JP2021074953A - Chip manufacturing method for liquid discharge head - Google Patents

Abstract

To prevent breakage of a chip when a substrate having an opening in a surface on a side to which dicing tape for a substrate is stuck is divided into chips.SOLUTION: A chip manufacturing method for a liquid discharge head comprises: a step of preparing a substrate on which a plurality of chips are arranged, the substrate having an ejected energy generation element on a first surface side and having an opening on a second surface side opposite the first surface side; a step of forming a cured part by curing a part of an adhesive layer of dicing tape; a step of sticking the substrate to the dicing tape so that at least the part of the cured part of the adhesive layer comes into contact with the second surface side of the substrate; a step of emitting a laser along a cutting line of the substrate to form a modified part in an interior part along the cutting line of the substrate; and a step of applying stress to the modified part to divide the substrate into individual chips.SELECTED DRAWING: Figure 10

Description

The present invention relates to a method for manufacturing a tip for a liquid discharge head.

For the semiconductor chip mounted on the liquid discharge head, a liquid discharge energy generating part, a liquid flow path, and a liquid discharge port for a plurality of chips are collectively formed on the surface of one silicon substrate, and the liquid discharge port is cut into small pieces. It is generally made in.

As a method for cutting a silicon substrate, there are blade dicing that cuts using a rotary blade and so-called laser stealth dicing that cuts by condensing laser light inside the silicon substrate.

In Patent Document 1, a silicon substrate is attached to an adhesive dicing tape, laser light is condensed inside the silicon substrate to form a deteriorated portion inside the substrate, and then the wafer is cut by applying tensile stress. The technology of the laser stealth dicing method is disclosed. According to this technique, since cutting powder is not generated as compared with blade dicing, contamination of chips can be prevented, and a step of cleaning the contamination of the wafer becomes unnecessary.

Japanese Unexamined Patent Publication No. 2005-268752

As shown in FIG. 15, when there is an opening on the surface of the silicon substrate on the side where the dicing tape is attached, the method of Patent Document 1 causes the following problems. That is, when the dicing tape 60 is attached to the silicon substrate 1, the adhesive layer 62 of the flexible dicing tape bites into the inside of the opening from the edge of the opening, and the biting portion 70 of the adhesive layer is formed. When the adhesive layer of the dicing tape bites into the inside of the opening from the edge of the opening of the silicon substrate in this way, when the dicing tape is expanded and the silicon substrate is cut, stress is applied to the portion 70 where the adhesive layer bites. Concentrate and easily lead to chip breakage.

Therefore, an object of the present invention is a chip for a liquid discharge head, which can suppress damage to the chip when the substrate has an opening on the surface on the side to which the dicing tape of the substrate is attached and is separated into chips. To provide a manufacturing method for.

According to one aspect of the invention
Manufacture of a liquid discharge head chip having a discharge energy generating element for generating energy for discharging a liquid, a liquid flow path for supplying the liquid to the discharge energy generating element, and a discharge port for discharging the liquid. It ’s a method,
A substrate on which a plurality of the chips are arranged, the ejection energy generating element is provided on the first surface side of the substrate, and an opening is formed on the second surface side opposite to the first surface side. The process of preparing the board that has been prepared
The process of curing a part of the adhesive layer of the dicing tape to form a cured part,
A step of attaching the substrate to the dicing tape so that at least a part of the cured portion of the adhesive layer is in contact with the second surface side of the substrate.
A step of irradiating a laser along the planned cutting line of the substrate to form an altered portion inside along the planned cutting line of the substrate.
The process of dividing the substrate into chips by applying stress to the altered portion, and
A method for manufacturing a chip for a liquid discharge head is provided.

According to the present invention, a chip for a liquid discharge head that can suppress damage to the chip when the substrate has an opening on the surface on the side to which the dicing tape of the substrate is attached is divided into chips. A manufacturing method can be provided.

