TWI782755B - Manufacturing method of inkjet head chip - Google Patents

Abstract

A manufacturing method of inkjet head chip includes: 1. Providing an inkjet head wafer, wherein a first surface of the inkjet head wafer includes at least one polymer thick film; 2. Providing a polymer thin film, wherein a second surface of the polymer thin film is coated with an adhesive accelerant; 3. Rolling and pressing the polymer thin film on the polymer thick film of the inkjet head wafer in a wafer-to-wafer method; 4. Spin coating a silicone photoresist on a third surface of the polymer thin film, seeing through the silicone photoresist and the polymer thin film, and performing mask alignment on the inkjet head wafer; 5. Exposing and developing the silicone photoresist; and 6. etching the polymer thin film to form a plurality of orifice sheets and at least one protective rib.

Description

Manufacturing method of inkjet head chip

This case is about the manufacturing method of inkjet head chips, especially a manufacturing method that integrates the advantages of high productivity at the wafer level and high yield at the grain level, and is reworkable to reduce loss.

The traditional inkjet head chip is manufactured using a grain-level manufacturing method, with a single inkjet head chip and a single orifice plate for alignment bonding. Although this method has a high yield rate, it is quite time-consuming.

With the development of the inkjet head process technology, high-capacity wafer-level manufacturing methods have been derived, such as the bonding of the inkjet head wafer and the orifice sheet wafer, and the direct definition of the orifice sheet on the inkjet head wafer, etc. . However, the technical threshold for such large-scale manufacturing is high, especially prone to thermal stress (Thermal Stress) and bubbles (Void) and other poor-bond problems. Shear stress, uneven pressure and deformation cause alignment shift (Alignment Shift). Furthermore, it is difficult to rework after the thermal process, often resulting in loss due to poor yield.

This case mainly provides a manufacturing method for inkjet head chips, which integrates the advantages of high productivity at the wafer level and high yield at the die level, without the need for a wafer-level bonding machine, so the manufacturing process is simple, and it is reworkable, which can further reduce loss.

In order to achieve the above object, one embodiment of the present case is to provide a method of manufacturing an inkjet head wafer, comprising: 1. providing an inkjet head wafer, one of the first surfaces of the inkjet head wafer has at least one high Molecular thick film; 2. A polymer film is provided, and a second surface of the polymer film is coated with an adhesion promoter; 3. The polymer film is rolled on the inkjet head wafer in a wafer-to-wafer manner 4. Spin-coat a siloxane photoresist on one of the third surfaces of the polymer film, see through the siloxane photoresist and the polymer film, and check the inkjet head crystal 5. Exposing and developing the siloxane photoresist; 6. Performing wafer-level etching on the polymer film to form a plurality of orifice sheets and at least one protective rib; 7. Removing Protective ribs; 8. Cut the inkjet head wafer to form a plurality of independent inkjet head grains with these orifice sheets; 9. Carry out hot pressing or high temperature baking on these inkjet head grains, By cross-linking the bonding promoter of the second surface of the orifice sheets with the polymer thick film of the inkjet head grains, a strong bond is formed; 10. removing the siloxane photoresist, wherein The polymer thick film of the ink-jet head crystal grains is baked at high temperature to strengthen internal polymer polymerization, and will not be corroded by the photoresist solution.

The implementation aspects embodying the features and advantages of this case will be described in detail in the description of the latter paragraph. It should be understood that the present case can have various changes in different aspects without departing from the scope of the present case, and the descriptions and diagrams therein are used for illustration in nature rather than limiting the present case.

