Flip chip and method of making flip chip

Abstract

Disclosed is a method for manufacturing a flip chip, in which a gold typically used in a flip chip manufacturing is adhered by conductive adhesives, wherein the method comprises steps of depositing a metal seed layer on a substrate; applying and patterning a photoresist or a dry film; forming a gold bump by electroplating; patterning the seed layer; forming an insulating layer on the seed layer and upper end of the gold bump; and patterning an insulating layer. Accordingly, it is possible to manufacture a flip chip, in which electrical function between bumps can be evaluated, with less cost.

Description

bump bumps 18 is are completely formed by electroplating. The gold bumps 18 constitute a plate bump layer 19.

In order to achieve an electrical connection between bumps, a process of patterning the conductive thin film 14 used as a seed layer in plating is performed. As shown in FIG. 7, for example, a photoresist or dry film 22 is disposed on the conductive thin film 14 and patterned by photolithography using a new mask to provide a first portion 14A covered by the patterned photoresist 22 and a second portion 14B not covered by the patterned photoresist 22.

A metal etching process is then performed so as to remove the second portion 14B of the conductive thin film 14, to which the photoresist or the dry film 22 is not disposed. Titanium (Ti) can be etched by hydrofluoric acid (HF) diluted solution, Au can be etched by iodination potassium (KI) solution, and Cu can be etched by ferric chloride (FeCl₃) aqueous solution. Through this etching process, the shape in which the conductive thin film 14 is patterned can be obtained, as shown in FIG. 8.

FIG. 9 shows a structure where the photoresist or dry film 22 used for etching of the conductive thin film 14 has been removed.

As shown in FIG. 10, an insulating layer 26 is formed so as to protect the thin conductive film 14 and achieve insulation from external environment. The insulating layer 26 includes insulating layers 26A, 26B and 26C that are formed on different surfaces. SiO₂, Si₃N₄, etc. may suitably be used as the insulating layer 26.

As shown in FIG. 11, a photoresist and dry film 24 is disposed on the insulating layer 26, and patterning is performed through the photolithography process, which provides the patterned photoresist film 24 on the insulating layers 26A and 26B but not on the insulating layer 26C, so as to achieve patterning of the insulating layer 26. Suitably, the mask used in this photolithography may be the same as the mask used in the process of FIG. 4, except that the polarity of the photoresist or dry film 24 is changed. For example, in a case where the photoresist or dry film 16 used in FIG. 4 is positive, the photoresist or dry film 24 used in FIG. 11 is negative so as to achieve a patterning having an opposite shape. Through such a process, two processes can be performed by using one mask.

As shown in FIG. 12, the insulating layer 26 26C is etched so as to expose the surface of the gold bump 18 while the insulating layers 26A and 26B are maintained under the patterned photoresist film 24.

As shown in FIG. 13, the photoresist or dry film 24 is removed, which was applied to etch the insulating layer 26C.

FIG. 14 is a top view of a flip-chip manufactured through the processes of FIGS. 2 to 13, which includes thereon the insulating layer 12 formed between the substrate 10 and the conductive film 14, the gold bump 18 formed by electroplating, and the electrically connecting layer (metal patterned seed layer) 20 formed by patterning the conductive thin film used as the seed layer in electroplating.

The present flip chips and manufacturing methods thereof can be applied to various areas. For example, it is possible to bond a core memory chip and a non-memory chip and stack a horizontal multi chip and a vertical multi chip, in the fields of high-end electronic machines, including, but not limited to, portable multimedia machines, such as cellular phones, and flat panel machines.

The invention has been described in detail with reference to preferred embodiments thereof. However, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A flip chip comprising:

an insulating layer arranged on and directly contacted with a substrate, wherein the insulating layer covers the substrate;

a metal patterned seed layer arranged on the insulating layer and directly contacted with the insulating layer; and

a plate bump layer formed on the metal patterned seed layer, wherein one two or more plate bumps are formed;

wherein a metal pattern is formed at a side of the two or more plate bump, bumps, and is formed by patterning a precursor of the metal patterned seed layer; wherein the metal pattern is at least a part of the metal patterned seed layer, and forms electrical connection between the plate bumps.

