JP7597565B2 - Method for processing plate-like object and method for processing package substrate - Google Patents

Description

The present invention relates to an ultraviolet-curable resin composition and a processing method using the resin composition, and more specifically, to a composition that has a thermal peeling function.

Conventionally, a technique has been known for appropriately removing burrs formed in a recess in a package substrate having a recess, as disclosed in Patent Document 1, for example.

In Patent Document 1, a recess (cavity) that intersects with the planned division line is formed on the surface of the package substrate to be processed, and electrodes are formed in the recess after the package substrate is divided into individual chips. During the division process, burrs are formed along the inner side surface of the recess, and these burrs are removed with high-pressure cleaning water.

In this way, by removing the burrs after dividing the package substrate, it is possible to prevent problems such as the burrs falling off during package mounting and causing mounting defects.

JP 2016-181569 A

As packages become smaller, the size of the electrodes and recesses formed on the package substrate are also becoming smaller, and are expected to continue to become smaller in the future.

Here, as the recesses become smaller, the gaps become smaller, making it more difficult to remove burrs using high-pressure cleaning water.

In particular, in package substrates in which recesses are formed on the inside of the electrodes, there is a concern that when the electrode portion is cut with a cutting blade during the separation process, burrs from the electrodes may get into the recesses on the inside of the electrodes, and these burrs may not be able to be sufficiently removed with high-pressure cleaning water and may remain as foreign matter.

In view of the above, the present invention proposes a new resin composition suitable for forming a protective layer on the surface of a plate-shaped object to prevent burrs from forming when a recess is cut with a cutting blade, and a new processing method using the resin composition.

In particular, when recesses are formed, there is a concern that if the recesses are small, the resin composition that gets into the recesses cannot be removed and remains as foreign matter.

Furthermore, in addition to plate-shaped objects such as package substrates in which recesses are formed, plate-shaped objects without recesses also require that, when a protective layer is formed from a resin composition, the protective layer is later removed, but even in this case, care must be taken to ensure that no foreign matter remains.

The present invention therefore proposes a resin composition that is easily removed after forming a protective layer, and a new processing method that uses the resin composition.

The problem that the present invention aims to solve is as described above, and the means for solving this problem will be explained next.

According to one aspect of the present invention,
A liquid ultraviolet-curable heat-peelable resin composition,
(meth)acrylate,
A photopolymerization initiator;
and a foaming agent that expands when heated, to form a liquid ultraviolet-curable, heat-peelable resin composition.

According to another aspect of the present invention,
The foaming agent has an outer shell made of a plastic resin and a low-boiling point hydrocarbon encapsulated in the outer shell.

According to another aspect of the present invention,
A method for processing a plate-shaped object using the liquid ultraviolet-curable heat-peelable resin composition, comprising the steps of:
A supplying step of supplying the liquid ultraviolet-curable heat-removable resin composition onto a surface of a plate-like object;
a curing step of irradiating the liquid ultraviolet-curable heat-peelable resin composition with ultraviolet light to cure the composition and form a protective layer on the surface of the plate-shaped object;
a cutting step of cutting the plate-shaped object on which the protective layer is formed;
After carrying out the cutting step, the method for processing a plate-shaped article includes a peeling step of heating the ultraviolet-curable heat-peelable resin composition to peel off the protective layer from the plate-shaped article.

According to another aspect of the present invention,
A method for processing a package substrate using a liquid ultraviolet-curable heat-peelable resin composition, comprising:
the package substrate has a surface on which a plurality of division lines and electrodes crossing the division lines are formed, and recesses opening on the surface and crossing the division lines are formed in the electrodes;
a supplying step of supplying the ultraviolet-curable heat-removable resin composition in liquid form onto a surface of the package substrate;
a filling step of filling the concave portion with the liquid ultraviolet-curable heat-peelable resin composition by disposing the package substrate in a vacuum atmosphere after the supplying step;
a curing step of curing the liquid ultraviolet-curable heat-removable resin composition by irradiating the ultraviolet ray thereto after the filling step;
a cutting step of cutting the package substrate together with the ultraviolet-curable heat-peelable resin composition along the intended division line with a cutting blade after the curing step is performed;
After the cutting step, the method for processing a package substrate includes a removing step of heating the ultraviolet-curable, heat-peelable resin composition to remove the ultraviolet-curable, heat-peelable resin composition from the package substrate.

According to one aspect of the present invention, by using a liquid resin composition, the resin composition can be easily filled into the recesses of a plate-like object having recesses formed on the surface, and by curing the resin composition by irradiating it with ultraviolet light while it is filled into the recesses, the recesses can be filled with the resin composition. This makes it possible to prevent burrs generated by cutting the electrode portion around the recesses from extending into the space of the recesses. Furthermore, by including a foaming agent, the resin composition can be expanded by heating after processing, making it easier for the resin composition to peel off from the recesses and the surface.

