JPH04167536A - Formation method of opening part in metallic bump formation substance - Google Patents

Abstract

PURPOSE:To enable an opening part having a smooth taper to be formed stably by a method wherein, after the formation of a vertical opening part on a part of insulating film using CF4 etching gas, the insulating film is further etched away while etching back the taper part of photoresist using CF4+O2 mixed gas. CONSTITUTION:An opening part 6 is vertically bonded by dry-etching process using CF4 etching gas as well as an individual insulating film 5 as a plating mask of a transfer bump formation substrate or using photoresist as an etching mask 9 on a part of the insulating film 5 and a conductive film 4. Next, a taper 10 is formed in the opening part 6 by dry-etching process using CF4+O2 mixed gas simultaneously etching away the etching mask 9 of photoresist and the insulating film 5 while etching back the opening part taper 8. Through these procedures, the opening part 6 having a smooth taper 10 can be formed stably.

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Application Field of the Invention The present invention 1 relates to a method for manufacturing a metal protrusion-formed substrate for forming bumps used in a transfer bump method which is a semiconductor mounting method.Prior art Conventional metal protrusions The manufacturing method of the formed substrate and the transfer bump mounting method will be explained with reference to the third plate and FIG.
Although the conductive film 32 is formed on the entire surface of the insulating substrate 31, it is preferable to use ceramic glass or the like for the insulating substrate 31.
Next, an insulating film to be used as a plating mask 33 is formed on the entire surface of the conductive film 32, and a photoresist is used as an etching mask to form a tapered film at a position corresponding to the electrode of the semiconductor element. Opening 34 with
This plating mask 33 is generally made of P-C.
Using inorganic thin films such as 5ide and 5isN4 formed by VD method etc., the film thickness is from about 500nm to 11000nm.
In terms of degree, CF=, Oe for the formation of the opening.
A dry etching method is used to form a metal protrusion (Au) on the upper surface of the conductive film 32 in the opening 34 formed in the plating mask 33 by electroplating using the conductive film 32 as a plating electrode. Thereafter, the bumps and priming are formed, and then the bumps 35 formed on the bump forming substrate 31 are aligned with the inner leads 42 of the film carrier 41 as shown in FIG. 4(a).FIG. 4(b) As shown in FIG. 4(c), the bump 35 and the inner lead 42 are bonded together by applying pressure with the heated pressure tool 43a.The pressure tool 43 is released as shown in FIG. Transfer to 42a Next
As shown in FIG. 4(d), the inner lead 42 with the bump 35 and the aluminum electrode 45 of the semiconductor element 44 are aligned L/%.As shown in FIG. 4(e), the pressure tool 43
After that, as shown in FIG. 4(f), the pressure is released and the mounting of the semiconductor element 44 is completed. Problems to be Solved by the Invention When used again as a plating substrate for bump formation, however, the conventional example has the following problems. It is necessary to form a smooth taper, however, when the conventional insulating film is thick or the conductive film is made of Ti.
When a three-layer film such as /Pt/Ti is used, Ti must be etched, but since Ti has a slow etching rate, there is a problem that the photoresist etching mask is used up before the opening is formed. The present invention provides an opening formation method for stably forming a tapered opening in an insulating film of a metal protrusion forming substrate or a film with a slow etch rate. In order to solve the problems, the present invention (L) forms a conductive film on an insulating substrate, forms an insulating film on the conductive film, and forms a tapered opening in the insulating film at a position corresponding to an electrode of a semiconductor element. CF-etching the photoresist as an etching mask on the insulating film alone or on a part of the insulating film and the conductive film in a chamber in which a quartz plate, a Teflon sheet, etc. is arranged around the substrate. An opening is formed perpendicularly to the insulating substrate by dry etching using an etching gas of . A method in which a smooth taper is formed on a part of the insulating film and the conductive film, and the photoresist is removed using plasma or a resist stripping agent.Metal protrusions such as AU are formed in the openings by electrolytic plating. The present invention provides a method for forming openings in a metal protrusion-forming substrate ((a method for forming metal protrusions repeatedly in the openings after the metal protrusions have been removed). A photoresist is applied as an etching mask to the insulating film alone or to a part of the insulating film and conductive film used as a plating mask for the bump-forming substrate.
After forming a vertical opening by a dry etching method using an etching gas of CF, etching is further performed while receding the tapered portion of the photoresist with a mixed gas of CF,. According to an embodiment of the present invention, an opening having a smooth taper can be stably formed in a part of the conductive film, regardless of the thickness or etch rate of the insulating film or the conductive film. The method will be explained with reference to the first plate and FIG. Use glass, etc. u% Use Ti for the conductive film 2, which easily forms chemical bonds with glass, etc. 1. X, Next, a conductive film 3 is formed on this conductive film 2 to become an electrode for electrolytic plating. Pt is used for the conductive film 3, but a chemical bond is formed on the conductive film 3 with an insulating film 5 which becomes a mask for plating. The conductive film 4 can be easily formed by using Ti for the conductive M4.The conductive film can be formed by sputter deposition, etc.The insulating film 5 can be formed by the P-CVD method (plasma CVD method), etc. IIE (hereinafter referred to as P-5iN) is formed to a thickness of about 650 nm (FIG. 1(a)). Using the photoresist with a taper 8 formed in the opening of this resistor as an etching mask 9, an opening 6 is formed at a position corresponding to the electrode of the semiconductor element.The photoresist used is 0MR83250cp manufactured by Tokyo Ohka Co., Ltd. After the photolithography process is completed, approximately A taper 8 is formed in the opening by heating at 160° C. (FIG. 1(b)). The angle of the taper 8 is adjusted by the heating time.To form the opening 6, the P-3iN is etched perpendicularly to the insulating substrate 1 by dry etching using CF4 gas in a chamber with a quartz plate placed around the substrate 1. Forming the opening 6 (Fig. 1(C)
). Next, the photoresist etching mask 9 and the insulating film 5 are simultaneously etched by a dry etching method using a CF, 02 mixed gas, thereby etching the insulating film 5 while retracting the opening taper 8 of the photoresist etching mask 9. A taper lO is formed in the opening 6 (FIG. 1(d)). taper 10
The angle of is adjusted by the angle of the taper 8 of the photoresist. After that, the photoresist is removed by O2 plasma (FIG. 1(e)).