It is a schematic plan view which shows the chip layout of a silicon substrate. It is a schematic cross-sectional view for demonstrating UV irradiation to the dicing tape in Embodiment 1 of this invention. It is a schematic cross-sectional view for demonstrating the silicon substrate in Embodiment 1 of this invention (cross-sectional view along the line BB'in FIG. 1). FIG. 4A is a schematic cross-sectional view for explaining a state in which a substrate is attached to a dicing tape according to the first embodiment of the present invention (FIG. 4A is a cross-sectional view showing a state in which the substrate shown in FIG. 3 is attached to the dicing tape. FIG. 4 (b) is an enlarged view of the stepped portion). It is a schematic cross-sectional view for demonstrating the stealth laser irradiation in Embodiment 1 of this invention. It is a schematic cross-sectional view for demonstrating division of a substrate in Embodiment 1 of this invention. It is a schematic plan view for demonstrating the UV irradiation region (the cured part of an adhesive layer) in Embodiment 2 of this invention. It is a schematic plan view for demonstrating the UV irradiation region (the cured part of an adhesive layer) in Embodiment 3 of this invention. It is a schematic cross-sectional view for demonstrating the substrate in Embodiment 3 of this invention (the figure which shows the cross section of the substrate 1 along the CC'line of FIG. 8). It is a schematic cross-sectional view for demonstrating the UV irradiation region (the cured part of the adhesive layer) in Embodiment 3 of this invention (cross-sectional view along the CC'line of FIG. 8). It is a schematic plan view for demonstrating another form of the UV irradiation region (the cured part of an adhesive layer) in Embodiment 3 of this invention. It is a schematic cross-sectional view for demonstrating another form of the UV irradiation region (the cured part of an adhesive layer) in Embodiment 3 of this invention. It is a schematic diagram which shows the state in which the dicing tape is attached to the ring frame (FIG. 13 (a) is a schematic plan view, and FIG. 13 (b) is a schematic cross-sectional view along the line EE'). It is a schematic diagram which shows the state which attached the silicon substrate to the dicing tape (FIG. 14A is a schematic plan view, FIG. 14B is a schematic cross-sectional view along the FF'line). FIG. 15 (a) is a schematic cross-sectional view for explaining a problem in the prior art (FIG. 15 (a) is a schematic cross-sectional view showing a state in which a silicon substrate is attached to a dicing tape, and FIG. 15 (b) is an enlarged view of a step portion).

In the manufacturing method according to the embodiment of the present invention, a plurality of chips (recording elements for a liquid discharge head) having a discharge energy generating element, a liquid flow path, and a discharge port on the front surface side and an opening on the back surface side are arranged. Prepare a silicon substrate, divide it, and separate it into individual chips. When dividing the silicon substrate, the silicon substrate can be divided by sticking the silicon substrate on a dicing tape, then irradiating a laser along the planned cutting line and applying stress. Examples of the opening of the silicon substrate include a supply port for supplying a liquid flowing through a liquid flow path, a groove formed corresponding to a planned cutting line, and the like.
In the present embodiment, at least a part of the adhesive layer of the dicing tape in contact with the silicon substrate is cured to form a cured portion. By forming this cured portion, when the silicon substrate is attached to the dicing tape, the adhesive layer of the dicing tape is less likely to bite into the recessed portion or the convex portion formed by the opening or the like on the back surface of the silicon substrate. That is, it becomes difficult for the adhesive layer to bite into the inside of the opening from the edge of the opening on the back surface. Therefore, when the silicon substrate is cut, stress is less likely to be concentrated on the stepped portion (edge portion of the opening), and damage to the chip can be prevented.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1 shows a silicon substrate 1 in which a plurality of liquid discharge head chips 2 are laid out. By cutting the silicon substrate 1 along the planned cutting line 8, the silicon substrate 1 is divided into a chip 2 for each liquid discharge head and an outer peripheral region 17 in which the chip is not arranged.

