JPH03219649A - Substrate for metal protrusion formation and its manufacture - Google Patents

Abstract

PURPOSE:To form an opening part for metal protrusion formation use in a photosensitive resin layer by a method wherein a transparent conductive film and the photosensitive resin layer are formed sequentially on one main face of a light-transmitting and insulating substrate, an ultraviolet-ray cutoff film having an opening part is formed on its opposite face, ultraviolet rays are transmitted from the opening part up to the photosensitive resin layer and a part exposed to light is removed. CONSTITUTION:A transparent conductive film 2 is formed on one main face of a light- transmitting and insulating substrate 1. The opposite face of the light-transmitting and insulating substrate 1 is spin-coated with a photosensitive polyimide film 3 acting as an ultraviolet- ray cutoff film; a photomask is aligned, and an exposure operation and a developing operation are executed; opening parts 4 are formed in its surface; after that, the whole surface of the transparent conductive film 2 is spin-coated with a photosensitive resin layer 5. Then, the whole surface of the photosensitive polyimide film 3 is irradiated with ultraviolet rays 6; the photosensitive resin layer 5 in positions corresponding to positions of the opening parts 4 is exposed partially to light. The photosensitive resin layer 5 is developed; the parts exposed to light are removed; opening parts 7 for metal protrusion formation use are formed. Metal protrusions 8 are formed in the opening parts 7 for metal protrusion formation use by an electrolytic plating operation. Lastly, the photosensitive resin layer 5 is removed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a metal protrusion-formed substrate used in a transfer bump method, etc., and a method for manufacturing the same.

(Prior Art) A film carrier mounting method is an effective mounting method for reducing the thickness and size of semiconductor elements.

In this technology, the A! Cr on the electrode,
After forming a barrier metal layer such as Cu, Ti or Pd, 10 to 30 metal protrusions such as Au or solder are formed on this surface.
It is formed on the order of μm. These metal protrusions and CuFi inner leads formed on an insulating tape made of polyimide, Gala Evo, or the like are bonded by applying pressure and heating.

However, such technology requires a vapor deposition process, a photolithography process, and an etching process to form a barrier metal layer on the Al electrode of a semiconductor element, and a photolithography process and electrolytic plating process to form metal protrusions. Many complicated processes are required, and therefore, various equipment for each of these processes is also required. In addition, in all the steps, wafers are processed in units, which causes problems such as a decrease in yield and an increase in cost.

As a technique for solving these problems, there is a transfer bump method. This method involves forming metal protrusions on a reusable substrate, transferring and bonding the metal protrusions to the inner leads of the film carrier, and bonding the metal protrusions of the inner leads and the electrodes of the semiconductor element by thermocompression bonding. It is a technology that

In such a technique, different lateral paths on the substrate on which metal protrusions are formed are formed depending on the type and amount of metal protrusions to be formed (suitable for small-lot, high-mix production, mass production, etc.).

Figure 2 (a), (b), (c), (d), (e
1 and (f) are process diagrams showing a conventional method for forming metal protrusions.

As shown in FIG. 2(a), on one main surface of the insulating substrate 9, a conductive layer 1lllO is formed to serve as an electrode for plating.

This conductive material is, for example, Pt, ITO (indium tin oxide), or the like. As a forming method, a sputter deposition method or an electron beam deposition method is used.

Next, as shown in FIG. 2(b), on the entire surface of the conductive film 10,
A photosensitive insulating resin layer (photomask 11) is spin-coded.Furthermore, in order to remove the solvent in this photosensitive tIIA edge resin layer 11, it is placed in an oven at a temperature of 80-100°C for about 15-20 minutes.

Note that the thickness of the photosensitive insulating resin layer 11 is approximately 0.5 to 1.5
It is about μm.

Next, as shown in FIG. 2(C), a photomask 12 is placed on the surface of the photosensitive insulating resin layer 11 using a mask alignment device.
The photosensitive insulating resin layer 11 is partially exposed by irradiating the surface of the photosensitive insulating resin layer 11 with ultraviolet rays 6 through the photomask 12.

Next, as shown in FIG. 2(d), the ultraviolet irradiated portions of the photosensitive insulating resin layer 11 are removed by immersion in a developer, and after rinsing, the photosensitive insulating resin layer 11 is opened (not shown).
The photosensitive insulating resin layer 11 is cured by heating.

In this way, openings 13 are formed in the photosensitive insulating resin layer 11.

Then, as shown in FIG. 2(e), metal protrusions 14 are formed on the conductive film 10 in the openings 13 to a height of about l by electrolytic plating.
It is formed with a thickness of 0 μm to 30 μm.

Thereafter, as shown in FIG. 2(f), the photosensitive insulating resin layer 11 is removed by a resist stripper.

The method of transferring the metal protrusions 14 formed in this way to the inner leads of the film carrier is shown in FIG. 3(a) below.
The explanation will be based on (b) and (C).

