CN114823351A - Metal bump structure and its manufacturing method and driving substrate - Google Patents

Abstract

The invention provides a metal bump structure, a manufacturing method thereof and a driving substrate. The manufacturing method of the metal bump structure comprises the following steps. A drive substrate is provided. At least one pad and an insulating layer are formed on the driving substrate. The pad is formed on the configuration surface of the driving substrate and has an upper surface. The insulating layer covers the configuration surface of the driving substrate and the connecting pad and exposes part of the upper surface of the connecting pad. And forming a patterned metal layer on the upper surface of the pad exposed by the insulating layer and extending to cover part of the insulating layer. And performing a chemical plating process to form at least one metal bump on the patterned metal layer. The first extending direction of the metal bump is perpendicular to the second extending direction of the driving substrate. The metal bump structure and the manufacturing method thereof have the advantages of simple manufacturing process, low cost, no environmental pollution and the like.

Description

Metal bump structure and its manufacturing method and driving substrate

technical field

The present invention relates to a bump structure, a manufacturing method thereof, and a substrate, in particular to a metal bump structure, a fabrication method thereof, and a driving substrate having the metal bump structure.

Background technique

At present, the Micro LED Displays of active driving (AM Driving) mostly use Thin Film Transistor (TFT) glass substrates to drive the light emitting diodes. However, the thin film transistor is a thin film process, and the metal wires on it and the indium tin oxide (ITO) in the pixel area are only nano-scale, so when the light emitting diode or surface mount device (Surface Mount Device, SMD) ) when soldering (Solder Bonding) on the indium tin oxide conductive layer, a reliable interface metal compound (Intermetallic Compound, IMC) cannot be formed and bonded together. In order to solve the above problems, a thick layer of copper is formed on the indium tin oxide conductive layer by electroplating at present. However, the process of electroplating thick copper is long and complicated, which not only increases the manufacturing cost, but also easily causes environmental pollution because it is a wet process.

SUMMARY OF THE INVENTION

The present invention is directed to a metal bump structure and a manufacturing method thereof, which have the advantages of simple manufacturing process, low cost, and no environmental pollution.

The present invention is directed to a driving substrate including the above-mentioned metal bump structure, which can have better structural reliability.

According to an embodiment of the present invention, a method for fabricating a metal bump structure includes the following steps. Supplied with drive substrate. At least one pad and an insulating layer have been formed on the driving substrate. The pads are formed on the disposition surface of the driving substrate and have an upper surface. The insulating layer covers the configuration surface of the driving substrate and the pads and exposes a part of the upper surface of the pads. A patterned metal layer is formed on the upper surface of the pad exposed by the insulating layer and extends to cover part of the insulating layer. An electroless plating (ELP) process is performed to form at least one metal bump on the patterned metal layer. The first extension direction of the metal bump is perpendicular to the second extension direction of the driving substrate.

In the method for fabricating a metal bump structure according to an embodiment of the present invention, the above-mentioned step of forming a patterned metal layer includes forming a catalyst layer on the insulating layer and the upper surface of the pads exposed by the insulating layer. The activation process and the patterning process are performed on the catalyst layer to form a patterned metal layer.

In the method for fabricating a metal bump structure according to an embodiment of the present invention, the above-mentioned method for forming the catalyst layer includes an inkjet printing method.

In the method for fabricating a metal bump structure according to an embodiment of the present invention, the material of the catalyst layer includes nano-palladium (Nano-Pd), or any nano-metal that can reduce chemical copper, such as nano-gold or nano-silver.

In the method for fabricating a metal bump structure according to an embodiment of the present invention, the above-mentioned activation procedure includes a laser activation procedure or a heating procedure.

In the method for fabricating a metal bump structure according to an embodiment of the present invention, the material of the patterned metal layer includes palladium, gold or silver.

In the method for fabricating a metal bump structure according to an embodiment of the present invention, the material of the above-mentioned metal bump includes copper, gold, tin or nickel.

In the method for fabricating a metal bump structure according to an embodiment of the present invention, the cross-sectional shape of the above-mentioned metal bump includes a circle or a rectangle.

In the method for fabricating the metal bump structure according to the embodiment of the present invention, the material of the above-mentioned pads includes Indium Tin Oxide (ITO), or any sputtered metal layer such as titanium, copper, molybdenum, Aluminum or Chrome.