Furthermore, according to one aspect of the present invention, the resin composition can be used to form a protective layer on the surface of a plate-like object, regardless of whether or not it has a recess, making it possible to realize a protective layer that is easily peeled off.

FIG. 2 is a diagram showing a package substrate as an example of a plate-like object to be processed; 1A is a diagram for explaining the supply of a resin composition, and FIG. 1B is a diagram for explaining the state of the surface of a package substrate to which the resin composition has been supplied. 1 is a flowchart showing the procedure of one embodiment of a processing method according to the present invention. FIG. FIG. 5A to 5C are diagrams illustrating a cutting step. 4A to 4C are diagrams illustrating cut grooves formed in a package substrate covered with a resin composition. FIG.

Figure 1 shows a package substrate 1 as an example of a plate-like workpiece.

The package substrate 1 has a plurality of first planned division lines 21 extending in a first direction F1 on the surface 11a of the substrate 11, and second planned division lines 22 extending in a second direction F2 perpendicular to the first planned division lines 21, which are arranged in a grid pattern.

A semiconductor device chip (not shown) is mounted on the back surface 11b of the substrate 11 in the mounting area 15 defined by the first planned division line 21 and the second planned division line 22, and is sealed with synthetic resin 16.

On the front surface 11a side of the substrate 11, planned division lines 21, 22 are set between each mounting area 15, and electrodes 30 are arranged so as to cross the planned division lines 21, 22.

Each electrode 30 has a long groove-shaped recess 32 formed in the longitudinal direction of the electrode 30, and when cutting is performed along the intended division lines 21, 22, each electrode 30 and each recess 32 is divided into two.

In the present invention, as shown in Figures 2(A) and 2(B), the resin composition 5 is filled into each recess 32 of each electrode 30 to fill the space, thereby preventing burrs from extending into the space when the electrode 30 is cut. Note that the present invention can also be applied to plate-like objects in which recesses are formed in places other than the electrodes 30.

As shown in Figures 2(A) and (B), the resin composition 5 is a liquid ultraviolet-curable, heat-peelable resin composition that contains (meth)acrylate, a photopolymerization initiator, and a foaming agent that expands when heated.

The blending ratio of each component is not particularly limited, but the foaming agent that expands when heated can be, for example, 5% by weight to 45% by weight based on the total amount of (meth)acrylate. If there is too little foaming agent, the peelability described below will be poor, and conversely, if there is too much foaming agent, curing will be poor or the viscosity will be too high, making it difficult to apply evenly or fill recesses.

(Meth)acrylate refers to acrylate, which is an acrylic acid compound, or methacrylate, which is a methacrylic acid compound, and (meth)acrylate is defined as either (meth)acrylate with a urethane bond or (meth)acrylate without a urethane bond, or a mixture thereof.

(Meth)acrylates having a urethane bond (urethane group) are those having a urethane group in the molecule. Examples include Light Acrylate IAA, AT-600, UA-306H, UA-306T, UA-306I, UA-510H, UF-8001G, DAUA-167, UF-07DF (all manufactured by Kyoeisha Chemical Co., Ltd.), R-1235, R-1220, RST-201, RST-402, R-1301, R-1304, R-1214, R- 1302XT, GX-8801A, R-1603, R-1150D, DOCR-102, DOCR-206 (all manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), UX-3204, UX-4101, UXT-6100, UX-6101, UX-7101, UX-8101, UX-0937, UXF-4001-M35, UXF-4002, DPHA-40H, UX-5000, UX-5102 D-M20, UX-5103D, UX-5005, UX-3204, UX-4101, UX-6101, UX-7101, UX-8101, UX-0937, UXF-4001-M35, UXF-4002, UXT-6100, DPHA-40H, UX-5000, UX-5102D-M20, UX-5103, UX-5005 (all manufactured by Nippon Kayaku Co., Ltd.), etc.

(Meth)acrylates that do not have a urethane bond are those that do not have a urethane group in the molecule. Examples include tetrahydrofurfuryl acrylate, isobornyl acrylate, phenyl glycidyl ether acrylate, 1,9-nonanediol diacrylate, etc.

The photopolymerization initiator is used to initiate photopolymerization (ultraviolet light) of the resin composition. Examples include 1-hydroxycyclohexyl phenyl ketone (e.g., Irgacure (registered trademark) 184 manufactured by BASF), α-hydroxyalkylphenone (e.g., Omnirad (registered trademark) 184 manufactured by IGM Resins B.V.), etc.

