TW201533807A - Sealing sheet attaching method - Google Patents

Abstract

After adhering a sealing sheet having the same shape as a semiconductor substrate to the center of a ring frame to which adhesive tape has been adhered, a semiconductor substrate (W) is positioned on a retaining table situated inside a decompression chamber, the retaining table having a heater embedded therein, the ring frame is positioned on a frame support arranged about the retaining table, and the semiconductor substrate and the adhesive tape are positioned facing one another. In this state, after the decompression chamber interior is decompressed to a vacuum state, the sealing sheet is placed under pressure by a pressing member while the sealing sheet is heated using the heater embedded in the retaining table and a heater embedded in the pressing member, and is adhered to the semiconductor substrate.

Description

Sealing sheet attachment method

The present invention relates to a sealing sheet in which a sealing layer composed of a resin composition is attached to a circuit surface of a semiconductor substrate including a circuit substrate, and a sealing sheet attaching method for sealing the circuit surface in the process of manufacturing a semiconductor device .

After the periphery of one semiconductor wafer is surrounded by the frame, the first sealing resin sheet and the second sealing resin sheet which are formed of the prepreg impregnated with the resin are respectively sandwiched from both sides of the semiconductor wafer. The semiconductor wafer is sealed to manufacture a semiconductor device (see Patent Document 1).

Advanced technical literature Patent literature

Patent Document 1 Japanese Patent Laid-Open No. Hei 5-291319

However, the above conventional methods cause the following problems.

That is, in recent years, due to the high-density installation relationship required for rapid advancement of applications, half The conductor device tends to be miniaturized. Therefore, since the semiconductor wafer is individually sealed with a resin by the dicing process, the semiconductor element is individually sealed with a resin, so that the amount of transfer is lowered, and the production efficiency is lowered.

The present invention has been made in view of such circumstances, and its main object is to provide a sealing sheet attaching method capable of attaching a sealing sheet to a semiconductor substrate with good efficiency and with good precision.

Then, the inventors of the present invention have obtained the following findings in order to solve the problem and to study the results of repeated experiments such as experiments and simulations.

It has been attempted to attach and seal a single-piece sealing sheet having a sealing layer made of a resin composition on the entire surface of a semiconductor substrate, and then to form the semiconductor device.

However, compared with the case where the wafer which is cut by the dicing process is attached to the semiconductor substrate with a sealing sheet having the same shape as the large-area semiconductor substrate, the sealing sheet itself has thickness and rigidity. As a result, in the attaching process, the adhesive interface between the sealing sheet and the semiconductor substrate easily contains air bubbles, and voids are generated in the sealing layer. In particular, when the sealing sheet is attached and the polymerization reaction of the sealing layer is promoted by heating to be completely cured, there is a problem that the bubble expands and the semiconductor device becomes a defective product.

Further, although the pressure-reducing chamber is in a vacuum state and the sealing sheet is attached while being heated on the semiconductor substrate, the air bubbles are contained in the adhesion interface.

In order to ascertain the cause and repeat the experiment, it was clarified that the case where bubbles are contained frequently occurs in the case where the attachment process is continuously repeated. In other words, when the decompression of the decompression chamber is started in a state where the resin sheet is placed on the semiconductor substrate on the holding stage, the sealing layer is caused by the residual temperature of the holding stage or the radiant heat before the chamber is brought into a vacuum state. Softens to contain bubbles.

In order to achieve the object, the present invention has the following constitution.

In the process of manufacturing a semiconductor device, a sealing sheet attaching a sealing sheet formed of a sealing layer composed of a resin composition to a semiconductor substrate, and having a first attaching process, a sealing sheet having the same shape as the semiconductor substrate is attached to the center of the annular frame to which the adhesive tape is attached; during the mounting process, the semiconductor substrate is placed in a holding chamber in which the heater is embedded in the decompression chamber, and the ring is formed at the same time The frame is placed on the support member disposed around the holding table to face the semiconductor substrate and the adhesive tape; the decompression process is performed to decompress the decompression chamber to form a vacuum state; and the second attachment process is in the vacuum state The pressure-reducing chamber is heated by a pressurizing member while heating the sealing sheet by a heater, and is attached to the semiconductor substrate.