In the method for fabricating a metal bump structure according to an embodiment of the present invention, the thickness of the aforementioned metal bump is between 1 μm and 10 μm.

According to an embodiment of the present invention, the metal bump structure is disposed on the driving substrate. A pad and an insulating layer are arranged on the driving substrate. The pads are arranged on the arrangement surface of the driving substrate and have an upper surface. The insulating layer covers the configuration surface of the driving substrate and the pads and exposes a part of the upper surface of the pads. The metal bump structure includes a patterned metal layer and metal bumps. The patterned metal layer is disposed on the upper surface of the pad exposed by the insulating layer and extends to cover part of the insulating layer. The metal bumps are disposed on the patterned metal layer, wherein the first extension direction of the metal bumps is perpendicular to the second extension direction of the driving substrate.

In the metal bump structure according to the embodiment of the present invention, the material of the above-mentioned patterned metal layer includes palladium, or any nano metal such as gold and silver that can reduce chemical copper.

In the metal bump structure according to the embodiment of the present invention, the material of the aforementioned metal bump includes copper, gold, tin or nickel.

In the metal bump structure according to the embodiment of the present invention, the cross-sectional shape of the above-mentioned metal bump includes a quasi-circle or a rectangle.

In the metal bump structure according to the embodiment of the present invention, the thickness of the aforementioned metal bump is between 1 μm and 10 μm.

According to an embodiment of the present invention, a driving substrate includes a driving substrate, at least one active element, at least one pad, an insulating layer, and at least one metal bump structure. The drive substrate has a configuration surface. The active element is arranged on the arrangement surface of the driving substrate. The pads are arranged on the arrangement surface of the driving substrate and have an upper surface. The insulating layer covers the configuration surface of the driving substrate, the active element and the pad, and the insulating layer exposes a part of the upper surface of the pad. The metal bump structure includes a patterned metal layer and metal bumps. The patterned metal layer is disposed on the upper surface of the pad exposed by the insulating layer and extends to cover part of the insulating layer. The metal bumps are disposed on the patterned metal layer. The first extension direction of the metal bump is perpendicular to the second extension direction of the driving substrate.

In the driving substrate according to the embodiment of the present invention, the material of the patterned metal layer includes palladium, and the material of the metal bump includes copper, gold, tin or nickel.

In the driving substrate according to the embodiment of the present invention, the cross-sectional shape of the above-mentioned metal bump includes a quasi-circle or a rectangle.

In the driving substrate according to the embodiment of the present invention, the thickness of the above-mentioned metal bumps is between 1 μm and 10 μm.

In the driving substrate according to the embodiment of the present invention, the material of the above-mentioned pads includes indium tin oxide, or any sputtered metal layer such as titanium, copper, molybdenum, aluminum or chromium.

Based on the above, in the method for fabricating the metal bump structure of the present invention, the metal bump is formed through an electroless plating process. Compared with the conventional wet process electroplating process to form the metal bumps, the present invention adopts the dry process to form the metal bumps, which has the advantages of simple process, low cost and no environmental pollution. In addition, when using the driving substrate of the metal bump structure of the present invention, when the light emitting element is subsequently bonded, a good interface metal compound can be formed between the light emitting element and the metal bump structure, which can have better structural reliability.

Description of drawings

1A to 1D are schematic cross-sectional views of a method for fabricating a metal bump structure according to an embodiment of the present invention;

2 is a schematic cross-sectional view of a metal bump structure according to another embodiment of the present invention;

3A is a schematic cross-sectional view of a driving substrate according to an embodiment of the present invention;

FIG. 3B is a schematic cross-sectional view of disposing a light-emitting element on the driving substrate of FIG. 3A .

Description of reference numerals

100: driving substrate;

110: driving the substrate;

112: configuration surface;

120: pad;

122: upper surface;

130: insulating layer;

140: active element;

200a, 200b: metal bump structures;

210: patterned metal layer;

210a: catalyst layer;

220a, 220b: metal bumps;

222: upper surface;

300: light-emitting element;

D1: the first extension direction;

D2: the second extension direction;

T: Thickness.

Detailed ways

Reference will now be made in detail to the exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numerals are used in the drawings and description to refer to the same or like parts.

