FR2510307A1 - SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING SUCH A DEVICE - Google Patents

Abstract

THE INVENTION RELATES TO A SEMICONDUCTOR DEVICE AND TO A PROCESS FOR MANUFACTURING SUCH A DEVICE. THIS DEVICE INCLUDES A SEMICONDUCTOR SUBSTRATE 1 INCLUDING A BONDING PLOT 28 PROVIDED ON AN INSULATING FILM 5 AND CONSISTS OF ALUMINUM MADE WITH AN ADDITIVE, A CONDUCTOR 4 LOCATED NEAR SUBSTRATE 1 AND CONNECTED BY A BONDING WIRE 10 AT THE BONDING PLOT 28, THE WIRE IS CONSTITUTED BY ALUMINUM CONTAINING THE SAME ADDITIVE AS THE BONDING PLOT, A FILM OF ALUMINUM AXIDE OXIDE 12, 13 ON THE WIRE AND THE BONDING PLOT 10, 28 , THE ASSEMBLY BEING COATED IN A RESIN 31. APPLICATION ESPECIALLY TO HIGH RELIABILITY INTEGRATED CIRCUITS WITH WELL RESISTANCE TO HUMIDITY.

Description

The present invention relates to a device for

  semiconductors and a method of manufacturing the same

  deny, and more particularly relates to an improvement in reliability through the implementation of countermeasures opposing moisture.

  One of the main modes of failure of a dis-

  semiconductor positive is a moisture-induced failure This moisture-induced failure is produced by the corrosion of aluminum (Al) in the semiconductor device. As is well known in the art, aluminum is very widely in use

  as the constituent material of semicon-

  because we can work on it and

  It is very difficult to use aluminum specifically.

  in a chip or semiconductor chip in the form of a wiring, a stud or a location of

  connection or welding and a connecting wire used to re-

  electrically bond the bonding pad and a connection terminal The aluminum thus used is likely to corrode when in contact with moisture

  having penetrated inside a casing or assembly

  This corrosion is more likely to occur in

  especially if there are ions such as Na + or Cl or -

  many stains in the vicinity of aluminum or if a

  voltage is applied to polarize an aluminum layer.

  In the art, various methods have been proposed for preventing such a failure by the presence of moisture. According to one of the known methods,

  taking into account that aluminum oxide (A 1203) possesses

  With excellent corrosion resistance, the surface of the aluminum is oxidized to form a film of aluminum oxide, so that aluminum is protected from corrosion by this corrosion-resistant oxide film. Japanese Patent Application Publication No. 52-117551, for example, discloses the fact that the surfaces of a wire and a stud

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  are made of aluminum, are oxidized with

  On the other hand, it is found in Japanese Patent Application Publication No. 51-9470,

  the fact that the surface of aluminum cabling

  nium inside the microchip is oxidized by

  to form an oxide film.

  As excellent as the resistance of the pel-

  oxides of aluminum oxide to corrosion, there is no

  during any existing article, in which the surfaces of an aluminum bonding pad and a bonding wire to be connected to the bond pad are oxidized to form oxide films.

  the failure due to moisture is more dependent on the

  the smoothness of a gas box, or the use of a

  resin-like material Failure to use the aluminum oxide film on the surface of the aluminum to prevent moisture failure in the prior art, as just described, is based on the fact that the method used in the art

  the previous one did not allow training to be

  Aluminum oxide film More specifically, the method of the prior art has not allowed

  to efficiently form a film of aluminum oxide

  minium having uniform thickness and resistance

  excellent corrosion This phenomenon has not been explained

  cited and caused significant problems.

  In addition, the realization of the prior art

  a problem in the fact that the wiring breaks frequently

  at the level of the part of the connecting link of

  you can not have an excellent connection.

  This is because, when the exposed or exposed surface of the bonding pad is to be oxidized to form the aluminum oxide film, the oxidized region is not merely limited to said surface portion, but reaches a deep part inside the layer of

  aluminum, which leads to a deterioration of the

  nexion between the aluminum layer of the bonding pad and

the aluminum layer of the wiring.

  The realization of the prior art raises another

  problem is that resistance to

  This is due to the fact that the aluminum wiring beneath a final passivation film corrodes under the action of moisture that has penetrated through the crack.

  formed in the final passivation film.

  Therefore, an essential object of the present invention is to provide a highly reliable semiconductor device, whose wiring layer including a bonding pad-aluminum and its connecting wire are

  protected against corrosion by the action of

  aluminum oxide formed on the surfaces of the

  wiring layer and wire connection.