FIG. 3 shows a cross-sectional view of the silicon substrate 1 shown in FIG. 1 along the line BB'.
In the liquid discharge head chip 2, the liquid discharge energy generating element 24 and the metal wiring 25 are formed on the first surface (hereinafter referred to as “surface”) of the silicon substrate 1. Further, on the surface of the silicon substrate 1, an ink flow path and an ink ejection port 22 are formed by an ink flow path forming member 23.

An ink supply port 28 for supplying ink is formed on a second surface (hereinafter, referred to as “back surface”) opposite to the first surface (front surface) of the silicon substrate 1. The ink supply port 28 penetrates to the surface side of the silicon substrate 1.

In the examples of this embodiment, a silicon substrate 1 having a thickness of 625 μm was used. The opening width of the ink supply port 28 was set to 150 μm.

Next, a step of dividing (cutting) the silicon substrate 1 to obtain individualized liquid discharge head chips will be described.
First, as shown in FIG. 13, the dicing tape 60 is attached to the ring frame 91. In the embodiment of the present embodiment, the dicing tape 60 has a two-layer structure consisting of a polyolefin base material and a layer (adhesive layer) made of a UV-curable (ultraviolet-curable) acrylic resin adhesive material. .. The thickness of the base material and the adhesive layer are 80 μm and 5 μm, respectively.

Of the area of the dicing tape 60, the portion that comes into contact with the outer peripheral area 17 (the area where the chip 2 is not arranged) of the silicon substrate 1 when the silicon substrate 1 is attached is selectively irradiated with UV, and the dicing tape is taped. The adhesive layer of was cured.

FIG. 2 shows a state of UV irradiation on a portion of the dicing tape 60 to be attached to the AA'line portion of the substrate 1 shown in FIG. Here, the dicing tape 60 has a base material 61 and an adhesive layer 62. By partially blocking the UV light (ultraviolet light) 81 using the mask 80, the region where the chip 2 is arranged is not irradiated with the UV light 81. On the other hand, the outer peripheral region 17 on which the chip 2 is not arranged is irradiated with UV light 81. As a result, the adhesive layer is cured for the portion to be attached to the outer peripheral region 17, and the cured portion 65 is formed. In this example, since the base material 61 is a polyolefin that transmits UV light, the UV light 81 was irradiated from the base material side. When the base material is a material that does not transmit UV light or has a low transmittance, UV light may be irradiated from the adhesive layer 62 side.
In the examples of this embodiment, the UV irradiation conditions were an illuminance of 15 mW / cm ² and an irradiation time of 120 sec.

Next, the portion 65 on which the adhesive layer 62 of the dicing tape 60 is cured and the outer peripheral region 17 of the silicon substrate 1 are aligned so as to correspond to each other, and the back side of the silicon substrate 1 is on the adhesive layer 62 side of the dicing tape 60. The surface was pasted (Fig. 14).

FIG. 4 shows a state when the dicing tape 60 is attached to the silicon substrate 1.
As shown in FIG. 4A, the outer peripheral region 17 of the silicon substrate 1 faces the portion 65 where the adhesive layer of the dicing tape 60 is cured. When the dicing tape 60 is attached to the silicon substrate 1, the shape of the cured portion 65 of the adhesive layer is less likely to change depending on its hardness, and the thickness of the adhesive layer is also less likely to change. When the thickness of the adhesive layer corresponding to the outer peripheral region 17 of the substrate 1 does not change, this portion acts as a beam, and the change in the thickness of the adhesive layer can be suppressed even in the portion of the uncured adhesive layer 62. it can. Therefore, as shown in the enlarged view of FIG. 4B, the adhesive layer 62 bites into the step portion generated by the ink supply port 28 formed on the back surface of the chip 2 (from the edge portion of the ink supply port). It is possible to suppress (biting into the inside of the ink supply port).