1A to 1D are schematic cross-sectional views of a method for fabricating a metal bump structure according to an embodiment of the present invention. Referring first to FIG. 1A , regarding the fabrication method of the metal bump structure of the present embodiment, first, a driving substrate 110 is provided. At least one pad (two pads 120 are schematically shown) and an insulating layer 130 have been formed on the driving substrate 110 . The pads 120 are formed on the disposition surface 112 of the driving substrate 110 and have an upper surface 122 . The insulating layer 130 covers the configuration surface 112 of the driving substrate 110 and the pads 120 and exposes a part of the upper surface 122 of the pads 120 . Here, the driving substrate 110 is, for example, a thin film transistor (TFT) glass substrate, and the material of the pads 120 is, for example, indium tin oxide, or any sputtered metal layer such as titanium, copper, molybdenum, aluminum or chromium. That is, the pads 120 and the pixel electrodes on the driving substrate 110 belong to the same layer, and are both made of indium tin oxide.

Next, referring to FIG. 1C , a patterned metal layer 210 is formed on the upper surface 122 of the pad 120 exposed by the insulating layer 130 and extends to cover part of the insulating layer 130 . In detail, for the steps of forming the patterned metal layer 210 , please refer to FIG. 1B , forming a catalyst layer 210 a on the insulating layer 130 and the upper surface 122 of the pads 120 exposed by the insulating layer 130 . The orthographic projection of the catalyst layer 210 a on the driving substrate 110 is larger than the orthographic projection of the corresponding pad 120 on the driving substrate 110 . Here, the method for forming the catalyst layer 210a is, for example, inkjet printing, and the material of the catalyst layer 210a is, for example, nano-palladium, or any nano-metal that can reduce chemical copper, such as nano-gold or nano-silver.

After that, please refer to FIG. 1B and FIG. 1C at the same time, and perform an activation process and a patterning process on the catalyst layer 210 a to form a patterned metal layer 210 . The orthographic projection of the patterned metal layer 210 on the driving substrate 110 is smaller than the orthographic projection of the corresponding pads 120 on the driving substrate 110 . Here, the activation procedure is, for example, a laser activation procedure or a heating procedure. If nano-palladium (in ionic state) is used as the catalyst layer 210a, metal palladium can be formed through the activated catalyst layer 210a, and then the patterned metal layer 210 can be formed by patterning the metal palladium. Therefore, the material of the patterned metal layer in this embodiment is embodied as palladium, or any nano metal such as gold or silver that can reduce chemical copper.

Finally, referring to FIG. 1D , an electroless plating process is performed to form at least one metal bump (two metal bumps 220 a are schematically shown) on the patterned metal layer 210 . The mechanism of electroless plating is through redox reaction, which has low cost and short production time, and can be selectively grown into a desired shape according to demand. The first extending direction D1 of the metal bumps 220 a is perpendicular to the second extending direction D2 of the driving substrate 110 . Here, the material of the metal bump 220a is, for example, copper, gold or nickel. The cross-sectional shape of the metal bump 220 a is, for example, a rectangle, and the thickness T of the metal bump 220 a is, for example, between 1 μm and 10 μm. So far, the fabrication of the metal bump structure 200a has been completed.

Structurally, please refer to FIG. 1D again, the metal bump structure 200 a is disposed on the driving substrate 110 . A pad 120 and an insulating layer 130 are disposed on the driving substrate 110 . The pads 120 are disposed on the disposition surface 112 of the driving substrate 110 and have an upper surface 122 . The insulating layer 130 covers the configuration surface 112 of the driving substrate 110 and the pads 120 and exposes a part of the upper surface 122 of the pads 120 . The metal bump structure 200a includes a patterned metal layer 210 and metal bumps 220a. The patterned metal layer 210 is disposed on the upper surface 122 of the pads 120 exposed by the insulating layer 130 and extends to cover part of the insulating layer 130 , wherein the material of the patterned metal layer 210 is, for example, palladium, or any nanometer capable of reducing chemical copper. Metals such as gold or silver. The metal bumps 220 a are disposed on the patterned metal layer 210 , wherein the first extending direction D1 of the metal bumps 220 a is perpendicular to the second extending direction D2 of the driving substrate 110 . Here, the material of the metal bump 220a is, for example, copper, gold or nickel, and the cross-sectional shape of the metal bump 220a is, for example, a rectangle, and the thickness T of the metal bump 220a is between 1 μm and 10 μm.