  Another object of the present invention is to provide

  a process for the formation of aluminum oxide films

  nium on both a bonding pad made of aluminum and a bonding wire made of aluminum and connected to the

bonding pad.

  In order to achieve the objectives of this

  invention and, according to one aspect of the latter, the

  element constituting the bonding pad and the material constituting

  tying the wire are materials based on

  luminium containing additives and having a tendency

this identical to ionization.

  In addition, according to another characteristic of the present invention, when the surface portion of the aluminum bonding pad, which is not covered by a final passivation film, and the surface of the wire of

  aluminum bond must be oxidised in order to achieve

  shooting at the formation of aluminum oxide films, these

  oxidation is carried out by short-circuiting the

  ductors which are connected to the respective wires of connection.

  According to another characteristic of the

  In addition, the bonding pad is made up of

  two layers of aluminum, namely a layer superior to

  re and a lower layer, among which the layer

  The lower aluminum layer constitutes the wiring layer re-

  linked to the bonding pad, while the aluminum top layer forms a connecting part, and the aluminum bonding wire is connected to the stacked part, in

  which these two aluminum layers are connected.

  In addition, according to another aspect of this

  two aluminum oxide films, one of which is formed by oxidation on the surface of the aluminum layer below the film of

  final passivation and the other of which is oxidized

  at the same time on a surface part of the bonding pad.

  its aluminum, which is not covered by the film

  the final passivation, and on the surface of the wire of

aluminum binding.

  Therefore the present invention is suitable

  to remarkably improve the reliability of a

  semiconductor positive, in particular of a device

  Semiconductor type resin molded type.

  Other features and advantages of the pre-

  invention will emerge from the description given below.

  after making reference to the accompanying drawings, on

  which: Figure 1 shows a sectional view showing

  part of a finished product of a semicon-

  ductors according to the present invention; FIG. 2 represents a plan view, at most

  large scale, showing schematically a plot of

  sound of the semiconductor device of Figure 1; and Figures 3A to 3F, Figure 4 and Figure 5 are views illustrating the manufacturing process of the

  semiconductor device of Figure 1.

  FIG. 1 is a sectional view showing a diagram showing

  merely an embodiment of the present invention.

  This embodiment provides a structure in which the present invention is applied to a

  semiconductor device of the type molded in the resin.

  This semiconductor device is molded in its entirety

  ble in a resin 31, except a portion of a conductor 4 which constitutes an outer terminal of the device On

  note that Figure 1 does not show the

  left of the sectional view of the semicon-

transducers.

  Reference numeral 1 denotes a substrate se-

  In this substrate 1 is formed a semiconductor element as shown in FIG. 3A. More specifically, on the substrate 1 is formed a first aluminum layer 6, which is located on a first interlayer insulating film. , made of Si O 2 This aluminum layer 6 con-

  both a part of a connection pad or of

  appearance 28 of a stacked structure in accordance with the

  the invention and a lower wiring layer serving

  to connect the connection pad 28 and another

  tie (for example an aluminum layer 81) on this

  layer of aluminum 6 is formed a second film

  interlayer insulating layer 7 in Si O 2, on which are produced second layers of aluminum 80 and 81 These aluminum layers consist of aluminum

  containing 1% silicon (Si) and 1% copper (Cu).

  These aluminum layers constitute the upper wiring layer 81 and the connecting portion 80 which constitutes a portion of the bonding pad 28 having the

  stacked structure according to the present invention.

  this to the stacked structure of the connection pad 28 constitutes

  killed from the aluminum layer 6 mentioned previously

  and the connecting portion 80, it is possible to

  dear the rupture that could otherwise occur at the level

  part of the bonding pad during subsequent oxidation

  of aluminum used to make film

of aluminum oxide 12.

  Additional silicon is added to prevent diffusion of aluminum

  or a reciprocal reaction, under the effect of a

  temperature, at the level of an area in which it

  contacts a semiconducting region constituting a

  thin, which would cause a break in the

  On the other hand, copper is added in such a way as to

  to prevent aluminum wiring from being broken by the phenomenon of electromigration References 90 and 91 designate aluminum oxide films, formed on the upper face and on the side of the connecting part

  and at the top and on the side (that is,

  parts that are not in contact with film

  5) of the aluminum wiring layer 81, which are respectively prepared by oxidation of the surfaces of the connecting portion 81 and the aluminum wiring layer 81.

  aluminum oxide thus formed consist mainly of

  A 1203 aluminum oxide films are

  Nium 90 and 91 are arranged below the final passivation film described later, so that they act as protective films by preventing the aluminum layer 81 from being corroded, and have an effective action for prevent corrosion especially in the case where a crack or the like

  is formed in the final passivation film.