According to the above method, the semiconductor substrate and the sealing sheet are opposed to each other until the vacuum chamber reaches a vacuum state. That is, the semiconductor substrate and the sealing sheet are kept in a non-contact state. Therefore, the sealing sheet is prevented from coming into contact with the semiconductor substrate while suppressing the sealing layer from being softened by the heat of the holding stage before the vacuum state is reached. As a result, air from the sealing sheet and the semiconductor base The adhesive interface of the board is completely discharged, so that it is avoided that bubbles are contained at the adhesive interface, thereby reducing the defective rate of the semiconductor device.

Further, in the above method, the holding frame is placed by the support member that can be advanced and retracted during the placing process, and preferably, the load applied to the sealing piece by the lifting and lowering of the pressing member is performed in the second attaching process. The aforementioned support member is raised and lowered.

According to this method, since the supporting member follows the lifting and lowering of the pressing member, the sealing sheet can be given a substantially uniform load.

Further, in the above method, the pressurizing member is provided with a heater, and the sealing sheet may be heated by the holding stage and the pressing member during the second attaching process.

According to this method, heat can be conducted to the sealing sheet sandwiched by the heating member and the holding table with good efficiency.

According to the sealing sheet attaching method of the present invention, the sealing sheet adhered to the annular frame can be attached to the semiconductor substrate with good precision.

23‧‧‧ Keeping the table

25‧‧‧Frame Support Department

26‧‧‧ Spring

27‧‧‧Support pins

30‧‧‧Decompression chamber

31‧‧‧ Pressing members

32‧‧‧heater

33‧‧‧heater

DT‧‧‧ adhesive tape

f‧‧‧Ring frame

T‧‧‧ Sealing film

M‧‧‧ sealing layer

S1‧‧‧First release liner

S2‧‧‧Second release liner

W‧‧‧Semiconductor substrate

Figure 1 is a cross-sectional view of a sealing sheet.

Fig. 2 is a flow chart showing the attachment process of the sealing sheet.

Fig. 3 is a view showing the conveyance of the substrate and the sealing sheet.

Fig. 4 is a front elevational view showing the constitution of the first attachment work.

Fig. 5 is a front view showing the attachment action of the adhesive tape.

Fig. 6 is a front view showing the attachment action of the adhesive tape.

Fig. 7 is a front view showing the cutting operation of the adhesive tape.

Fig. 8 is a front view showing the peeling action of the adhesive tape.

Fig. 9 is a front elevational view showing the peeling action of the first release liner.

Fig. 10 is a front elevational view showing the transport operation of the substrate.

Fig. 11 is a front elevational view showing the operation of placing a substrate on a holding table.

Fig. 12 is a front elevational view showing the operation of providing the annular frame to the frame support portion.

Fig. 13 is a front elevational view showing the action of attaching a sealing sheet to a substrate.

Fig. 14 is a front elevational view showing the action of attaching a sealing sheet to a substrate.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. A case where a sealing sheet having a sealing layer made of a resin composition is attached to a semiconductor substrate having a plurality of semiconductor elements formed on its surface will be described as an example.

<sealing sheet>

The sealing sheet T is, for example, the same shape as that of the semiconductor substrate W (hereinafter referred to simply as "substrate W") as shown in FIG. Moreover, this sealing sheet T is provided with the first release liner S1 and the second release liner S2 for protection on both surfaces of the sealing layer M. The first release liner S1 and the second release liner S2 may have the same shape or a rectangular shape, and may be the same size or larger than the substrate W.

The sealing layer M is formed into a sheet shape from a sealing material. Examples of the sealing material include thermosetting resin, epoxy resin, thermosetting polyimide resin, phenol resin, and urea resin. A thermosetting resin such as a (urea resin), a melamine resin, an unsaturated polyester resin, a diallyl phthalate resin, or a thermosetting urethane resin. Moreover, the thermosetting resin and the thermosetting resin composition containing an additive in an appropriate ratio are also mentioned as a sealing material.

