Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Making named article
Reexamination Certificate
1999-08-16
2001-06-26
McPherson, John A. (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Making named article
C430S967000, C205S070000
Reexamination Certificate
active
06251565
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention discloses another method that employs micro photo etching technique used in semiconductor manufacturing to fabricate a plurality of molds then stacking up and electroplating the molds to form a multiple-lead punch die for producing microparts.
2. Description of the Prior Art
Traditional ways of manufacturing microparts generally include optical projective wheel grinding and wire cutting EDM (Electro-Discharged Machining). These methods use mechanical machining to make the parts to the required dimension. As mechanical machining has its inherent precision limitation, it usually is difficult or impossible to produce the microparts in large quantity while still maintain high degree of dimensional precision.
Another traditional way to produce microparts in large quantity is through punching process that uses molds such as punches, strippers and die plate. However the molds usually have to be made by mechanical machining which has precision problem set forth above. Moreover the machining stress and residual stress becomes another factor making precise dimension difficult to attain.
Nevertheless using punch molds for producing microparts is still a widely used method. This method includes to fabricate single or simple parts by mechanical machining, then assemble the parts to become molds such as punches, strippers and die plates. However this method introduces other type of problems. One is that it needs multiple working stations to perform all the machining required. Production time and cost become higher. Another problem is that the pitch between leads is large due to mechanical factors. It therefore becomes very difficult to produce large number of leads within a small dimension. All this becomes serious issue to be resolved when trying to mass produce microparts with high precision at low cost.
FIGS. 1 and 2
illustrate an example of the traditional ways set forth above. A press board
1
consists of four different mold plates (FIG.
1
A). Each mold plate has one or more guided hole
10
which is formed by wire cutting EDM (FIG.
1
B). The mold plate may also consist of an upper mold plate
12
and a lower mold plate
14
which are made respectively by optical projective wheel grinding and then be assembled together (FIG.
1
C).
FIG. 2
illustrates a mold assembly made by the pressboard shown in FIG.
1
. There is a fixed board
20
which has a plurality of screw holes
28
and grooves
29
formed therein. A punch
15
for a guided hole
16
is mounted on a groove. Each punch
15
has a slant section
18
adjacent the guide hole
16
and a key way
24
adjacent the groove
29
. A metal key
22
engages with the keyways of the assembled punches and being fastened tightly to the fixed board
20
by means of screws
26
engaging with screw holes
28
.
FIG. 3
illustrates the method of using LIGA technique to make molds for producing multiple-lead microstructures disclosed by Applicant in U.S. Pat. No. 5,645,977. It includes disposing a layer of resist
30
on a base plate
33
. Then a mask
31
is placed above the resist
30
. A X-ray (or ultraviolet light)
32
is employed to project upon the mask
31
to form a lead punch
34
in the resist layer
30
(FIGS.
3
A and
3
B). Then an electroplating process is performed on the lead punch
34
to form an electroforming metal layer
35
thereon (FIG.
3
C). Finally, the base plate
33
and the lead punch
34
are removed to obtain the electroforming metal layer
35
with lead dies
351
formed therein.
SUMMARY OF THE INVENTION
The object of this invention is to further extend the aforesaid method by including microetching technique used in semiconductor manufacturing process and a co-pattern mask to form punch molds for producing high density and high precision multiple-lead microstructures.
In one embodiment of this invention, a conductive layer is firstly formed on a lower photoresist layer and an upper photo resist layer is then formed on the conductive layer. Then a mask is placed above the upper photo resist layer. The mask and the photo resist layer are then exposed to an ultraviolet light to produce reaction in the upper photo resist layer. After etching process, the upper photo resist layer forms the mold releases required. The mold recesses are then processed by electroplating to form a metal mold. The upper photo resist layer and the conductive layer are then removed. The remaining structure is subjected to a X-ray exposure and another etching process. Then the base plate and the co-pattern mask are removed to get the punch mold required. The aforesaid process is repeated a number of times to obtain multiple number of punch molds. Then stacking and overlaying the punch molds one upon another until a desired height is reached. The stacked up punch mold then is processed by another round of electroplating to become a finished punch mold.
Through the X-ray co-pattern mask, a punch mold for multiple-lead microstructures may be made for producing the multiple-lead microstructures. The thickness of the punch mold may be made more than the depth of X-ray engraving. The lead number density may be increased and flexibly deployed. Through electroplating process, the punch mold surface may be covered by a layer of material of high hardness. It greatly enhances wear resistance and durability. It thus may be used for mass production of microparts at a low cost.
REFERENCES:
patent: 5645977 (1997-07-01), Wu et al.
patent: 6093520 (2000-07-01), Vladimirsky et al.
Chou Min-Chieh
Mu Chuan-Kang
Pan Cheng-Tang
Yang Hsi-Harng
Industrial Technology Research Institute
Liauh W. Wayne
McPherson John A.
LandOfFree
Method of making molds for manufacturing multiple-lead... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of making molds for manufacturing multiple-lead..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of making molds for manufacturing multiple-lead... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2511141