Please refer to FIG. 1, a method of manufacturing an inkjet head wafer, comprising: 1. providing an inkjet head wafer 10, at least one polymer thick film 11 on a first surface 101 of the inkjet head wafer 10 2. A polymer film 20 is provided, and a second surface 201 of the polymer film 20 is coated with an Adhesion Promoter (Adhesion Promoter) 21; 3. The polymer film 20 is rolled on the wafer in a wafer-to-wafer manner On the polymer thick film 11 of the inkjet head wafer 10; 4. spin-coat a siloxane (Siloxane) photoresist 22 on a third surface 202 of the polymer film 20, see through the siloxane The photoresist 22 and the polymer film 20 are aligned to the inkjet head wafer 10; 5. The siloxane photoresist 22 is exposed and developed; 6. The polymer film 20 is wafer Level etching, forming a plurality of orifice sheets 30 and at least one protective rib 31; 7. removing the protective rib 31; 8. cutting the inkjet head wafer 10 to form a plurality of independent orifice sheets 30 9. Carry out hot pressing or high-temperature baking to these inkjet head crystal grains 4, through the bonding promoter 21 of the second surface 201 of the orifice sheet 30 and the The polymer thick film 11 of the inkjet head grain 4 produces cross-linking (Cross-link) to form a strong bond; 10. Remove the siloxane photoresist 22, wherein the polymer of the inkjet head grain 4 After the thick film 11 is baked at a high temperature, the internal polymer polymerization is strengthened, so that it will not be corroded by the photoresist stripper.

Please refer to FIG. 2A in conjunction with it. In the embodiment of this case, step 1 is to provide an inkjet head wafer 10 , and there is at least one polymer thick film 11 on the first surface 101 of the inkjet head wafer 10 . It should be noted that the size of the inkjet head wafer 10 is one of 6 inches, 8 inches or 12 inches, but not limited thereto, and the size of the inkjet head wafer 10 can be adjusted according to actual needs. It is worth noting that the inkjet head wafer 10 has a plurality of heating plates 12, a plurality of electrodes 13, a plurality of test keys 14, a plurality of ink supply holes 15 and at least one polymer thick film 11, the polymer thick film 11 It includes a plurality of thick film channels 16 and a plurality of thick film pads 17 . It should be noted that the material of the polymer thick film 11 can be Epoxy, such as SU-8, but not limited thereto, and the material of the polymer thick film 11 can be adjusted according to actual needs.

Next, step 2 is to provide the polymer film 20 , and the second surface 201 of the polymer film 20 is coated with the adhesion promoter 21 . It should be noted that the material of the polymer film 20 can be polyimide (Polyimide, PI), but not limited thereto, and the material of the polymer film 20 can be adjusted according to actual needs. It should be noted that the thickness of the polymer film 20 is one of 12.5 μm, 25 μm or 50 μm, but not limited thereto, and the thickness of the polymer film 20 can be adjusted according to actual needs. It should be noted that the application range of the accelerant 21 can be only the second surface 201 of the polymer film 20 or the entire surface of the polymer film 20 , and the application area of the accelerant 21 can be adjusted according to the process requirements. It is worth noting that the accelerant 21 is a medium for tightly bonding the polymer film 20 and the polymer thick film 11 of the inkjet head wafer 10 , and its thickness is very thin, so it will not affect the overall structure.

Please refer to FIG. 2B together. In the implementation of this case, step 3 is to roll the polymer film 20 on the polymer thick film 11 of the inkjet head wafer 10 in a wafer-to-wafer manner (including a plurality of thick films. flow channel 16 and a plurality of thick film pads 17). It is worth noting that the polymer film 20 has good rigidity, and it will not collapse and sag even when the ink supply hole 15 of the inkjet head wafer 10 is suspended.

Please refer to FIG. 2C together. In the implementation of this case, step 4 is to spin-coat the silicone photoresist 22 on the third surface 202 of the polymer film 20, and see through the silicone photoresist 22 and the polymer film 20. , performing photomask alignment on the inkjet head wafer 10 . It is worth noting that the siloxane photoresist 22 has good affinity to both organic and inorganic substances, and can be well attached to the polymer film 20. In addition, both the siloxane photoresist 22 and the polymer film 20 can see through, and are easy to mask counterpoint.

Please refer to FIG. 2D together. In the embodiment of this case, step 5 is to expose and develop the siloxane photoresist 22 . It is worth noting that, due to the poor heat dissipation in the floating part of the inkjet head wafer 10, the plasma bombardment is likely to be intensified, so only one layer of siloxane photoresist 22 is occasionally insufficient in blocking ability. Please refer to FIG. 2E. In another embodiment of this case, a thickened layer 23 is added on the siloxane photoresist 22 to enhance the etching resistance. The material of the thickened layer 23 is siloxane photoresist , aluminum oxide (Al ₂ O ₃ ), aluminum (Al), titanium (Ti) or silicon dioxide (SiO ₂ ), but not limited thereto, the material of the thickening layer 23 can be adjusted according to actual needs .