  The whole surface of the chip,

  apart from the connection pad 28, is covered by the pel-

  final passivation tip 27, which is constituted by a glass film with Kphosphosilicates (that is to say

a film of PSG).

  The structure, which has just been described, is

  welded under pressure to a conductor in the form of

  watch 2 using a gold-silicon eutectic 3 The tongue-shaped conductor 3 is part of the frame

  and consists of a "42" (or bron-

phosphorous).

  On the other hand, the outer connecting conductor 4 forming part of the mounting frame and consisting of the alloy "42" (or phosphor bronze) has one of its ends made with an aluminum film 11 deposited in vapor phase in order to make the junction of the wire, while its other end makes

  protrusion outside the resin 31.

  Reference numeral 10 denotes a connecting conductor which is used to connect the outer connecting conductor 4 and the bonding pad 28 and one end of which is connected by welding to the bonding pad 28 and the other end of which is soldered to the vapor-deposited aluminum film 11 covering the

  external connecting conductor 4 This connecting wire

  sound consists of aluminum containing a

  percent of silicon and one percent of copper, i.e., according to the present invention, a material having

  a tendency to ionization identical to that of the

linkage 80.

  The present inventor has investigated the causes of failure so as to effectively form a corrosion-resistant aluminum oxide film of uniform thickness and

  that the causes lie in the reaction of

  It occurs locally in the vicinity of an oxidized portion when the surface of the aluminum-based material is oxidized to form a film of aluminum oxide. , that one of the causes of the establishment of this local stack reaction lies in the difference

  between the material of the aluminum wiring layer

  minium constituting the bonding pad and the material of the

aluminum wire.

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  Usually silicon and copper are added

  to the aluminum wiring layer, while

  adds silicon and magnesium to the aluminum wire.

  In accordance with the differences in materials and quantities

  different additives with different ionization tendencies added to aluminum,

  apart from silicon, there is a difference in the

  ionization between the aluminum wiring layer

nium and aluminum wire.

  For example at the aluminum wiring layer

  copper (Cu) is added to prevent electromigration.

  on the other hand, magnesium is added

  (Mg) with aluminum wire for excellent durability

  especially during the lapse of

  in this case, in accordance with the expe-

  all these things done by the author of the present invention,

  the oxidation rate of the aluminum wiring layer

  nium is substantially equal to that of pure aluminum, while the oxidation rate of the aluminum wire is

  significantly higher than that of pure aluminum,

  A thicker aluminum oxide film than the part of the wiring layer has been made. This has partly been due to the fact that it is

  equivalent way a local pile constituted by humi-

  both substances with different ionization trends, and in part due to the fact that

  trends in the ionization of aluminum and

  are expressed by the inequalities Mg> Al> Cu De

  specifically the reaction between moisture and aluminum

  nium is favored by the catalytic action of magnesium having a tendency to ionization, greater than

  of aluminum, so that an aluminum oxide forms

  On the contrary, since copper possesses

  has a lower ionization tendency than aluminum

  nium, the catalytic action described above does not occur

  not so that the rate of oxidation of aluminum

  minium becomes substantially equal to that of pure aluminum In addition this difference in oxidation rates

  is further increased by the fact that

  Electron placement during oxidation is limited by the local stack reaction mentioned previously. The present invention was conceived on the basis of the researches mentioned above and carried out by the author of the present invention in accordance with the present invention, by producing the aluminum wiring layer constituting the bonding pad and the wire of

  aluminum with materials with a similar tendency

  ionization, it is possible to prevent

  of a local battery reaction, which, if not,

  could be caused by the difference between the ionization tendencies of the aluminum wiring layer and

  aluminum wire Thanks to this protection, the

  growth of oxide films to be

  on the surfaces of the two elements can be

  identical so that one can obtain a thick

  In addition, since the oxidations are carried out uniformly at an identical speed on all the surfaces, it is possible to obtain

  aluminum oxide films having an excellent

  In addition, since it is possible to obtain

  Because of the uniformity of the invention, unlike in the prior art, the disadvantage that one of the oxide films can

  a thickness greater than the thickness required for

  hold the necessary thickness, so that training

  oxide films can be efficiently

  that's. The resulting effects, which have just been described, are not limited to the case of the addition of copper to the aluminum region. More specifically, in the case where a substance with a tendency to change is used. ionization as an additive either in the aluminum bonding pad or in the bonding wire, it is possible to obtain

  the effects mentioned above in accordance with the

  If the same substance is added to the other element, regardless of the additive In this case, it is desirable that the quantities of additive be made

  in proportions as identical as possible.

