CN1631673A - Fluid ejection device and method of manufacturing the same - Google Patents

Abstract

The invention discloses a fluid ejection device and a manufacturing method thereof. The device includes: the liquid crystal display device comprises a first substrate, a second substrate, a manifold, a fluid cavity and a plurality of jet holes, wherein the first substrate is provided with a first lattice arrangement direction, the second substrate is bonded on the first substrate and is provided with a second lattice arrangement direction, the first lattice arrangement direction is different from the second lattice arrangement direction, the manifold penetrates through the first substrate and the second substrate, the fluid cavity is formed on the second substrate and is communicated with the manifold, and the jet holes are communicated with the fluid cavity. The invention also discloses a manufacturing method of the fluid jet device.

Description

Fluid ejection device and method of manufacturing the same

technical field

The present invention relates to a semiconductor device, in particular to a fluid ejection device and a manufacturing method thereof.

Background technique

In today's silicon wafer process, a strong alkaline solution such as tetramethylammonium hydroxide (TMAH), potassium hydroxide (KOH) or sodium hydroxide (NaOH) is often used as an etching solution in the etching process. This type of solution has different etching performances for different crystal planes of silicon single crystals. Although the etching performance will vary slightly with the type, concentration or etching temperature of the etching solution, generally speaking, there are differences in the etching rates for different crystal surfaces. The characteristic of (111)<(110)<(100), especially the etching rate of (111), is much smaller than that of other crystal planes.

Please refer to FIG. 1 and FIG. 2 to illustrate the etching performance of strong alkaline etchant on wafers with different crystal planes. Fig. 1 shows the etching result to (100) wafer, and it can form an anisotropic etching track that the included angle is 54.7 degree in substrate 10, and then shown in Fig. 2 is the etching result to (111) wafer, It forms an anisotropic etch track in the substrate 10 at a vertical angle.

Therefore, when fabricating a fluid ejection device and performing a backside etching process that penetrates the wafer from the backside to form holes, if a wafer with a crystal plane of (100) is used, it will result in a manifold whose openings on the backside are much larger than the narrow part of the front side, For example, in an inkjet device with only about 200 microns in the narrow part of the manifold, the opening at the back will expand to a width of about 1,100-1,200 microns due to the etching performance. (100) Manifolds will occupy a very large area at the bottom of the wafer, reducing other available areas.

In addition, in the assembly of the inkjet head, there must be enough space on the back of the chip for gluing, so that the ink cartridge and the chip can be tightly combined. Generally speaking, the gluing area reserved on both sides is about 1,200 microns on the left and right. Therefore, together with the backside opening of the above-mentioned manifold, a single wafer must provide at least a space of approximately 3,500-3,600 microns for the fabrication of the fluid ejection device, which considerably reduces the availability of the bottom area of the wafer.

In order to reduce the area occupied by the manifold at the bottom of the wafer, the industry has changed to use the crystal plane (111) wafer as the etching substrate, but although the width of the back opening area can be reduced in due course (due to its vertical angle etching performance), However, the shape of the manifold will be deflected, which will cause the problem that the shape of the fluid chamber is not easy to control, and seriously affect the inkjet effect of the device.

A conventional fluid ejection device can be illustrated with reference to FIG. 3 . This fluid injection device is based on a silicon substrate 10, and a manifold (manifold) 20 is used to transport fluid; a fluid cavity (chamber) 30 is located on both sides of the upper end of the manifold 20 to accommodate the fluid; A nozzle 40 is disposed on the surface of the fluid cavity 30 for the fluid to be sprayed out.

According to the design of the above-mentioned fluid injection device, the manifold 20 is in a shape with a width at the bottom and a narrow top at the top, so that the openings on the back of the manifold 20 occupy a large area of the bottom of the wafer, reducing the efficiency of the wafer area.