2. The flip chip as claimed in claim 1, wherein the substrate is one selected from the group consisting of a silicon wafer, a compound semiconductor, quartz, glass, and ceramic material.

3. The flip chip as claimed in claim 1, wherein the insulating layer comprises SiO₂ or Si₃N₄.

4. The flip chip as claimed in claim 1, wherein the seed layer comprises an adhesive layer and an electrode layer.

5. The flip chip as claimed in claim 4, wherein the adhesive layer comprises titanium, and the electrode layer comprises copper or gold.

6. A flip chip manufacturing method comprising:

(a) forming a seed layer on a substrate by using a conductive thin layer;

(b) applying and patterning a photoresist or a dry film;

(c) forming gold bumps by electroplating;

(d) patterning the seed layer to form a metal pattern;

(e) forming an insulating layer on the seed layer and the upper end of the gold bumps; and

(f) applying and patterning a photoresist or a dry film so as to pattern the insulating layer;

wherein the metal pattern forms electrical connection between the gold bumps, and the polarity of the photoresist or a dry film in step b) is opposite to the polarity of photoresist or a dry film in step f).

7. The flip chip manufacturing method as claimed in claim 6, wherein the patterning of steps (b) and (f) are performed by photolithography.

8. The flip chip manufacturing method as claimed in claim 7, wherein a photolithography mask used in the patterning processes of step (b) is the same as that of step (f).

9. The flip chip manufacturing method as claimed in claim 6, wherein the patterning process of step (d) comprises applying and patterning a photoresist or a dry film and etching a portion of the conductive thin film on which portion the photoresist or the dry film is not, so as to form a metal pattern for electrical connection between gold bumps.

10. A flip chip comprising:

a first insulating layer arranged on and directly contacted with a substrate, wherein the first insulating layer covers the substrate,

a metal patterned seed layer arranged on the first insulating layer and comprising a conductive metal directly contacted with the first insulating layer,

a plate bump layer formed on the metal patterned seed layer, wherein two or more plate bumps are formed with a horizontal gap therebetween and constitute the plate bump layer over the first insulating layer, wherein a metal pattern is formed at a side of the two or more plate bumps and is formed by patterning a precursor of the metal patterned seed layer, wherein the metal pattern is at least a part of the metal patterned seed layer and forms electrical connection between the two or more plate bumps, and

a second insulating layer formed over and covering the metal pattern such that the electrical connection electrically connecting between the two or more plate bumps is interposed between the first insulating layer and the second insulating layer, wherein the second insulating layer does not cover top surfaces of the two or more plate bumps.

11. The flip chip of claim 10, wherein the flip chip further comprises a third insulating layer that covers a portion of the first insulating layer on which the conductive metal of the metal pattern is not provided such that the third insulating layer directly contacts the first insulating layer without a conductive layer interposed therebetween.

12. The flip chip of claim 10, wherein the two or more plate bumps are made of at least one material selected from the group consisting of gold, copper and solder.

13. The flip chip of claim 10, wherein each of the first and second insulating layers comprises at least one selected from the group consisting of SiO₂ and Si₃N₄.

14. The flip chip of claim 10, wherein the metal patterned seed layer comprises an adhesive sublayer and an electrode sublayer that is thicker than the adhesive sublayer.

15. The flip chip of claim 14, wherein the adhesive layer comprises titanium, and the electrode layer comprises copper or gold.