  Possibly we can adjust the hardness of the wire

  aluminum, which can increase during the final phase of

  tion or linking, giving it an appropriate value

  required for the binding and fixing operation, in

  adding silicon and copper.

  The aluminum oxide films 12 and 13 are formed so as to cover the surfaces of the connecting portion 80 and the connecting wire 10 of the structure thus connected by wire or connection.

  of aluminum oxide are formed by oxidation of the

  faces of the aluminum regions they cover, and

  mainly consist of A 1203 pellets

  In this way, aluminum oxide particles are formed so that they are fused together as a single film. As a result of the formation of dandruff

  aluminum oxide in the way that we have just de-

  the connecting wire 10 and the connecting part 80 can be protected from corrosion, by having their

  humidity resistance increased remarkably.

  On the other hand reference numbers 12, 13 and 14

  refers to aluminum oxide films, which are

  to form an integral layer and which are obtained by means of simultaneous oxidation of the connecting portion 80, the connecting wire 10 and the

  aluminum film 11 deposited in the vapor phase.

  In accordance with the present invention, both aluminum oxide films 90 and 91 are formed,

  covering the upper aluminum wiring layer

  nium below the final passivation film, and the aluminum oxide films 12 and 13 1 1 (and 14) which cover the aluminum film and bonding pad (as well as the aluminum film deposited in the vapor phase) In addition the aluminum oxide film

  12 and 90 are formed to merge into a film.

  in one piece at the connecting portion 80.

  Therefore, in accordance with the present invention,

  aluminum may be protected from corrosion

  by joint actions between the moisture, which enters from the outside of the integrated circuit either in the resin 31 itself, or through the clearance between the resin 31 and the conductor 4, and the impurity ions contained therein In addition, due to the presence of the aluminum oxide films 12, 13 and 14, the

  connection 80, the aluminum conductor 10 and the film

  aluminum oxide l deposited in the vapor phase, covered

  wire, must be protected against any corrosion

  In addition, since these aluminum oxide films are fused together, corrosion does not propagate from the boundary areas between the three previously mentioned regions. On the other hand, even if a crack were formed in the final passivation film 27

  as a result of a molding stress, due to

  bridging of the region, or contraction stresses due to the difference in

  thermal expansion of the respective regions or to diversify

  its other mechanical stresses, corrosion of the

* upper aluminum wiring layer 81 is

  In addition, since the aluminum oxide films 12 are formed to be fused with one another, the corrosion can not propagate through the aluminum oxide film.

  through the clearance between the end portion of the film

  final passivation 27 and the connecting portion 80.

  FIG. 2 represents a schematic plan view

  as showing the oxidized bond pad 28 of FIG.

  In the same figure, the aluminum oxide film 12 or 13 has been removed appropriately to show

  the underlying aluminum region 80 or 10.

  The first aluminum layer 6, which constitutes the bonding pad 28 of the stacked structure, such as

  indicated by dashed lines of the type a trait-

  a point, and the connecting part 80, which constitutes the

  second layer of aluminum, as indicated by

  mixed lines of the type a line-two points a

  line, are in direct contact with each other via

  of a contact hole 32 which is open, as

  diamed by lines formed of broken lines,

  in the interlayer insulating film (not shown in

  formed between the bonding pad and the connecting part

  Its that is to say that, in the contact hole 32, the bonding pad 28 is constituted by the stacked structure in which the first layer 6 and the aluminum layer 80 are in direct contact. with the wire is carried out so as to cover the part

  of this stacked structure, that is to say the hole of

  tact 32 Specifically the liaison or

  fixing of the wire is carried out in such a way that

  connection, in which the aluminum wire 10 and

  the connecting part 80 are in contact, covers completely

  the contact hole 32, as indicated by

  lines 33 dashed in Figure 2.

  Therefore it is possible to prevent

  at the level of the bonding pad, a break that can

  otherwise, intervene when the aluminum oxide film

  The aluminum oxide film 12 is formed on all regions except for the part covered by the phosphosilicate glass film 27 and the bonding region 33 (which is covered by by the aluminum wire 10), but not on the covering part - the hole

  It follows that, even if the part of the

  its 80 is entirely oxidized from the surface in di-

  rection of the base thereby allowing the aluminum oxide film 12 to reach the underlying interlayer insulating film 7, the electrical connection is maintained at an excellent level by the stacked structure

  at the contact hole 32 The connecting part

  in the bonding region 33, which is covered by the aluminum wire 10, is not oxidized since it is not exposed to moisture in an oxidizing atmosphere. As a result, the connection between the connecting portion 80 and the underlying aluminum layer 6 through the contact hole 32 can be maintained at a

excellent level.