The foaming agent that expands when heated is composed of an outer shell made of a plastic resin and a low-boiling point hydrocarbon encapsulated in the outer shell. Examples include Kureha Microsphere (registered trademark) (manufactured by Kureha Corporation), Advancell (registered trademark) EM (manufactured by Sekisui Chemical Co., Ltd.), etc.

Next, an example of a method for processing a plate-like object according to the present invention will be described. Figure 3 is a flow chart showing the steps of one embodiment of the processing method. Each step will be described in order below.

<Supply step>
As shown in FIGS. 2A and 2B, this is a step of supplying a liquid resin composition 5 onto the surface 11 a of the substrate 11 of the package substrate 1 .

As shown in FIG. 2(A), liquid resin composition 5 is dripped from a supply nozzle 6 onto the surface 11a of the substrate 11 so that the resin composition 5 spreads over the entire surface 11a. After dripping, the resin composition 5 may be spread and applied over the entire surface 11a using an application device (not shown). Alternatively, the resin composition may be applied only to the recesses rather than over the entire surface, so that the recesses are filled with the resin composition.

<Filling step>
After the supplying step is performed, as shown in FIG. 4, the package substrate 1 is placed in a vacuum atmosphere, thereby filling the liquid resin composition 5 into the recess 32 (FIG. 2(B)).

In the example of FIG. 4, the package substrate 1 is set in a vacuum chamber 8 connected to a vacuum source 9b via a valve 9a, and a vacuum is drawn for a predetermined period of time to create a vacuum atmosphere in the vacuum chamber 8. At this time, as shown in FIG. 2(B), the gas remaining in the recess 32 is extracted, and the resin composition 5 is filled into the recess 32 without leaving any gaps.

<Curing step>
After the filling step, as shown in FIG. 5, the liquid resin composition 5 is irradiated with ultraviolet light to harden it.

In the example of FIG. 5, ultraviolet light is irradiated from a light source 14, such as an ultraviolet lamp, onto the surface side of the package substrate 1 for a predetermined period of time to harden the resin composition 5. As the resin composition 5 hardens, a protective layer 50 is formed on the surface side of the package substrate 1. The thickness of the protective layer 50 is preferably set to, for example, about 200 μm, which is a sufficient thickness so that it does not peel off during the cutting step.

<Cutting step>
After the curing step, as shown in FIG. 6, the package substrate is cut together with the resin composition 5 (protective layer 50) by a cutting blade 60 along the intended division lines 21 and 22 (FIG. 1).

In the example of FIG. 6, a cutting jig 64 is placed on a holding table 62, and the package substrate 1 is held by suction on the cutting jig 64. The cutting jig 64 has an escape groove 64a formed along the planned division lines 21, 22 (FIG. 1) of the package substrate 1, and when the cutting blade 60 cuts into the package substrate 1, the cutting blade 60 fits into the escape groove 64a.

The holding table 62 is connected to a suction source 62b via a valve 62a, and the package substrate 1 is held by suction by generating negative pressure on the holding surface of the cutting jig 64.

When cutting, the cutting blade 60 is positioned at a predetermined cutting height and rotated at high speed, and cutting water is supplied to the cutting blade 60 and the package substrate 1 from a nozzle (not shown) while the holding table 62 is moved in the processing feed direction, thereby performing cutting along the planned division line 21 extending in the first direction F1. Next, the holding table 62 is rotated 90 degrees, and cutting is performed along the planned division line 22 (Figure 1) extending in the second direction F2, thereby dividing the package substrate 1 into multiple chips 1C (Figure 8).

As shown in FIG. 6, the cutting blade 60 cuts the package substrate 1 together with the resin composition 5, forming a cutting groove 25 along the intended division line 21 as shown in FIG. 7. During this cutting, the resin composition 5 that has filled the recess 32 without any gaps has hardened, so that burrs can be prevented from extending toward the space that existed in the recess 32.

<Removal step>
After the cutting step, the resin composition 5 is heated to remove it from the package substrate 1, as shown in FIG.

In the example of FIG. 8, the package substrate 1 is set under the heater 80, and the resin composition 5 formed on the surface of the package substrate 1 is heated by the heater 80 for a predetermined time. When the temperature of the resin composition 5 rises, the foaming agent contained in the resin composition 5 expands. That is, the outer shell of the foaming agent made of a plastic resin softens, and the encapsulated low-boiling point hydrocarbons turn into gas and become foamed, and the resin composition 5 expands as a whole, making it easy to peel off from the inner wall surface of the recess 32 and the surface of each chip 1C, achieving high peelability. In addition to heating using the heater 80, heating may be performed using other heating means such as a lamp, oven, or hot plate.