Examples of the additive include a filler, a phosphor, and the like. Examples of the filler include inorganic fine particles such as silica, titania, talc, alumina, aluminum nitride, and tantalum nitride, for example, silicone particles. Etc. Organic particles and so on. The phosphor has a wavelength conversion function, and examples thereof include a yellow phosphor that converts blue light into yellow light, a red phosphor that converts blue light into red light, and the like. Examples of the yellow phosphor include a garnet-type phosphor such as Y ₃ Al ₅ O ₁₂ :Ce (YAG (yttrium aluminum garnet): Ce). Examples of the red phosphor include a nitride phosphor such as CaAlSiN ₃ :Eu or CaSiN ₂ :Eu.

The sealing layer M is adjusted to be semi-solid before sealing the semiconductor element. Specifically, when the sealing material contains a thermosetting resin, it can be, for example, completely cured (C-staged), that is, in a semi-hardened state. Adjust in the (B phase) state.

The size of the sealing layer M can be appropriately set depending on the size of the semiconductor element and the substrate. Specifically, when the sealing sheet is prepared as a long piece, the length of the sealing layer M in the left-right direction, that is, the width is, for example, 100 mm or more, preferably 200 mm or more, for example, 1500 mm or less, preferably 700 mm or less. Further, the thickness of the sealing layer M can be appropriately set in accordance with the size of the semiconductor element, and is, for example, 30 μm or more, preferably. It is 100 μm or more, and is, for example, 3000 μm or less, preferably 1,000 μm or less.

The first release liner S1 and the second release liner S2 may, for example, be a polymer sheet such as a polyethylene sheet, a polyester sheet (PET or the like), a polystyrene sheet, a polycarbonate sheet, or a polyimide sheet. For example, a ceramic sheet, such as a metal foil or the like. A release treatment such as fluorine treatment may be performed on the contact surface of the release liner which is in contact with the sealing layer M. The size of the first release liner and the second release liner can be appropriately set depending on the peeling conditions, and the thickness is, for example, 15 μm or more, preferably 25 μm or more, and is, for example, 125 μm or less, or preferably 75 μm or less.

<Sealing sheet attachment method>

The operation of attaching the sealing sheet to the center of the annular frame after the adhesive tape is attached to the center of the annular frame in accordance with the flow chart of FIG. 2 and FIGS. 3 to 14 will be described.

First, the adsorption ring 2 of the transport mechanism 1 moves and holds the annular frame f stacked in the stocker 18 from above, and then moves toward the sealing sheet supply unit (step S1A). As shown in Fig. 3, the bottom surface of the suction plate 3 in the center of the conveying mechanism 1 is lowered at a position lower than the annular frame f, and the laminated sealing sheet T is adsorbed and held (step S2A). After that, the conveying mechanism 1 raises the suction plate 3 to the bottom surface of the sealing sheet T at the same height as the bottom surface of the annular frame f, and moves to the first attachment process while holding the sealing sheet T and the annular frame f.

In the first attachment process, as shown in FIGS. 4 and 5, the raw material rolls of the supply unit 4 successively feed the adhesive tape DT (cut tape), and the adhesive tape DT is passed through the peeling roller 5, the guide roller, and The peeling unit 6 is properly adapted The belt tension recovery unit 7 is wound in a state of tension. The adhesive tape DT is supplied to the attaching position in a state where the separation tape S of the surface has been peeled off by the peeling roller 5. The separation tape S peeled off by the peeling roller 8 is taken up and recovered by the separation belt collecting portion 9. The transport mechanism 1 that has arrived at the attaching position is lowered to a predetermined height, and the annular frame f and the sealing sheet T are brought close to the adhesive tape DT and face the adhesive tape DT.

As shown in FIG. 6, the attaching unit 10 provided under the adhesive tape DT is horizontally moved in the conveying direction of the adhesive tape DT. At this time, since the attaching roller 11 having the width of the attaching unit 10 longer than the adhesive tape DT is raised to a predetermined height, the adhesive tape DT is pressed by the attaching roller 11 and attached to the ring. The frame f and the sealing sheet T (step S3A).

Once the attaching unit 10 reaches the end position, the cutting unit 12 provided under the adhesive tape DT rises to a predetermined height as shown in FIG. The cutting unit 12 is provided with a cutter 14 that is provided at the front end of the arm 13 through the holder so that the blade is directed upward. The cutting unit 12 cuts the adhesive tape DT while rotating the tip end of the cutter 14 into the adhesive tape DT and rotating along the shape of the annular frame f. At this time, the roller 16 mounted on the other arm 15 follows from the rear of the cutter 14. That is, the roller 16 presses the floating portion of the cut adhesive tape DT and attaches it to the annular frame f.