Please refer to FIG. 2F and FIG. 2I together. In the embodiment of this case, step 6 is to perform wafer-level etching on the polymer film 20 to form a plurality of orifice plates 30 and at least one protective rib 31 . It should be noted that the polymer film 20 is etched by anisotropic inductively coupled plasma (ICP), and the etching gas contains oxygen (O ₂ ), carbon tetrafluoride (CF ₄ ) and sulfur hexafluoride (SF ₆ ). etc., but not limited thereto, the gas type, gas flow rate, process chamber pressure, temperature, and time during etching can be adjusted according to the process requirements.

Please refer to FIG. 2G together. In the implementation of this case, it is also included that when the polymer film 20 is etched by anisotropic inductively coupled plasma (ICP), by changing the chamber pressure and temperature of the etching process, the etching process can be increased. The bottom of the polymer film 20 is laterally etched to produce a taper angle of 2°-4°. And at the same time, only pure O ₂ plasma is used for etching, which also reduces the risk of over etching by fluorine ions on the surface coating of the heating plate 12 , such as tantalum (Ta). In addition, the electrodes 13 and the thick film pads 17 of the inkjet head wafer 10 are covered and protected by the polymer film 20 to avoid etching damage and reduce the adhesion of etching residues.

Please refer to FIG. 2H and FIG. 2I together. In the embodiment of this case, step 7 is to remove the protective rib 31 to expose the electrode 13 . It is worth noting that the contact surface between the polymer film 20 and the thick film spacer 17 of the inkjet head wafer 10 is extremely small, so the thick film spacer 17 will not be damaged when the protection rib 31 is removed, especially the protection rib 31 can be connected in series Together, they can be torn off in one go without any tools. The schematic diagram after removing the protective rib 31 is shown in FIG. 2J.

Please refer to FIG. 2J and FIG. 2I together. In the embodiment of this case, step 8 is to cut the inkjet head wafer 10 to form a plurality of independent inkjet head dies 4 with orifice holes 30 . Then, the orifice plate 30 of each inkjet head chip 4 is inspected.

Please refer to FIG. 2K. In the implementation of this case, step 9 is to heat-press or bake the inkjet head grain 4 at a high temperature. The polymer thick film 11 of the ink head grain 4 is cross-linked, and can be closely bonded without an additional glue layer. It is worth noting that in this case, after cutting into independent inkjet head grains 4, bonding is carried out, which is less likely to cause thermal stress (Thermal Stress) and air bubbles (Void) and other poor-bond problems, and is also free from polymer The alignment shift (Alignment Shift) caused by the shear stress or uneven pressure and deformation of the polymer during the wafer-level bonding process. It is worth noting that in this case, the orifice sheet 30 of each inkjet head grain 4 is inspected before the thermal process, so the orifice sheet 30 with abnormal inspection can still be peeled off, and the inkjet head grain 4 can be recovered and reused. It is aligned with another single orifice plate 30 by conventional grain-level manufacturing method, and finally hot-pressed or high-temperature baked to complete the connection. Such process design is reworkable, which can further reduce loss.

Please refer to FIG. 2L. In the implementation of this case, step 10 is to remove the siloxane photoresist 22, wherein the polymer thick film 11 of the inkjet head grain 4 is baked at a high temperature to strengthen the internal polymer polymerization. Will be attacked by photoresist stripper.

Please refer to FIG. 2M and FIG. 2N together. In the embodiment of the present case, the inkjet head die 4 is bonded by inner lead bonding (ILB). It is worth noting that the electrode layout generally has two forms: the short side of the inkjet head die 4 and the long side of the inkjet head die 4. There are often test keys 14 on the outside, and the test key 14 is mainly used for monitoring In the wafer manufacturing process, it is inevitable that there will be metal exposure (such as the electrode of the test key 14 ), so the addition of the thick film spacer 17 can effectively prevent the short circuit of the ILB wire.

To sum up, this project provides a manufacturing method for inkjet head chips, which integrates the advantages of high productivity at the wafer level and high yield at the grain level, and does not require the use of a wafer-level bonder, so the manufacturing process is simple. Reduce loss.