As shown in FIG. 3(a), the inner leads 16 of the film carrier 15 and the metal protrusions 14 are aligned.

Next, as shown in FIG. 3(b), the aligned inner leads 16 and metal protrusions 14 are heated and pressurized (in the direction of arrow A) with a pounding tool 17.

Note that the heating temperature is 300° C. to 320° C., and the pressurizing pressure is 5 to 20 g per lead.

Then, as shown in FIG. 3(C), when the heating and pressurization by this bonding tool 17 is released, the insulating substrate 9
The upper metal protrusion 14 is transferred and bonded to the inner lead 16 side.

[Problems to be Solved by the Invention] However, in such conventional techniques, each time a metal protrusion 14 is formed on the insulating substrate 9,
A photosensitive insulating resin layer (photoresist) 11 is spin-coded (coated) on the conductive film lO formed on the insulating substrate 9.
Among these steps, forming the opening 13 in the photosensitive insulating resin layer 11 requires repeating the steps of mask alignment, exposure, development, and rinsing, and the step of forming the metal protrusion 14 by electrolytic plating. This process requires expensive equipment such as a mask alignment device and has the problem of complicating the process. Therefore, there have been problems in that yields are lowered and cost reductions are hindered.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a metal protrusion-formed substrate and a method for manufacturing the same, which can simplify the process, improve yield, and reduce costs.

(Means for Solving the Problems) The metal protrusion-formed substrate according to claim (1) includes a transparent/insulating substrate, and a transparent conductor 1 formed on one main surface of the transparent/insulating substrate, and a film on the transparent conductor 1 formed on one main surface of the transparent/insulating substrate. , an ultraviolet blocking film having an opening formed on the opposite side of the transparent/insulating substrate; and a metal protrusion formed on the transparent conductive film at a position corresponding to the opening of the ultraviolet blocking film. The photosensitive resin layer includes a photosensitive resin layer having a forming opening.

The method for manufacturing a metal protrusion-formed substrate according to claim (2) includes the step of preparing a transparent/insulating substrate on which a transparent conductive film is formed on one main surface and an ultraviolet blocking film having openings on the opposite surface. forming a photosensitive resin layer on the transparent conductive film; and irradiating the photosensitive resin layer with ultraviolet rays through the openings by irradiating the ultraviolet rays from the surface side of the ultraviolet blocking film. Step: By developing and removing the exposed portions of the photosensitive resin layer due to the ultraviolet irradiation, an opening for forming a metal protrusion is formed at a position corresponding to the opening of the ultraviolet blocking film. The method is characterized in that it includes a step of curing the plastic resin layer.

(Function) According to the configuration of the present invention, a transparent conductive film is formed on one main surface of a light-transmitting/insulating substrate, a photosensitive resin layer is formed on the transparent conductive film, and the light-transmitting/insulating substrate is further formed with a photosensitive resin layer. Since a UV-blocking film with openings is formed on the opposite side of the film, ultraviolet rays are transmitted from the openings of the UV-blocking film to the photosensitive resin layer formed on the opposite side, and the exposed areas are developed and removed. A gate part for forming a metal protrusion can be formed in a photosensitive resin layer.Therefore, the patterning process by mask alignment, which was conventionally required when forming an opening in a photosensitive resin layer where a metal protrusion is to be formed, can be formed. By using the ultraviolet blocking film, openings for forming metal protrusions can be easily and repeatedly formed in the photosensitive resin layer.

[Example] Figure 1 (a), (b), (cl, (d), (e
) and (f) are process diagrams showing a method of manufacturing a metal protrusion-formed substrate according to an embodiment of the present invention.

As shown in FIG. 1(a), a transparent conductive film 2 is formed on one main surface of a transparent/insulating substrate 1 using a sputter deposition method, an electron beam deposition method, or the like.

This transparent conductive film 2 is made of ITO (indium nine oxide) or the like, and its sheet resistance is preferably 10Ω/hole or less. This reduces the variation in the metal protrusions formed by 2
This is because it can be suppressed to below pm.

Further, a photosensitive polyimide film 3 serving as an ultraviolet blocking film is spin-coded on the opposite surface of the light-transmitting/insulating substrate 1, a photomask is placed on this surface, and openings 4 are formed by exposure and development.

Note that the light-transmitting/insulating substrate l is heat-resistant glass.

A quartz substrate or the like is used.

Next, as shown in FIG. 1(b), a photosensitive resin layer 5 is spin-coded over the entire surface of the transparent conductive film 2.

Next, as shown in FIG. 1(C), the photosensitive polyimide film 3
The entire surface of the opening 4 is irradiated with ultraviolet rays 6, and this ultraviolet 6
By transmitting light through the transparent/insulating substrate 1 and the transparent conductive film 2, the photosensitive resin layer 5 at a position corresponding to the position of the opening 4 is partially exposed and exposed.

Next, as shown in FIG. 1(d), this photosensitive resin layer 5 is subjected to processing such as development, removal of the exposed portion 5, rinsing, and curing in an oven to form openings 7 for forming metal protrusions.