After the cutting of the adhesive tape DT is completed, the cutting unit 12 moves to the lower standby position. At the same time, the peeling unit 6 releases the nip of the adhesive tape DT, and as shown in Fig. 8, the peeling unit 6 and the attaching unit 10 are horizontally moved toward the attachment start position side. At this time, the adhesive tape DT cut into the shape of the annular frame f is taken from the annular frame f by the peeling roller 17 At the same time as being peeled off, it is taken up and recovered in the belt recovery unit 4. Thereafter, the peeling unit 6 is returned to the initial position. At this time, as the peeling unit 6 moves, the self-contained supply unit 4 successively delivers the adhesive tape DT of a predetermined length.

The sealing sheet T held by the annular frame through the adhesive tape DT is transported to the second attachment project by the transport mechanism 1. During this transfer, the annular frame f is transferred to the adsorption plate of the other transfer mechanism 19, and is reversed upside down as shown in FIG.

In the process of being conveyed by the transport mechanism 19, the peeling tape 24 is attached to the end portion of the first release liner S1 by the peeling roller 24 of the peeling unit, and then the transport mechanism 19 is horizontally moved by the peeling roller 24. While the peeling tape Ts is attached to the first release liner S1 while rotating, the first release liner S1 is gradually peeled off from the seal layer M by rolling up the release tape Ts (step S4A).

On the other hand, the substrate W which is housed at a predetermined interval and which is accommodated in a plurality of layers placed in the cassette C of the ejectable cassette table is not covered by a Bernoulli chuck 20 The way is kept hanging. As shown in FIG. 10, the Bernoulli chuck 20 transmits the substrate W taken out from the cassette C to the adsorption pad 22 which protrudes from the center of the holding surface of the self-aligner 21 (step S1B). The aligner 21 performs alignment based on a notch or the like formed on the substrate W (step S2B). Thereafter, the substrate W is again transported from the aligner 21 by the Bernoulli chuck 20 and placed on the holding table 23 (step S3B).

As shown in FIG. 11, an annular frame support portion 25 surrounding the periphery of the holding table 23 is provided. The frame supporting portion 25 is elastically biased upward by a plurality of support pins 27 which can be raised and lowered by the spring 26 which is an elastomer Pressure. Therefore, when the annular frame f is placed on the frame supporting portion 25, the bottom surface of the sealing sheet T is set to be higher than the surface height of the substrate W placed on the holding table 23. The height of the frame supporting portion 25 is appropriately set depending on the thickness of the sealing sheet T to be used and the thickness of the substrate W. Further, the frame support portion 25 corresponds to the support member of the present invention.

Therefore, as shown in FIG. 12, after the substrate W is placed and held by the holding table 23, the annular frame f is placed on the frame supporting portion 25 by the conveying mechanism 19 (step S5).

The upper casing 30B that is placed in the upper casing 30A in which the holding table 23 and the frame support portion 25 are housed and is placed on the upper side is lowered to a predetermined height. The upper end of the upper and lower casings 30A and 30B face the lower end surface to form a decompression chamber 30 (step S6). Thereafter, the inside of the decompression chamber 30 is gradually depressurized until a vacuum is reached (step S7).

As shown in FIG. 13, when the inside of the chamber 2 is in a vacuum state, the pressing member 31 which can be raised and lowered by the cylinder 29 is lowered and abutted against the sealing sheet T in the upper casing 30B. At this time, in the upper casing 30B, the pressing members 31 and the heaters 32 and 33 provided in the holding table 23 are operated and the sealing sheet T is heated (step S8). As shown in FIG. 14, as the sealing sheet T starts to soften due to heating and the pressing member 31 is lowered to a predetermined height to press the sealing sheet T, the sealing sheet T is attached to the surface of the substrate W (step S9).

Once the heating and pressurization treatment has reached a predetermined time, the heaters 32, 33 are stopped. Then, the pressing member 31 is raised and the pressing of the sealing sheet T is released (step S10). Further, the air pressure inside the decompression chamber 30 is gradually increased to return to the atmospheric state.