Since the metal bumps 220a are formed by the electroless plating process in this embodiment, compared with the conventional wet process electroplating process to form the metal bumps, the metal bump structure 200a of this embodiment adopts a dry process To form the metal bumps 220a, it has the advantages of simple process, low cost and no environmental pollution.

It must be noted here that the following embodiments use the element numbers and part of the contents of the previous embodiments, wherein the same numbers are used to represent the same or similar elements, and the description of the same technical contents is omitted. For the description of the omitted part, reference may be made to the foregoing embodiments, and repeated descriptions in the following embodiments will not be repeated.

FIG. 2 is a schematic cross-sectional view of a metal bump structure according to another embodiment of the present invention. Please refer to FIG. 1D and FIG. 2 at the same time, the metal bump structure 200b of the present embodiment is similar to the above-mentioned metal bump structure 200a, the difference between the two is: in the present embodiment, the metal bump structure 200b of the metal bump structure 220b The cross-sectional shape is embodied as a quasi-circle. In other words, the metal bump structure 200a can be further subjected to a high temperature reflow process to form the desired shape of the metal bump 220b.

FIG. 3A is a schematic cross-sectional view of a driving substrate according to an embodiment of the present invention. FIG. 3B is a schematic cross-sectional view of disposing a light-emitting element on the driving substrate of FIG. 3A . Referring first to FIG. 3A , in this embodiment, the driving substrate 100 includes a driving substrate 110 , at least one pad (shown schematically with two pads 120 ), an insulating layer 130 , and at least one active element (shown schematically One active element 140) and at least one metal bump structure (two metal bump structures 200a are schematically shown). The driving substrate 110 has a configuration surface 112 , wherein the driving substrate 110 is, for example, a thin film transistor (TFF) glass substrate. The active element 140 is disposed on the disposition surface 112 of the driving substrate 110 , wherein the active element 140 is, for example, a thin film transistor, but not limited thereto. The pad 120 is disposed on the configuration surface 112 of the driving substrate 110 and has an upper surface 122, wherein the material of the pad 120 is, for example, indium tin oxide, or any sputtered metal layer such as titanium, copper, molybdenum, aluminum or chromium. That is, the pads 120 and the pixel electrodes on the driving substrate 110 belong to the same layer, and are both made of indium tin oxide. The insulating layer 130 covers the configuration surface 112 of the driving substrate 110 , the active element 140 and the pads 120 , and the insulating layer 130 exposes a part of the upper surface 122 of the pads 120 . The metal bump structure 200a includes a patterned metal layer 210 and metal bumps 220a. The patterned metal layer 210 is disposed on the upper surface 122 of the pad 120 exposed by the insulating layer 130 and extends to cover part of the insulating layer 130 . The metal bumps 220 a are disposed on the patterned metal layer 210 . The first extending direction D1 of the metal bumps 220 a is perpendicular to the second extending direction D2 of the driving substrate 110 .

Referring to FIG. 3B , the light emitting element 300 is suitable for being disposed on the driving substrate 100 to form a display with the driving substrate 100 , wherein the light emitting element 300 is disposed on the metal bump 220a of the metal bump structure 200a. Further, the light-emitting element 300 is, for example, a miniature light-emitting diode, wherein each light-emitting element 300 is bonded to the two metal bump structures 200 a of the driving substrate 100 in a flip-chip manner. The light emitting element 300 is structurally and electrically connected to the upper surface 222 of the metal bump 220 a, and is electrically connected to the pad 120 through the metal bump 220 a and the patterned metal layer 210 . Since the present embodiment adopts an electroless plating process to form the metal bumps 220 a with a certain thickness, when the light-emitting element 300 and the metal bump structure 200 a are welded, a good interface metal can be formed between the light-emitting element 300 and the metal bump structure 200 a compound, and thus can have better structural reliability.