Next, as shown in FIG. 5, the laser 85 was irradiated from the surface side of the silicon substrate 1 along the planned cutting line 8, and the altered portion 87 was formed inside the silicon substrate 1 by the laser stealth dicing method. The altered portion 87 refers to a portion where a single crystal silicon substrate is polycrystallized by irradiating a laser.
In the embodiment of the present embodiment, by scanning 10 times while changing the laser irradiation depth inside the silicon substrate, 6 steps of altered portions 87 were formed in the height direction (thickness direction of the substrate 1).

Next, as shown in FIG. 6, the dicing tape 60 is expanded in the direction of the arrow in the drawing, and stress is applied to the altered portion 87 to generate a crack between the altered portions 87 to divide the silicon substrate and discharge the liquid. A head chip 2 was obtained.

According to this embodiment, it is possible to prevent the adhesive layer 62 of the dicing tape from biting into the stepped portion on the back surface of the silicon substrate 1. Therefore, when the dicing tape 60 is expanded, stress is not concentrated in the vicinity of the stepped portion, and the expanding force is efficiently used to generate cracks between the altered portions 87 in the substrate. As a result, the substrate is not damaged, the substrate is divided along the planned cutting line 8, and the chips can be separated into individual pieces.

In the present embodiment, a dicing tape having an adhesive layer made of an adhesive material of a UV curable acrylic resin is used, but the present invention is not limited to this, and any region of the adhesive layer can be partially cured. Just do it. For example, a dicing tape having an adhesive layer made of an adhesive material of a thermosetting resin may be used. In that case, heat may be applied to the dicing tape using a laser or the like to cure a necessary portion.

(Embodiment 2)
FIG. 7 corresponds to an enlarged view of the D portion of the substrate 1 shown in FIG. 1 and shows the back surface of the substrate to which the dicing tape is attached. As shown in FIG. 7, ink supply ports 28 are formed on the back surface of the substrate 1 on both sides of the planned cutting line 8. In addition, this figure also shows the UV irradiation region (cured portion 65 of the adhesive layer) of the dicing tape.

In the first embodiment described above, the adhesive layer of the dicing tape was cured only in the portion corresponding to the outer peripheral region 17 of the silicon substrate 1. On the other hand, in the present embodiment, the cured portion 65 is formed in the entire region of the adhesive layer in contact with the silicon substrate. The cured portion 65 is a region where the adhesive layer is cured in a dot pattern. Not limited to the dot pattern, it is possible to form a cured region with a regular pattern.
As an example of this embodiment, as shown in FIG. 7, UV irradiation was performed so as to form a cured portion 65D having a regular dot pattern to cure the adhesive layer. The shape of the cured portion 65D was a circular shape having a diameter of 50 μm, and the cured portion 65D was arranged at a pitch of 100 μm.

According to this embodiment, the hardened portion 65D of the dot pattern acts as a beam, and even if the silicon substrate 1 is attached to the dicing tape 60, the adhesive layer of the dicing tape bites into the step by the ink supply port 28 (ink). It is possible to suppress the dicing from the edge of the supply port into the inside of the ink supply port). As a result, the substrate is not damaged, the substrate is divided along the planned cutting line 8, and the chips can be separated into individual pieces.

In the above-described first embodiment, it is necessary to align the cured portion 65 of the adhesive layer with the outer peripheral region 17 of the silicon substrate 1. On the other hand, in the present embodiment in which the cured portions 65 are regularly arranged as the cured portions 65D of the dot pattern, the silicon substrate 1 can be attached to the dicing tape 60 without any particular alignment. ..

If the dicing tape is expanded while the area in which the dicing tape and the silicon substrate are in close contact with each other is small, it may be difficult for the force due to the expansion to be uniformly transmitted to each planned cutting line, and the splittability may decrease. The cured portion of the adhesive layer of the dicing tape has low adhesion to the silicon substrate. Therefore, if the area of the cured portion of the adhesive layer is large, the area in which the dicing tape and the silicon substrate are sufficiently adhered to each other becomes small, and the splittability of the silicon substrate due to the expansion of the dicing tape may decrease. Although it depends on the chip layout in the silicon substrate, in general, in order to obtain good breakability, the area of the adhesive layer between the silicon substrate and the dicing tape should be 60% or more of the chip area of each chip. It is preferable that the non-cured portion is in close contact with the non-cured portion.