  FIGS. 3A to 3F, FIG. 4 and FIG. 5 illustrate a process for manufacturing the device

  semiconductors of the present invention.

  On the silicon semiconductor substrate of

  type P 1, one forms, according to the well-known process, an element

  semiconductor element which is shown in FIG. 3A for example. This semiconductor element is a transistor

  bipolar NPN type, which has a region of

  a N + type buried or buried layer with an Ni-type epitaxial layer 17, a base region consisting of a P-type region 19 and an N-type emitter region. isolating this bipolar transistor from another semiconductor element, both a field oxide film 18, which consists of Si O 2, and a P-type channel stop device 16 which is located at the same time are formed. below the previous film This device of

  P + 16 channel stop and the buried layer of ty-

  N + are formed by means of ion implantation or a similar process prior to the formation of the epitaxial layer. On the other hand, the field oxide film 18 is formed by local oxidation of the epitaxial layer 17.

  Once the formation of the semi-

  the driver just described, it is placed on the

  a film of Si O 2 5 serving as the first inter-layer insulating film appears to appear on the surface of the substrate.

  chemical vapor deposition 8T Then,

  holes 23, 22 and 21 intended to correspond to

  to lay the regions of the collector, the

base and transmitter.

  Then, as shown in FIG. 3B, a first wiring layer is deposited on the entire surface of the Si O film 5 a first aluminum layer having a thickness of

  2 microns by evaporation under vacuum In addition one struc-

  this layer of aluminum so that it possesses

  of the desired shape in order to make the aluminum layer

  6 constituting a part of the bonding pad 28 of

  the stacked structure and providing a connection cabling

  cord between the bonding pad 28 and another resistor

  located in the chip Moreover, at the same time

  time that this operation, we form layers of

  24, 25 and 26 for connecting the respective semiconductor regions As shown in FIG. 3C, a second wiring layer is formed and the connection portion 80 of the bonding pad 28 forms the Si film. As a second inter-layer insulating film over the entire surface, using the chemical deposition process

  Then we open the contact hole

  at the connection of the wiring layers and the contact hole 32 for making the bonding pad 28 inside the stacked structure.

  this is deposited on the entire surface, by

  vacuum poration, an aluminum layer having a thickness of 4 microns and containing 1% of silicon and 1% of copper Then this layer is structured to give it a desired shape to achieve the part

  link 80 of the bonding pad 28 of the structure

  At the same time as this operation, we form the

second wiring layer 81.

  Then, as shown in FIG. 3D, a first oxidation of the aluminum is carried out so as to form the aluminum oxide films 90

  and 91 placing the tablet entirely in a

  mosphere at a temperature of 1200 ° C. and under a vapor pressure of 21 5 Pa for 10 minutes, the

  bare surfaces of the aluminum struc-

  The aluminum oxide films 90 and 91 are produced under the effect of these oxidations. These films of aluminum oxide

  mainly consist of A 1203 pellets

  Aluminum oxide particles are arranged beneath a final passivation film to be formed.

  later and act as protective films

  to prevent corrosion of

  80 and 81, so that these films provide

  effective protection against corrosion, in particular

  particular in the case where a crack is formed in the

film of final passivation.

  Hereinafter, as shown in FIG.

  3E, the phosphosilicate glass film 27 is formed as a final passivation film on

  the entire surface of the pellet by means of

  800 nanometers thick chemical vapor phase deposit. In addition both the aluminum oxide film 90 and the glass film 27 to

  phosphosilicates on the connecting part 80 are removed.

  using the sinter corrosion process.

  such as, for example, the plasma etching

  tick, so as to expose the aluminum surface

of the connecting part 81.

  The lozenge thus covered with the

  film of final passivation to bring it under the

  me of separate elementary pellets, which are then

  compression welded to the tongue-shaped driver

te on the mounting frame.

  The two ends of the aluminum wire 10 are welded to the bonding pad on the elementary chip and to the external connection conductor of the mounting frame. This aluminum wire has a diameter of microns and consists of aluminum containing 1% of aluminum. silicon and I% copper The material used

  to form this aluminum wire has the same tendency

  this ionization that of the connecting part 80,

  as previously described.

