T 0076/96 () of 24.7.2001

European Case Law Identifier: ECLI:EP:BA:2001:T007696.20010724
Date of decision: 24 July 2001
Case number: T 0076/96
Application number: 91300566.6
IPC class: H01J 37/34
Language of proceedings: EN
Distribution: C
Download and more information:
Decision text in EN (PDF, 430 KB)
Documentation of the appeal procedure can be found in the Register
Bibliographic information is available in: EN
Versions: Unpublished
Title of application: Sputtering apparatus with a rotating magnet array having a geometry for specified target erosion profile
Applicant name: Varian Semiconductor Equipment Associates Inc.
Opponent name: -
Board: 3.5.02
Headnote: -
Relevant legal provisions:
European Patent Convention 1973 Art 84
Keywords: Clarity - (yes, after amendment)


Cited decisions:
Citing decisions:

Summary of Facts and Submissions

I. This is an appeal from the refusal of European patent application No. 91 300 566.6 on the ground that claim 1 was not clear.

II. The following prior art documents are mentioned in the European search report:

EP-A-0 399 710 (prior art according to Article 54(3) EPC)

Patent Abstracts of Japan, Vol. 7, No. 39(C-151)(184), & JP-A-57 192 262 (cited as D1 in the examining division's communication dated 14 January 1994)

US-A-4 498 969 (cited as D2 in the examining division's communication dated 14 January 1994).

III. In response to a communication from the board indicating amendments which appeared necessary to overcome those objections of the examining division which the board was inclined to sustain, the appellant filed an amended claim 1 which is reproduced below with amendment insertions in bold type and deletions in square brackets:

"A magnetron sputter apparatus comprising:

a vacuum chamber;

means for holding a target having a dished front surface in said vacuum chamber, said front surface being a surface of revolution; and

rotatable magnetic means for generating a rotating magnetic field over said front surface of said target,

said magnetic field having a centerline forming a curve in the front surface of the target,

characterised in that

said magnetic means is [being] configured so that at least a first portion of the normalized centerline of said magnetic means is describable by an equation in cylindrical coordinates (r, z, ) of the form


where (r) is a preselected normalized erosion profile to be generated in said target during rotation of said magnetic means about the z-axis, z(r) defines said surface of revolution, C is a selected constant, and has a selected range."

IV. The examining division took the view, albeit in relation to the unamended claim, that, in order to clarify "magnetic means" it would be at least necessary to state in claim 1 that a number of magnetic dipoles were arranged along a certain curve. It also objected to the fact that the distance between the magnetic means and the target surface was not specified. It considered the expressions "normalized centerline" and "normalized erosion profile" to be obscure and maintained that as a consequence of the various obscurities a person of ordinary skill in the art would not be able to determine the constant C.

The examining division further considered that acceptance of the appellant's explanation in his letter of 14 March 1995, paragraph 3, of how the constant C could be determined would imply that the application as originally filed did not disclose the invention in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art (Article 83 EPC).

V. The appellant argued essentially that it was not necessary for claim 1 to specify the arrangement of the components of the magnetic means because it was within the ability of the skilled person to select any magnetic field generator which would fit the other conditions of the claim. The centerline was called a normalized centerline because the equation was dimensionless. The invention was not limited to any particular units or range of values in a given unit. It was not necessary to mention the distance between the magnetic means and the target surface because this did not affect the uniformity of the magnetic field at the target, only its intensity. The erosion profile was a shape, as illustrated in some of the figures, and was normalized because it had no units; like the normalised centerline, it was concerned with shape and not with absolute values. The constant C was to take account of the axis from which was measured.

VI. The appellant requests that the decision under appeal be set aside and that a patent be granted in the following version:

Claims: 1 filed with the letter dated 23 May 2001, 2. to 10, as originally filed;

Description: pages 2,3,4,9, and 26 filed with the letter dated 23 May 2001, pages 7, 19 and 20 filed with the letter dated 21 October 1994, pages 1, 5,6 8,10 to 18, 21 to 25, 27 to 31. as originally filed;

Drawings: sheets 1 to 15 as originally filed.

Reasons for the Decision

1. The appeal is admissible.

2. Amendments

2.1. Claim 1 has been put in the two part form prescribed by Rule 29(1) EPC. The pre-characterizing part is based on D1. An obvious error in the equation has been corrected: claim 1 as originally filed had a plus sign under the second square root in the equation, but comparison with the description on page 29 and the equation in claim 2, which is for the special case when the preselected erosion profile is constant, shows that the plus sign was an error and that only a minus sign could have been intended. This also deals with the discrepancy between claims 1 and 2 as originally filed which the examining division pointed out at point 3 of the decision under appeal.

2.2. The description has been amended to mention the prior art according to D1 and to replace the statement of invention on pages 2 and 3 by a reference to claim 1.

2.3. The claim amendments are allowable under Article 123(2) EPC. In particular, the link now established in the claim between the centerline of the magnetic means and the centerline of the magnetic field is based on the definition of the centerline of the magnetic means given in the application as originally filed at page 16, lines 13 to 18, (page 7, last line to page 8, line 4 of the published application), which defines "the centerline of the magnetic means" as (the locus)"..where the tangents to the magnetic field lines (shown in Figs 1 and 9) are parallel to the surface of the target."

3. Clarity of claim 1

3.1. The expressions "normalized centerline" and "normalized erosion profile" are commonly employed terms in the art as used, for example, in claim 1 of the patent granted on EP-A-0 399 710 cited in the search report. The qualifier "normalized" simply indicates that the curves and profiles are universal or standardized expressions of relative values and do not specify any absolute dimensions; they specify shape not size.

3.2. The amended claim 1 now makes it clear that the "normalized centerline of said magnetic means" is to be taken as the centerline of the magnetic field generated at the front surface of the target by the said magnetic means, in accordance with the definition in the description (cf point 2.3 above). In the board's view, this clarified functional definition of the "magnetic means" makes it inappropriate to require the applicant to restrict the claim to the dipole array of the preferred embodiment.

3.3. In the judgement of the board, amended claim 1 defines the matter for which protection is sought in a clear manner. It is also supported by the description. Thus, the requirements of Article 84 EPC are met.

The board does not share the view expressed by the examining division that the explanation offered by the appellant as to how the person skilled in the art would interpret and determine the constant C in the equation implies that the original disclosure was insufficient. In the judgement of the board, the person skilled in the art would appreciate from the examples in the description how the constant C allowed for a choice of a reference axis for .

The board therefore concludes that the decision under appeal must be set aside.

4. In view of the nature of the objections to claim 1, the examining division was unable to proceed with the examination of the application in respect of the other requirements of the EPC. Not least having regard to the fact the application contains an independent claim 7, which appears indeed to be the broadest claim despite its misleading position, and which has not been the subject of any comment in the examination procedure, it would not be appropriate for the board to complete the examination of the application in exercise of its powers under Article 111(1) EPC, first part of second sentence.


For these reasons it is decided that:

1. The decision under appeal is set aside.

2. The case is remitted to the department of first instance for further prosecution.

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