Another conventional method for manufacturing a fluid ejection device is as follows, please refer to FIG. 4a and FIG. 4b. As shown in FIG. 4a, a substrate 10, such as a silicon substrate, is provided, and its lattice arrangement direction is (100). A patterned sacrificial layer 20 is formed on the substrate 10 . The sacrificial layer 20 is made of borophosphosilicate glass (BPSG), phosphosilicate glass (PSG) or silicon oxide, wherein phosphosilicate glass is a preferred choice. Next, a patterned structure layer 30 is formed on the substrate 10 and covers the patterned sacrificial layer 20 , the structure layer 30 may be a silicon oxynitride layer formed by chemical vapor deposition (CVD).

Then a patterned resistive layer 40 is formed on the structural layer 30 to be used as an actuator such as a heater. The resistive layer 40 is made of HfB ₂ , TaAl, TaN or TiN. Next, a patterned isolation layer 50 is formed to cover the substrate 10 and the structural layer 30, and a heater contact window 45 is formed. Afterwards, a patterned conductive layer 60 is formed on the structural layer 30 and filled with heater contacts. window 45 to form a signal transmission line 62 . Finally, a protective layer 70 is formed on the isolation layer 50 and the conductive layer 60 , and a signal transmission circuit contact window 75 is formed in the protective layer 70 to expose the conductive layer 60 to facilitate subsequent packaging operations.

Next, referring to FIG. 4b, the back surface of the substrate 10 is etched by a wet etching method, such as potassium hydroxide solution, to form a manifold 80, and the sacrificial layer 20 is exposed, and then etched with a hydrofluoric acid (HF) solution The layer 20 is sacrificed to form a fluid cavity 90 , and finally, the protection layer 70 , the isolation layer 50 and the structure layer 30 are sequentially etched to form an injection hole 95 communicating with the fluid cavity 90 . So far, the fabrication of a fluid ejection device is completed.

Select the wafer whose crystal lattice arrangement direction is (100) to make the manifold 80. Due to the specific lattice arrangement, the structure of the manifold 80 formed in the substrate 10 presents a shape that is wide at the bottom and narrow at the top, while the manifold 80 The wide openings of the structures show that they take up too much wafer floor area.

Contents of the invention

In view of this, the purpose of the present invention is to disclose a fluid ejection device, which can effectively reduce the opening size of the manifold and control the shape of the fluid chamber through the arrangement of the double-layer substrate.

In order to achieve the above object, the present invention provides a fluid ejection device, comprising: a first substrate having a first crystal lattice alignment direction, a second substrate bonded on the first substrate and having a second crystal lattice alignment direction, and the first lattice alignment direction is different from the second lattice alignment direction, a manifold passing through the first substrate and the second substrate, a fluid chamber formed in the second substrate and connected to the second substrate A manifold communicates, as well as a plurality of orifices, communicates with the fluid cavity.

According to the combined design of different crystallographic plane substrates of the present invention, when etching to form the manifold structure, for example, the wafer whose crystallographic plane is (111) and the etching track is at a vertical angle is first encountered, the size of the opening area on the back of the wafer is reduced, and thereafter When etching a wafer with, for example, a crystallographic plane of (100), due to the difference in etching behavior, effective control of the shape of the fluid cavity can then be achieved.

The present invention further provides a method for manufacturing a fluid ejection device, including the following steps: providing a first substrate, the first substrate has a first lattice alignment direction, bonding a second substrate on the first substrate, and the The second substrate has a second lattice alignment direction, and the first lattice alignment direction is different from the second lattice alignment direction. Then a patterned sacrificial layer is formed on the second substrate, and the patterned sacrificial layer is used as a predetermined area for forming at least one fluid cavity.

Then, a patterned structure layer is formed on the second substrate and covers the patterned sacrificial layer. A manifold is formed continuously, passing through the first substrate and the second substrate, and exposing the patterned sacrificial layer. Afterwards, the sacrificial layer is removed to form the fluid cavity, and the fluid cavity is etched to expand the volume of the fluid cavity so that the fluid cavity occupies the second substrate. Finally, the structural layer is etched to form at least one spray hole communicating with the fluid cavity.