  Thus one can pocket the local battery reaction

  which is caused by the difference in ionization tendencies during a second oxidation of aluminum described hereinafter, so as to obtain an aluminum oxide film having excellent quality and uniform thickness. The present invention, the bonding phase of the wire just described, is performed at the level of the portion in which the stud

  link 28 has the stacked structure, as shown in FIG.

  in Figure 2, that is, above the hole in

  In addition, it is desirable that the operational phase

  The binding procedure is such that the bonded or bonded surface of the bonding wire covers the surface including the contact hole 32. Referring to FIGS. 1, 3 F and 4, it is clearly understood that

  state of connection or connection of the wire -

  Then, as shown in FIG.

  performs a second oxidation of the aluminum in such a way

  to form the aluminum oxide layers 12, 13 and 14 Firstly, the remarkably thin aluminum oxide films, which form naturally on

  the exposed surface of the connecting portion 80, on the surface

  face of the aluminum wire 10 and on the aluminum film

  vapor phase nium 11 (about which reference will be made to FIG. 1) on the outer conductor in FIG. 3F, are eliminated as pretreatment

  before the oxidation of aluminum.

  These surfaces are immersed in oxalic oxide, for example, in such a way that they are attacked by corrosion.

  aluminum oxide film, which will be

  subsequently, and to form a film having a

  uniform thickness Then, the second oxy-

  aluminum by completely placing the mounting frame, to which the small pellets are attached, in an atmosphere at a temperature of 1200 C and

  vapor pressure of 2 105 Pa The exposed surface of the

  81, the surface of the aluminum wire 10 and the vapor-deposited aluminum film 11 on the outer conductor in the figure are oxidized, so as to form the aluminum oxide films 12,

  13 and 14 These aluminum oxide films are

  The aluminum oxide films 12, 13 and 14 are reacted in the usual manner with A 1203.

  protective films in order to prevent any damage

  erosion of the connecting portion 80, the aluminum wire, the vapor-deposited aluminum film 11

  on the outer conductor in the figure In addition one realizes

  read the aluminum oxide films 12, 13 and 14 so that they are fused together not only with each other, but also with the oxide film

  of aluminum below the film of passi-

  the final oxidation of aluminum, so that an intense effect can be obtained to prevent corrosion,

as will be described below.

  The present invention is characterized in that all the conductors are short-circuited by means of a short-circuit portion 34, as is

  shown in FIG. 4, when this second oxidation

  aluminum is to be made.

  The author of the present invention has studied

  causes at the base of the impossibility of forming effective-

  aluminum oxide film with excellent corrosion resistance and uniform thickness and found that these

  de-battery reaction that is locally established in neighboring

  of the oxidized part when the surface of the material

  aluminum is oxidized to form the pel-

  Aluminum oxide filler In accordance with the results

  studies by the author of the present invention.

  It has also been established that one of the causes of this local stack response is that the potential present at the respective pads and

  respective connecting conductors differ from

  these potential at the level of PN junctions in the sub-

  semiconductor stratum and potential differences of

  contact at the level of the parts connecting the semi-

  conductive and aluminum wiring layers.

  The algebraic sum of potential differences in

  of the PN junctions and contact potential differences at the parts connecting the respective semiconductor regions and the aluminimum wiring layers appear as differences of

  relative potential of the respective bond pads.

  Since bonding or bonding conditions are common to all conductors, the potential differences of the bond pads become, when they exist, the relative potential differences between

  respective drivers If at this stage the microplate

  it is placed in a humid atmosphere, the difference

  potential between conductors and moisture

  present in the atmosphere act in a corre-

  the potential of contact between the two substances of a cell and a solvent, which

  is the equivalent of a local stack.

  For example, in the case where a first plot of

  connection placed at a certain potential is connected a se-

  bonding pad having a potential greater than the first potential, in accordance with the experiments carried out

  by the author of the present invention, the speed of

  of the aluminum oxide film on the first pad mentioned above is greater than the rate of formation of the aluminum oxide film on the

  second pad, so that a film of toxin

  thick aluminum This is due to the fact that elec-

  During this oxidation reaction, many products are attracted to the relatively higher potential side (i.e., the side of the second pad).

  the electrons produced at the level of the first plot are at-

  As a result, the ionization of the aluminum of the first pad increases, since the electrons are held outside the first pad.

  system of the oxidation reaction, so the plot of

  is likely to oxidize On the contrary the ionisa-

  the aluminum of the second stud is removed by

  the excess of electrons, so that this plot becomes

resistant to oxidation.

  The present invention was conceived on the basis of the above-mentioned researches carried out

  by the author of the present invention.