In FIG. 8, the resin composition 5 is shown in a state in which it has expanded and warped as a whole, and the resin composition 5 in this state can be easily removed by washing it away with a cleaning solution using a cleaning device (not shown). In addition, the enlarged portion of FIG. 8 shows an image in which the resin composition 5 expands and swells inside the recess 32, pressing against the inner wall surface, and the bulge cannot be suppressed and rises upward, and further, the resin composition 5 warps as a whole, creating a gap between the inner wall surface of the recess 32 and making it easier to peel off. In addition to washing away the resin composition 5, it may also be removed by blowing air.

By using the liquid resin composition 5 of the present invention as described above, the recess 32 can be easily filled in a plate-like object such as a package substrate 1 having a recess 32 formed on the surface as shown in Figures 2 (A) and (B), and the recess 32 can be filled with the resin composition 5 by curing the resin composition 5 by irradiating it with ultraviolet light while the resin composition 5 is filled in the recess 32. This prevents burrs generated by contacting the electrodes 30 around the recess 32 from extending into the space of the recess 32. Furthermore, by including a foaming agent as shown in Figure 8, the resin composition 5 can be expanded by heating after processing, and the resin composition 5 can be easily peeled off from the recess 32 and the surface 11a.

In the above examples, the package substrate 1 has been described as an example, but regardless of whether or not there is a recess, by supplying a resin composition to the surface of a plate-like object to form a protective layer, the protective layer can be easily peeled off and removed after necessary processing, and the resin composition can be prevented from remaining as a foreign matter. This protective layer is formed, for example, for the purpose of protecting a device formed on the surface of a semiconductor wafer.

The processing method in this case includes a supplying step of supplying a liquid resin composition to the surface of the plate-like object, a curing step of irradiating the liquid resin composition with ultraviolet light to cure it and form a protective layer on the surface of the plate-like object, a cutting step of cutting the plate-like object on which the protective layer has been formed, and a peeling step of heating the resin composition to peel off the protective layer from the plate-like object after the cutting step has been performed. In this case, the filling step by vacuum drawing described above is omitted.

REFERENCE SIGNS LIST 1 Package substrate 1C Chip 5 Resin composition 6 Supply nozzle 8 Vacuum chamber 9a Valve 9b Vacuum source 11 Substrate 11a Front surface 11b Back surface 14 Light source 15 Mounting area 16 Synthetic resin 21 Planned division line 22 Planned division line 25 Cutting groove 30 Electrode 32 Recess 50 Protective layer 60 Cutting blade 62 Holding table 64 Cutting jig 80 Heater F1 Direction F2 Direction

Claims (4)

A method for processing a plate-shaped object using a liquid ultraviolet-curable heat-peelable resin composition containing a (meth)acrylate, a photopolymerization initiator, and a foaming agent that expands when heated, comprising :
a supplying step of supplying the liquid ultraviolet-curable heat-removable resin composition onto a surface of a plate-like object on which a recess is to be formed ;
a filling step of filling the concave portion with the liquid ultraviolet-curable heat-peelable resin composition by disposing the plate-like object in a vacuum atmosphere after the supplying step;
a curing step of irradiating the liquid ultraviolet-curable heat-peelable resin composition with ultraviolet light to cure the composition and form a protective layer on the surface of the plate- shaped article;
a cutting step of cutting the plate -shaped object on which the protective layer is formed;
After carrying out the cutting step, the method for processing a plate-shaped article includes a peeling step of heating the ultraviolet-curable heat-peelable resin composition to peel off the protective layer from the plate- shaped article. 2. The method for processing a plate-like object according to claim 1, wherein the foaming agent has an outer shell made of a plastic resin and a low-boiling point hydrocarbon encapsulated in the outer shell. A method for processing a package substrate using a liquid ultraviolet-curable heat-peelable resin composition containing a (meth)acrylate, a photopolymerization initiator, and a foaming agent that expands when heated, comprising the steps of :
the package substrate has a surface on which a plurality of division lines and electrodes crossing the division lines are formed, and recesses opening on the surface and crossing the division lines are formed in the electrodes;
a supplying step of supplying the ultraviolet-curable heat-removable resin composition in liquid form onto the surface of the package substrate;
a filling step of filling the concave portion with the liquid ultraviolet-curable heat-peelable resin composition by disposing the package substrate in a vacuum atmosphere after the supplying step;
a curing step of curing the liquid ultraviolet-curable heat-removable resin composition by irradiating the ultraviolet ray thereto after the filling step;
a cutting step of cutting the package substrate together with the ultraviolet-curable heat-peelable resin composition along the intended division line with a cutting blade after the curing step is performed;
After carrying out the cutting step, a removing step is performed in which the ultraviolet-curable, heat-peelable resin composition is heated to remove the ultraviolet-curable, heat-peelable resin composition from the package substrate. 4. The method for processing a package substrate according to claim 3, wherein the foaming agent has an outer shell made of a plastic resin and a low-boiling-point hydrocarbon encapsulated in the outer shell.