After that, when the inside of the decompression chamber 30 reaches the atmospheric state, the upper casing 30B is raised, and the mounting frame in which the substrate W is attached by the sealing sheet T is held by a transfer mechanism such as a robot arm. Move to the next project or store it in the cassette (step S11). The above ends a series of actions. Thereafter, the series of processing is repeated until the predetermined number of processing sheets is reached (step S12). Further, the step S3A corresponds to the first attaching process of the present invention, and the step S6 to the step S8 corresponds to the second attaching process of the present invention.

According to the above-described sealing sheet attaching method, before the decompression chamber 30 reaches the vacuum state, since the sealing sheet T and the substrate W are kept separated from each other, the heat conduction of the holding stage 23 is blocked, and the sealing layer M is suppressed from coming. It softens by the influence of the radiant heat of the holding table 23. Therefore, it is possible to prevent the air bubbles from being contained in the adhesive interface of the sealing sheet T and the substrate W before the sealing sheet T is attached. Therefore, even after the sealing sheet T is attached, even if the main curing treatment for completely curing the sealing sheet T is performed, voids are not generated in the sealing layer M, resulting in product failure.

Further, the present invention can also be implemented in the following forms.

(1) In each of the above embodiments, the heater 23 may be provided with one of the holding base 23 and the pressing member 31.

(2) In the above embodiment, the circular substrate W has been described as an example, but the substrate shape may be square, rectangular or polygonal.

(3) In the above embodiment, the support pin 27 of the frame support portion 25 may be raised and lowered in synchronization with the lifting and lowering of the pressing member 31 by an actuator such as a cylinder.

(4) In the above embodiment, the transport mechanism for transporting the substrate W may be a robot arm having a horseshoe shape at the tip end and having an adsorption function. In the case of using the robot arm, the back surface of the substrate W may be suctioned and held by the robot arm to carry it. Further, the holding table 23 is provided with a suction pad that advances and retracts from the center of the holding surface, similarly to the aligner 21, and the adsorption pad is configured to receive the substrate W at a position higher than the frame supporting portion 25.

(5) In the above embodiment, the adhesive tape DT may be attached in a state where the first release liner S1 is peeled off from the self-sealing sheet T.

(6) In the above-described embodiment, in the first attachment process, the respective configurations of the tape supply unit 4, the tape collection unit 9, and the like are reversed upside down, and attached from the annular frame f and the back side of the sealing sheet T. Adhesive tape DT composition.

[Industry use possibility]

As described above, the present invention is suitable for attaching a sealing sheet to a semiconductor substrate with good efficiency and with good precision.

23‧‧‧ Keeping the table

25‧‧‧Frame Support Department

26‧‧‧ Spring

27‧‧‧Support pins

29‧‧‧Cylinder block

31‧‧‧ Pressing members

32‧‧‧heater

33‧‧‧heater

DT‧‧‧ adhesive tape

M‧‧‧ sealing layer

W‧‧‧Semiconductor substrate

Claims (3)

A sealing sheet attaching method is a sealing sheet attaching method in which a sealing sheet formed with a sealing layer composed of a resin composition is attached to a semiconductor substrate in the process of manufacturing a semiconductor device, and is characterized in that: a bonding process in which a sealing sheet having the same shape as the semiconductor substrate is attached to the center of the annular frame to which the adhesive tape is attached; and a mounting process is performed to mount the semiconductor substrate in a decompression chamber and a heater holding unit At the same time, the annular frame is placed on a support member disposed around the holding table to make the semiconductor substrate and the adhesive tape face each other; during the decompression process, the decompression chamber is depressurized to form a vacuum state; the second attaching process Then, the sealing sheet is heated by the heater while being heated in the vacuum chamber, and is pressed by the pressing member and attached to the semiconductor substrate. The sealing sheet attaching method of claim 1, wherein the placing process is performed by holding the holding frame by the support member that can advance and retreat, and the second attaching process is applied to the sealing piece by the lifting of the pressing member. The support member is lifted and lowered by the load. The sealing sheet attaching method according to claim 1 or 2, wherein the pressing member is provided with a heater, and the second attaching process heats the sealing sheet by the holding table and the pressing member.