In the embodiment of the present embodiment, the UV irradiation region (the cured portion of the dot pattern 65D) is such that the silicon substrate 1 and the non-cured portion of the adhesive layer of the dicing tape 60 are in close contact with each other in an area of about 80% of the chip area. ) Shape and layout were set. Embodiments of the present invention are not limited to the shape and layout of the UV irradiation region of this example.

In the present embodiment, the area of the UV non-irradiated region in the adhesive layer corresponding to each chip is preferably 60% or more, more preferably 70% or more, based on the chip area. That is, of the contact area between the adhesive layer of the dicing tape and each chip of the silicon substrate, the area ratio of the portion where the adhesive layer is cured is preferably less than 40%, more preferably less than 30%. This area ratio is preferably 5% or more, more preferably 10% or more, still more preferably 15% or more, from the viewpoint of more sufficiently suppressing the biting of the adhesive layer at the step portion.

The shape of the UV irradiation region and the shape of the portion where the adhesive layer corresponding to the UV irradiation region is cured are not limited to a circular shape, but may be a quadrangular shape, a triangular shape, a lattice shape, or the like.

(Embodiment 3)
This embodiment will be described with reference to FIGS. 8 to 12.
FIG. 8 corresponds to an enlarged view of the D portion of the substrate 1 shown in FIG. 1, and shows the back surface of the substrate after the dicing tape is attached. As shown in FIG. 8, ink supply ports 28 are formed on the back surface of the substrate 1 on both sides of the planned cutting line 8. In addition, this figure also shows the UV irradiation region (cured portion 65 of the adhesive layer) of the dicing tape.
FIG. 9 shows a cross section of the substrate 1 (before applying the dicing tape) along the CC'line of FIG. In the present embodiment, in order to reduce the cutting thickness by laser stealth dicing, a groove 82 is formed from the back surface of the silicon substrate 1 along the planned cutting line 8.
FIG. 10 is a cross-sectional view taken along the line CC'of FIG.

As shown in FIGS. 8 and 10, in the present embodiment, all the stepped portions (the edge portion of the ink supply port 28 and the edge portion of the groove 82) formed by the ink supply port 28 and the groove 82 are dicing tapes. It is covered with a line-shaped hardened portion 65L of the adhesive layer of. This configuration was obtained by irradiating the dicing tape with UV light so that the cured portion 65L faces the ink supply port 28 and the groove 82 of the substrate 1 and covers the stepped portion.

In this configuration, since all the stepped portions on the back surface of the silicon substrate 1 face the hardened portion of the adhesive layer, not only the effect of the beam due to the hardened portion in contact with the back surface portion of the substrate other than the stepped portion, but also the adhesiveness that is hardened. The layer itself is less likely to bite into the step.

When the contact area between the back surface of the silicon substrate and the non-cured portion of the adhesive layer of the dicing tape cannot be sufficiently secured, it is not necessary to cure the adhesive layer portion corresponding to all the stepped portions on the back surface of the silicon substrate. For example, the adhesive layer portion of the dicing tape facing only the specific step portion may be cured by focusing on the portion of the step portion where the chip is easily damaged.

Specifically, for example, in the substrate shown in FIG. 9, when chip damage is particularly likely to occur in the vicinity of the ink supply port 28, the form shown in FIGS. 11 and 12 can be used. FIG. 11 is the same schematic plan view as in FIG. 8 except that the formation position of the cured portion 65 of the adhesive layer is different. FIG. 12 is a partial cross-sectional view of the form shown in FIG. 11, which is the same schematic cross-sectional view as that of FIG. 10 except that the arrangement of the cured portion 65 of the adhesive layer is different.