This case can be modified in various ways by people who are familiar with this technology, but it does not deviate from the intended protection of the scope of the attached patent application.

10: Inkjet head wafer 11: Polymer thick film 12: Heating plate 13: Electrode 14: Test key 15: ink supply hole 16: thick film runner 17: thick film spacer 101: First Surface 20: polymer film 21: followed by accelerator 22: Silicone photoresist 23: thickened layer 201: second surface 202: The third surface 30: Orifice sheet 31: Protective rib 4: Inkjet head grain S1~S10: Steps of the manufacturing method of wafer-level inkjet head chip

Fig. 1 is a schematic diagram of the steps of a manufacturing method of an inkjet head chip. FIG. 2A to FIG. 2N are process schematic diagrams of a manufacturing method of an inkjet head chip.

S1~S10: the steps of the manufacturing method of the inkjet head chip

Claims (11)

A method of manufacturing an inkjet head wafer, comprising: 1. providing an inkjet head wafer, having at least one polymer thick film on a first surface of the inkjet head wafer; 2. providing a polymer film, the A second surface of the polymer film is coated with an adhesion accelerator; 3. The polymer film is rolled on the at least one polymer thick film of the inkjet head wafer in a wafer-to-wafer manner; 4. Spin-coat a siloxane photoresist on one of the third surfaces of the polymer film, see through the siloxane photoresist and the polymer film, and perform photomask alignment on the inkjet head wafer; 5. Exposing and developing the siloxane photoresist, adding a thickened layer on the siloxane photoresist to enhance the etching barrier capability; and 6. performing wafer-level etching on the polymer film to form a plurality of orifice sheets and at least one protective rib. The manufacturing method of the inkjet head wafer as described in Claim 1, wherein the size of the inkjet head wafer is 6 inches, 8 inches or 12 inches. The manufacturing method of the inkjet head wafer as described in Claim 1, wherein the inkjet head wafer has a plurality of heating plates, a plurality of electrodes, a plurality of test keys, a plurality of ink supply holes and the at least one polymer thick film , and the at least one polymer thick film includes a plurality of thick film channels and a plurality of thick film pads. The method of manufacturing an inkjet head chip according to claim 1, wherein the thickness of the polymer film is 12.5 μm, 25 μm or 50 μm. The method for manufacturing an inkjet head chip as claimed in claim 1, wherein the thickened layer material is one of siloxane photoresist, aluminum oxide, aluminum, titanium, or silicon dioxide. The method for manufacturing an inkjet head chip as described in claim 1, wherein the polymer film in step 6 is etched by anisotropic inductively coupled plasma, and the etching gas includes oxygen, carbon tetrafluoride, and sulfur hexafluoride, etc. . The manufacturing method of the inkjet head chip as described in claim 1, wherein step 6 further includes when performing anisotropic inductively coupled plasma etching on the polymer film, by changing the chamber pressure and temperature of the etching process, increasing the The bottom of the polymer film is laterally etched to produce a 2°~4° cone angle. The manufacturing method of the inkjet head wafer as described in claim 1, further comprising: 7. removing the at least one protective rib; 8. dicing the inkjet head wafer to form independent sheets having the orifices A plurality of ink-jet head crystal grains; 9. Carry out hot pressing or high-temperature baking to these ink-jet head grains, through the bonding accelerator on the second surface of the orifice sheets and the ink-jet head crystal grains The at least one polymer thick film of the grains is cross-linked to form a strong bond; and 10. removing the siloxane photoresist, wherein the at least one polymer thick film of the inkjet head grains is strengthened after high temperature baking The internal polymer is polymerized and will not be corroded by the photoresist stripper. The manufacturing method of the inkjet head wafer as described in Claim 8, wherein the bonding is carried out after cutting the inkjet head chips. In the manufacturing method of the inkjet head chip as described in claim 8, step 8 further includes the orifice sheets of the inkjet head crystal grains. If the inspection is abnormal, the orifice sheets can be peeled off, and the inkjet head chips The head die is reworked with another orifice sheet in a die-to-die manner. In the method for manufacturing an inkjet head chip as claimed in claim 8, step 10 further includes performing internal lead bonding on the inkjet head chips.

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