Description of drawings

In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, a preferred embodiment is specifically cited below, together with the accompanying drawings, and described in detail as follows, wherein:

Figures 1 to 2 are schematic diagrams of the etching performance of different crystal planes;

3 is a schematic cross-sectional view of the structure of a conventional fluid ejection device;

4a to 4b are schematic cross-sectional views of a conventional fluid ejection device process; and

5a to 5c are schematic cross-sectional views of a fluid ejection device process according to an embodiment of the present invention.

Explanation of reference signs

Existing Parts (Figure 1 to Figure 3)

10~substrate; 20~manifold; 30~fluid cavity; 40~spray hole.

Existing parts (Figure 4a to Figure 4b)

10～substrate; 20～sacrifice layer; 30～structural layer; 40～resistance layer; 45～heater contact window; 50～isolation layer; 60～conductive layer; 62～signal transmission line; 70～protective layer; 75～signal Transmission line contact window; 80~manifold; 90~fluid cavity; 95~spray hole.

Embodiment part of the present invention (Fig. 5a to Fig. 5c)

500～first substrate; 510～second substrate; 520～sacrificial layer; 530～structural layer; 540～resistance layer; 550～isolation layer; 555～heater contact window; 560～conductive layer; 570～protective layer; 580 ~Signal transmission line contact window; 590~manifold; 600~fluid chamber; 610~spray hole.

Detailed ways

Example

Please refer to FIGS. 5 a to 5 b , illustrating an embodiment of the present invention, the fabrication of a fluid ejection device. First, as shown in FIG. 5a, a first substrate 500 and a second substrate 510 are provided, wherein the first substrate 500 is, for example, a silicon substrate with a lattice alignment direction of (111), and the second substrate 510 is, for example, a Silicon substrate, the crystal lattice alignment direction is (100). The thickness ratio of the first substrate 500 to the second substrate 510 is approximately 10:1, the thickness of the first substrate 500 is approximately 500-675 microns, and the thickness of the second substrate 510 is approximately 30-50 microns.

The above-mentioned second substrate 510 is bonded to the first substrate 500. The bonding methods include direct bonding and dielectric bonding. The reaction temperature of the direct bonding is above 1000 degrees Celsius, and the medium in the dielectric bonding is oxide.

Next, as shown in FIG. 5b, a patterned sacrificial layer 520 is formed on a first surface 5001 of the second substrate 510. The sacrificial layer 520 is made of borophosphosilicate glass (BPSG), phosphosilicate glass (PSG) or silicon oxide. The thickness of the sacrificial layer 520 is about 5,000˜20,000 angstroms, wherein phosphosilicate glass is preferred. And as an area predetermined to form at least one fluid chamber.

Then form a patterned structural layer 530 on the second substrate 510, and cover the patterned sacrificial layer 520. The structural layer 530 can be a silicon oxynitride layer formed by chemical vapor deposition (CVD). The thickness of the structural layer 530 is approximately Between 0.5 and 2 microns. In addition, the structural layer 530 is a low-stress material, and its stress value is generally between 50-200 megapascals (MPa).

Next, a patterned resistive layer 540 is formed on the structural layer 530 to serve as a fluid ejection actuator (actuator), such as a heater, so that the fluid is ejected from the subsequent nozzle holes after being driven by the ejection actuator, The resistive layer 540 is made of HfB ₂ , TaAl, TaN or TiN, among which TaAl is a preferred choice.

A patterned isolation layer 550 is then formed to cover the structural layer 530 and a heater contact window 555 is formed. After that, a patterned conductive layer 560 is formed on the isolation layer 550 and filled into the heater contact window 555 to form a signal transmission line. . Finally, a protective layer 570 is formed on the second substrate 510 to cover the isolation layer 550 and the conductive layer 560 , and a signal transmission line contact window 580 is formed in the protective layer 570 to expose the conductive layer 560 for subsequent packaging operations.

Next, referring to FIG. 5c, a series of etching processes are performed to form the final fluid ejection device. First, an anisotropic wet etching method is used to etch the back side of the first substrate 500, that is, a first Two sides 5002 to start forming a manifold 590 structure.