Unlike the forms shown in FIGS. 11 and 12, the adhesive layer portion corresponding to the step portion formed by the groove 82 is not cured, and only the adhesive layer portion corresponding to the step portion formed by the ink supply port 28 is formed. It is cured. As shown in FIG. 12, the cured portion 65 of the adhesive layer faces the stepped portion of the ink supply port 28, and the portion of the adhesive layer facing the stepped portion of the groove 82 is not cured. In such a configuration, as shown in FIGS. 11 and 12, only the portion of the adhesive layer 62 of the dicing tape corresponding to the step portion formed by the ink supply port 28 is irradiated with UV light to form the adhesive layer. It can be formed by curing.

1 Silicon substrate 2 Liquid ejection head chip 8 Scheduled cutting line 17 Outer peripheral area 22 Ink ejection port 23 Ink flow path forming member 24 Liquid ejection energy generating element 25 Metal wiring 28 Ink supply port 60 Dicing tape 61 Dicing tape base material 62 Dicing Adhesive layer of tape 65, 65D, 65L Hardened part of adhesive layer of dicing tape 70 Biting part of adhesive layer of dicing tape 80 Mask 81 UV light 82 Groove 85 Laser 87 Altered part 91 Ring frame

Claims (10)

Manufacture of a liquid discharge head chip having a discharge energy generating element for generating energy for discharging a liquid, a liquid flow path for supplying the liquid to the discharge energy generating element, and a discharge port for discharging the liquid. It ’s a method,
A substrate on which a plurality of the chips are arranged, the ejection energy generating element is provided on the first surface side of the substrate, and an opening is formed on the second surface side opposite to the first surface side. The process of preparing the board that has been prepared
The process of curing a part of the adhesive layer of the dicing tape to form a cured part,
A step of attaching the substrate to the dicing tape so that at least a part of the cured portion of the adhesive layer is in contact with the second surface side of the substrate.
A step of irradiating a laser along the planned cutting line of the substrate to form an altered portion inside along the planned cutting line of the substrate.
The process of dividing the substrate into chips by applying stress to the altered portion, and
A method for manufacturing a tip for a liquid discharge head, including. The tip for a liquid discharge head according to claim 1, wherein when the substrate is attached to the dicing tape, the cured portion of the adhesive layer of the dicing tape comes into contact with at least a part of the edge of the opening of the substrate. Production method. The chip has the opening and
The method for manufacturing a chip for a liquid discharge head according to claim 1, wherein when the substrate is attached to the dicing tape, the cured portion of the adhesive layer of the dicing tape comes into contact with at least the edge of the opening of each chip. The aspect according to any one of claims 1 to 3, wherein the area ratio of the portion where the adhesive layer is cured is less than 40% in the contact area between the adhesive layer of the dicing tape and each chip of the substrate. A method for manufacturing a tip for a liquid discharge head. The cured portion of the adhesive layer of the dicing tape is formed in a region corresponding to an outer peripheral region of the substrate on which the chip is not arranged.
The method for manufacturing a chip for a liquid discharge head according to claim 1, wherein when the substrate is attached to the dicing tape, the cured portion contacts only the outer peripheral region of the substrate. The method for manufacturing a chip for a liquid discharge head according to any one of claims 1 to 5, wherein the cured portion of the adhesive layer of the dicing tape is arranged in a regular pattern. The method for manufacturing a chip for a liquid discharge head according to claim 6, wherein the cured portion is arranged in the entire region of the adhesive layer in contact with the substrate. The method for manufacturing a chip for a liquid discharge head according to claim 6 or 7, wherein the cured portion of the adhesive layer of the dicing tape is a region where the adhesive layer is cured in a dot pattern. The method according to any one of claims 1 to 8, wherein the adhesive layer of the dicing tape is made of an ultraviolet curable resin, and a part of the adhesive layer is cured by irradiating with ultraviolet light to form a cured portion. A method for manufacturing a tip for a liquid discharge head. The method for manufacturing a chip for a liquid discharge head according to any one of claims 1 to 9, wherein the substrate is a silicon substrate.

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