserted, the cover does not rotate relative to the support frame, and when the pin is removed, the cover can be rotated relative to the support frame.

The rotating hole 13.1 is a waist hole, and the rotating shaft can move left and right in the waist hole. The clamp 2.2 is provided with a guiding groove 16, and the cover 2.1 is provided with a guiding protrusion matched with the guiding groove 16. 17. When the cover 2.1 is placed over the clamp 2.2, the guide projection 17 is fitted into the guide groove 16. As shown in FIG. 6, the lower end surface of the cover is provided with a guiding protrusion, and the outer side of the upper end surface of the clamp is provided with a guiding groove, and when the guiding protrusion enters the guiding groove downward, the center line of the cover and the clamp can be ensured. Ensure the accuracy of the matching of the upper and lower wafers when the press moves downward.

S1, placing the first wafer coated with the bonding glue on the tray;

In the step S4, the set value of the degree of vacuum is 5 to 15 Pa, the time t of the pressing in the step S6 is 2 to 10 minutes, and the heating temperature in the step S7 is 200 to 300 degrees. It is 5 to 15 minutes.

Embodiment: In this embodiment, two wafers having a thickness of 0.3 mm or more and a diameter of 200 mm are used, and the bonding steps are as follows:

S1, placing the first wafer coated with the bonding glue on the tray;

S2, controlling a plurality of positioning blocks to advance in a tray direction by a cylinder, and positioning the first wafer at a center position;

S4, when the vacuum reaches 10 Pa, the plurality of positioning blocks are controlled to retreat, and the second wafer is dropped from the positioning block holder onto the first wafer;

S5, controlling a plurality of positioning blocks to advance toward the tray by the cylinder, and positioning the two wafers to completely overlap the edges of the two wafers;

S6, controlling the pressure plate downward through the press to press the first wafer and the second wafer for 15 minutes;

S7, by controlling a plurality of positioning blocks to retreat again, and then controlling the heating plate and the heating device to perform heating to cure the bonding glue, the heating temperature is 300 degrees, and the heating time is 10 minutes;

Claims

A wafer vacuum bonding machine, characterized in that it comprises a box (1), a vacuum generator is arranged in the box (1), and an internal closed press is arranged on the box (1) (2) The press (2) includes a jig (2.2) provided on the case (1) and a cover (2.1) provided on the jig (2.2) and closed inside the cover, the cover (2.1) is provided with a pressing plate (7), a lower surface of the pressing plate (7) is provided with a heating plate (9), and a heat insulating layer (8) is arranged between the pressing plate (7) and the heating plate (9) a tray (3) for placing a wafer is disposed in the fixture (2.2), a heating device is disposed below the tray (3), and a plurality of diametrical movements are disposed around the tray (3) Positioning blocks (4), each of which is driven by a cylinder (5) disposed on an outer wall of the clamp (2.2), and each of the positioning blocks (4) is further provided with a bracket (4.1) .
The wafer vacuum bonding machine according to claim 1, wherein the bracket (4.1) is formed by bending a wire connected to a head portion of the positioning block (4).
The wafer vacuum bonding machine according to claim 1, characterized in that: the clamp (2.2) is further provided with a plurality of contour block (6) perpendicular to the bottom of the clamp (2.2).
The wafer vacuum bonding machine according to claim 1, characterized in that there are three positioning blocks (4), and the three positioning blocks (4) are evenly arranged around the tray (3).
The wafer vacuum bonding machine according to claim 1, characterized in that: the box body (1) is provided with at least one "C" shaped chuck (12) driven by a pushing mechanism (11), when the cover is (2.1) When the cover (2.2) is placed on the clamp (2.2), the clamp (12) is pushed inward to clamp the edge of the clamp (2.2) and the cover (2.1) to clamp the clamp (2.2) and the cover (2.1) .
The wafer vacuum bonding machine according to claim 1, wherein the cover (2.1) is connected to the casing (1) via a support frame (13), and the casing (1) is provided with a a support base (14), one end of the support frame (13) is hinged to the support base (14), and the other end of the support frame (13) is hinged to the middle of the outer side of the cover (2.1) so that the cover (2.1) can be opposite to the support The frame (13) rotates.
The wafer vacuum bonding machine according to claim 6, wherein the cover (2.1) is hinged to the support frame (13), and the support frame (13) is provided with a rotating hole (13.1) and The pin hole (13.2), the cover (2.1) is connected to the support frame (13) through a rotating shaft (13.1) through a rotating shaft (1) and is rotatable relative to the support frame (13), and the cover (2.1) is worn through a pin The pin hole (13.2) is connected to the support frame (13).
The wafer vacuum bonding machine according to claim 6, wherein the rotating hole (13.1) is a waist hole, and the rotating shaft (15) is movable left and right in the waist hole, the jig (2.2) a guide groove (16) is disposed on the cover (2.1), and a guide protrusion (17) is engaged with the guide groove (16). When the cover (2.1) is placed on the clamp (2.2), The guide projection (17) is embedded in the guide groove (16).
A wafer bonding method characterized in that it comprises the following steps:

S1, placing the first wafer coated with the bonding glue on the tray;

S2, controlling a plurality of positioning blocks to advance in the direction of the tray by the cylinder, and positioning the first wafer;

S3, placing a second wafer on the positioning block bracket, then closing the cover to close the pressing machine, and vacuuming;

S4, when the vacuum reaches the set value, controlling the plurality of positioning blocks to retreat, and the second wafer is dropped from the positioning block bracket onto the first wafer;

S5, controlling a plurality of positioning blocks through the cylinder to advance toward the tray again, and positioning the two wafers;

S6, controlling the pressure plate downward through the press, pressing the first wafer and the second wafer to maintain t minutes;

S7, controlling a plurality of positioning blocks to retreat again, and then controlling the heating plate and the heating device to perform heating to cure the bonding glue;

S8. After the bonding is completed, the press is opened, and the bonded wafer is taken out.
The wafer bonding method according to claim 9, wherein in the step S4, the set value of the degree of vacuum is 5 to 15 Pa, and the time t of the pressing in the step S6 is 2 to 10. In the minute, the heating temperature in the step S7 is 200 to 300 degrees, and the time is 5 to 15 minutes.