Due to the combination of substrates with different crystallographic planes, when etching to form the manifold 590 structure, it will first encounter the first substrate 500 whose crystallographic plane is (111) and the etching track is at a vertical angle, and the etching performance is more current. In the prior art, the size of the opening area on the back of the first substrate 500 is significantly reduced, and the usable range of the bottom of the first substrate 500 is greatly increased.

Then etch the second substrate 510 whose crystal plane is (100) to complete the manufacture of the complete structure of the manifold 590. After this etching step, the control of the shape of the subsequent fluid cavity 600 is more effective due to the different etching performance from the former. Great help. After the manifold 590 is manufactured, its structure passes through the first substrate 500 and the second substrate 510 and exposes the sacrificial layer 520 .

The width of the narrow opening of the manifold 590 is approximately 90-200 microns, and the width of the rear opening is approximately 150-300 microns. Compared with the conventional rear openings that require at least approximately 1,100-1,200 microns, it is indeed much reduced. Another manifold 590 communicates downwardly with a fluid storage tank.

Then, the sacrificial layer 520 is etched with a wet etching method containing a hydrofluoric acid (HF) solution, and then the sacrificial layer 520 is etched again with an alkaline etching solution such as a potassium hydroxide (KOH) solution to enlarge the sacrificial layer. The area of the layer 520 is hollowed out to form a fluid chamber 600 , and the fluid chamber 600 occupies the space of the second substrate 510 after the volume of the fluid chamber 600 is enlarged by the etching solution.

Finally, the protection layer 570 , the isolation layer 550 and the structure layer 530 are sequentially etched to form the nozzle holes 610 communicating with the fluid chamber 600 , and the fluid chamber 600 communicates with the above-mentioned manifold 590 . The nozzle hole 610 is fabricated by laser or reactive ion bombardment. So far, the fabrication of a fluid ejection device is completed.

If the design of each single row of fluid chambers has a resolution of 300dpi (dot per inch), this embodiment can also increase the injection density to 600-1,200dpi by means of the dislocation arrangement between the rows of fluid chambers, and achieve the unit The effect of jetting the fluid more quickly within a short time, but this technology is not the focus of the present invention, so it will not be repeated here.

The present invention utilizes the bonded double-layer base, on the one hand, improves the problem in the prior art that the opening on the back of the manifold occupies too much base area; The type also makes the fluid cavity fabricated later have a preferred structural shape to stabilize the fluid ejection effect.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Those skilled in the art can make changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection of the present invention The scope is to be determined by the appended claims.

Claims (40)