  Invention, all the conductors 4 are short-circuited

  electrically by means of the short-circuit portion 34 Since all the conductors are short-circuited, it is possible to prevent the local battery reaction; which is favored by the potential difference existing between these conductors, and to make the growth rates of all the layers of aluminum oxide identical, so that a film having a uniform thickness can be formed. Since the oxidation reaction develops at a uniform rate over the entire surface, it is possible to form an excellent oxide film having a thickness

  Moreover, since it is possible to make

  the film thickness, contrary to the prior art, this obviates the disadvantage that another region would have a film of a thickness

  greater than that required to obtain the thick

  necessary, so that the oxidation of aluminum

  can be performed effectively.

  Then we coat the entire structure in

  resin 31 and subsequently removed by

  page the short-circuit part 34 so as to give

  the desired shape to the drivers 4.

  Then, as shown in FIG.

  immersed the semiconductor device embedded in the

  for example in a solution of sulfuric acid (H 2 SO 4) so as to remove the oxide film from the surfaces of the conductors 4 More specifically, the unwanted oxide film, which is formed on the surfaces of the conductors alloy "42" (or copper or bronze) since the fact that the drivers

  were kept in a humid atmosphere for oxy-

  The removal of aluminum is eliminated exclusively and locally by using the difference between the properties of the aluminum oxide film and the unwanted oxide film. For this purpose, the sulfuric acid solution is used. as a solution that is not applied to the film of

  aluminum oxide, but is active to eliminate by

  only chemical film-undesired

  ble, so that the latter is eliminated from the

  4 when these last ones are immersed in this

  During a period of about 5 minutes, even if, at that moment, the sulfuric acid solution

  inside the resin, the aluminum foil

  In the vapor phase, the aluminum wire and the bonding pad are protected by the aluminum oxide layer so that these elements do not undergo any influence. Thus the oxide film, which has been formed on the conductor surfaces during 1 ', can be removed.

  oxidation of aluminum, after the operating phase of

  robbing with the resin, using the difference of

  these properties in relation to the film of oxide of

  Therefore, at least this film of oxy-

  on the surfaces of the drivers, which is ex-

  put to the outside atmosphere, can be completely

  eliminated, which exposes the clean surfaces of

  ductors in relation to the external atmosphere

  As a result, the electrical connections can be

  at an excellent level, which increases the reliability of

  On the other hand, in the case where the surfaces of the conductors are to be covered by solder layers during the welding operation phase, the welding operation can be carried out in a satisfactory manner, without subjecting, in a complicated way, the surface treatment drivers involved in

the welding operation.

  The present invention is not limited to the example

  For example, before the chip is coated in a resin, it may be previously coated with a base resin or a flexible undercoat, such as the resin known in the art under the name RTV-11 So

  it is possible to prevent any breakage of the aluminum wires

  minium under the effect of the molding stress and any separation of the resin and aluminum wires that may

  allow the moisture to reach the pellets elemen-

  It is also possible to improve the resistance

moisture.

  In addition the present invention can be applied

  enclosures other than those of the type embedded in the

  ne, namely ceramic or glass type shells, so that the cost can be reduced by

  high reliability, while maintaining the characteristics

  characteristics of the respective shoemakers.

Claims (11)

