FR2699329A1 - A method of positioning semiconductor wafers relative to each other. - Google Patents

Abstract

The invention relates to a method for positioning two semiconductor wafers relative to each other. At least two cavities of determined size are arranged in the surface of each of the plates. A ball of known diameter is placed in each cavity of the first wafer so that the ball penetrates to its equatorial line in the cavity concerned and the second wafer is placed. The balls ensure precise positioning of the two pads relative to each other.

Description

Positioning method with respect to each other

of semiconductor chips.

  The invention relates to a method for the prepositioning of

  cis, one with respect to the other, two semiconductor wafers

  tors. The problem that arises during the manufacture of detectors, in particular during the manufacture of micromechanical detectors,

  is that we must first position one against the other two

  semiconductors or more and then connect them by

  suitable techniques (eg anodic bonding, other bonding of

  Various methods are known for carrying out this position.

ment.

  In the transmitted infrared light process, the

  two semiconductor wafers with long-lasting light

  With the aid of a microscope, an infrared camera and a positioning device, particular structures are located between the semiconductor wafers and positioned relative to each other. disadvantage of this process is that

  long-wave infrared light does not allow to obtain

  to provide sufficient positioning accuracy and that

  doped or metallized materials can not be illuminated with

infrared.

  The bilateral positioning process uses two half

  croscopes; the first microscope is directed on the upper face of the first semiconductor wafer and the second microscope is directed on the lower face of the second wafer. First, the two microscopes are positioned with respect to each other. using a transparent mask The two plates are then placed

  semiconductors in the apparatus and, by means of a po-

  sitioning, one adjusts the position of the upper plate with its marks relative to the reticle of the upper microscope The same procedure is used for the lower plate The disadvantage of this

  This process is among other things the high cost of equipment.

  Moreover, the disadvantage of these two methods is that the

  link (commonly known as bonding) must be carried out immediately

  after positioning, which link takes place at

  erations of a few hundred degrees C In terms of equipment

  the combination of heaters and mechanical devices

  high precision is very delicate and very expensive.

  By Japanese Patent Application Publication 3-106012 of

  02.05 1991, a method for positioning and adjusting optical

  semiconductor substrates, which process requires the application of

  plication on the substrates of layers with a pre-permeability

determined by light.

  The object of the present invention is to provide a simple means that allows positioning and precision to adjust one by

  report to the other two semiconductor wafers.

  The problem is solved according to the invention by the fact that a ball of known diameter is introduced into a cavity in the

  first semiconductor wafer so that the ball penetrates the

  to reach its equatorial line in the said cavity and that

  a corresponding cavity of the second semiconductor wafer

  in relation to the other half of the diameter of the ball, so that the ball ensures exact positioning of the two plates

  of semiconductors relative to each other.

  According to a feature of the invention, cavities

  in semiconductor wafers are carried out by means of

  ceded anisotropic or isotropic chemical or physical cavities The cavities have defined dimensions and are arranged at points facing the semiconductor wafers The ball penetrates into a technically adapted proportion of its diameter in the cavity

  corresponding semiconductor wafers to be positioned.

  According to one characteristic of the invention, each of the semiconductor chips to be positioned comprises several

  cavities and a ball is associated each time with two cavities which coincide

  tooth. The process according to the invention is described below from

  the example of a flow detector shown in Figure 1.

  The flow detector consists of

  semiconductors 1 and 2 between which are arranged the flow channel

3 and the sensor 4.

  By a photolithographic process, at least two openings are made on each of the surfaces to be assembled. Then, by a chemical or physical process, cavities are made in the platelets.

  semiconductors 1 and 2 at the openings (Figure 2).

  the cavity thus obtained must be known; it must be such that a ball 6 of perfectly defined diameter can be placed in said cavity and penetrates into it precisely to its line

  equatorial or up to half its diameter

  placing the first semiconductor wafer 1 so that its cavities are turned upwards and balls 6 are placed in the cavities, the second semiconductor wafer 2 can be brought

  provided with cavities 5 similar on the first, only one position-

  In this case, by the action of the weight of the upper plate, the cavities are positioned on the projecting halves of the balls so that a positioning is obtained.

  Precise platelets relative to each other The sensor delimits

  electrical signals to the outside for the intermediate

number of contacts 7.

  This process has a number of other advantages: the steps of the photolithographic process, the steps of

  chemical and physical attack processes are part of

  standard semiconductor manufacturing process and therefore

  the cavities can be made in a simple manner during a

quence of a standard process.

  automatic positioning of semiconductor wafers

  conductors by their own weight is carried out with a precision of gold-

dre of the micrometer.

  semiconductor wafers can be transported

  without difficulty in the positioning state with a low application pressure. no expensive installation, such as microscopes at

  red, bilateral devices and other manipulators, is necessary.

  platelet positioning can be done directly

  the link execution device with little additional

  tional. The method can be applied not only to the manufacture of silicon micro-mechanical detectors but also in all

  areas of microelectronics and micro-mechanics where a po-

  extremely precise sitioning is necessary and where it is not possible

  to use mechanical stops arranged at the outer edges

substrates.

Claims (4)

  Method for the positioning and adjustment of two semiconductor wafers with respect to one another, characterized   by the fact that a ball of known diameter is introduced into a   of the first semiconductor wafer so that it penetrates to its equatorial line in said cavity and that   the other half of the ball is brought into relation with a cavity corresponding to   of the second semiconductor wafer so as to obtain with the aid of the ball a positioning of the two wafers of   semiconductors relative to each other.   Process according to Claim 1, characterized in that the cavities (5) are produced by chemical or physical processes anisotropic or isotropic.   Process according to any one of the preceding claims   characterized by the fact that the cavities have defined dimensions   and located at points facing the plaquet- semiconductors.   Process according to any one of the preceding claims   characterized by the fact that the ball enters a technical report   nically adapted from its diameter in the corresponding cavities of   semiconductor chips to be positioned.   A process according to any preceding claim   characterized by the fact that each of the semiconductor wafers   positioning conductors has a plurality of cavities and a ball   is associated each time with two coincidental cavities.