Next, as shown in FIG. 1(e), a metal protrusion 8 having a height of 10 to 30 μm is formed in the metal protrusion forming opening 7 by electrolytic plating.

Finally, as shown in FIG. 1(f), the illuminating resin layer 5 is removed using a resist stripper.

Note that the resist stripper is a fuming nitric acid or the like, and the ultraviolet blocking film (photosensitive polyimide WII3) is not attacked by this resist stripper.

In addition, as a UV blocking film, this photosensitive polyimide WA
Not limited to 3, metal film that is not attacked by resist stripper (
Cr, Ti, PL, etc.) can be used.

The metal protrusion 8 formed in this way is shown in FIG. 3(a).

In the same manner as the conventional method shown in (b) and (C), it is transferred and bonded to the inner lead of the film carrier.

When forming metal protrusions again on the metal protrusion-forming substrate on which the metal protrusions have been transferred to the inner leads, the steps shown in FIG. 1(b) are repeated. That is, a light-transmitting/insulating substrate 1 having the structure shown in FIG. 1(a). The transparent conductive film 2 and the ultraviolet shielding film (photosensitive polyimide film 3) can be used repeatedly, and in subsequent steps, the conventional patterning step by mask alignment becomes unnecessary.

Note that when the above metal film is used as a UV blocking film, the transparent/insulating substrate on which the metal protrusions are formed becomes opaque due to this metal film, so when the metal protrusions are transferred and bonded to the inner leads of the film carrier, The alignment can only be done from above, but if transparent photosensitive polyimide llll3 is used as the ultraviolet blocking film, the alignment between the metal protrusion 8 and the inner lead of the film carrier can be done from above as well as from below. Therefore, it is preferable that the ultraviolet blocking film is transparent.

〔Effect of the invention〕

According to the structure of the present invention, a transparent conductive film is formed on one main surface of a transparent/insulating substrate, a photosensitive resin layer is formed on the transparent conductive crotch, and further, a photosensitive resin layer is formed on the opposite surface of the transparent/insulating substrate. Since an ultraviolet blocking film with openings is formed, ultraviolet rays are transmitted through the openings of the ultraviolet blocking film to the photosensitive resin layer formed on the opposite side, and by developing and removing the exposed areas, metal protrusions are formed on the photosensitive resin layer. A forming opening can be formed. Therefore, by using an ultraviolet blocking film having openings, it is possible to avoid the patterning process by mask alignment, which was conventionally necessary when forming openings in a photosensitive resin layer where metal protrusions are to be formed. It is possible to easily and repeatedly form the metal protrusion forming grooves on the resin layer.As a result, there is no need for expensive mask alignment equipment as in the past, and a simple UV irradiation machine can be used to form photosensitive resins. It becomes possible to pattern the openings for forming metal protrusions in the layer, making it possible to significantly reduce costs, greatly simplifying and shortening the process, and improving yield.

[Brief explanation of drawings]

Figure 1 (a), (b), (cl, (d), (e
), (f) is a process diagram showing a method for manufacturing a metal protrusion-formed substrate according to an embodiment of the present invention, and FIGS. 2(a), (b),
(C), (d), (e), (f) are process diagrams showing the conventional method for forming metal protrusions, Figures 3 (a), (b),
(C1 is a process diagram showing the process of transferring and bonding the formed metal protrusion to the inner lead of the film carrier. l... Transparent/insulating substrate, 2... Transparent conductive film, 3...
・・Photosensitive polyimide film (UV blocking 1lI), 4・・
- Opening, 5... Photosensitive resin layer, 7... Opening for forming metal protrusions (a) (b) Figures (a) (b) (c) ◇ Figures (e) (f) figure

Claims (2)

[Claims] (1) A light-transmitting/insulating substrate, a transparent conductive film formed on one main surface of the light-transmitting/insulating substrate, and an ultraviolet shield having an opening formed on the opposite surface of the light-transmitting/insulating substrate. A metal protrusion forming substrate comprising: a film; and a photosensitive resin layer formed on the transparent conductive film and having an opening for forming a metal protrusion at a position corresponding to the position of the opening of the ultraviolet blocking film. (2) A step of preparing a light-transmitting/insulating substrate on which a transparent conductive film is formed on one main surface and an ultraviolet blocking film having openings on the opposite surface, and a photosensitive resin layer on the transparent conductive film. a step of irradiating the photosensitive resin layer with ultraviolet rays through the openings by irradiating the ultraviolet rays from the surface side of the ultraviolet blocking film; and a step of irradiating the photosensitive resin layer with ultraviolet rays through the openings; A metal protrusion comprising the step of forming an opening for forming a metal protrusion at a position corresponding to the position of the opening of the ultraviolet blocking film by developing and removing a photosensitive portion of the layer, and then curing the photosensitive resin layer. A method for manufacturing a forming substrate.