  A semiconductor devicecharacterized in that it comprises a semiconductor substrate (1) in which a circuit element is formed and which contains a bonding pad (28) disposed on an insulating film (5) formed on the main surface of the substrate and who is   consisting of aluminum containing a metal additive   ionizing tendency, a conductivity   tor (4) disposed in the vicinity of the semiconductor substrate (1), a connecting wire (10) made of aluminum and one end of which is connected to a bonding stud (28),   while its other end is connected to the   (4), the aluminum of the connecting wire (10) containing the same material as the metal additive of the aluminum constituting the bonding pad, and a film of aluminum oxide (12, 13) formed both on the surface of the connecting wire (10) and on the surface of the bonding pad (28), which is exposed to the external atmosphere from the portion of the bonding pad (28) connected to the wire of link (10).   2 Semiconductor device according to the invention   1, characterized in that the metallic additive   the bonding pad (28) is copper.   3 Method of manufacturing a device for securing   characterized in that it comprises the phase   procedure for both preparing a semi-   conductor (1) in which a circuit element is formed.   cooked and having a plurality of connection pads (28)   made on an insulating film (6) on the primary face.   of the substrate and made of aluminum, and   several conductors (4) arranged in such a way as to   in the vicinity of the semiconductor substrate (1) and in correspondence with the said connection pads (28), the connection phase of the bonding pads (28) and the corresponding conductors (4) by means of wires (10)   made of aluminum, and the operational phase of   of aluminum oxide films (12,13) on the   surfaces of the connecting wires (10) and connecting pins   its sound (28) by oxidation of said surfaces, said conductive   (4) being electrically connected so that they can be maintained at an identical potential.   4 Method of manufacturing a device for securing   in accordance with claim 3, characterized in that   it also includes the operative phase of coating   of said semiconductor substrate (1) and a part of   said conductors (4) in a resin (31), and the operating phase of removing the oxide films (13) from surfaces of said conductors (4).   Semiconductor device, characterized in   it comprises a first conductive layer (6)   on a first insulating film (5) arranged on   a semiconductor substrate (1), a second insulating film   lante (7) formed on the first conductive layer (6) and having a contact hole (32) exposing to the external atmosphere a portion of the first conductive layer (6), a second conductive layer (81) made of aluminum and formed on the second insulating film   (7) and used to cover the part of the first section   conductor (6) and exposed to the external atmosphere   through said contact hole (32), a connecting wire (10) connected to the second conductive layer (80, 81) so as to cover the contact hole (32), and a film (91) formed by an aluminum oxide and formed on the part of the surface   the second conductive layer (81) other than the   of the surface of the latter, to which the link (10) is connected.   Semiconductor device according to claim   cation 5, characterized in that the connecting wire (10) is made of aluminum and that its surface is provided with a aluminum oxide (13).   7 Semiconductor device according to any one of   conque of claims 5 and 6, characterized in that   the first conductive layer (6) is made of aluminum   minium. 8 Process for manufacturing a semiconductor device, characterized in that it comprises the   phase of the operation of forming a first layer   ducting (6) on a first insulating layer (5)   above a semiconductor substrate (1), the operating phase   to form on the first layer   (6) a second insulating film (7) which   a contact hole (32) serving to expose the atmosphere to   outer sphere a part of the first layer   trice, the operating phase of forming a second conductive layer (80) in the hole (32) and on the second insulating film (7), the operating phase of   connection of a connecting wire <10) to the second   conductive layer (80) so as to cover a contact hole (32) and the operating phase of forming a film (91) of aluminum on the part of the surface   the second conductive layer (80) other than the   part of the surface of this layer, to which strung the connecting wire (10).   9 Method of manufacturing a device for securing   Conductor according to Claim 8, characterized in that the connecting wire (10) is made of aluminum and that an aluminum oxide film (13) is produced on its surface at the same time. operating phase of formation of the oxide film   aluminum (12) on the second conductive layer (7).   10-semiconductor device, characterized in that it comprises an aluminum layer (6) formed on a first insulating film (5) arranged on a semiconductor substrate (1), an aluminum oxide film formed on the surface of the aluminum layer   (6), a second insulating film (7) formed on the   an aluminum oxide film, a hole (32) formed in the aluminum oxide film and in the second insulating film (7) so as to expose the part of the aluminum layer to the external atmosphere. to be provided with a bonding pad (28), a bonding wire (10), a portion of which is connected to the aluminum layer that is exposed through said hole, an aluminum oxide film (90) formed on the part of the surface of the   layer of aluminum (6), which is exposed through   said hole around the connected part of the wire of link (10).   11 Semiconductor device according to the invention   10, characterized in that the connecting wire <10)   is made of aluminum and that on its surface is aluminum oxide filler (13).   12 Method of manufacturing a device for securing   characterized in that it comprises the operating phase of forming a wiring layer (81) and   a bonding pad (28) made of aluminum   on a first insulating film (5) over   above a semiconductor substrate (1), the operating phase   forming a film of aluminum oxide film (90, 91) on the surfaces of the wiring layer (81) and the bonding pad (28), which are not in contact with the first insulating film, the operative phase   forming on said film of aluminum oxide   minium (90,91) a second insulating film (12) for coating the semiconductor substrate (1), the local elimination phase of the film of aluminum oxide and the second insulating film (12) in order to expose to the outside atmosphere a part of the surface of the bonding pad (28), the operating phase of fixing a wire (10) to a bare surface   of the bonding pad (28), and the operating phase of   of an aluminum oxide film (13) on the   part of the bare surface of the bonding pad (28), other   that part of the surface to which the wire is attached.   13 Method of manufacturing a semiconductor device   conductors according to claim 12, characterized in that the connecting wire (10) is made of aluminum and at its surface an aluminum oxide film (13) is formed at the same time as the use of the operating phase of forming the aluminum oxide film (13) on the part of the exposed surface of the bonding pad (28), other than that part of the surface to which the wire link is fixed.   14 Semiconductor device according to any one of   of claims 1, 5, 6, 7, 10, and 11, characterized   in that the semiconductor substrate (1) and the wire   of binding (10) are coated with a resin (31).