Next, as shown in FIG. 1(f), a conductive film 3 is placed in the opening 6.
Metal protrusions and bumps 7 are formed by electrolytic plating using the metal bumps 7 as plating electrodes.Next, as shown in FIG. As shown in FIG. 2(b), the bump 7 and the inner lead 22 are joined by applying pressure with the heated pressure tool 23. As shown in FIG. 2(c), the pressure tool 23 is Release the bump 7 and transfer it to the inner lead 22. Next Align the inner lead 22 with the bump 7 and the aluminum electrode 25 of the semiconductor element 24 as shown in FIG. 2(d) L as shown in FIG. 2(e). As shown in FIG. 2(f), the pressure is released after joining the plums all at once using the pressure tool 23.
After completing the mounting of the semiconductor element 24, bumps 7 are formed on the substrate 1 from which the bumps 7 have been removed by repeated electrolytic plating.Advantages of the InventionAs in the present invention, an insulating film used as a plating mask for a bump-forming substrate for transfer. C using a photoresist as an etching mask alone or on a part of the insulating film and conductive film.
The insulating film alone or the insulating film and To stably form an opening having a smooth taper necessary for smoothly transferring a formed bump in a part of a conductive film, regardless of the film thickness or etch rate of the insulating film or conductive film. It is a material that can fully contribute to the mounting of semiconductor devices.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the formation process of a bump-formed substrate used in an embodiment of the present invention. FIG. 2 shows the process of transferring bumps to leads and the process of bonding bump-plated leads to semiconductor elements in the present invention. Fig. 3 is a cross-sectional view of a conventional bump-forming substrate. Fig. 4 is a cross-sectional view showing the process of bonding bumps and leads and the bonding of bumped leads and semiconductor elements in the same conventional example. Group jfi, 2...first layer conductivity lL 3
...Second layer conductive 11L4...Third layer conductive wind 5
... Insulating film mass length 6... Opening 7... Bump 8... Photoresist opening taper, 9...
Photoresist etching mask length 10...Opening taper. -~suφI/) Mouse work

Claims (2)

[Claims] (1) For photoresist etching, in which a conductive film is formed on an insulating substrate, an insulating film is formed on the conductive film, and a tapered opening is formed in the insulating film at a position corresponding to the electrode of a semiconductor element. In a chamber in which a mask is formed and a quartz plate or a Teflon sheet is arranged around the substrate, a photoresist is etched as an etching mask on the insulating film alone or on a part of the insulating film and the conductive film.
After forming an opening perpendicular to the insulating substrate by dry etching using an etching gas of F_4, CF_
4. After further etching the tapered portion of the photoresist using a mixed gas of O_2 to form a smooth taper on the insulating film alone or on a part of the insulating film and the conductive film, O_2 plasma or a resist stripping agent is applied. 1. A method for forming an opening in a metal protrusion-formed substrate, the method comprising: removing the photoresist, and then forming a metal protrusion of Au or the like in the opening by electrolytic plating. (2) The method for forming an opening in a metal protrusion-formed substrate according to claim 1, wherein the metal protrusion is repeatedly formed in the opening after the metal protrusion is removed.