1. A fluid ejection device comprising: A first substrate having a first lattice alignment direction; a second substrate, bonded to the first substrate, and has a second lattice alignment direction, and the first lattice alignment direction is different from the second lattice alignment direction; a manifold passing through the first base and the second base; a fluid cavity formed in the second base and communicated with the manifold; and A plurality of spray holes communicate with the fluid cavity. 2. The fluid ejection device as claimed in claim 1, wherein the first lattice alignment direction is (111), and the second lattice alignment direction is (100). 3. The fluid ejection device of claim 1, wherein the first substrate is a silicon substrate. 4. The fluid ejection device of claim 1, wherein the second substrate is a silicon substrate. 5. The fluid ejection device of claim 1, wherein a ratio of the first substrate thickness to the second substrate thickness is about 10:1. 6. The fluid ejection device as claimed in claim 1, wherein the thickness of the first substrate is about 500-675 microns. 7. The fluid ejection device as claimed in claim 1, wherein the thickness of the second substrate is about 30-50 microns. 8. The fluid ejection device as claimed in claim 1, wherein the bonding method of the first substrate and the second substrate comprises direct bonding or medium bonding. 9. The fluid ejection device as claimed in claim 8, wherein the dielectric substance in the dielectric bonding method is an oxide. 10. The fluid ejection device as claimed in claim 1, wherein the width of the narrow opening of the manifold is approximately 160-200 microns. 11. The fluid ejection device of claim 1, further comprising at least one fluid ejection actuator located within the fluid chamber. 12. The fluid ejection device as claimed in claim 1, further comprising a structural layer, an isolation layer, a conductive layer, and a protection layer in sequence on the second substrate. 13. The fluid ejection device as claimed in claim 12, wherein the structural layer is made of silicon oxynitride material. 14. The fluid ejection device as claimed in claim 12, wherein the thickness of the structural layer is about 0.5-2 microns. 15. The fluid ejection device of claim 12, wherein the structural layer is formed of a low-stress material. 16. The fluid ejection device as claimed in claim 15, wherein the stress value is about 50-200 MPa. 17. A method of manufacturing a fluid ejection device comprising the steps of: providing a first substrate, the first substrate has a first lattice alignment direction; bonding a second substrate on the first substrate, and the second substrate has a second lattice alignment direction, and the first lattice alignment direction is different from the second lattice alignment direction; forming a patterned sacrificial layer on the second substrate; forming a patterned structure layer on the second substrate and covering the patterned sacrificial layer; forming a manifold, passing through the first substrate and the second substrate, and exposing the patterned sacrificial layer; removing the sacrificial layer to form at least one fluid chamber; etching the fluid cavity to expand the volume of the fluid cavity; and At least one spray hole is formed to pass through the structural layer and communicate with the fluid chamber. 18. The manufacturing method according to claim 17, wherein the first lattice alignment direction is (111), and the second lattice alignment direction is (100). 19. The manufacturing method as claimed in claim 17, wherein the first substrate is a silicon substrate. 20. The manufacturing method as claimed in claim 17, wherein the second substrate is a silicon substrate. 21. The manufacturing method of claim 17, wherein a ratio of the first substrate thickness to the second substrate thickness is about 10:1. 22. The manufacturing method as claimed in claim 17, wherein the thickness of the first substrate is about 500-675 micrometers. 23. The manufacturing method as claimed in claim 17, wherein the thickness of the second substrate is about 30-50 microns. 24. The manufacturing method according to claim 17, wherein the bonding method of the first substrate and the second substrate comprises direct bonding or medium bonding. 25. The manufacturing method as claimed in claim 24, wherein the reaction temperature of the direct bonding method is above 1,000 degrees Celsius. 26. The manufacturing method as claimed in claim 24, wherein the dielectric substance of the dielectric bonding method is an oxide. 27. The manufacturing method as claimed in claim 17, wherein the sacrificial layer is made of borophosphosilicate glass, phosphosilicate glass or silicon oxide. 28. The manufacturing method as claimed in claim 17, wherein the thickness of the sacrificial layer is about 0.5-2 microns. 29. The manufacturing method as claimed in claim 17, wherein the structural layer is made of silicon oxynitride. 30. The manufacturing method as claimed in claim 17, wherein the thickness of the structural layer is about 0.5-2 microns. 31. The manufacturing method of claim 17, wherein the structural layer is made of a low-stress material. 32. The manufacturing method as claimed in claim 31, wherein the stress value is about 50-200 MPa. 33. The manufacturing method as claimed in claim 17, wherein the width of the narrow opening of the manifold is about 90-200 microns. 34. The manufacturing method as claimed in claim 17, wherein the step of forming the manifold utilizes an anisotropic wet etching method. 35. The manufacturing method as claimed in claim 34, wherein the etching solution used in the wet etching method is potassium hydroxide. 36. The manufacturing method as claimed in claim 17, wherein the step of removing the sacrificial layer utilizes a wet etching method. 37. The manufacturing method as claimed in claim 36, wherein the etching solution used in the wet etching method is hydrofluoric acid. 38. The manufacturing method as claimed in claim 17, wherein the step of etching the fluid cavity utilizes a wet etching method. 39. The manufacturing method as claimed in claim 38, wherein the etching solution used in the wet etching method is potassium hydroxide. 40. The manufacturing method as claimed in claim 17, wherein the step of forming the orifice is by laser or reactive ion bombardment.

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