To sum up, in the method for fabricating the metal bump structure of the present invention, the metal bump is formed through an electroless plating process. Compared with the conventional wet process electroplating process to form the metal bumps, the present invention adopts the dry process to form the metal bumps, which has the advantages of simple process, low cost and no environmental pollution. In addition, when using the driving substrate of the metal bump structure of the present invention, when the light emitting element is subsequently bonded, a good interface metal compound can be formed between the light emitting element and the metal bump structure, which can have better structural reliability.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features thereof can be equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present invention. scope.

Claims (20)

1. A method for fabricating a metal bump structure includes:

providing a driving substrate, wherein at least one connecting pad and an insulating layer are formed on the driving substrate, the at least one connecting pad is formed on a configuration surface of the driving substrate and has an upper surface, and the insulating layer covers the configuration surface of the driving substrate and the at least one connecting pad and exposes a part of the upper surface of the at least one connecting pad;

forming a patterned metal layer on the upper surface of the at least one pad exposed by the insulating layer and extending to cover a part of the insulating layer; and

and performing an electroless plating process to form at least one metal bump on the patterned metal layer, wherein a first extending direction of the at least one metal bump is perpendicular to a second extending direction of the driving substrate.

2. The method of claim 1, wherein the step of forming the patterned metal layer comprises:

forming a catalyst layer on the insulating layer and the upper surface of the at least one pad exposed by the insulating layer; and

and performing an activation process and a patterning process on the catalyst layer to form the patterned metal layer.

3. The method of claim 2, wherein the method of forming the catalyst layer comprises ink-jet printing.

4. The method of claim 2, wherein the catalyst layer comprises pd, au or ag.

5. The method of claim 2, wherein the activation process comprises a laser activation process or a heating process.

6. The method of claim 1, wherein the patterned metal layer comprises Pd, Au or Ag.

7. The method of claim 1, wherein the metal bump is made of copper, gold, tin or nickel.

8. The method of claim 1, wherein a cross-sectional shape of the metal bump includes a circular-like shape or a rectangular shape.

9. The method of claim 1, wherein the at least one pad comprises ito, ti, cu, mo, al, or cr.

10. The method of claim 1, wherein the metal bump has a thickness of 1-10 μm.

11. A metal bump structure disposed on a driving substrate, wherein the driving substrate is disposed with a pad and an insulating layer, the pad is disposed on a disposition surface of the driving substrate and has an upper surface, and the insulating layer covers the disposition surface and the pad and exposes a portion of the upper surface of the pad, the metal bump structure comprising:

the patterned metal layer is configured on the upper surface of the connecting pad exposed by the insulating layer and extends to cover part of the insulating layer; and

and the metal bump is arranged on the patterned metal layer, wherein the first extending direction of the metal bump is vertical to the second extending direction of the driving substrate.

12. The metal bump structure of claim 11, wherein the material of the patterned metal layer comprises palladium, gold, or silver.

13. The metal bump structure of claim 11 wherein the metal bump material comprises copper, gold, tin, or nickel.

14. The metal bump structure of claim 11, wherein a cross-sectional shape of the metal bump comprises a quasi-circular shape or a rectangular shape.

15. The metal bump structure of claim 11 wherein the metal bump has a thickness of between 1 and 10 microns.

16. A drive substrate, comprising:

a drive substrate having a disposition surface;

at least one active element configured on the configuration surface of the driving substrate;

at least one pad disposed on the disposition surface of the driving substrate and having an upper surface;

the insulating layer covers the configuration surface of the driving substrate, the at least one active element and the at least one connecting pad, and the insulating layer exposes part of the upper surface of the connecting pad; and

at least one metal bump structure, comprising:

the patterned metal layer is configured on the upper surface of the connecting pad exposed by the insulating layer and extends to cover part of the insulating layer; and

and the metal bump is arranged on the patterned metal layer, wherein the first extending direction of the metal bump is vertical to the second extending direction of the driving substrate.

17. The driving substrate as claimed in claim 16, wherein the material of the patterned metal layer comprises palladium, and the material of the metal bump comprises copper, gold, tin or nickel.

18. The driving substrate as claimed in claim 16, wherein the cross-sectional shape of the metal bump comprises a circular-like shape or a rectangular shape.

19. The driving substrate as claimed in claim 16, wherein the metal bump has a thickness of 1-10 μm.

20. The driving substrate as recited in claim 16, wherein the at least one pad comprises ito, ti, cu, mo, al or cr.

Images