16. A method of making the flip chip of claim 10, the method comprising:

forming the first insulating layer over the substrate;

forming a conductive metal on the first insulating layer to provide a metal seed layer that is the precursor of the metal patterned seed layer;

forming a photoresist layer over the metal seed layer;

selectively patterning the photoresist layer to provide two or more openings that expose the metal seed layer through the photoresist layer;

electroplating to grow two or more plate bumps from the metal seed layer exposed through the two or more openings, in which the metal seed layer works as an electroplating electrode for the two or more plate bumps so that an electrode wire does not have to be formed for each of the two or more plate bumps;

subsequent to electroplating, removing the photoresist layer to provide an intermediate structure comprising the substrate, the first insulating layer over the substrate, the metal seed layer over the first insulating layer and the two or more plate bumps that are on the metal seed layer with a horizontal gap therebetween;

subsequent to removing the photoresist layer, patterning the metal seed layer to form an intermediate device with the metal pattern comprising the electrical connection connecting between the two or more plate bumps, wherein patterning the metal seed layer removes a portion of the conductive metal to expose the portion of the first insulating layer;

forming an insulating material over the intermediate device to provide the second insulating layer over the metal pattern and a third insulating layer over the portion of the first insulating layer, wherein forming the insulating material further forms a fourth insulating layer over the two or more plate bumps; and

removing the fourth insulating layer to expose a top portion of each of the two or more plate bumps.

17. The flip chip of claim 1, wherein the insulating layer is referred to as a first insulating layer,

wherein the two or more plate bumps constitute the plate bump layer over the first insulating layer,

wherein the metal pattern is formed at a side of the two or more plate bumps when viewing in a direction from top of the plate bumps toward the substrate,

wherein the metal pattern is at least a part of the metal patterned seed layer and forms electrical connection between the two or more plate bumps,

wherein the flip chip further comprises a second insulating layer formed over and covering the metal pattern such that the metal pattern comprising the electrical connection between the two or more plate bumps is interposed between the first insulating layer and the second insulating layer.

18. The flip chip of claim 17, wherein the flip chip further comprises a third insulating layer formed over a portion of the first insulating layer on which the metal pattern is not provided such that no conductive layer is interposed between the first insulating layer and the third insulating layer, wherein the second insulating layer and the third insulating layer are formed together but at different levels from the substrate.

19. The flip chip of claim 17, wherein the two or more plate bumps are made of at least one material selected from the group consisting of gold, copper and solder.

20. The flip chip of claim 17, wherein each of the first and second insulating layer comprises at least one selected from the group consisting of SiO₂ and Si₃N₄.

21. The flip chip of claim 17, wherein the metal patterned seed layer comprises an adhesive layer and an electrode layer.

22. The flip chip of claim 21, wherein the adhesive layer comprises titanium, and the electrode layer comprises copper or gold.

23. A method of making the flip chip of claim 17, the method comprising:

forming the first insulating layer over the substrate;

forming a conductive metal on the first insulating layer to provide a metal seed layer that is the precursor of the metal patterned seed layer;

forming a photoresist layer over the metal seed layer;

selectively patterning the photoresist layer to provide two or more openings that expose the metal seed layer through the photoresist layer;

electroplating to form two or more plate bumps from the metal seed layer exposed through the two or more openings, in which the metal seed layer works as an electroplating electrode for the two or more plate bumps so that an electrode wire does not have to be formed for each of the two or more plate bumps that would need to be removed after electroplating;

subsequent to electroplating, removing the photoresist layer to provide an intermediate structure comprising the substrate, the first insulating layer over the substrate, the metal seed layer over the first insulating layer and the two or more plate bumps that are on the metal seed layer with a horizontal gap therebetween;

subsequent to removing the photoresist layer, patterning the metal seed layer to form an intermediate device with the metal pattern comprising the electrical connection between the two or more plate bumps, wherein patterning the metal seed layer removes a portion of the conductive metal to expose the portion of the first insulating layer;

forming an insulating material over the intermediate device to provide the second insulating layer over the metal pattern and a third insulating layer over the portion of the first insulating layer, wherein forming the insulating material further forms a fourth insulating layer over the two or more plate bumps; and

removing the fourth insulating layer to expose a top portion of each of the two or more plate bumps.