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Full text of "USPTO Patents Application 10020506"

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Appln No. 10/020,506 
Azndt date March 15, 2004 

Reply to Office action of February 27, 2004 



REMARKS / ARGUMENTS 

In order to place the application in condition for 
allowance, FIGS. 1A and IB have been cancelled and FIG. 10 has 
been amended to include the reference numerals 14, 16 and 18 
that are shown in FIG. 1A. In addition, references in the 
specification to FIGS. 1A and IB have been modified to refer to 
FIG. 10 and 11A respectively. The following text shows the 
changes that have been made to the 11 paragraphs originally 
submitted via amendment on December 15, 2003 by the substitution 
of the 11 paragraphs submitted in this amendment: 

Referring now to the drawings, a printed wiring 
board ("PWB") 10 [a] | 1 ' 1 in accordance with an 
embodiment of the present invention is shown in FIG. 
1[A]0. The PWB includes a first laminate 120, and a 
second laminate 122, multiple layers of prepreg 124 and 
multiple layers of metal 126. The PWB 10 Tal 1 ' ' ' 
contains circuits and is used for mounting integrated 
circuits (ICs) and components. The term circuit is used 
to describe an electrically conductive path between two 
or more points. Individual layers of the PWB can 
include circuits and a number of circuits on several 
layers of the PWB can be connected to create an overall 
PWB circuit. The layers on which circuits are located 
are often referred to as functional layers. 

The laminates 12 0 and 122 comprise a carbon 
containing layer 14 sandwiched between a first layer of 
metal or other electrically conductive material 16 and 
a second layer of metal or other electrically 
conductive material 18. Both of the laminates 120 and 
122 are electrically conductive, which enables the 



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Appln No. 10/020,506 
Amdt date March 15, 2004 

Reply to Office action of February 27, 2004 



laminate to be used as a functional layer within the 
PWB. The functions that can be performed by the 
laminates include acting as a ground plane within the 
PWB, a power plane within a PWB or both a ground and 
power plane in the PWB where routing is used to 
electrically isolate portions of the laminate. Various 
examples of other laminate structures that can be used 
in accordance with the present invention to implement 
the laminates 120 and 122 are discussed below. 

The layers of metal can act as functional layers 
in the PWB. In one embodiment, the layers of metal or 
other electrically conductive material are patterned 
with electrical circuits. Electrical contact between 
the various layers of metal or laminates can result in 
the functions of the electrical circuits patterned onto 
the layers of metal being interrupted. Therefore, 
prepregs are used to electrically insulate the 
electrically conductive laminates 12 0 and 122 and the 
layers of metal 126. 

A prepreg is a composite layer that includes a 
substrate or supporting material composed of fibrous 
material that is impregnated with resin. The prepregs 
are electrical insulators having dielectric constants 
less than 6.0 at 1 MHz. A prepreg may also be a film. A 
film is a type of prepreg that does not include a 
substrate but is instead a composite that only includes 
resins. Materials that can be used to construct 
prepregs in accordance with the present invention are 
discussed below. 

Often, the circuits within a PWB include plated 
"through holes" to establish connections between the 
functional layers of the PWB. In one embodiment, the 



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Appln No. 10/020,506 
Azndt date March 15, 2004 

Reply to Office action of February 27, 2004 



PWB 10 [a] ; ' ; ; includes through holes 130 lined with 
electrically conductive material that are used to 
establish electrical connections between the functional 
layers in the PWB. These lined through holes enable 
electrical signals to pass between circuits on the 
metal layers and/or the laminates. It is well known in 
the art that connections can be created between the 
electrically conductive linings of plated through holes 
and circuits patterned on a layer of metal by locating 
the plated through hole such that the lining of the 
plated through hole contacts a portion of the circuit 
patterned on the layer of metal . When a connection 
between a laminate and a plated through hole is 
desired, the through hole is simply drilled through the 
laminate at the desired location and an electrical 
connection is established where the electrically 
conductive lining of the through hole contacts the 
electrically conductive laminate. 

Techniques for avoiding electrical connections 
between circuits patterned on a layer of metal in a PWB 
and a plated through hole are well known in the art. 
Each of the options essentially involves designing the 
circuit routings and the locations of the plated 
through holes to avoid contact between the electrically 
conductive lining of the plated through hole and the 
circuit. Where connections between the plated through 
holes and the first or second laminates are not 
desired, then an annulus of dielectric material 132 
such as an epoxy resin with a dielectric constant less 
than 6.0 at 1 MHz can be used to ensure that an 
electrical connection does not exist between the 



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Appln No. 10/020,506 
Amdt date March 15, 2004 

Reply to Office action of February 27, 2004 



laminate and the electrically conductive lining of the 
through hole. 

A process in accordance with the present invention 
for manufacturing the PWB 10 [el ' ' ' ; illustrated in FIG. 
1[A]0 is shown in FIG. 1 [B1 1A. The process 150 
commences with the step 152, which involves 
constructing two laminates in accordance with the 
present invention using any of the appropriate 
processes described below including the process 
illustrated in FIG. 2A. Power or ground regions are 
then patterned on the laminates in the step 154. 

Once the patterning is complete, the laminates are 
subjected to oxide treatment in the step 156. After 
oxide treatment, clearance hole drilling is performed 
in the step 158. Clearance hole drilling involves 
drilling holes in the laminate of a first diameter and 
filling the resulting holes with a dielectric material 
such as any of the resins described below with a 
dielectric constant less than 6.0 at 1 MHz. Prior to 
filling the drilled holes, they are inspected and 
cleaned using high pressure dry air. 

Once the clearance holes have been drilled, the 
second lamination cycle is performed in the step 160. 
The second lamination cycle is similar to the second 
lamination cycle described below in relation to FIG. 
2A. After the second lamination cycle, circuits are 
etched onto the layers of metal that will be located 
within the interior of the finished PWB are patterned 
in the step 166 and then subjected to oxide treatment 
in the step 168. 

Following the oxide treatment, the third 
lamination step is performed in the step 170. The third 



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Appln No. 10/020,506 
Amdt date March 15, 2004 

Reply to Office action of February 27, 2004 

lamination involves aligning the two structures 
produced in the second lamination with additional 
prepreg layers to correspond with the layers of the PWB 
10 [a] 1 1 ' ' illustrated in FIG. 1[A]0. The layers are 
then exposed to temperatures and pressures similar to 
those experienced during the second lamination cycle. 

After the third lamination cycle, the final 
through hole drilling is performed in step 172. The 
final through hole drilling involves drilling holes 
through the entire PWB that have a second diameter, 
which is less than the first diameter described above. 
The through holes are then lined in the step 174. 
Preferably, the through holes are lined with copper. In 
other embodiments, the through holes can be plated with 
materials similar to those that can be used in the 
construction of the layers of metal. If a through hole 
passes through one of the filled clearance holes in a 
laminate, then the lining of the through holes are 
electrically isolated from the laminate in which the 
clearance hole is drilled. If a through hole does not 
pass through one of the filled clearance holes in a 
laminate, then the lining of the through holes is in 
electrical contact with the laminate. 



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Appln No. 10/020,506 
Axndt date March 15, 2004 

Reply to Office action of February 27, 2004 

Applicant submits that the application is now in condition 
for allowance and respectfully requests the prompt issuance of a 
Notice of Allowance. 



Respectfully submitted, 



CHRISTIE, PARKER & HALE, LLP 



By 



David J^Bai 
Spec&kl reco 
626/795-9900 




on 37 CFR ยง 10.9(b) 



DJB/mlm 

MLM IRVl075414.1-*-03/15/04 1:01 PM 



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Appl. No. 10/020,506 
Amdt. Dated March 15, 2004 
Reply to Office action of February 27, 2004